In a massive region of space, astronomers find far fewer galaxies than they expected

In a massive region of space, astronomers find far fewer galaxies than they expected
Computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. A University of California study demonstrated that opaque regions of the universe are like the large voids in the galaxy distribution in this image because too little light from the galaxies is able to reach such regions and render them transparent. Credit: TNG Collaboration

University of California astronomers, including three from UCLA, have resolved a mystery about the early universe and its first galaxies.

Astronomers have known that more than 12 billion years ago, about 1 billion years after the Big Bang, the gas in was, on average, much more opaque than it is now in some regions, although the opacity varied widely from place to place. But they weren't sure about what caused those variations.

To learn why the differences occurred, the astronomers used one of the world's largest telescopes, the Subaru telescope on Mauna Kea in Hawaii, to search for of young stars in an exceptionally large of space—500 million light-years across—where they knew the was extremely opaque.

If the region had an unusually small number of galaxies, the scientists would be able to conclude that starlight could not penetrate as far as expected through the intergalactic gas; if it had an unusually large number of galaxies, the implication would be that the region had cooled significantly over the previous several hundred million years. (Having few galaxies in a region would mean not only that there was less light created by those galaxies, but also that even more opaque gas was being formed, so the light could not travel as far as astronomers had expected.)

"It was a rare case in astronomy where two competing models, both of which were compelling in their own way, offered precisely opposite predictions, and we were lucky that those predictions were testable," said Steven Furlanetto, a UCLA professor of astronomy and a co-author of the research.

The researchers found that region contains far fewer galaxies than expected—clear evidence that starlight could not get through. The paucity of galaxies could be the reason this region is so opaque.

"It is not that the opacity is a cause of the lack of galaxies," Furlanetto said. "Instead, it's the other way around."

They concluded that because the gas in deep space is kept transparent by from galaxies, fewer nearby galaxies might make it murkier.

The research is published in the Astrophysical Journal.

In the first billion years after the Big Bang, ultraviolet light from the first galaxies filled the universe with gas in deep space. This would have occurred earlier in regions with more galaxies, the astronomers concluded. The astronomers plan to further study whether the void and others like it will reveal clues about how the first generations of galaxies illuminated the universe during that early period. Furlanetto said the astronomers hope that studying the interplay of galaxies and gas in deep space will reveal more about how the intergalactic ecosystem took shape during that period of the .


Explore further

Image: Hubble's compact galaxy with big-time star formation

More information: George D. Becker et al, Evidence for Large-scale Fluctuations in the Metagalactic Ionizing Background Near Redshift Six, The Astrophysical Journal (2018). DOI: 10.3847/1538-4357/aacc73
Journal information: Astrophysical Journal

Citation: In a massive region of space, astronomers find far fewer galaxies than they expected (2018, August 14) retrieved 25 May 2019 from https://phys.org/news/2018-08-massive-region-space-astronomers-galaxies.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
871 shares

Feedback to editors

User comments

Aug 14, 2018
"The researchers found that region contains far fewer galaxies than expected—clear evidence that starlight could not get through. The paucity of galaxies could be the reason this region is so opaque."

This statement makes absolutely no sense at all! Far fewer than expected? Did not know that the universe had a density requirement. And then that is the evidence that the light could not go through? Huh? Then then the lack of stars is the reason it is opaque? You need to inform readers with fancy words that if there are no stars, there shall be no light?

Maybe this region is the N Korea of deep space?

Aug 14, 2018
This statement makes absolutely no sense at all! Far fewer than expected? Did not know that the universe had a density requirement.


I had to read the entire article through to the UV part before its compositional opacity started to abate. But it's still badly written. I became puzzled enough a day or so ago by the phys·org expository style to have searched its "about" to see what their philosophy of explication was about, thinking my problem was that it was geared for a high-academic reading level beyond my grasp. Apparently not, despite their claims.

I'd recommend a book to this site's authors, that was written many years ago, with the beautifully self-explanatory title:
"Simple and Direct."

Aug 14, 2018
"The researchers found that region contains far fewer galaxies than expected."

Oops, looks like a major misinterpretation of the "data". This is one of the biggest blunders that repeatedly occur in science - "Data misinterpretation". A vast source from which to derive WAGs. (WAG = Wild Ass Guess).

Since the data is 12 billion years old, perhaps we should cut them some slack. But if they were wrong about this issue, one has to back up a little and question what else they might be wrong about. Nobody is perfect!

Dark matter seems to be pretty solid, but I suspect that "galaxy density" WAS too. And then there is the issue of dark energy, which is on a lot shakier ground than dark matter. Do these people really have any idea about what is going on out there other than the obvious?, which I define as data derived from various space and ground-based instruments capturing various wavelengths of light. Certainly some, but ONLY if you interpret the data correctly.


Aug 14, 2018
For those of you with all the right data interpretations, can anyone explain what we are doing here since the Big Bang was supposed to be symmetrical, creating equal amounts of matter and antimatter (not). When it went bang, all of this stuff should have been converted into electromagnetic radiation, and the universe should be filled with photons, and no matter. Another misinterpretation of data? Or just a WAG, likely based on some other WAGs, none of which can be demonstrated in any way......

Cosmology certainly has some tough nuts to crack.

Aug 14, 2018
"The researchers found that region contains far fewer galaxies than expected—clear evidence that starlight could not get through. The paucity of galaxies could be the reason this region is so opaque."

No. The vacuum of Space is not a total vacuum. Instead, it harbours innumerable pieces of Matter/Mass in the form of dust and gas that are capable of blocking Light from transiting through the Space between galaxies, regardless of the quantity of galaxies and the Light from galaxies in the region. The opacity is a result of the bits and pieces of floating Matter in the partial vacuum of Space. Perhaps the remnants of a primordial "soup".

-CONTINUED-

Aug 14, 2018
-CONTINUED-
"It is not that the opacity is a cause of the lack of galaxies," Furlanetto said. "Instead, it's the other way around."

That should go without saying. But Furlanetto omits explaining what the "other way around" is, in the second part of his sentence. So, we are left to assume an educated guess which may not be accurate enough.

"They concluded that because the gas in deep space is kept transparent by ultraviolet light from galaxies, fewer nearby galaxies might make it murkier."

The gas in deep Space will only be kept transparent in the absence of such innumerable bits and pieces of Matter residing in the partial vacuum of the Space between galaxies and other bodies. The partial vacuum of Space is not empty and devoid of Matter, which is in the form of dust and gas. UV light is from Stars within galaxies, so that it is not the galaxy itself that is producing Starlight. There is also gas and dust in Interstellar Space which could block UV light from Stars.

Aug 14, 2018
danR

I assume it has a recommendation to convert all scientific units from K to F, and from m/s to miles per hour, so we dimwits will believe to understand at least one term?

Aug 14, 2018
I'd recommend a book to this site's authors, that was written many years ago, with the beautifully self-explanatory title:
"Simple and Direct."

The site to a large extent doesn't write anything, it just regurgitates press releases.

Aug 15, 2018
danR

I assume it has a recommendation to convert all scientific units from K to F, and from m/s to miles per hour, so we dimwits will believe to understand at least one term?

I don't see much point in making it clearer to dimwits; They STILL wouldn't understand the physics.
In science, the standard is metric and I think rightly so.

Aug 15, 2018
For those of you with all the right data interpretations, can anyone explain what we are doing here since the Big Bang was supposed to be symmetrical, creating equal amounts of matter and antimatter (not). .
dfjohnsonphd

That's right, "(not)". So it wasn't "symmetrical". This just leaves science to explain that asymmetry and its very reasonable to assume its just a matter of time before it does.
Just because science doesn't currently have the answer to something doesn't mean it never would. New scientific discoveries are regularly made with one mystery after another being solved.
It used to be a mystery what causes rainbows and lighting etc. Some people just said a stupid "Goddidit", which explains nothing. Real explinations require more than that; Real explinations require real evidence and/or real thinking. I see no reason why the asymmetry problem should be treated any different.
See

https://en.wikipe...symmetry

Aug 15, 2018
What if there never was a "Big Bang", after all how is it possible to get something (and everything) from nothing (a singularity)?

If there never was a "Big Bang" with its associated other impossibility, the cosmic inflation, - which defies natural physics in that it started all by itself, accelerated to super-luminal speeds and then inexplicably stopped all by itself - then where does that leave this little bit of research.

Aug 15, 2018
This comment has been removed by a moderator.

Aug 15, 2018
This comment has been removed by a moderator.

Aug 15, 2018
What if there never was a "Big Bang", after all how is it possible to get something (and everything) from nothing (a singularity)?
FredJose

Nobody who understands the theory could correctly claim that the big bang theory says something LITERALLY came from nothing. You obviously don't understand the theories.

If time had a beginning then the singularity didn't 'come' because there was no 'before' from which it could have 'come' in which case its truth should be treated a bit like the truth of a timeless and causeless mathematical constant. What 'caused' Pi? Where did Pi originally 'come' from? How did Pi 'get started'?

If time had NO beginning then either the singularity was there for an eternity (one theory but one generally thought unlikely) or it came from something (various theories on what it came from. Examples on request).

Aug 15, 2018
This comment has been removed by a moderator.

Aug 16, 2018
evidence of SPIRAL's 'Cosmological blue-shift offset' hypothesis perhaps?
where the shorter wavelength, higher frequency would be more Opaque on the near side of galaxies at least 5778 LY year to date. (Thus the blue-stars on near side spiral galactic arms starting x LY and up to y LY from us..

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more