Weak gravitational lensing and weak arguments




HST images
Gravitational lenses as seen by the Hubble Space Telescope in 2008.



The second accusation displays such ignorance it undermines the credibility of the whole article. One of the most important observations for establishing the current cosmological model* comes from gravitational lensing, especially "weak gravitational lensing" which is the distortion of observed galaxies by the dark matter which lies between us and them. This allows astronomers to work out the distribution of mass in the universe, and it is certainly not "absolutely uniform" as Ormell claims they assume. They didn't exactly keep this quiet, so I don't know how Ormell missed it if he has even a passing interest in cosmology.

Now it may be that cosmology is creaking at the seams. The current model requires not only some mysterious dark matter (which we may even be able to create at the LHC) but also dark energy. Maybe there's a better, more predictive theory out there which describes all the data and doesn't need these extra components. Maybe some new observation will point the way. But since this is science, not blind faith, many people are looking rather hard for such things, and anyone who makes a convincing breakthrough will be lauded, not burned at the stake.

Later on in the article, Ormell makes up a nonsense number, does some simple mathematics with it, and seems to think this proves that we don't know anything about the early universe. This is a very nice demonstration of a disconnection between maths and reality, in that if you do correct maths on rubbish data you still end up with rubbish. But I am not sure he intended it that way.

I read Times Higher Education for many reasons; one of them is to keep myself in touch with academic disciplines other than my own. So it's disturbing when an article discourses confidently about something adjacent to my own area and displays such ignorance. On the other hand it's a good excuse to discuss gravitational lensing and show some cool pictures and a video.


* please note "current", "model" i.e. not blind faith