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90% of the Universe Found Hiding In Plain View
The Bad Astronomer writes "As much as 90% of previously hidden galaxies in the distant Universe have been found by astronomers using the Very Large Telescope in Chile. Previous surveys had looked for distant (10 billion light years away) galaxies by searching in a wavelength of ultraviolet light emitted by hydrogen atoms — distant young galaxies should be blasting out this light, but very few were detected. The problem is that the ultraviolet light never gets out of the galaxies, so we never see them. In this new study, astronomers searched a different wavelength emitted by hydrogen, and voila, ten times as many galaxies could be seen, meaning 90% of them had been missed before."
Anyone got any idea how this impacts our estimates of dark matter?
Does dark matter disappear or do we still need some hiding to explain things?
If we only saw 10% of them before, how do we know we're seeing all of them this time?
Merely 90% of the Visible Universe that we couldn't see before.
The Visible Universe probably constitutes a very small (perhaps even infinitesimally small) fraction of the actual physical Universe. The rest will, according to Relativity, always be hidden.
Azural - instrumentals
People are far too enamored with dark matter. It is extremely frustrating having to place everything in the context of dark matter (often with only the most tenuous connection) when trying to explain interesting observations to the general public. The author of this article, thankfully, made it clear at the top of the article that it was NOT related to dark matter and went on to explain the observation.
This has absolutely nothing do to with dark matter. So, yes it is a coincidence. And an approximation.
They're improving their technique for observing distant galaxies. Which doesn't in any way invalidate observations of (astronomically) very close galaxies. Which is what we base the existence of dark matter on.
Azural - instrumentals
That's what Zoolander would name it.
I was thinking Leonard of Quirm.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
A quote from the summary, which should appear directly above the comments in case you are not familiar with slashdot, is:
.
X is the previous amount, and 10x as the new amount of galaxies.
So simple math gives you X + YX = 10X
X(1+Y)=10x
(1+Y)=10
Y=9
So we see a 10-fold total galaxies, which is 9-fold improvement. Or to put it another way, the new 100% is 10 times the previous amount, which must have been 10%, leaving 90% more.
You're reading it as "90% of the universe found", from the headline, which is an attempt, although a poor one, at conveying the increase in observable galaxies. It is correct if you assume that we found 90% of the now-current estimate of the number of galaxies, in other words insert the word "known" in the title somewhere. Choosing not to even read the summary has left you understandably confused, and I'm glad that I was able to help. At the same time, I'm concerned that the other replies did not draw your attention to this. But I was able to post an accurate reply while maintaining an air of disdain and condescension, so that makes me feel good about myself. Thank you for affording me the opportunity, and welcome aboard.
Asking if professional astronomers took the red shift into account is like asking if some surgeons washed before performing surgery.
Anarchists never rule
I always thought that dark matter was a hack. "our numbers don't add up.. therefore 90% of the universe is a type of matter that has gravity but doesn't interact with the electromagnetic spectrum, or anything else, also there's none of it near earth, it's like the 90% that's far away." sounds good to me :-p