Understanding business types. Which legal structure is best for you? Okay, so you've started a business and you have to get a business license and you don't know what to get. Well, you're gonna want to watch this video to the very end because I'm gonna go through each legal business structure so that you'll know exactly what will fit your situation. I'm not a attorney, you should consult your employer. I'm not giving you legal advice, I'm just gonna explain what each one of these are and you can make your own decision in the end and I think you're gonna be a little surprised when you hear the last one. All right guys, let's get started. And don't forget, don't forget, make sure you hit the subscribe button down there, turn it from red to gray, hit the bell, turn on all bell notifications so you're notified every time I go live or I upload a new video. All right, let's get into this. Legal structure, oh my God, we don't wanna get into this, do we? We have to, it's something we have to do, but once you figure it out, you can move forward and that's what you need to do. Now keep in mind guys, you can change your legal structure down the road, it's not like you have a certain legal structure and you can never change it again. You do have the ability to change it. I've started off with one type and switched over to other types and I'll talk about that also in this video. Let's check it out. Now first off, why are there other legal structures? Why isn't there just one? Well, because they serve different purposes and based on your business, you're gonna wanna check these out. Let me put a few pointers up on the screen here real quick. First thing, there's plenty of benefits of incorporating your business. Some of the most important being protection of your personal assets, transferable ownership, potential for lower taxes. It's easier to secure business funding and separate credit rating regardless of owner's personal score and of course simpler to create retirement plans. So let's talk about the different types of legal structures so you can decide which one's best. Now the first one that comes in mind, the simplest and easiest one is just a sole proprietorship. Basically a sole proprietorship doesn't distinguish between the business and the individual that owns it. It's just all one thing. So whatever affects the business affects the individual. Whatever affects the individual will affect the business. A sole proprietorship is probably one of the most popular type of businesses in the US. They account for 40% of all small businesses but a lot of sole proprietors will tell you they only depend on it for about 60% of their income. Now I wanna throw some of the advantages up on the screen here real quick. Let's check these out. First one is lower taxes. With a sole proprietorship, you only have to do your taxes once whereas a LLC requires that you file state and federal taxes separately. The company doesn't file taxes but the owner does. Now complete control of your business because you don't have any partners or investors to consider, it's all you. You get to make every business decision the way you wanna make it. It's also easy to change the structure in the future. So if you start off as a sole proprietorship and you're not stuck with that company structure, you can change to a different type of business at a future date whenever you're ready to do so. Now the disadvantages of course are personal liability. With a sole proprietorship, taxes need to be filed under the individual who owns the business. This adds risk because there's no distinction between the individual and the company. So the individual is personally liable for everything that the company does. Thus the individual's personal assets are on the line. You could lose everything in a sole proprietorship but if you don't have a lot of risk, then you don't have to worry about it. But if you do have some risk, you may wanna look at some of the other alternatives. Next one I wanna look at is a partnership. Now let me throw up on the screen the two different types of partnerships so you can decide which one may be best for you if you choose to go this route. The first one is a general partnership, a GP. A general partnership assumes the business is either evenly divided or split into percentages that have been documented and agreed on beforehand. The next one is a limited partnership. A limited partnership can limit both control and liability for specific partnerships are based on the pass through method of calculation of income. So whatever the individual's tax are calculated on, so is the business, it's a pass through tax. Now let's look at some of the advantages of having a partnership. The first part is you share the responsibility. There's a saying about power in numbers and you could say it applies to partnerships. Rather than bearing all the burden yourself, you can share it with your partner. This also grants you more access to capital in many cases. Next one, it's simple to start and manage. It's relatively easy to establish an official partnership and in terms of ongoing management, you have fewer tax forms than other business structure. But there are a couple disadvantages I want to bring to the forefront. So let's check those out real quick. Partner conflicts, okay, here it is. In most partnerships, both parties don't always agree on every single decision. Many compromise, but over time, this can cause conflict between owners and within the company. It's important to make sure that you and your partner are on the same page when you enter into this agreement. Now keep in mind also, if it's a husband and wife or relatives, brother, sister, mom, dad, whatever, and you have a conflict, you also have a business conflict here too. So keep that in mind when you're setting this up. The other thing is personal liability because taxes for partnerships don't include a distinct separation of the business from the individual. Owners assume more personal risk, plus owners pay individual taxes instead of the business paying taxes, and this can result in a greater amount owed. The next one up is a corporation. Now the corporation is considered its own entity, okay? So that protects the individual from any liability that the corporation may have. None of those problems will pass through to the individual unless it's some rare, rare case. But for the most part, it's a separate entity altogether. Now the other advantage to corporations is that if you were to sell the business, it's a whole lot easier to transfer it to a new owner. It's very simple to do so, but you're also gonna be responsible for filing local, state, and federal taxes on a corporation, which other business types don't have to. Now keep in mind corporations may or may not pay lower taxes than an individual. It's a good idea to check with an accountant to see what it's gonna be like in your state, but it could actually save you money on taxes. Now let's look at some of the advantages. I'll put that up on the screen here real quick. The primary benefit of forming a corporation is that regarding the corporation's assets or debts, a shareholders' personal property is protected. For example, if a customer sues a retail corporation wins, the corporation could be forced to pay. If the corporation doesn't have enough money to pay, the liability isn't passed onto the shareholders so they wouldn't have to make up any of the difference. That person who sued them just doesn't get all their money. Here's the next thing that is kind of an advantage. Raise capital through shares. Corporations can sell shares to raise capital. This makes corporations more attractive to some workers because it signifies stability and reliable compensation. If the corporation runs out of cash, it can always sell shares. Now of course, there are disadvantages. Let's check out some of the disadvantages real quick. There is more work to incorporate and maintain. Generally speaking, corporations are more difficult to form and manage than other business entities. There's more setup and you have to carefully maintain the business as a separate legal entity every step of the way. Personal liability isn't completely eliminated. If the corporation's records are improperly managed, you could be more personally liable than expected. When attorneys sue corporations and prove the corporate records weren't maintained and the corporation wasn't acting as a separate legal entity, they've pierced the corporate veil, they call it. In other words, you lose protection for your personal assets. Next up is an LLC that's a limited liability corporation. These are actually a form of a corporation but it's a little bit different. I'll put my best explanation up on the screen here real quick. Owners frequently called members pay taxes on LLC profits directly. The LLC itself doesn't file taxes as a separate legal entity. LLCs with at least two members get the option to be taxed like partnerships or corporations if they prefer. This taxation election eliminates the separation of business and personal taxes. Now, LLCs are a new type of formation and since the 80s, the other types of corporations have seen a decline whereas LLCs have actually grown in popularity. Now, depending on the state, LLCs may have a limited lifetime and what I mean by that is a member of an LLC, they can dissolve that actual corporation as soon as they actually leave the company. Let's check out a couple of the advantages real quick. I'll put them up on the screen. A simple management LLC require a lot less record keeping and have fewer profit sharing requirements than corporations in particular. It's a relatively simple and straightforward business structure that works for small, medium and early stage businesses. Personal protection with an LLC or personal assets have a level of protection that reduces your liability but of course, there's going to be disadvantages. Let's check those out. I'll put them on the screen here real quick. They're not available for all businesses. Each state has parameters around which types of businesses and industries are eligible for LLC status. Commonly prohibited businesses include banks and insurance companies. Special rules also apply for foreign LLCs. Also, state and federal taxes, LLC members will have to file additional forms for both federal and state taxes depending on the number of members, local laws or even the LLC's articles of organization. Often, the member of an LLC pay payroll tax too. Now, what's the best structure for you? That's not an easy question. I will say most online retailers, people who are selling online, generally start with a sole proprietorship. As they grow and they have more and more liability and possibility of somebody suing them, then they switch over to a corporation. So it really depends on your individual situation. You've also got to look at your personal liability. If you don't feel like you have a lot of personal liability in the beginning, that's cool. Do a sole proprietorship. But as your liability and as your risk increases, as your business increases, we sell food, so we're a corporation. We sell food, so that could be dangerous. If somebody gets sick, they never have, not going wood, but if anything happened like that, we have to have product liability insurance and all these other things that protect our corporation.  They won't let you do that. So you can't have any employees because it's called a sole proprietorship.   So you're forced into a partnership or a corporation. You also wanna think about business funding. If you incorporate your business, you can build business credit, which is separate from your personal credit. And they don't get hooked up at all, okay? So it doesn't matter what your personal credit is. It doesn't matter what your business credit is. They don't affect each other. And you can establish business credit even if you had bad personal credit by people loaning money or you having credit extended to your business. Now we'll add to this. It's really gonna be dependent upon your state. So you're gonna wanna search your state for the state incorporation rules and what they require and what they don't require and see what's available to you. Sometimes narrowing down what's available to you will tell you exactly what type of business you need to be. Now, this video is important. It's really important, you know? It's not the most exciting, sexy stuff in the world, but it's stuff that you need to know, guys. And if you're running a business online, then you need to get the right type of licensing, the right type of business. The funniest question I always get is with an online business, do I need a business license? Yeah, it's called an online business. There's no difference. The only difference is you're selling online. It is a business. So don't think that because you're selling stuff online, you don't need a business license. You need a business license most definitely, 100%. You gotta have that. If you're taking money from other people and selling them stuff or products or digital products or services, you need a business license. Now, I hope this helped you out a little bit. I hope you understand it a little bit better. For more information on this, I would check with an attorney. Before you do any of this, just get an attorney, get a consultation, say, hey, this is what I'm thinking about doing. What are your recommendations? Make sure when you're talking to an attorney that you talk to an attorney that knows about this. Be very careful. There's some attorneys that will do anything, anything. You don't want those attorneys. You want the attorneys that specialize in setting up business structures. That's super important.  Not a problem. And that's not legal advice. I'm just telling you the easiest thing to do. I actually own sole proprietorships and I also own corporations. So it really depends on the business that you have too, which one is gonna be more suitable. Thank you so much for watching this video. I hope you got something out of it. If you did, give me a thumbs up down there. I would greatly appreciate it. I also have a $97 course that's below in the description. All you gotta do is click and learn. No credit card required. Did you hear that? 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talk about circular security is complete for KDM security. I'm Fuki from NTT. This is a joint work with Takahiro Matsuda from ICE. Keydependent message security, or KDM security for short, is a security notion that captures situations where an adversary can get a ciphertext of secret keys. Such situations naturally occur in many cryptographic primitives. Moreover, until today KDM security has found a number of applications in constructions of advanced cryptographic primitives. This is a definition of KDM security. KDM security is defined by using a security game played by a challenger and an adversary. In this game, the adversary can make a KDM query consisting of two functions f0 and f1 contained in function class capital F. And for this query, the challenger returns an encryption of fb of sk, where sk is the secret key and b is the challenge bit. Then, if no ppt adversary can guess the challenge bit b correctly, with probability significant greater than one half, we say that the scheme is fkdmcpa secure or just fkdm secure. We can similarly define fkdmcca security by allowing the adversary to make decryption queries. The definition I just explained is KDM security in single key setting. We can similarly define KDM security in merge key setting by considering a security game where there are multiple secret keys. One of the most widely studied security notion among KDM security is projection KDM security. Roughly speaking, projection KDM security allows us to encrypt copy and negation of secret key bits. So at first glance, this security notion looks somewhat weak, but approval shows that projection KDM security is complete in the sense that projection KDM secure encryption scheme can be transformed into bounded KDM secure encryption scheme. Boundless KDM security is one of the strongest form of KDM security that allows us to encrypt a message of the form f of sk for any function f of a purely bounded size. This completeness results shown by approval holds for any of cpa or cca secure sk and pke in merge key setting. Also, some recent works showed the power of projection KDM security by showing that projection KDM secure encryption scheme implies in cca secure pke and dv disk. In this work, we tackle the question whether circular security is also complete for KDM security or not. Circular security is a security notion that allows us to encrypt only copy of secret key bits. So circular security is a weaker form of KDM security compared to even projection KDM security that allows us to encrypt both copy and negation of secret key bits. So in other words, the question we study is whether the weakest form of KDM security implies the strongest form of KDM security. Let me talk about some additional motivations. The question we study is interesting from the viewpoint of negation complexity. For example, Goldreich and Isaac showed that one way function can be computed by a monotone circuit, but pseudorandom generator cannot. We believe that it is interesting to clarify whether such a barrier exists for KDM security, namely whether the ability to encrypt both negation and copy of secret key bits is stronger than the ability to encrypt only copy of secret key bits. Also, studying the completeness of circular security gives impacts on the study of public cryptography given some recent results showing the power of projection KDM security. If we can show the completeness of circular security, we can see that circular security is as powerful as projection KDM security. Based on these motivations in this work, we show that circular security is in fact complete for KDM security. Our completeness result holds for any of CPE or CCA secure SK or PKE in market setting, similarly to the completeness results shown by approval. More precisely, we show that we can transform circular secure SK and PKE against chosen pretext attack into bounded KDM CCA secure SK and PKE respectively. So I will talk about the outline of how to obtain our results. I will start with the case of SKE. In the case of SKE, as shown by Parkes et al., we can easily transform bounded KDM CPE secure SK into bounded KDM CCA secure one. So in this setting, all we have to do is to construct bounded KDM CPE secure SK from circular secure SK. We accomplish this task by using targeted encryption. Targeted encryption is a primitive introduced by Barak et al. to achieve bounded KDM CPE secure encryption scheme. This is the outline for SKE. Then we move on to the case of PKE. In the case of PKE, it is not known whether we can transform bounded KDM CPE secure PKE into bounded KDM CCA secure one in market setting. So also it seems that we can construct bounded KDM CPE secure PKE from circular secure PKE via targeted encryption. Similarly to the case of SKE, we need a different way. We accomplish this task by introducing a new primitive that we call conformed targeted encryption. A conformed targeted encryption is a variant of targeted encryption conformed to achieve KDM CCA security. So by using conformed targeted encryption we construct bounded KDM CCA secure PKE directly from circular secure PKE without going through bounded KDM CPE secure PKE. As a corollary of this result, we can see that KDM CPE security and KDM CCA security are equivalent in market case setting. This result improves the result of ourselves appeared in TCC 19 that showed that KDM CPE security and KDM CCA security are equivalent in single key setting. In the rest of my talk, I will talk about the technical details of this work. Especially using the vast majority of the remaining time, I will talk about how to realize targeted encryption from circular secure encryption. For simplicity, I will explain how to construct secret key variant of targeted encryption based on circular secure SKE in single key setting. So I will start with the syntax of targeted encryption. A targeted encryption consists of three algorithms, TKG, TENG and TDEK. TKG is given the security parameter and output secret key SK, the length of the secret key SKBL. The encryption algorithm TENG is given the secret key SK some index i from 1 to L and two messages x0 and x1 are output a ciphertext CT. Finally, the encryption algorithm given the ciphertext CT and secret key SK are outputs only a single message xs, where s is the ice bit of the secret key SK. Targeted encryption should satisfy two security notions. The first one is security against receiver, which guarantees that the ciphertext hides x1 minus s even against the receiver holding the secret key. Second security notion is security against outsiders, which guarantees that the ciphertext hides both x0 and x1 against outside adversaries who do not have the secret key. So, targeted encryption is a primitive similar to a previous transfer, and thus is compatible with garbled circuit. Barclay told us that the combination of targeted encryption and garbled circuit implies bounded KDM secure encryption scheme. So, next I will explain that targeted encryption can be realized naturally from projection KDM secure SKE. So, consider the following natural realization of targeted encryption based on SKE. In this construction, when we generate a secret key of targeted encryption, we just generate secret key of SKE. And when we encrypt two messages x0 and x1 for the ice bit s of the secret key SK, we just encrypt xs by using the underlining SKE in the bit by bit manner as described in the slide. Of course, by decrypting these bit by bit ciphertext, the receiver can correctly obtain xs. The construction satisfies security against receiver. This is because in this construction, the ciphertext is completely independent of the message x1 minus s. Moreover, if the underlining SKE scheme satisfies projection KDM security, the construction satisfies security against outsiders. The reason why we need projection KDM security is as follows. Let the length of messages x0 and x1 be n. We can classify indices from 1 to n into the following four types. We classify an index j as type 1 index if the j speed of both x0 and x1 are 0. And we classify an index j as type 2 index if the j speed of x0 and x1 are 0.1 respectively. And we classify an index j as type 3 index if the j speed of x0 and x1 are 1 and 0 respectively. And finally, we classify an index j as type 4 index if the j speed of x0 and x1 are 1. Then, when encrypting xs in a bit by bit manner into construction, we have to generate the following ciphertext by the underlining SKE for each type of indices. First, for indices of type 1, we see that we have to generate an encryption of 0. And for indices of type 2, we have to generate an encryption of a copy of s. And for indices of type 3, we have to generate an encryption of negation of s. And finally, for indices of type 4, we have to generate an encryption of 1. We can confirm that by decrypting these ciphertexts, the receiver can obtain xs correctly. So in this way, in this construction, we have to encrypt both copy and negation of circuit qubits. So this is the reason why we need projection cadence security to prove security against outsiders. We now try to realize targeted encryption from circular secure SKE, which allows us to encrypt copy of circuit qubits. So as a first try, we modify the construction of targeted encryption based on SKE I explained in last two slides. In this modified construction, when we encrypt xs in the bit by bit manner, for indices of type 1, 2, and 4, we generate a ciphertext of the underlining SKE in exactly the same way as before. But indices of type 3, we replace the ciphertext of the underlining SKE with the special symbol flip. The receiver can decrypt this modified ciphertext in exactly the same way as before, except that the receiver sets the j-skit of xs as the negation of s, namely 1 minus s, for j of type 3 indices. So we can confirm that this construction still satisfies the functionality of targeted encryption. Also in this construction, now we need to encrypt only copy of circuit qubits. So there is a hope that this construction satisfies security against outsiders based only on circular security of the underlining SKE. However, this construction satisfies only leaky security based on the circular security of the underlining SKE. The leaky security means that the receiver and outside adversaries can obtain some leaked information. Concretely, the receiver can clearly know that the j-speed of x1 minus s is s for the indices of type 3 by seeing the special symbol flip. Similarly, the adversary can know that the j-speed of x0 and x1 are 1 and 0 respectively for indices of type 3. Structurally speaking, the receiver additionally can know that the j-speed of x1 minus s are depending on the value of s for either one of the indices of type 1 or type 4. As due to those leakages, though we can enjoy that the remaining bits are hidden against the receiver and outside adversaries, this construction is only leaky targeted encryption. So summarizing discussions so far, we can see that we can transform circular secure SKE into leaky targeted encryption. So in order to achieve our final goal, we propose a transformation from leaky targeted encryption into full-fledged targeted encryption. Concretely, we propose a transformation using weak leaky targeted SKE, which is implied by circular secure SKE. So finally, I will briefly provide that transformation and explain that the needed leaky targeted SKE in the transformation is in fact implied by circular secure SKE. The transformation is a simple hybrid encryption construction where leaky targeted encryption is used as can, and the leaky targeted SKE is used as can. Concretely, when we encrypt two messages x0 and x1 for the ice bit s of the circuit key SKE, we first generate two circuit keys LSK0 and LSK1 of leaky targeted SKE. Then, we encapsulate those circuit keys of leaky targeted SKE into the ciphertext of leaky targeted encryption. Also, we encrypt the messages x0 and x1 by using leaky targeted SKE under the key LSK0 and LSK1 respectively. So the resulting ciphertext consists of three ciphertexts. When decrypting this ciphertext, the receiver first recovers LSKS from the ciphertext of leaky targeted encryption, and then the receiver can obtain XS by decrypting the ciphertext of XS using LSKS. In this construction, leaky targeted encryption leaks information or a partial information of encapsulated keys LSK0 and LSK1, but we can prove that if the underlying leaky targeted SKE scheme is secure against those leakages, this construction satisfies both security against the receiver and security against outsiders. So finally, I will explain that the needed leaky targeted SKE in the transformation is in fact implied by circular secure SKE. Without loss of generality, secret keys of leaky targeted SKE are just uniform random strings. In this case, we have to replace only one fourth fraction of ciphertext of circular secure SKE with a special symbol flip. Then we can see that the leakage amount is only one half fraction for the receiver and one fourth fraction for the outside of bursaries. Also, when secret keys of leaky targeted SKE are uniform random strings, the leakage positions are determined completely at random and is out of the control of bursaries. SKE resilient against such kind of leakages can be achieved from in the CPA secure SKE, which is in town implied by circular secure SKE by using universal hash function and leftover hash lemma. So overall, we can see that targeted encryption can be realized only from circular secure SKE. So by combining the construction with some previous results, we can obtain the circular security's completeness in secret key setting. So in order to obtain completeness of circular security in public key setting, we introduce a new primitive that we call conform targeted encryption. And we construct bounded KDM CCA secure PKE directly from circular secure PKE without going through bounded KDM CPA secure one. For this result, please see our paper. This is the end of my talk. Thank you for your attention.


All right, thank you all for coming This is the session about advanced configuration management with configuration split and similar modules I'm Fabian Bircher or bircher on Drupal.org I work for Nuvole a hundred percent Drupal company well We also do other things with Sylex and simply since Drupal 8 adopted these kind of things We are a distributed team in Belgium Italy and the Czech Republic our clients are mostly international organizations and institutions and They have a need often for a fast delivery. So we have several developers working on the same projects and We need to frequently update sites and I'm pretty sure this matches almost all of your experience as well So we need a safe way to manage the configuration between different instances of the same site of the project Okay So the first chapter is about okay, wait a minute This Twitter notifications is not gonna happen. Yeah, sorry about that So the first chapter is about the configuration management in Drupal core as you may know Drupal 8 has this amazing new feature of configuration management And it is really great and we love it but the use case Drupal core covers is Kind of limited and so often we have more needs But nevertheless the the core scenario is Answers the questions of how I can develop and test configuration on a development copy and keep this site running at the same time and Then export the configuration changes and import them on the live site in production and that's it So I Will this is not exactly the same presentation as I gave before I will try to Explain the concepts so that then You can adapt them to your own needs and so the configuration management in core works essentially around a configuration storage. I will use the same kind of Pictures for for all the things so this square with the slightly rounded corners represents a configuration storage The blue here the Drupal blue is the active storage. That's the one When your Drupal site is functioning reads the configuration from by default it is in the database so That has a several reasons one of them is that you don't go in and just change stuff because when configuration changes Other fields or other database tables also have to be updated And it's also faster to read from you can read the configuration from it and you can Get configuration to read in a form and save it back to to this database There is also caching layer involved and and a lot more advanced things, but this this is a basic concept I put the little asterisks on the reading We will get to that later because there is a layer in between that allows for for overrides And that's also why the writing operation has a separate read arrow, right? So so all good. The next step is to synchronize the configuration so you have this active storage and You have another configuration storage, which is backed by files the sync storage and You can export the configuration which you can do either by downloading that tarbal or With drush or to a console and basically what it does is it removes all the configuration from the files It leaves all the files reads all the active configuration and writes all the configuration to the files again the import configuration is slightly more advanced Because it doesn't just wipe the active configuration It makes a diff and sees what is new and what is old or what what should be deleted and adds the ones that Are new and removes the ones that are not in the files anymore and Then also updates all the other database tables Like for the fields when when you add new fields and so on so when you Deploy configuration or you manage the configurations between different environments You have in one environment these two These two configuration storages the database and the files so you click around in the UA and you build your site this Track after all then you export the configuration to the files you add the files to get You on the other environment you pull the files and you import that configuration Of course, this also works the other way around so you can have several developers and you synchronize the configuration Over git as as you do with the other codes that you develop All great, right The configuration management in Drupal 8 core works perfectly for this use case But we need to cover a couple of more things when I when I showed you this Actually the database has to be the same it has to be copied from before you cannot just import into an empty database and This is what the next Chapter is about this in installing from existing configuration. It's a very important step and It's for bootstrapping another environment of the same Site that you install before There's a contra project. It's an installation profile called config installer and it creates a Site another instance of the same site usually when you Go through the Drupal installer and you install a profile like standard or minimal or your own it creates a new site With the configuration installer it's just used to install the existing site and Not and then after the site is installed the configuration installers is not used anymore We use it in all our projects and so you should you Or actually core it even has a nice UI so you can upload the tar ball that you downloaded from the other site so it You don't need the command line for that, but of course it also works with the command line There's two issues to add this functionality to core Profiles at the moment that the API of a profile Was never meant to be reinstalled so for example profiles They can have dependencies, but you can uninstall the dependencies and that really makes no sense I mean you you have a dependency, but then it's not a dependency and so this creates a lot of problems when you want to Bootstrap a site from from with a profile that is like has a dependency but not and so there's two issues that try to solve this and I hope we can get them rolling during this week again more Another thing that is already in core, but it's kind of outside this use case is for example if you want to differentiate the environment and Simple examples are error logging to verbose on your development environment or API keys on production that you don't want to add to git and You can do that With core and the there's different mechanisms for overriding configuration. The easiest one is using the config variable in settings of PHP So basically you just add this this override in settings of PHP The system logging and you set the error log a level to verbose and That's it and you could also do that with API keys To go back to our graphics this this is where this arrow Comes in so basically you read from the configuration from the database, but then you read the overrides and you You use the overridden configuration In like the site title or wherever you use the configuration That's all great, but it has a couple of shortcomings One of them is that you can only alter existing configuration Using this method and you cannot add new configuration to it or unset completely other configuration and You cannot for example Change which modules are enabled And and a couple of other things like you can't overwrite the color of Bartik this way um Yeah, so Can we do better? Can we do more and this is where the configuration filter module comes in? So this is the schema of configuration management and Magic this is the configuration management with the configuration filter You can see the only thing that changed is This sync storage so instead of writing directly to the file you write to this magic configuration filter storage Configuration filters or config filter the module provides configuration filters and Filters are like a glorified alter hook for the configuration Storage so you they can apply they can change the data for every operation that you can do on a on a configuration storage Filters are plugins or can be plugins and plugins are sorted by weight and then applied after each other so they they're daisy chained and The data that goes into one filter and then comes out goes into the next filter and and so on and at the end gets written to the Storage or and the other way around First gets written then passed to all the filters and then gets passed back to Drupal Plugins can be active or inactive the inactive plugins. They they're just defined, but they're not used So they're just skipped The modules right now has more than 6,000 sites using it or reporting to use it And so one of the top 100 modules right now and has zero bugs. Well Not exactly. There was one bug that someone reported after I refactored the code but it turned out that the APCU cache was turned on and this is because the The the API of this module that the interface that it interacts with Drupal is really small Like it doesn't do anything else. It doesn't affect the running of the site except for the synchronization storage it that's the only thing it does it replaces the storage and Other modules provide the filters for it So let's unveil the the matching it look look behind the this configuration filter storage and as you can see there is the the green file storage again from before the the original sync storage and Before and after the data goes in and out filters are applied High-level example of this is for example with configuration split where configuration split has a secondary file storage and splits the storage splits the configuration between the main one and the secondary one Another example is the config ignore Which basically when you read the configuration? You read it from the active storage and therefore It's the same as the one you already have and therefore there's no diff and therefore the configuration is ignored This presentation is also meant as documentation for configuration split a lot of people have said that It's a bit complicated sometimes and there's a lot of options and It's not really clear what they do and how they work and You have to find out, but then you don't know if you did it correctly or or what? So let we will go here now through the the different options that you have to configure it so The first part that there's three field sets the first part is the static settings and where you have the folder so you you specify the directory of the secondary configuration storage and The you can use an absolute path or a relative path to the Drupal root the the same way you configure the Sync storage in settings.php. It's the same kind of way If you leave it empty it will use a separate specialized database storage for this split You can have multiple splits, of course, and then they get Used one after the other depending on on the weight and the split can be active or not and All of these you can override in settings.php with the normal configuration override mechanism that I showed you before So for example, we will get to that in a second The next section is the complete split also known as the blacklist I still might refer to that when when we talk because that's what it was named for a long time and Yeah, I'm still very used to blacklist and graylist, but it's now named a complete split and Conditional split so the complete split has a an option to specify modules and What happens is when The configuration goes through it. So there's the the list of enabled modules is specified in corded extensions and When you export the configuration what what the split does is it removes the module that you specify here and Save them in the configuration of the split and so they're removed from from corded extension as it goes on and When when you read from it, it adds them again it also Automatically detects all the configuration that depends on these modules because the configuration that depends on modules that are not Enabled don't make sense. So it also moves them away and puts them in in the secondary storage and There there's basically two ways one is a Select where we've chosen the UI is very nice and the other one is a text area that you can use to Use wild cards for example, so you can you can select a whole array of configuration In in the end Both of them are the same if you write the configuration name in the text area. It's the same as the drop down the conditional split or formerly known as graylist has the same kind of way to Select the configuration Important to know here is that this configuration will not be deleted when you export it I mentioned in the very beginning the way the export works is you delete all the configuration and then you read it and write it again but the conditional split Does what it does is it checks if it's different than the one you already have Exported but to check whether it's different the thing still needs to exist. So It doesn't get deleted and this has an important application. We will see in a second Then there's a checkbox for the dependent configuration you can select to also find all the configuration that depends on the configuration that you listed and Condition is split that too and there's a checkbox for split only when different so then it checks and it It splits only When when the things are are actually different And this is useful when when using wildcard. So you have like block placements and then one of the block placements changed But you don't want to split off all the block placements, but only the ones that are not the same as you you want to deploy from there There's a CLI commands The config split import and the config split export If you use them without an argument they're the replacement for the drush commands prior to 8.1.10 and for Drupal console And if you use them with an argument use them with an argument of the machine name of the split and then it will import or export only that specific split and will leave the rest of the configuration alone So that was all theoretical. Let's let's look at an example. So we have three configuration names, let's call them a b and c a for not being listed in in the configuration at all B for the configuration listed as a complete split. So the first part that might be Module or something like that and see the conditional split Obviously, it's a very simplified But you I think you you'll understand. So let's write when let's let's export A what happens it Goes through the filter it it gets passed along as it is Let's try to write B It will go in the secondary storage and you will not get passed on to Do the next filter or the other storage because it gets split apart see Here we assume it already existed in the exported configuration If it doesn't it's the same as if it would be different So if it already exists it didn't get removed. So when you when we export it, it just Passed it on If you look at the reading it's the same it reads the a Nothing to it continue to a The B comes from the secondary config storage And the C you read the C and you return to see so now Let's look at if we have a changed C a C prime so We see the C was the conditional split and now this will hopefully make sense to you The conditional split gets split off now because it's different than the seed is already exported And so when we read the the C We we read it from the the secondary storage So it will be the the C prime and and you see the the config filter behaves the same way so if if you Give it a certain amount of a certain configuration you will get the same back when you read it, but what happens on the other side is Also consistent, so you you see like ABC prime and goes in and a C Comes out for right and the other way for read so far so good, right? So how do we use this for making environment specific modules or configuration? So for example, you have the develop module and you don't want to develop module on on your production site But the configuration management just is all or nothing So you would have to disable the develop module then export and you don't want that It's a hassle and it's air prone if you do it manually so You can guess You do it with configuration split You list the module that you want to split off And you add the environment specific configuration and then you override which split is active per environment and If the split is active The module will be active if the split is not active when you import it It's as if the module was not there and therefore we get disabled or Will not be enabled Another small thing is the if you want to have environment specific permissions as you know permissions are part of roles and so The easy solution is you you have like a developer role that you have only on one environment But then you you can't just use the The same users and then you have to give them in this additional role. So there's another module called config role split The UI for the moment is not great because they to make the proper UIs Like how you should be configuring this is not so easy. So right now. It's just a text area where you essentially post YAML. It's described on the product project page It's also a config filter plug-in. So it Operates in the same way as the config split and what it does. It's exactly the same as the Core extensions and you add and or remove modules. So basically you just add or remove permissions to a role And this is useful if you want to have in some environments additional permissions for Authenticated users or Anonymous users Of course this split can then also be active or inactive depending on settings of PHP or you can even split off the Role split in another split so you you can make this as crazy as you want One of the things that you should keep in mind is when you import the configuration it will take into account the active Plugins that Drupal already knows about so when you import A split like when a split becomes active while you import the configuration this split will not be taken in account Already or this role split, but when you import the configuration again like a second time Then the split might be active and so basically for for every new plug-in You you import a configuration again So what we usually do is just config import and then review and then everything can and then just run it again and to see The message that says nothing has changed and all is good So before we go to the next chapter Where config split is used? I also want to say a little bit more about configuration management in general because as talking with some of you During the events a couple of things happen come up again and And so we use git for configuration management. You don't have to but it's the easiest in my opinion And it's great because the configuration files or the configuration are exported to files Which are text files and git can handle text files But there's a little bit more to it and you have to be a bit careful sometimes With configuration management and git so this is important for the team of developers when You you share that the repository for both the code and the configuration and So how you do that when you bootstrap a configuration the first developer Initialize the repository and installs the site and exports the configuration and adds everything to git All the other developers or all the other environments I should say They clone the code and they install from existing configuration that that may be other developers That may be production and that may be continuous integration So like you you install the site instance only once and the first person that makes the first commit Is this the person that does that and everybody else?  It's it's all git and it all works right but You have to be a bit careful with that because git is just the files But Drupal needs to import and export so there's this extra step and you you need to follow a couple of rules and If you're not careful what can happen is that you lose the uncommit work You accidentally overwrite Work done by others Or that it looks fine at first, but it's actually not So here's the safe sequence that the holy grail that the rules that you have to follow Sometimes you get away with not following them But then you're in danger and so this is always safe this this this works so just to say it you Do your site building?  If you import the configuration before you export it All your work is gone like It's it's gone. I mean no backups.  Yeah, and there's no help there If you merge before export And that means you you you have the Exported code from your colleague, but it's only in the files and not in your database when so when you export it it all goes away from your colleague and The files will reflect what you had on your development Everything works for you. Yeah, right, but you actually removed all of your colleagues works This is not a huge problem You can solve it with the advanced git knowledge and you can go back and make a proper merge but You have to discover it and you you have to then fix it and It's not just git pull. It's like checking out stuff and making new branches and properly merging them If you don't do the composure install You may have updated and not updated code so that Can lead to breaking things in several spectacular ways If you do not merge Or if you do merge before the commit Then you don't have a safe state that you can go back to and you might have Additional manual labor to to solve conflicts I don't mean necessarily merge conflicts because those git will tell you about but the conflicts will see in a second And if you forget to import at the end then you will continue with the state that you had before and not Have all the stuff your colleagues have been worked on so next time you export the configuration You're in the same places before except Some time has passed since and it will be more difficult to fix it so Say sequence remember, right? So but there's another sequence when you update the modules So you you get the new modules with Composure update for example then you run the update hooks The update hooks might change the configuration So you export the configuration again that with the updated configuration You add all of that to git and you commit and you push of course if your colleagues have worked in the meantime before the push you You go back to the other workflow I think that's all clear So I was talking about before you should always run the update hooks before the config import and and Like If you conceptually the update hooks they're there to fix the database so that it corresponds to your code that you run and When when you update code and the database are out of sync You live in dangerous territory. So the first thing is always update the database so if you want to abuse the update hooks to do stuff after the config import Then you're tempted to do configuring patient for first and then the update hooks but You live in this dangerous territory and there's an issue in Drupal.org that will not allow to import a configuration when you have outstanding updates And There's a proof of concept module It's it's on GitHub right now that adds Another hook like a hook update as the pre-config import hook and the post-config import hook And they get fired in a safe environment as in the code is aligned with the database and everything is fine And they get called before and after the configuration import There's an issue to do that in core because the other issue is blocked on that essentially Yeah, so Maybe that's also one of the things we can work on this week and hopefully move on with this Right now you can do both and Often it will work and and sometimes it doesn't and Maybe you will remember this presentation and Remember I told you so So let's see an example of how you can break the configuration with git You all know the standard profile, right? So you install the standard profile developer a so you both start from the same place developer a Makes a new branch and deletes the tags field from the article content type This results in two configuration changes Basically, it removes two files the field instance and the field storage because it was the only field instance There was on the site Great commit developer B adds the tags to the basic page That results in another configuration change, which is adding a new file Since these files have nothing in common with each other git is very happy to merge this it's there is no no conflict but now you have configuration that has field instance without a field storage and Yeah, Drupal will not allow you to import this configuration because the configuration is is not in a good state and so Always import a configuration and you will notice this and if you Share the configuration often the the differences will not be that big and you will probably find out what happened and The import will tell you what is wrong. It will tell you The field instance doesn't have a storage can't import and then you go back and so what happened Where does this storage go and you see in the other commit that it goes removed there? And then you just add it again and it's solved but Git is great for Managing files and Drupal needs a little bit more care for that So how do we handle configuration changes on production? I just told you Configuration changes is like development, right? So if you change configuration on production One could argue that you do development on production.  So you have to take care of that of course The solution that you might know You have someone that clones the database to your slot local laptop exports a configuration puts that in git and does that? It's yeah, maybe a bit painful to do that But it's a solution you have like some person that's dedicated to to be the the client's developer, so to say Um That that can work if there's nothing in between that goes wrong. So if like If if the client changes something after you exported to the database to your local stuff, it's still gonna be gone. So First option you don't allow the client to do that Problem so Often often though often though, this is not really a solution and the client has a legitimate use case for changing some configuration. So This is great. And if you can do it, it will solve you lots of headaches, but sometimes you can't so there's other solutions to Coming back to configuration split because it can also help you out there So essentially you you specify which Configuration the client can change with what what is okay for the client to do because the client will not go and I don't know change all the the view settings and cron and add fields to everything and I mean at that point the client is Really a developer so but you know, maybe the site name can change or things like that So you specify what is okay to change in in a split settings? for example the gray list then before you deploy you Export that specific split so that your clients configuration is safe Then you pull the configuration business usual you deploy the configuration with Configuration import and what happens is it will import the configuration from the files that you had and it will also import this second split All good. All configuration is in the files That the dogma that the configuration that is in the files represents the configuration that's on the site after config import is still okay But you have to do this extra step of exporting so the third option is with config ignore Which you can skip this this step, but like the first so it's still the same you decide which config is okay to ignore Then you just pull the configuration and Config import and the configuration is then imported from the files but also some of the ones that are in the active storage and it goes in in into the The magic config filter storage and nothing will have changed in this configuration. And so it will not get removed and everything is fine This is great, but it Departs a little bit from from the philosophy that all your configuration is in the files and therefore reproducible and You you can have like the files and you know when you import it will be the same But it can it can be a solution for for this case Finally for a shared configuration, so if you want to reuse configuration or Use configuration on a multi-site Before the last Drupal con in the US, I wrote a little blog post introducing configuration Dimensions so You have this vertical dimension of the same site in different environments and then you have another site like on a horizontal separation If you were to have the same that the graphics from before it would be like a third dimension between you so This this is something that core does not take care of at all and You you can use the same kind of things. I mean the exporting to files is great and so on so There's other solutions and For example features Is useful for for that? Where you can bundle some of the configuration in into their own features into their own modules and and reuse them on other sites? But once you install the feature The site owns the configuration and not the feature anymore So when you update the feature you have to make sure that the configuration that the updated feature then gets Re-imported into your site and then the site gets Deployed with the normal configuration management workflow as we have so it features is for development only It's it's like on the the lower level on on on this Dimension And but it's great for like starter kits when you have like optionally more features that you want to add But it it Can help you to solve this problem, but it's You have to find a good workaround For for multi sites the You can use configuration split. I've used it for on sites. There's two basic approaches that you can do one is you have a shared sync directory and then separate splits per site and the other approach is the other way around where you have Each site has their own sync directory, but you share some of the splits Which suits best? I don't know. It's depending on on your use case But there will be a buff on Thursday, so you can join us there to to talk about that a little more and Yeah, that's it join us for the contribution sprint on on Friday and Make sure that you leave some feedback that always helps to improve the presentations. Thank you very much If you have questions, please use the microphone because it will be recorded so one common problem is that you don't export before you Check out something with gate or merge from from upstream or something it would be feasible to either have something that a Mechanism that always exports everything then as soon as someone changes a conflict will be exported or maybe with a cron like every five seconds They import yes, there's two modules that do exactly that. There's config tools which Basically on each safe of a configuration entity exports it directly. It doesn't have like Disadvantages in some way well, yeah, it does Git or it doesn't like a file right on on every safe I mean, but it only writes like one conflict file. Yeah, it's not so bad. It's you can totally use it Yes, it's a good solution for this problem Okay, it would be maybe a good hook that prevents get from doing anything harmful unless the conflict is in sync or something That would also be an option. Yeah Yeah, but if you export it automatically then then you will know I mean if you just pull and then if Yeah Hi, what is your solution when you're installing site in database you have profile standard but when you export your profile in for Configuration you have profile config installer and when someone wants to import changes from configuration There is a bug then we can't change profile from standards No, you you don't change the profile to config installer So when when you use config installer, it will still be standard that is installed Okay, it's so the way config installer works is it installs another profile and it jumps through a lot of hoops to to do that and That's why there's this issue to to move this functionality in core because a lot of things like You know, you like to do for example, it can't handle with the the case when modules have or Profiles have modules in them Because then if you install config installer it it can't detect these modules and don't doesn't find them and and so on But so profile it when you when you install a site with Config installer the configuration you have at the end Will not say that the profile was installed with config installer, but with the profile that was installed initially Hello should notice about features and configurations you can use used features import or features drush features import or features import all when you pull new changes In your future just Zendron Drush import features all and it solves problem You are to delivery Yes, but so if you then change this configuration yourself, then you know, you know, you will have to review this process it's it's a and I have question about Station About in protein blocks you know blocks issue when you Create block instance in Yeah, production Conculation and cannot import this configuration because you haven't content Yes, exactly. So one of the things that I didn't mention now because I expanded the other parts of the presentation Is is the the issue that you have when configuration depends on content and the block is like the conan canonical example for that So when when you have configuration that depends on content, you you have to make sure that this content also gets imported one of the one of the solutions is this The pre-config import hook that I talked about another solution is you you implement an event listener that listens to the Content not found event when when you import the configuration. I forgot the exact name of it But it's something like that another option is use default content and then Have like an additional step to to import and export the content that you need You can also use deploy the deploy suite for more advanced Use cases for that in in in our case. We usually use default content and it works great Hi, how can I handle? Multilingual multi-side with the same feature set, but different base languages on each side so The configuration split works with multi-lingual configuration as well It it splits the configuration with its languages What you cannot do right now is override only specific Language so I mean you can with the Like No, no you can't really I Mean but it wouldn't be too difficult to to add another configuration Filter that only does languages so like The thing is the configuration split works with a separate config storage and so It works the same way and that's also how it deals with languages it natively just supports languages because configuration storage to support languages So if you want to only have special Languages, then then you need to treat the languages differently than than the rest of the configuration and It shouldn't be too difficult to add another configuration filter that Deals languages and saves them somehow in a in a separate way Yeah, but if you have questions about this if like if you're implementing a config filter And I know it can be pretty daunting because it's like a lot of things and and Don't don't hesitate to contact me and I'll be happy to Assist you. Yeah. Thank you very much lunchtime


All right, I think we'll make a start. So, welcome to Digital Mount Stromlo Observatory live streams. My name is Adam Reigns. I'm a PhD student at the Observatory at the Australian National University where I study a variety of things and I'll be talking about one of them this morning. But before we get started, I'll just mention this talk will go for about 20 minutes to half an hour. We'll have time for questions afterwards. So, if you have any questions during the talk, just type them in the Facebook chat and I'll have a look and I'll get to them at the end. And I'll mention that a few other times throughout the talk. But yeah, if anything takes you fancy about what I'm talking about or something related, just pop it in the chat and I'll get to it. So, now to get started. So, what I'm going to talk about is a technique in astronomy where we combine the light from telescopes to essentially get more bang for our buck to make them greater than the sum of our parts because having one telescope is fantastic. But we can only build telescopes so big and sometimes in order to have a bigger telescope, we can combine them, combine the light from them in order to do really impressive things, really cool things. But get onto that right now. So, this here is a beautiful, I've got some sunset pictures and videos here because telescope observatories, I think make the best sunset pictures, but this is from Siding Spring Observatory, which in the telescope we can see here is the AAT. The AAT is the largest optical telescope in Australia. So, optical means light we can see with our eyes. And the AAT does some fantastic stuff. It studies stars in our local galaxy, figuring out what they're doing, studying their chemical, like the chemistry of them. They even looks to plants these days and even looks outside our galaxy to see distant galaxies. But sometimes even that's not big enough. So, the AAT has a mirror about four meters across.  And sometimes that's not enough because the reason we build telescopes is because we can see extra detail with them. And the reason for that is that the bigger your mirror or your lens, your light collecting area, the more detail you can see.  The collecting area is bigger. Because when it comes to astronomy, it's all about collecting lots of light, but also light over a large area. And so, what I'm gonna talk about today is a technique called interferometry, which is essentially telescope teamwork. We combine our telescopes together and we can do lots of stuff with them. So, we can only build telescopes so big. We can't actually make a telescope the size of a football field with a mirror. That's simply too big. But what we can do is put telescopes either end the football field and collect their light. And so, we'll get into that. But first of all, we need to talk a bit about sizes and resolution. This here is a scale picture. Well, not picture, but it's to scale of the Earth and the Moon. And so, the Moon is actually really far away. You could fit 30 Earths between the Earth and the Moon. And really, really big. But we can still see the Moon when we look into the night sky or the daytime sky. And as we all kind of know as humans, as things get further away, they get smaller and as they get closer to us, they get bigger. So, if the Moon was further away, it would look smaller in our sky. Or if it was closer, it would take up more size on the sky and our full moons would look much more interesting but our tides would be a bit weird as well. So, this lets something really cool happen on Earth because the Sun is much bigger than the Moon, but it's also much further away. So, by a quirk of nature, we're really fortunate here on Earth to be able to have the Moon be about the same size as the Sun. And when they overlap, that causes what's called the solar eclipse and the Moon blocks light from the Sun, which lets us see all the faint outer atmosphere of the Sun, which is really, really, really neat. And this is just a demonstration of that, the fact that you can, if you've got something smaller that's closer, you can cover something larger that's farther away. So, to bring this a bit closer to home, if we take an Australian dollar coin, it's 25 millimeters across, how far away would you need to hold that dollar coin from your eyes, such that you could exactly cover the Moon and the Sun? Well, the answer is about 2.8 meters.  And then if you put it on a big stick, you could hold it out and exactly cover the Moon or the Sun. And I'm gonna take this analogy a bit further. But let's zoom in a bit. So, this is the Moon and if we zoom in, well, not zoom in, this is the size of the planets in our solar system compared to the Moon. And all of these planets are bigger than our Moon. It's just that they're much further away, so they look smaller. And that green circle there, that's the resolution of the human eye, which means anything smaller than that, the human eye can't see any detail on. So, this is why if you look up at the night sky with your eyes, you can't see the strikes on Jupiter. But if you have a telescope, you make that green circle smaller because the resolution of the telescope is smaller, it's better, you can see more detail. So, when that circle is smaller than something, you can actually begin to see detail on. And this tiny dot, it's a bit hard to see, but that dot is about the average size of a twinkling star and a good observatory. So, Siding Spring Observatory that I mentioned, it's one of the best places in Australia to do astronomy. It's in the middle of New South Wales, in the middle of nowhere, where there's nice, dark skies. And the air is somewhat stable, which means the air is all moving all throughout our atmosphere. Some of it's going this way, that way, some of it's hot and wants to rise up and some of it's cool and comes down. And what this means is the air is very what we call turbulent. There's lots of motion there.  But because of all the light everywhere, the light blows that out. So, it's like taking your wet dot of paint and smearing it out, and it makes the dot bigger. But just how much bigger? So, we zoomed in again, this is about the size of a twinkling star. And this is Betelgeuse. Betelgeuse is a star in the constellation of Orion, but we'll get to that in a bit. But it's a really, really big star. And it's actually one of the stars that looks biggest to us from the earth. It's not the biggest star, but just because of it's reasonably close to the earth, it looks reasonably big on our sky. But if you, even with a good telescope, Betelgeuse is going to get smeared out to much bigger than it actually is, which means you can't really tell anything about Betelgeuse, because it's, or you can't see detail on Betelgeuse because it's been smeared out. And so, here's a lovely picture from Chile of the night sky. And we're gonna zoom in a bit up here. And some of you, if you know anything about the night sky and constellations, might be able to pick out Betelgeuse. But for the others, I'll give this a hand. So, this is the constellation of Orion, the hunter. And we can see here in his shoulder that reddy star, that is Betelgeuse. And so, it's a red supergiant star. And if I took Betelgeuse and clicked my fingers and replaced the sun with Betelgeuse, so that the Betelgeuse was now in our solar system, we would all be inside of Betelgeuse and it wouldn't be a good time. Because Betelgeuse, its atmosphere extends out as far as about the orbit of Mars, which is really big. So, Mercury, Venus, Earth, and Mars would be inside of this really, really big star. And it's about, it's relatively close, 700 light years away, a light year is a distance. Like if I went outside with a torch and shot it at the sky at night, that light would take 700 years to get to Betelgeuse. That's what a light year is. And if we turn light years into kilometers, that's a really big number that I'm not even gonna bother reading out. But let's think back to our coin analogy. Betelgeuse was one of the biggest stars. How big would I need to make that coin, or half-far away, to be able to exactly cover Betelgeuse? And remind everyone here again that if you just joined us, I'll take questions at the end, so put any questions in the comments and I'll take them at the end. So, our coin would have to be 103 kilometers away to exactly cover Betelgeuse, the actual apparent size of Betelgeuse if we remove the twinkling, which is really far. I don't have a stick long enough to put the coin on the end of, that's a very long stick. I need to drive for like an hour, at 100 kilometers an hour, to go put that coin far enough away where it would exactly cover Betelgeuse. It's pretty far. But the thing is, how do we study these stars? And what stars do I study? So this is an actual picture of Betelgeuse. It may not look as pretty as one of the star pictures of the sun, for instance, but the sun's a lot closer. We can study it in a lot better detail. This here actually shows us that Betelgeuse has a lot of gas and dust that it's sort of billowing off it because it's a really big star and it's so spread out that it can't hold on to its atmosphere as well. So it kind of just throws it out into space. And so we can see that Betelgeuse has a pretty odd shape and it's quite bright in the middle and that green circle is about where we actually think the atmosphere of the star is. But this was taken with an eight meter telescope. So the stars that I've recently studied, these are some of them. My biggest star is the one at the bottom right, the Lambda Sanjiteria. And my smallest is HR7221. Not all stars get cool names, unfortunately, but keep HR7221 in mind because we'll come back to it in a bit. So how do we do this? So this is the BLT. This is the very large telescope in Chile. BLT, very large telescope. Astronomers are really good with names. So these four telescopes are 8.2 meters across. So that means they have a mirror that's 8.2 meters across. That's really, really big. And these are among the largest telescopes in the world. And this is what we took that picture of Betelgeuse with. And these telescopes have special technology on them and special mirrors that can change their shape that let us take the twinkle out of the stars. And so they were able to take that picture of Betelgeuse. But how do we do better? Because that picture of Betelgeuse is approaching the limit of what you can do with an 8-meter telescope. And our biggest optical telescopes currently in the world have mirrors about the size of 10 meters across. So it's hard to do much better with a single telescope. Well, what we can do and indeed what I did is we can combine the light from telescopes that are spread out. This is interferometry. And so I use these four 1.8-meter telescopes and you can move them around onto these tracks that you can see here. And when you spread them out, they can be up to 130 meters away from each other, which means that their resolution is the size of 130-meter telescope, which we can't actually build. We can't build a telescope that big, but we can spread our telescopes out and make one that big. Now, coming back to HR 7.221, what, how much detail can we see if we look at it with 130-meter telescope? Well, our coin, remember from before? The eye with this interferometer, I looked at the coin 4,600 kilometers away and measured its size. That's equivalent to the tip of Queensland in Australia to Wellington in New Zealand. And the size of the coin, how well I know its size? Well, I measured its size to about the precision of one of the kangaroo's eyes on the coin from 4,600 kilometers away. That's what you can do with an interferometer. But let's backtrack a bit. Let's talk about how telescopes work. So here's just a single-dish telescope. And what do I mean by single-dish? We have one big mirror and we have a secondary mirror. So what's gonna happen when we're looking at a star and we wanna get the light from that star to our camera? And so the light from the star comes off, bounces off the big mirror, hits the little mirror, and then goes down to our camera. You might have some extra mirrors, but this is how a single telescope works. How do you combine the light if you have two of these telescopes or more? And so the light has to travel exactly the same distance from the star to get to the camera, because otherwise it didn't leave the star at the same time and you can't really combine it sensibly. So you gotta make sure the light arrives at the same time. And so that makes, that's easy to do if your telescopes are here and your star's right overhead.  Like it's over near the horizon? Well, you've gotta move your camera, which is kind of hard to do. How do we do this? And the answer is we can do it with mirror trains. And so what you have is, you have essentially these big tunnels that sort of connect underneath your telescopes. And you have like a train or a cart on them, which have mirrors. And you can move that cart further away so that the light has to go further to bounce off the mirror and come back to your camera. So you can change the distance between your telescope and the mirror and sort of equalize the light. And here's another picture, like me looking inside one of these. So this cart system, this isn't at the BLT, but it's at another telescope, another interferometer that'll get to a little bit later. What about radio telescopes? Radio telescopes look really different to optical telescopes because they're using a different technology. Like with a radio telescope, as we'll see, they can look a bit strange, but they don't need to have as finely polished surface. They don't need to be reflective to our eyes. And this is Parks. It's a pretty famous telescope in Australia. There's only one of them. I've just duplicated the picture here, but if you wanna do interferometry with a radio telescope, they can do something neat is because of how radio technology works, radio telescopes can combine the signals later in a computer, which means we don't need those mirror trains, which makes it easy to put the telescopes really far away. Because think about it with an optical interferometer, like the BLT, I've got those telescopes 130 meters away, but that means that I need to have those mirror carts able to move a really, really big distance. If I wanted to put those telescopes kilometers away, I'd need to dig really long tunnels to be able to have those mirror trains move back and forth. And it's a bit hard to do, but with radio telescopes, because of the way that you can detect radio lights, and radio is a kind of light, we just can't see it with our eyes. The technology allows you to sense a bit extra about the lights, and so you can do it in a computer later. So, now we'll talk about some other interferometers. So this is Charo. This is an interferometer at Mount Wilson, near Los Angeles in California in America. And this is where I actually took that video of the mirror trains. And I'll just remind everyone again, if you've got any questions for those that have just joined us, pop them in the comments and I'll get to them at the end. So, what we can do with Charo. Charo can put their telescopes further away than the BLT. And so what they've actually done is something pretty cool. This is a star, zeta and drometer. And this is a model, an image that we've made of it by observing it. And we can see star spots like sunspots on zeta and drometer, which is really cool because sunspots are regions on the star where they sort of block the magnetic fields like magnets that stars have lots of magnetic fields. And what happens is they can block the heat which makes the star a bit cooler and thus appear darker because it's not glowing as brightly. And so something prior to observing the star, we didn't actually know that stars with strong magnetic fields could have sunspots on their North Pole and their South Pole. And so this is a map of that. And so what we're seeing here is the strange oval shape, that's the map and the dark spot and the color is temperature. And so the lightest color is about 4,600 degrees and the darkest color, which you can see right on the top of the star, is about 3,400 degrees. And so that's a pretty big difference in temperature, but the thing is we can't study this on the sun because the sun has changed in how much magnetic, how active its magnetic fields are over the years. And it used to be more active, but we don't have a time machine. But one of the good things about astronomy is there's lots of other stars out there that are all different ages. And so we can look at a star that's a bit like what the sun was in the past. And then we can see what it's like today and say maybe the sun was like that in the past. So what we can see here, I'm gonna flip between two images. One was taken in 2011, one was taken in 2013. And we can see that that big dark spot on the top of the star stayed there over those years, which means that this doesn't happen on the sun today, but it probably did in the past. And that's something that we can do within its parameter, see a star. All right, let's go back to the VLT. And so the VLT is in the Southern Hemisphere in Chile. And what we can do, we can look at a star Akina and it's spinning so quickly that it's not actually round anymore. The Earth sort of does this too, the Earth spins and it's about 21 kilometers bigger at its equator, but this is only 0.03%, which is pretty small. But this star is really flattened and this isn't a picture of a star, these are just some measurements, but we figured out that this is about the shape of the star. And parts of the star that are closer to the middle are going to be hotter than parts of the further away. This is why red giants are really red because their atmosphere is really spread out and it's colder, they can't be hot over the whole surface of the star. So all we can see here that the white bit of the star near its top and its bottom, that's 17,000 degrees. And the band around the equator is really thrown out because it's spinning so quickly, that's about only 13,000 degrees, which means there's 4,000 degrees difference in temperature on this star because it's spinning so quickly. This isn't a picture of the star, this is just a computer model, but we can only do this with interferometry, like measuring these things about the stars. Now that move on to something a little bit different, I've got to make a quick digression about how stars and planets are actually made. So here we've got a video playing and it's showing stars making planets and disks. So what happens? You have a big cloud of gas and dust and gravity wants to pull it together. But the thing is the cloud is spinning. And so much like if you've ever seen a chef with making pizza and it's sort of the dough in the air and it spins out and becomes flat, that's sort of like what's happening here. And so it becomes, gravity pulls it flat and it's spinning.  And so this is a computer simulation done by Professor Mark Kromholz at ANU. And this is the sort of stuff you use a big supercomputer for. I don't have a computer that's powerful. And so what, why I showed you that is because we can look for those disks. We can look for those pancakes in the sky. Now this is another telescope in Chile. This is Alma. And it has 66 telescopes and you can spread them out between 150 meters away from each other all the way out to like 16 kilometers which is much further than you can do with an optical telescope because these are like radio telescopes. And so this here is an image taken by Alma. And what it is is at one of those pancakes. There is a star in the middle of that, of that circle in the brightest bit and all the rings around it are gaps in the disk in this pancake. And those gaps might be planets that are traveling through the disk and gobbling up all the gas in the dust. Cause what we're seeing here is the gas that has grown glowing really brightly. And do you like that one? How about any of these? Pick one of them. They're all different shapes and the solar system could have looked like any combination of these. Some of these have really thin rings like the one at the top left. Some of them even have spirals sort of like our galaxy. And these are all baby stars. These are baby stars that are making planets and they haven't cleaned up their solar system yet. Like our asteroid belts in our solar system is sort of the leftovers of these disks.  But with an interferometer, you can see these and very nice details. So let's go to Australia. So this is ASCAP, the Australian Square Kilometre Ray Pathfinder. And you've got 36 of these big telescopes, the big radio telescopes and they're big 12-meter dishes. And it's in the outback because if I went there with my mobile phone, the mobile phone, the telescopes would see the mobile phone and the mobile phone would be really, really, really bright and brighter than anything in the sky. So it's out in the outback where there's not as much mobile phone coverage so we can have clearer skies because that's the equivalence of looking up if you've got a big city and you look up in the sky how there's lots of light pollution. Light pollution for radio telescopes is mobile phones. And so what can we do with this? Well, researchers at ANU led by Professor Naomi McClure Griffiths studied the gas in two of our neighbouring galaxies the large and the small Magellanic clouds. And so with these, they've got extreme detail, three times smaller detail than ever before. And why is this important though? So what we're looking at here is like hydrogen gas which is the most common kind of stuff in the universe. So if you're in the Southern Hemisphere and you go outside to a dark site and you look to the south, you can see these, the large and the small Magellanic clouds and the large one is on the right and the small ones on the left. And these are small galaxies that orbit the Milky Way. But they're also kind of orbiting, they're tugging on each other, they're having like a tug of war. And between them, there's actually a big strip of gas that baby stars have been born from. And so by using different kinds of lights, study these galaxies and getting the extreme detail that you can only get with an interferometer we can learn about our close friends. So still in the Southern Hemisphere, how don't we look at a radio telescope that's a bit strange? It's not really what you'd expect a telescope to look like. This is the Murchison, this is WA, MWA sorry. And so this is a telescope or one tile from a telescope. It looks sort of more like a fence or an art exhibition but each of those white contractions is actually an antenna and you get a bunch of them together and put them on this big tile and that's a telescope. And then you have lots of these tiles spread out really far away and you can see stuff in the radio. And so what we're seeing here, this is what MWA would see what the sky would look like to MWA if or us if we had radio eyes. And so that big strip, that's the Milky Way and then off to the right you can see sort of something that looks a bit like an hourglass. What is that? Well, that is Centaurus A and it's a galaxy that didn't want its gas.  And what we see on the left is what MWA sees and on the right is what we would see if we looked with a telescope with our eyes. And you can see that everything there that we can see with our eyes is really small. That's tiny, it's in the middle of that and all this stuff coming out of the top and the bottom is all the gas, all like the hydrogen gas that Centaurus A has just thrown out and it's really, really, really long. Millions of light years long. Like if you was right next to the black hole and you shot a torch up, that light would take millions of years to get to the current top of all that gas. And your W.A. gives us an extreme amount of detail. So coming back to parks, this is what park sees if it looks at MWA. And so parks has a 64-meter ditch and it's a really big telescope. But let's jump back and forth between these a bit. This is the difference in resolution that you can get when you put your telescope really far apart, like three kilometers apart, like MWA. You can see much more detail. And this is what an interferometer can do. Parks is still a great telescope and actually can do some complimentary science because we need all kinds of telescopes, big and small, single and joined together to do astronomy that gives you a good idea. So to wrap up, talk about the biggest interferometer. So this here is a map of the Earth and all those little points on it are telescopes, radio telescopes that all observe the same thing. This is the event horizon telescope. And you may have heard about this in recent years or you may have seen this picture because this is a black hole. We used radio telescopes spread out across the entire planet, which means we essentially had a planet-sized telescope to look at a black hole. But what are we seeing here? So this shadow is the size of our solar system.  So this is why we need a rocket to get off the Earth because you need to go fast to overcome gravity. But black holes have such strong gravity, they're not even light. The fastest thing there is, you've heard of the speed of light can go fast enough to get out. And so there's a shadow around that where any light that falls in never comes out. So this is a disk, like a pancake of hot gas that's orbiting the black hole and it's shining really brightly. So this is 25 times smaller than HR7-221, my smallest star that I looked at. What's that number? One and a half million times smaller than the human eye resolution and it's 45 million times smaller than the moon. This is really incredible and this is something we could have only done with an interferometer and a planet size interferometer at that. And so different wavelengths of light let us see different things. We use radio waves here because they can kind of see through the gas. This isn't our black hole, I should mention, it's a black hole in another galaxy, the Messier 87 galaxy. But by using radio light, we can kind of see through the gas and the dust that's in the way of the galaxy. And this study, this telescope also looked it out black hole and we'll get a picture about it at some point as well. But here's a completely unrelated sunset video that I took at Sighting Spring Observatory. But for resolution, two telescopes really are better than one. And so this brings me to the end of what I wanted to talk about. But by combining a light from multiple telescopes by doing telescope teamwork, getting our telescopes to get together, this lets us do something called interferometry, which allows us to get telescopes that are greater than the sum of their parts and see things that we can't with our own eyes because we need gigantic telescopes to see it. But it lets us study stars and how stars make planets and even galaxies and clouds of gas in space in fantastic detail. So thank you all for listening and I'll take any questions now. And so I've got a question here about what's my favorite interferometer and why? So I've only used two interferometers. I used the BLT in Chile to do my science, to measure the sizes of like HR7221 in the land of Sagittarius, M16 stars. And so that was really fun and interesting. And the way that works is I didn't actually go to Chile because astronomy is really international. And what you can do with that observatory is you can say, hey, I'd like you to observe these stars for me when the sky is pretty clear and there's no clouds and the air is pretty still, the stars aren't twinkling much. And what'll happen is they'll observe for me those stars when the conditions arrive. And so there was another astronomer using those telescopes in Chile that observed for me. I'd observed with Chara though three times now. And been pretty unsuccessful. Like I actually went to Los Angeles, like LA, California, went up to Mount Wilson and was on Mount Wilson Observatory in the observatory control room, picking the stars we wanted to observe. But as happens with astronomy, the sky was cloudy and it was rainy and it was too humid to open our telescope domes. Because if it's too humid, then the water can drop on the telescope mirror. And so that wasn't a very good time. We lost three nights, I think, to weather. And then I observed again last year and weren't very successful that time either. Like the sky was just really, really, really turbulent. And so what we were trying to use Chara for is Chara has a better resolution than the BLT, but it's in the Northern Hemisphere. So there are benefits and trade-offs to both of them, but you can see stars that are in the North that you can't see with the BLT in the South. But we were trying to look at red dwarf stars, which are stars much smaller than the Sun. And they're pretty hard to understand because they're really faint and their atmospheres are a bit weird. And so they're really hard to model in computers. So we're trying to observe them and measure how big they were to get their sizes so that we can put them into the computer models and see what happens. I'll just mention as well, if there's any more questions, keep putting them in the comments and I'll take them as long as you're giving them to me. But yeah, but because these red dwarf stars are so faint, like these stars are maybe 10%, like 10 times smaller than the Sun or smaller. And as a result, they're much, much fainter. And so we need much, much better weather to see them. These aren't stars, you can just walk outside and see, yeah, that's a red dwarf and that's a red dwarf, which makes it a little difficult. And we did have, this week actually, were the world not currently locked down because we've had to close all our observatories in the pandemic to make sure that we're safe and all the astronomers and people who work on the telescopes, the technicians are safe. And so I would actually be observing with Chara this afternoon to look at these red dwarfs, but Chara is closed. So not having very luck with, much luck with Chara, but I have hope for the future that we'll eventually be able to get some data on these red dwarfs and figure out just what's going on with them. Ah, so we have another question. Why can't we have optical interferometers the size of radio interferometers? And so I've touched on this a bit earlier, but the reason is that we need to make sure that the light arrives at the camera at the same time for optical telescopes, but like we can see with our eyes. But the problem is that we can't combine it at a computer. So if I wanted to have an optical telescope here in Canberra, say, and put one in New South Wales or one in Sydney or something like that, those are really far apart and I would need to bring the light from one telescope from both telescopes to probably like the middle, like where they are. So if I had a telescope in, you know, if we said to say one in Canberra, one in Sydney, I would need to bring the light 150 kilometers to the middle from Canberra and another 150 kilometers from the middle from Sydney, have the light there in a laboratory, combine it and have my camera there. And so I'd essentially need to have tunnels under the earth or I guess on top of the earth where I'm shining this light through to bring it to the center. And that gets a bit tricky. It's a really big distance and it makes it a really big construction project to build. Whereas with the radio telescope, because they have antennas and radio technology is a bit different, it's, you can combine the light in a computer. So about a radio telescope here in Canberra and a radio telescope in Sydney, I don't actually need to build that big tunnel. I can just save the data on a hard drive at one end and a hard drive at the other and like bring it together and then like line up the lights in a computer and it makes it much easier. And so that's just a limitation with optical telescopes. So we've got a question about what is my favorite planet? I like Jupiter. Jupiter's gorgeous to look at. I had a very small picture of Jupiter before which didn't really do it justice but looking at it even through a relatively small telescope, you can see the stripes on Jupiter which are the bands of clouds that go around the planet. And you can see the Great Red Spot which is a big storm that's been raging for hundreds of years and might actually be getting a bit smaller. And you can see the moons of Jupiter. So Jupiter has, you know, some 60 plus 70 moons now, I think and you can see the four biggest ones, the Galilean moons and each of these moons is about the same size as our own moon. And if you crawl back to the beginning, I showed you the size of the Earth compared to the moon and so each of those moons is about the size of our moon. But around Jupiter. And so you can see them just going around Jupiter and if you check back, like you've looked at it a few now and then a few hours later, for instance, you could see the moons actually change position because they all that pretty quickly. But yeah, the first time I actually saw those moons was just with a pair of binoculars as well because remember, binoculars let you get that extra detail leaning against the gum tree at my parents house. Just looking up at Jupiter and that was really exciting just seeing those moons for the first time. It doesn't actually take much to see them. But yeah, any other questions? Otherwise we'll probably wrap up soon but thank you for everyone who has joined us. I hope you learned something. I guess if we're not getting any more questions that all do us for now. Thank you everyone for tuning in. We'll be having more of these chats with some of the other astronomers from the observatory. You can watch this later or again if you want. If you only just quarter or you can catch it the first time. You can come ask me questions on Twitter if you want. So I'm at Adam D. Reigns. If you want to ask me any astronomy question, I can either do my best to answer it or point you to another astronomer on Twitter who knows better than I do because there's a lot to learn and we all know very little of it because the universe is really big. But anyway, thank you for joining us and I'll catch everyone next time.