Wednesday, October 09, 2013

Planck telescope: the funeral

In March 2013, ESA's Planck telescopelaunched in 2009 – brought us the most accurate cosmological data about the Universe. Last year, the unit became mostly useless as it ran out of helium (the coolant) and the cruel European Space Agency is putting the gadget down now (BBC).

Recall that the telescope was working at the L2 Lagrange point, about 1.5 million kilometers away from the Earth in the opposite direction than the Sun. Because ESA is so cruel, they decided to make the funeral thorough.

Today, Planck is scheduled to burn the fuel for the first time. On Monday, October 21st, they will burn it for the second time. The two maneuvers will kick the spacecraft out of the L2 Lagrange point and then to an independent orbit.

ESA seems highly determined to make sure that all the batteries are disconnected, all the fuel is burned, and the device will never be ready to be reactivated again. I don't understand these desires to make their euthanasia so perfect. They suggest that they're scared that the fuel tanks could explode. What a big deal if an explosion like that would take place millions of kilometers from the Earth (and from other satellites).

And why are they so obsessed with the idea that the device will never be resuscitated? It sounds almost as hostile as the U.S. Congress that decided to ruin the SSC tunnels so that even mushroom growers couldn't succeed with their alternative plan to use the already existing SSC's tunnels (worth $1 billion). They just hated the SSC so much that even hopes that it could be revived in the future had to be killed.

To say the least, I can't get rid of the feeling that such desires to make the liquidation "perfect" are both hostile and counterproductive. In the future, some fuel located millions of kilometers away from the Sun may be found useful – to fight against asteroids, aliens, or whatever ;-) or, more realistically, to allow another probe to refuel.

At any rate, the Planck telescope's active life is over but that doesn't mean that we have already extracted all the data that the telescope should give us. Quite on the contrary, much of the data will be published in the following year – through Summer 2014.

Polarization of the CMB

One of the things it should shed some light on are the B-modes in the cosmic microwave background. Note that in astronomy, it's sometimes fun to look whether the incoming light is polarized. Linear polarization often arises by reflection from the dust; circular polarization is created when light goes through powerful magnetic fields etc.

The cosmic microwave background (CMB) is also known to be slightly polarized, despite its being mostly thermal, but the known polarization is mostly described by the E-modes ("E" stands for "electric"). Much weaker B-modes ("B" stands for "magnetic" – or "bagnetic" if you can't find "b" in the word "magnetic") are harder to be seen. However, in a development 10 weeks ago that I forgot to mention on this blog, the B-modes were finally seen
B-mode polarization spotted in cosmic microwave background (Physics World)

Detection of B-mode Polarization in the Cosmic Microwave Background with Data from the South Pole Telescope (arXiv)
by the South Pole Telescope (SPT). These modes are the "leading ones" which are fully theoretically explained by gravitational lensing; the B-modes depend on the mass distribution in the Universe. However, weaker components of the B-modes may be created in more complicated ways and they may be used to check some features of cosmic inflation. In this context, the leading B-modes are the background that has to be subtracted when we want to find gravitational waves which would have profound implications for the cosmic inflation and its competitors.


  1. Could the helium supply not be replenished...?

    I hope this "cremation" funeral does not mean that Europe will become as hostile to experimental fundamental physics as the US .... :-/

  2. Nope, Dilaton! I didn't want to suggest anything like that. The broader plan is of course different than in the SSC case. With Planck, these final operations have been pretty much a part of the plan by those who like their gadgets and work. It just "feels" hostile towards the telescope. ;-)

  3. "L2 Lagrange point, about 1.5 kilometers away from the Earth"

    Uhm I guess it's about 1500000 km :-)

  4. LOL, fixed, thanks. I was trying to ask the people on the central square, a mile from here, where is the L2 Lagrange point but no one knew it. So it simply had to be a bit further - although, let's admit, six zeroes are essentially nothing (6*0=0).

  5. I presume the idea is to remove any risk of damaging other satellites sent to L2. If the battery exploded it would leave debris that could not be tracked. With JWST heading to L2 soon they would not want that risk no matter how slight.

  6. Good... and what about the mushroom growers? Was the SSC tunnel sold to a millionaire to create a
    luxurious nuclear shelter?

  7. Hi Lubos ,
    I've discovered a theory that can explain everything and unify gravity with quantum mechanics . In breif , thetheory say that gravity doesn't exist and that quantum mechanics is wrong , for more information please contact me . I can't tell you the theory here becasue I'm afraid someone would steal my idea . By the way , My theory is very simple and doesn't contain mathematical formula

  8. The ESA doubtless wants to avoid bad publicity from crackpot environmentalists who might raise a stink about all of those “chemicals” floating around in our pristine solar system. We’ve already contaminated earth and we certainly should not start polluting the whole solar system, should we?

    Tell me, vixra, how can a battery, which will quickly cool to cryogenic temperatures, explode? Removing it from the earth’s shadow might re-introduce that possibility, of course.

  9. Indeed; it would be unlikely for those metres to be among the "earliest along the path to the L2 Lagrange point" and therefore the true distance is probably comparable to a mile. Yet another successful application of the principle of mediocrity ;)

  10. Do you work for IPCC? I heard they invented something similar.


    A real man would drop Planck into the moon.

  12. OK . I don't know how you guessed , but I'm one of it's major funders and contributors .

  13. Nice , but wouldn't planck get angry because he've been dropped into the moon without his consent ? He's one of the founders of Quantum mechanics and he deserves our respect


  14. I hate to break it to you but someone has already stolen your idea (or maybe you stole his).

  15. "And why are they so obsessed with the idea that the device will never be resuscitated?"

    Because they are all Star Trek fans, have seen "Star Trek: The Motion Picture", and know what happened to Voyager 6...

  16. Nobody will hear him scream, re disintegration by parts. Drop him on the dark side where nobody can look, embracing the shrewd zinger catastrophe.

  17. The risk of a battery or fuel tank exploding does seem very small, however the JWST is also very expensive and delicate