Student Finds Universe's Missing Mass 210
An anonymous reader writes "A 22-year-old Australian university student has solved a problem which has puzzled astrophysicists for decades, discovering part of the so-called 'missing mass' of the universe during her summer break."
Another source for the story (Score:5, Informative)
Re:Noteworthiness (Score:5, Informative)
Any astrophysicists (or at least postgrads) here to say how important or true this achievement really is?
The article (got to it prior Newton's First Law of ./ effect) actually did quite a good job of addressing exactly that.
Takeaways were:
-Missing mass (not dark matter, but matter which was seen to exist during creation of universe but is now someplace different) turns out to have migrated to filaments that span across the universe.
-Claimed that astrophysicists have long postulated (~2 decades) that the mass had moved there, but that the imaging capabilities weren't able to resolve it.
-Then in a fit of bipolar impetus, also went on to say how exciting a discovery this was for the community.
-Finally acknowledged that most likely nothing useful (to mankind) will come of this discovery.
Ok, interestingish (Score:5, Informative)
A student has found that if you observe in the x-ray range you discover ordinary matter between the galaxies that was clearly evident in the early universe and isn't visible in other parts of the spectrum.
I'm not sure that it's altogether news that different frequencies let you see different things - to me, by far the biggest news is that despite having x-ray telescopes for a very long time and computers quite capable of crunching that data to detect potentially interesting observations, the astronomers have been opting for cheap student labor instead.
Missing mass but not "dark matter" (Score:4, Informative)
Re:Noteworthiness (Score:5, Informative)
Any astrophysicists (or at least postgrads) here to say how important or true this achievement really is?
It's fairly significant. They have confirmed that some fraction of the missing baryonic matter (the ordinary stuff we are made of, like Galactic Dark Matter, not the exotic new-particle stuff) is in the filaments that exist on very large scales in the universe. If they had failed to find it the result would have been more interesting, but even so they've done a good bit of science by testing the idea that the missing baryonic matter is in these filaments by actually going and looking for it rather than taking it on faith that it must be there.
We know there is missing baryonic matter because we know what the baryonic density in the universe is from the primordial helium/hydrogen ratio. Free neutrons only live about fifteen minutes, so as the Big Bang cooled and neutrons and protons condensed out of the primordial quark-gluon plasma there was a relatively short interval in which helium could form. We know the size of the universe at that time from the temperature, and we know the density because the denser it was the more neutrons would have been captured onto protons to form heavier isotopes, so by figuring out the primordial density of deuterium, helium and lithium we can put pretty strong constraints on the total baryonic mass of the universe.
Horrible article/summary (Score:5, Informative)
http://arxiv.org/abs/1104.0711 [arxiv.org]
The abstract does not make any grandiose claims of finding the missing mass of the universe but instead states how the article presents properties of mass in filaments.
Re:Ok, interestingish (Score:5, Informative)
Here's the paper: An estimate of the electron density in filaments of galaxies at z~0.1 [arxiv.org].
The student got listed as first author, which is cool for her. The paper itself is a follow-up to Pimbblet's (the actual prof with the actual grant) 2004 study of filaments. The major finding seems to be that the press is gullible enough to print anything if you say an undergrad did the work. In this case, the press manages to avoid looking like total idiots, since the study is pretty cool and interesting. Nonetheless, the hype is vastly out of proportion to the significance.
Order of importance (Score:3, Informative)
It's not that you're wrong, you're just using different metrics. In physics (and astronomy, I think), the authors are usually listed in decreasing order of work done, starting with the person who did the most. The people at the end of the list have done so little work, why are they even on the paper? Because, as you say, they are listed in increasing order of importance (read: amount of grant money received). If you have enough people, sometimes they just throw them all into alphabetical order and pretend that everybody reading the CVs of the people who actually did the work will somehow know that they did.
This guide may also be helpful: PHD's Guide to the Author List [phdcomics.com]
she didn't find anything (Score:5, Informative)
"Ms Fraser-McKelvie said the ‘Eureka moment’ came when Dr Lazendic-Galloway closely examined the data they had collected. “Using her expert knowledge in the X-ray astronomy field, Jasmina (Dr Lazendic-Galloway) re-analyzed our results to find that we had in fact detected the filaments in the results, where previously we believed we had not.”"
So the student found nothing, it wasn't until an expert looked at it and actually found the mass.
So I guess it depends on your perspective as to if the student found it or not. If you're throwing out a bunch of "junk" and an expert goes through it and discovers a priceless artifact does that mean you discovered it or did the expert?