Standard model of the universe withstands most precise test by Dark Energy Survey (Update)

August 3, 2017
Map of dark matter made from gravitational lensing measurements of 26 million galaxies in the Dark Energy Survey. Red regions have more dark matter than average, blue regions less dark matter. Credit: Chihway Chang/University of Chicago/DES collaboration

Astrophysicists have a fairly accurate understanding of how the universe ages: That's the conclusion of new results from the Dark Energy Survey (DES), a large international science collaboration, including researchers from the Department of Energy's SLAC National Accelerator Laboratory, that put models of cosmic structure formation and evolution to the most precise test yet.

The survey's researchers analyzed light from 26 million galaxies to study how structures in the universe have changed over the past 7 billion years - half the age of the universe. The data were taken with the DECam, a 570-megapixel camera attached to the 4-meter Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile.

Previously, the most precise test of cosmological models came from measurements with the European Space Agency's Planck satellite of what is known as the (CMB) - a faint glow in the sky emitted 380,000 years after the Big Bang.

"While Planck looked at the structure of the very early universe, DES has measured structures that evolved much later," said Daniel Gruen, a NASA Einstein postdoctoral fellow at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of Stanford University and SLAC. "The growth of these structures from the early ages of the universe until today agrees with what our models predict, showing that we can describe cosmic evolution very well."

Gruen will present the results, which are based on the first year of data from the 5-year-long survey, today at the 2017 Division of Particles and Fields meeting of the American Physical Society at the DOE's Fermi National Accelerator Laboratory.

KIPAC faculty member Risa Wechsler, a founding member of DES, said, "For the first time, the precision of key cosmological parameters coming out of a galaxy survey is comparable to the ones derived from measurements of the cosmic microwave background. This allows us to test our models independently and combine both approaches to obtain parameter values with unprecedented precision."

Images taken by the DES Collaboration with the DECam mounted on the Blanco Telescope. Credit: DES Collaboration

Largest Map of Mass Distribution

The standard model of cosmology, called Lambda-CDM, includes two key ingredients. Cold dark matter (CDM), an invisible form of matter that is five times more prevalent than regular matter, clumps together and is at the heart of the formation of structures such as galaxies and galaxy clusters. Lambda, the cosmological constant, describes the accelerated expansion of the universe, driven by an unknown force referred to as dark energy.

Astrophysicists need precise tests of the model because its ingredients are not completely certain. Dark matter has never been directly detected. Dark energy is even more mysterious, and it's not known whether it actually is a constant or changes over time.

DES has now succeeded in carrying out such a precision test. The scientists used the fact that images of faraway galaxies get slightly distorted by the gravity of galaxies in the foreground - an effect known as weak gravitational lensing. This analysis led to the largest map ever constructed for the distribution of mass - both regular and dark matter - in the universe, as well as its evolution over time.

"Within an error bar of less than 5 percent, the combined Planck and DES results are consistent with Lambda-CDM," Wechsler said. "This also means that, so far, we don't need anything but a constant form of to describe the expansion history of the universe."

Key Contributions from KIPAC

In addition to Gruen, who led the weak lensing working group, and Wechsler, whose group provided realistic simulations of the survey critical to testing several aspects of the cosmological analysis, a large number of KIPAC scientists, postdoctoral fellows, graduate students and alumni have made crucial contributions to DES - from building the instrument to developing theory and simulations and analyzing the data.

Blanco Telescope dome and Milky Way. Credit: Reidar Hahn/Fermi National Accelerator Laboratory

Postdoctoral fellow Elisabeth Krause, for example, leads the DES theory and combined probes working group. In that role, she led the charge in developing theoretical models that match the experimental precision obtained with the DES data. This involved writing computer codes that calculate what weak gravitational lensing should look like for a given model.

"Different people develop slightly different codes that are meant to do the same thing," she said. "I helped bring code developers together to cross-check their results and to make sure that we get the most precise theory codes possible."

Another key to the creation of the mass distribution map was to accurately determine the distances to the observed galaxies - information that is usually derived from independent surveys that analyze the properties of light coming from those objects or from exploding stars.

"We've shown that we can use the color of certain red galaxies - red is the color they would have if you were right in front of them - to determine how far they are away," said SLAC staff scientist Eli Rykoff, who had a leading role in this part of the analysis. "It turns out that if we map where these red galaxies are in the sky, we can use them to calibrate the distances of the lenses and background galaxies used in the study."

This image of the NGC 1398 galaxy was taken with the Dark Energy Camera. This galaxy lives in the Fornax cluster, roughly 65 million light-years from Earth. It is 135,000 light-years in diameter, just slightly larger than our own Milky Way galaxy, and contains more than a billion stars. Credit: Dark Energy Survey

Toward Even Deeper Cosmic Insights

In the near future, more DES data will allow astrophysicists to test their with even more precision. The analysis of data collected during the first three years of the survey will begin soon, and the fifth year of observations will also soon be underway.

With even better data, the researchers said, we might find out if the relatively simple Lambda-CDM model needs to be modified.

"The methods developed for DES and the experience its researchers are gaining along the way will also benefit the natural flow of ever-evolving experiments," said KIPAC faculty member David Burke, head of SLAC's DES group.

Both will prepare scientists for future surveys, including ones with the Large Synoptic Survey Telescope (LSST). With its 3.2-gigapixel camera, which is under construction at SLAC, astrophysicists will be able to explore the depths of our universe like never before.

Explore further: Dark Energy Survey reveals most accurate measurement of dark matter structure in the universe

More information: www.darkenergysurvey.org/des-y … ology-results-papers

Related Stories

Mapping dark matter

July 24, 2017

About eighty-five percent of the matter in the universe is in the form of dark matter, whose nature remains a mystery. The rest of the matter in the universe is of the kind found in atoms. Astronomers studying the evolution ...

A unique data center for cosmological simulations

June 20, 2017

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have established 'Cosmowebportal', a unique data center for cosmological simulations located at the Leibniz Supercomputing Centre ...

Recommended for you

Star mergers: A new test of gravity, dark energy theories

December 18, 2017

When scientists recorded a rippling in space-time, followed within two seconds by an associated burst of light observed by dozens of telescopes around the globe, they had witnessed, for the first time, the explosive collision ...

Single-photon detector can count to four

December 15, 2017

Engineers have shown that a widely used method of detecting single photons can also count the presence of at least four photons at a time. The researchers say this discovery will unlock new capabilities in physics labs working ...

35 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Hyperfuzzy
1.7 / 5 (6) Aug 03, 2017
If we only see the wrinkles in the field, i.e. light, we miss the field. Maybe our approximations are wrong.
Zzzzzzzz
4.2 / 5 (10) Aug 03, 2017
The ground the anti dark matter/energy crowd occupies gets smaller still......
bschott
1 / 5 (5) Aug 03, 2017
The ground the anti dark matter/energy crowd occupies gets smaller still......

LMAO...still plenty of room to house the survivors of the sinking ship powered by dark forces...
Da Schneib
4.6 / 5 (9) Aug 03, 2017
The key here is consilience. With the Planck CMB and DES telling us the same thing, we now can compare them and get a much clearer answer. ΛCDM fits both. Show me another theory that does.
RealityCheck
1.4 / 5 (11) Aug 03, 2017
@Zzzzzzzz, @Da Schneib (and IMP-9, RNP etc etc if reading this).
The ground the anti dark matter/energy crowd occupies gets smaller still......
Why keep making obviously incorrect statements like that, mate? More recent astronomical/cosmological discovery/reviews, finding humongous quantities of *ordinary* material which was previously undetected by older telescopes/surveys, has put paid to all the old/naive/simplistic assumptions/narratives and interpretations/estimates which were 'fitted' post hoc to now-falsified BB etc 'models'! How long will it take for you and the authors of the above paper/article to *catch up* and stop with the lame obsolete fantasy-fitting masquerading as 'science'. :)
The key here is consilience. With the Planck CMB and DES telling us the same thing, we now can compare them and get a much clearer answer. ΛCDM fits both. Show me another theory that does.
Planck/Bicep3 proved e-m signals from far distant sources UNRELIABLE. Rethinkit! :)
Da Schneib
4.5 / 5 (10) Aug 03, 2017
And up rolls @RC to lie again.

More recent
This is fresh news, being published this month. There isn't anything "more recent." You're lying again, @RC.

Planck/Bicep3
BICEP3 is not associated with Planck. You have not shown any evidence to support your claim that the Planck mission is unreliable, and your previous claim was not against BICEP3 but BICEP2. Finally, your previous claim against BICEP2 was flawed by a number of lies you told when presenting it, and has been rejected here definitively.

So that's three lies in one sentence.

You always lie, @RC. You lie in every post. Everyone can see it. You just lied again four times (and that's not an exhaustive list) in this post.
RealityCheck
1.4 / 5 (10) Aug 03, 2017
@Da Schneib.
More recent
This is fresh news, being published this month. There isn't anything "more recent." You're lying again, @RC
This is your problem, DS; you misunderstand/kneejerk to insults. The "more recent" remark went to ACTUAL NEW discovery/review of OLD claims/data/observations etc, re "DM". Whereas ABOVE 'news' is about YET ANOTHER flawed-BB-DM etc 'fitting' exercises (like Bicep2).
Planck/Bicep3
BICEP3 is not associated with Planck. You have not shown any evidence to support your claim that the Planck mission is unreliable, and your previous claim was not against BICEP3 but BICEP2. Finally, your previous claim against BICEP2 was flawed by a number of lies you told when presenting it, and has been rejected here definitively.
Again you misunderstand and kneejerk to YOUR reading confirmation biased 'strawman', DS. I allude to Planck/Bicep COLLABORATION/RESULTS (after Bicep2 episode). Get facts straight instead of kneejerking, DS. :)
Da Schneib
4.4 / 5 (7) Aug 03, 2017
I don't have a problem, @RC. You do. You lie. You lie in every post, and look here, you just told another one.
RealityCheck
1.4 / 5 (9) Aug 03, 2017
@Da Schneib.
I don't have a problem, @RC. You do. You lie. You lie in every post, and look here, you just told another one.
The above exchanges now make it abundantly clear to the @Forum that you can't get the facts straight even if you tried, DS; which is why you immediately default to "strawman and cry liar!" mode to distract from your woeful arrogance-in-ignorance way of 'discussing' based on bias and evasion of the actual points made/explained to you for your benefit/understanding DESPITE your inability to appreciate learning something you did not know despite you pretending to and calling me "liar" though I am correct all along (that old phrase, "pearls before swine", comes to mind). Listen, DS, mate, make a fresh start; admit to yourself at least that you have been wrong and me correct all along on many fronts. Then maybe you can heal what seems to ail you so profoundly that it leads you to denial, lying and insulting to beat the band! Get better soon, mate. :)
Da Schneib
4.6 / 5 (9) Aug 03, 2017
Bye now, @RC. I see no further point in engaging with you; you've proven that you'll shamelessly lie every time you post, and double down and deny it and keep on denying forever. There is no point to this.
RealityCheck
1.6 / 5 (7) Aug 03, 2017
@Da Schneib.
I see no further point in engaging with you; you've proven that you'll shamelessly lie every time you post, and double down and deny it and keep on denying forever. There is no point to this
You are only running away from yourself, here, DS. You're in denial. You misunderstand and lie and cry "liar" at the drop of a hat. You won't face reality that you are being a CS-gangmember troll rather than an objective discourser on the science issues. The @Forum can see where you misunderstood the Planck/Bicep allusion; and that you avoided the acknowledgement of that collaboration/results re e-m signal/info from far distant sources being UNRELIABLE....which makes the above article/paper 'exercise' yet another Bicep2-like FLAWED BB/DM etc 'model fitting exercise', for the reasons already stated. Why keep ignoring, denying, kneejerking, strawmanning, insulting, DS? Don't you ACTUALLY KNOW ANYTHING worth knowing, DS? Is 'parroting flawed orthodoxy' all you got? Bye.
Parsec
3 / 5 (2) Aug 04, 2017
The key here is consilience. With the Planck CMB and DES telling us the same thing, we now can compare them and get a much clearer answer. ΛCDM fits both. Show me another theory that does.


Every theory in existence requires at least 2 independently derived lines of collaborating evidence to attain a status of provisionally confirmed. That is one of the main complaints of string theory is that it is quite difficult to see how it can be experimentally tested at all. For example, climate change can show at least 8 different completely independent and confirmed lines of evidence.
Da Schneib
5 / 5 (5) Aug 04, 2017
Every theory in existence requires at least 2 independently derived lines of collaborating evidence to attain a status of provisionally confirmed.
Not so sure about that, @Parsec. Neutrinos, for example, were originally accepted as a theory with only one line. It had pretty high sigma though. And I'll also point out that the only evidence for the Higgs so far is the detectors at the LHC.
Shootist
1 / 5 (5) Aug 04, 2017
The key here is consilience. With the Planck CMB and DES telling us the same thing, we now can compare them and get a much clearer answer. ΛCDM fits both. Show me another theory that does.


Every theory in existence requires at least 2 independently derived lines of collaborating evidence to attain a status of provisionally confirmed. That is one of the main complaints of string theory is that it is quite difficult to see how it can be experimentally tested at all. For example, climate change can show at least 8 different completely independent and confirmed lines of evidence.


The climate changes. That's what chaotic systems do.
Dingbone
Aug 04, 2017
This comment has been removed by a moderator.
Dingbone
Aug 04, 2017
This comment has been removed by a moderator.
rrwillsj
1 / 5 (2) Aug 04, 2017
These comments have been the purrfecto example of "The Seven Blind Wisemen" Describing an elephant based on which part of the elephant each Wiseman touched.
Dingbone
Aug 06, 2017
This comment has been removed by a moderator.
Dingbone
Aug 06, 2017
This comment has been removed by a moderator.
rrwillsj
3 / 5 (2) Aug 07, 2017
Hey Db, I actually have an answer for your question, from Philosophy-R-Us. "If the Universe is expanding? Why aren't we also expanding?

Well, no and yes and definitely, maybe! (ain't philosophy a funny punny, honey?).

The expansion of Relativistic Space/Gravity/Time is a completely different fundamental phenomena from Quantum Mechanics. Which is the fundamental basis of Life.

Space/Gravity/Time, uni-directionally kinda drags us squirmy little macro-micros lifeforms along willy-nilly. A sort of after-thought too the Cosmos.

"Okay, you joker deities! Who forgot to sterilize the experiment this time?"

Hyperfuzzy
1 / 5 (2) Aug 08, 2017
Hey Db, I actually have an answer for your question, from Philosophy-R-Us. "If the Universe is expanding? Why aren't we also expanding?

Well, no and yes and definitely, maybe! (ain't philosophy a funny punny, honey?).

The expansion of Relativistic Space/Gravity/Time is a completely different fundamental phenomena from Quantum Mechanics. Which is the fundamental basis of Life.

Space/Gravity/Time, uni-directionally kinda drags us squirmy little macro-micros lifeforms along willy-nilly. A sort of after-thought too the Cosmos.

"Okay, you joker deities! Who forgot to sterilize the experiment this time?"


We have not begun to understand the universe. To busy QM ing nonsense. Telling the public theory as fact with no axiomatic structure. This diversion into fantasy belongs to the 20th century money grubbers. Expect without knowledge it will bury us.
Da Schneib
5 / 5 (4) Aug 08, 2017
@rrwillisj, an important fact you may wish to take note of.

Expansion is something that happens between galaxies sometimes, and galaxy clusters most of the time. It depends on the masses involved and it's not nearly as clearcut as the #physicscranks claim. If it were it wouldn't be a normal distribution.
torbjorn_b_g_larsson
5 / 5 (4) Aug 09, 2017
It is remarkable how well the new data resolves uncertainty (degeneracy) in the old data, cuts of the parameter space show rounded regions instead of stretched due to dependencies.

Besides the result of constant vacuum (dark) energy the constraint of flat space (large universe) is well tested.

Neat!
torbjorn_b_g_larsson
5 / 5 (4) Aug 09, 2017
@Zzzzzzzz, @Da Schneib (and IMP-9, RNP etc etc if reading this).
The ground the anti dark matter/energy crowd occupies gets smaller still......
Why keep making obviously incorrect statements like that, mate? More recent astronomical/cosmological discovery/reviews ...


Right back at you of course, the article describes standard and known as fairly accurate understanding - and it is getting better, this is a *new and more precise test*. So why are you commenting the trivial drivel you did?

By the way, too many obvious errors in your comments, but already the first that baryonic (standard) matter would somehow suffice to explain observations is trivially wrong. Even a layman can see that with *own eyes* in the Planck spectra peaks, if described what to look for.
torbjorn_b_g_larsson
5 / 5 (4) Aug 09, 2017
One of cosmology's most confusing questions: https://www.forbe...iverse/. Einstein himself opposed the notion of expanding space.


No, Einstein accepted expanding universe (certainly expanding space, since the possibility of expanding or collapsing space popos out of his general relativity theory) and kicked himself for not realizing the possibility. Similarly he got gravity waves incorrect at first, his initial result was wrong.

It was immediately known that expansion rate is far too weak to affect chemical bonds such as planets. Even gravity of galaxies suffice for local clumping, et cetera. *It is an inevitable part of the model described in the article*, see the clumping mirrored in local small density fluctuations. So not only understood for a century, also better confirmed with the new test.
torbjorn_b_g_larsson
5 / 5 (4) Aug 09, 2017
For example, climate change can show at least 8 different completely independent and confirmed lines of evidence.


The climate changes. That's what chaotic systems do.


How does that affect the described strong evidence in any way? And you are describing the weather, which is chaotic on small scales, not the climate that is currently in a negative feedback loop moderated by CO2 uptake from erosion when heated or less uptake when cooled.

The current climate regime has been fairly stable for 5 Myrs. modulated by Earth axis changes (which driving force is indeed chaotic over long periods >> 1 Myrs). But now it is known to be forced mainly by human CO2 release, and nothing chaotic about that signal by the way. You can now just do a correlation analysis on known factors, and timing gives you human CO2 release first, warming later. That is why roughly all nations has agreed to force the climate back by cutting down CO2. See basic climate science (say, in Wikipedia).
Hyperfuzzy
not rated yet Aug 09, 2017
OK, think people. Einstein, the Standard Model, Dark Matter, all are wrong. Please no comment with more of the same. I reject these. Show me your axiomatic definition of Charge. Don't quote Nobels, simply deny the 20th century bull $hit. Maxwell is correct without any doubt. Einstein's interpretation of Maxwell is without merit. The neutron is two "particles", a proton and an electron. By the way only charge exists, there is no definition for a particle other than a field event. Get Real!
rrwillsj
not rated yet Aug 11, 2017
Hf, I can think of a physical experiment that would prove or disprove or at least dismay your contention that an atom only contains protons and electrons.

Take an ordinary atom bomb. (Yeah, that one over there will do just fine.) Trigger it... Where did all those cascading neutrons come from?

Dance Shiva! Dance!
Hyperfuzzy
not rated yet Aug 11, 2017
Hf, I can think of a physical experiment that would prove or disprove or at least dismay your contention that an atom only contains protons and electrons.

Take an ordinary atom bomb. (Yeah, that one over there will do just fine.) Trigger it... Where did all those cascading neutrons come from?

Dance Shiva! Dance!

Sorry dude, you know nothing. That energy is exactly that, protons and electrons and neutrons(i.e. combo, doing it's thang! You cannot prove anything with nonsense or atom bombs. If that's your only defense, please shut up!
rrwillsj
not rated yet Aug 12, 2017
Hf, if you fear someone disagreeing with you? Never get married... Or teach a writing class to teenagers... Or try to convince your dog not to bark at squirrels.

I think it's childish behavior for so many commentators to this site to have tantrums over debatable concepts, for which there may never be definitive proof.

Do not be afraid to be wrong, make a mistake or accept correction. That's what separates Science from Theology!

Self-control is the key to expanding your self-awareness to including the rest of the world.
Hyperfuzzy
not rated yet Aug 12, 2017
Hf, if you fear someone disagreeing with you? Never get married... Or teach a writing class to teenagers... Or try to convince your dog not to bark at squirrels.

I think it's childish behavior for so many commentators to this site to have tantrums over debatable concepts, for which there may never be definitive proof.

Do not be afraid to be wrong, make a mistake or accept correction. That's what separates Science from Theology!

Self-control is the key to expanding your self-awareness to including the rest of the world.

Tell me Mr. Oh So Wise, what is charge?
RealityCheck
1 / 5 (2) Aug 13, 2017
@torbjorn_b_g_larsson.
So why are you commenting the trivial drivel ...
It sounds like 'drivel' only to those who haven't kept abreast of more recent important discoveries/reviews in their own field, mate (is it true you are an astrophysicists by profession, torbjorn?). :)
By the way, too many obvious errors in your comments, but already the first that baryonic (standard) matter would somehow suffice to explain observations is trivially wrong. Even a layman can see that with *own eyes* in the Planck spectra peaks, if described what to look for.
Your claim is based on OLD, NAIVE, UNDER-estimates NOW superseded/surpassed greatly by more recent discoveries of vast ORDINARY matter everywhere we look.

By now it should be obvious, to anyone NOT 'wedded' to old/naive orthodoxy/estimates/interpretations etc, that your response is based on old/superseded 'narratives' which you/many astrophysicists/theorists have YET to DISCARD/UPDATE, torbjorn. Catch up, mate! :)
Hyperfuzzy
not rated yet Aug 13, 2017
@torbjorn_b_g_larsson.
So why are you commenting the trivial drivel ...
It sounds like 'drivel' only

100 years of 'drivel', even Nobels!
rrwillsj
not rated yet Aug 14, 2017
"Tell me Mr. Oh So Wise, what is charge?" Hf

How my wife drove me into bankruptcy!

Truly, a recipe for humbleberry Pi.

That's how I got to be and knotted to be "Mr. Oh So Wise".
Hyperfuzzy
not rated yet Aug 27, 2017
Charge's field f(1/r^2) therefore from zero to infinity, charge is conserved; therefore, never created or destroyed. Think! You don't have to be smart; but, if a little stupid you won't understand!

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

Click here to reset your password.
Sign in to get notified via email when new comments are made.