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."

Comments

I Smell Another Apple Ad

[WrongSizeGlass]

90% of the Universe was discovered by thinking differently? Steve Jobs just felt a tingle somewhere.

Re:I Smell Another Apple Ad

[calibre-not-output]

A tingle? Steve Jobs just had to go get a change of pants.

Re:I Smell Another Apple Ad

[nacturation]

Shit, man... he had to change his liver!

Re:I Smell Another Apple Ad

[AuMatar]

I hate that. Just to make that stop happening I now search for at least 5 minutes after I find something.

Re:I Smell Another Apple Ad

[SoVeryTired]

There's a big fat gap between what the calculations say the rate of galaxy formation should be, and what it is actually observed to be. This new observation accounts for 90% of that rate.

Re:I Smell Another Apple Ad

[b4dc0d3r]

A quote from the summary, which should appear directly above the comments in case you are not familiar with slashdot, is:

and voila, ten times as many galaxies could be seen

.

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.

Implications for dark matter estimates?

[Anonymous Coward]

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?

Re:Implications for dark matter estimates?

[Mab_Mass]

Anyone got any idea how this impacts our estimates of dark matter?

From TFA:

"I'll note: this has nothing to do with dark matter. As it happens, 90% of the matter in the Universe is in a form that emits no light, but affects other matter through gravity. We know it exists ... locally, in nearby galaxies and clusters of galaxies, too. This new result doesn't affect that, since the now un-hidden galaxies are very far away, like many billions of light years away. They can't possibly affect nearby galaxies, so they don't account for dark matter."

Re:Implications for dark matter estimates?

[oldspewey]

More likely, a huge intellectual battle will break out among humankind, between the Dark Matter proponents and the Dark Matter deniers. Auditoriums full of angry people will hurl insults back and forth at each other, news stations will interview various scientific experts and political commentators in an effort to boost ratings, deniers will accuse the proponents of wanting to destroy the free-market universe and enslave humankind in some kind of subatomic socialism, while proponents will accuse the deniers of being selfish and greedy, willing to gamble the heat death of the entire universe just so they can run their colliders a little longer.

But that's just my prediction.

Re:Implications for dark matter estimates?

[spun]

Absolutely wrong. TFA even states this means nothing for dark matter, we knew that these galaxies were out there, we just hadn't spotted them yet. Besides, we've seen dark matter much closer to home. When galaxies collide, the gas pressure stops the regular matter, while the dark matter keeps moving along at the same speed. The dark matter has mass, so it creates a gravatic lens. We have seen these lenses, with no visible matter to create them, when galaxies collide.

Re:Implications for dark matter estimates?

[MozeeToby]

Dark matter isn't just matter that isn't lit up (that was one of the original theories, but has since fallen to the wayside), it is matter that is fundamentally different and doesn't appear to interact with regular matter at all, except gravitationally.

Re:Implications for dark matter estimates?

[Chris Burke]

I knew about the fudge factor we needed to get the equations to work - I didn't know we have actually seen something like that.

It was never a "fudge factor" to make the equation of gravity "work". It was a prediction of the already extremely well-working equation. Not "Oh noes gravity is broken, we need 'dark matter' to fix it." Rather "Huh, gravity implies there is a mass here that we can't see with our electromagnetic detection devices".

Think of it this way. You're walking around a room blindfolded with a cane that has a pressure sensor on the end that uses a voice synthesizer to tell you the readings. You notice that all along a large flat plane the pressure sensor detects pressure equal to that with which you push. Newton's 3rd Law tells you that for this to happen, something must be pushing back with equal force. Something like a wall.

Now, do you say that the wall is a fudge to make Newton's 3rd Law work?
Or do you say that Newton's 3rd Law implies that there is a wall there?

I mean you might as well say that the existence of the Sun is a fudge to make electromagnetic and gravitational equations work.

I'm not trying to rag on you or anything (I mean you said 'thank you' for evidence after all), just trying to clear up a misconception that I think has lead to a lot of unnecessary skepticism of dark matter.

I RTFA...

[Torrance]

...and this isn't the conclusion that I immediately jumped to - the discovery of dark matter. It's merely the discovery of the visible matter that they though should always be there.

Re:Dark stuff?

[Sponge Bath]

Does this account for any missing mass and/or dark matter?

FTFA: "...this has nothing to do with dark matter."

Scientists' pledge.

[Spazntwich]

Scientists on earth were said to be embarrassed by overlooking what had been there all along, and promised to never again take what they have for granted.

"It's like some crappy teen drama, and we just had to wait for the prom scene to realize how beautiful our soft-spoken nerdy friend is."

90% of the universe could not be reached for comment, as it decided itself too good for its unappreciative inattentive "friends" and went to the football players' afterparty.

Not "90% of the Universe"

[Neon Aardvark]

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.

Next step: a better name

[spun]

The "Very Large Telescope?" Come on. We can do better than that. I suggest "Really Big Round Glass Thing for Seeing Further."

Re:Next step: a better name

[maxwell demon]

Actually it's the Overwhelmingly Large Telescope.

Re:Dark stuff?

[mcgrew]

The missing mass is comprised of all the socks that have slipped through the spacetime continuum when you put them in the washing machine. They emit no radiation, but exert gravity. It's especially grave when you can't find a matching pair.

Redshift?

[rsborg]

My first thought was, did they compensate for redshift? Apparently they did, the article didn't explain, but a commenter did:

30. TMB Says: March 24th, 2010 at 7:02 pm To everyone who's asking "why didn't they look at this before?" - it's a lot harder. In the rest frame, Lyman-alpha is in the far-UV and H-alpha (what physicists call Balmer-alpha) is in the optical. But out at these redshifts, Lyman-alpha is redshifted into the optical (which is easy to observe) and H-alpha is redshifted out into the infrared (which is harder to observe).

Someone update the Drake Equation!

[scorp1us]

Since we just got a 10 fold increase in galaxies.

I think that moves us from 0.006 to 0.06, (plus one obviously)

Way to go

[Cryacin]

Shining some light on dark matter.

Re:Way to go

[Ian Alexander]

From the article:

I’ll note: this has nothing to do with dark matter. As it happens, 90% of the matter in the Universe is in a form that emits no light, but affects other matter through gravity. We know it exists, and you can find out why here. We know it exists locally, in nearby galaxies and clusters of galaxies, too. This new result doesn’t affect that, since the now un-hidden galaxies are very far away, like many billions of light years away. They can’t possibly affect nearby galaxies, so they don’t account for dark matter.

This will change the ratio of luminous matter:dark matter but not eliminate dark matter entirely.

Not that you said that it would necessarily get rid of dark matter, but it was a conclusion that suggested itself from the summary's wording.