We're not alone—but the universe may be less crowded than we think

universe
This is the "South Pillar" region of the star-forming region called the Carina Nebula. Like cracking open a watermelon and finding its seeds, the infrared telescope "busted open" this murky cloud to reveal star embryos tucked inside finger-like pillars of thick dust. Credit: NASA

There may be far fewer galaxies further out in the universe than might be expected, according to a new study led by Michigan State University.

Over the years, the Hubble Space Telescope has allowed astronomers to look deep into the universe. The long view stirred theories of untold thousands of distant, faint . The new research, appearing in the current issue of the Astrophysical Journal Letters, however, offers a theory that reduces the estimated number of the most distant galaxies by 10 to 100 times.

"Our work suggests that there are far fewer faint galaxies than we once previously thought," said Brian O'Shea, MSU associate professor of physics and astronomy. "Earlier estimates placed the number of faint galaxies in the early universe to be hundreds or thousands of times larger than the few bright galaxies that we can actually see with the Hubble Space Telescope. We now think that number could be closer to ten times larger.

O'Shea and his team used the National Science Foundation's Blue Waters supercomputer to run simulations to examine the formation of galaxies in the early universe. The team simulated thousands of galaxies at a time, including the galaxies' interactions through gravity or radiation.

The simulated galaxies were consistent with observed distant galaxies at the bright end of the distribution - in other words, those that have been discovered and confirmed. The simulations didn't, however, reveal an exponentially growing number of faint galaxies, as has been previously predicted. The number of those at the lower end of the brightness distribution was flat rather than increasing sharply, O'Shea added.

These simulations will be tested further when the much-anticipated James Webb Space Telescope comes online in late 2018. The improved technology will afford astronomers even more-detailed views of space than the amazing images that the Hubble has produced in recent years.

The Hubble Space Telescope can see the tip of the iceberg of the most-distant galaxies, said Michael Norman, co-author of the paper and director of the San Diego Supercomputer Center at the University of California, San Diego.

While the James Webb telescope will improve views of distant galaxies, the telescope has a relatively small field of view. As a result, the observations must take into account cosmic variance - the statistical variation in the number of galaxies from place to place.

That's what makes these simulations pertinent even as improved technology becomes available, O'Shea said.

"A deeper understanding based on theory may be necessary to correctly interpret what's being seen, such as high redshift survey results," he said.


Explore further

Image: Hubble captures galaxy PGC 18431

Journal information: Astrophysical Journal Letters

Citation: We're not alone—but the universe may be less crowded than we think (2015, July 1) retrieved 22 July 2019 from https://phys.org/news/2015-07-alonebut-universe-crowded.html
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rgw
Jul 01, 2015
Instead of 100-200 Billion Galaxies, there are only 1-20 Billion. That makes the known Universe tiny.

Jul 01, 2015
rgw: Also that's only visible universe and most of it in the deep past. God only knows what's really there at this moment and also outside the visible universe. Most likely more of the same would be my guess.

Jul 01, 2015
I hear on the TV/Cable Space Shows that there are more planets and stars than grains of sand throughout the entire earth, so does this study debunk that theory? And, is the count of galaxies a fact from data or a theory?

Jul 01, 2015
The universe is infinite and eternal. It is like a living being whose constituents in any observable region are in a dynamic equilibrium of old matter going out of existence and new matter forming at the core of the galaxies as a quantum dynamical necessity (Bigbangcon) : http://phys.org/n...ure.html

Mathematics based official cosmology have no idea about and cannot comprehend the infinite. But it is possible to comprehend the infinite from a dialectical point of view as was done by philosophers starting from Epicurus to Hegel:
http://www.ptep-o...9-04.PDF

Jul 02, 2015
The simulations are based on WMAP cosmology, hence LCDM, hence linear structure formation. Utterly useless, as JWEB will show.

Jul 02, 2015
The universe is infinite and eternal

It's a bit difficult to accept this statement when we have definitely established that the second Law of Thermodynamics applies consistently wherever we've looked.

If the universe was eternal then by now the total useful energy would have already run out and none of us would be commenting on this site.

However, since the universe is still in such a highly organised state, plus there is red-shift observable in the cosmos, one has to conclude that at some point the universe had to have had a beginning. As to when it began, that is up for speculation.

Jul 02, 2015
The simulations didn't, however, reveal an exponentially growing number of faint galaxies, as has been previously predicted.

We shouldn't lose sight of the importance of this statement. What this means is that according to the BB theory scientists expected to find a huge number of faint and YOUNG proto-galaxies at the uttermost limit of observation. This expectation arises because it is assumed that we are looking back in time to the beginning of the universe.
Now, in reality the actual observations show that lo and behold, there are actually mostly bright, MATURE looking galaxies at those positions, not the faint young ones they expected. This in total contradiction of the BB theory, i.e. it is another case where actual observations falsifies the BB Theory.
Finding fully matured galaxies at that distance implies that some assumptions might need to change in the BB theory.
Either galaxies get created very fast OR those galaxies were created with ours OR both!

Jul 02, 2015
@ DavidTheShephard:

Thermodynamics is not valid at quantum level, in fact it breaks down for the quantum vacuum. From Paul Dirac on, we know that the quantum vacuum is teeming with "virtual particles" pairs of matter and antimatter that pop in and instantly goes out of existence. Under certain circumstances (as discussed in the references above and the one cited below) they can turn into "real particles"; breaking the laws of thermodynamics. The "virtual particles" have been verified at quantum level as the Lamb Shift with an accuracy of 1 part to a million. At macroscopic scale they show their effect as Casimir force.
http://www.ptep-o...9-03.PDF

From the point of view of quantum electrodynamics (QED) and dialectics; an infinite and eternal universe is not only possible but is a logical necessity. From the point of view of causality of course this is impossible; because you need a "first cause" - the "effect" of a "cause" that is a mystery.

Jul 02, 2015
Tendentious headline, agreed, the number of stars is still huge. While structure formation isn't well understood (though now the CDM models that include supernova action makes the best predictions for galaxies as well), it is the best future cosmological tool we will have. [Planck Archive.] The microwave background gives "only" a few hundred thermal angular peaks, the SF promises to give 1000s IIRC.

Jul 02, 2015
@rgw: Was that a joke? The size of the universe remains the same.

@NR: "God". Prove it!

While magic can't tell you anything, standard cosmology will. Inflation gave us a universe that is homogeneous and isotropic, so on average it is the same everywhere as here at the same age and so on when we go back in time.

Planck's latest data release also tell us that the universe is at least 10 000 000 [!] times larger than the observable universe.

Those are established facts.

Unfortunately the other subjects of comments are crackpot physics, so there isn't much to add besides that Wikipedia on cosmology and thermodynamics reject these comments out of hand, the usual boring not-even-basic-physics-right level of crackpotism. (Big bang and quantum physics has no problem with thermodynamics; causality isn't philosophic "cause" but relativity. (And hence processes can be eternal - if inflation is backwards eternal is unknown.))

rgw
Jul 04, 2015
@Torbjorn_Larsson:
Of course it was a joke! When and if humans understand the Universe, we will be building our own as research projects. Size on the scale of near (or actual?!) infinity has to be humorous. Otherwise the only alternative is to quail at our unimaginable insignificance and curl, gibbering into a fetal ball.

Jul 05, 2015
Instead of 100-200 Billion Galaxies, there are only 1-20 Billion. That makes the known Universe tiny.


I believe it refers only to the fringes not the entire observable universe and then again only to what they estimate to be there via calculation. It does make the universe smaller yes.

I hear on the TV/Cable Space Shows that there are more planets and stars than grains of sand throughout the entire earth, so does this study debunk that theory? And, is the count of galaxies a fact from data or a theory?


The numbers of stars are still so high that the would still outnumber the grains of sand on Earth.

Jul 05, 2015
@rgw: Was that a joke? The size of the universe remains the same.

@NR: "God". Prove it!

While magic can't tell you anything, standard cosmology will. Inflation gave us a universe that is homogeneous and isotropic, so on average it is the same everywhere as here at the same age and so on when we go back in time.

Planck's latest data release also tell us that the universe is at least 10 000 000 [!] times larger than the observable universe.

Those are established facts.

Ummmmm... where? Which data set? And how?

Commentator expects angry assertion to counter another assertion because it has more anger. Sin.

I watched too much cinemasins yesterday.

Jul 05, 2015
The universe is infinite and eternal.


The Universe is not infinite and eternal, because the known laws of the universe "post-dict" that it has a finite beginning.

I will agree with you that "something" is eternal, but this continuum we call "the universe" is not eternal. It has a finite beginning and it will have a finite end.

The Set Theory argument proves through purely secular logic and math that there is at least one eternal, creative, uncaused entity, and that entity is not the universe we reside in, because the universe we reside in has finite past and finite laws.

Nothing{P} is an invalid statement.
Nothing{} is an empty set, and has no creative potential.

"P" must be eternal, else nothing could ever have existed, and "P" could not have been created by "Nothing{}" because Nothing doesn't have any potential or properties.

Therefore "P", which created everything else, is an eternal entity, but the universe is definitely not eternal.

Jul 05, 2015

The Set Theory argument proves through purely secular logic and math that there is at least one eternal, creative, uncaused entity, and that entity is not the universe we reside in, because the universe we reside in has finite past and finite laws.


The logic may be sound, but assessing its validity is another matter entirely. Determining that you've accurately identified the correct givens to work from is not straightforward or simple at all, especially in a cosmological context! And if the givens are inaccurate, the conclusions will be invalid too, however sound the logic that relies on them may be.

Jul 05, 2015
This in total contradiction of the BB theory, i.e. it is another case where actual observations falsifies the BB Theory.


You may want to hold off on popping that cork until better data from JWST starts coming in.

Jul 06, 2015
Is the author claiming that LCDM can be ruled out? I don't believe so. Trillions of excuses can be popped up. But if one wants to open the eyes, see the tension with LCDM between the number of predicted clusters and the number of observed clusters in the Subaru post http://phys.org/n...ory.html

Jul 06, 2015
@ Returners:

Geometry and mathematics start with presuppositions and although consistent within their own domain, are mere tautologies - the conclusion is contained and limited by the premise! Also, these become meaningless in the context of the infinite.

Einstein assumed (by his own admission) a finite universe in formulating GR, because his field equations has no meaning in an infinite setting and also his cosmology based on Mach's principle collapses in an infinite universe. If Mach's principle is followed, then an infinite universe means that the inertia and the mass of atoms etc. also become infinite.

Following causality and geometry based GR, modern cosmology is in a fix and is bound by the finite. Only a dialectical approach can help us move forward both in the realm of cosmology and quantum dynamics. Please see:
http://www.ptep-o...9-04.PDF

http://www.amazon...40414445


Jul 06, 2015
The universe is infinite and eternal. It is like a living being whose constituents in any observable region are in a dynamic equilibrium of old matter going out of existence and new matter forming at the core of the galaxies as a quantum dynamical necessity (Bigbangcon) : http://phys.org/n...ure.html


How much for a kilogram of this stuff?
Meet me in Amsterdam and if the price is right we can make serious business.

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