Research reinforces role of supernovae in clocking the universe

January 4, 2017 by Greg Borzo
New research confirms the role Type Ia supernovae, like G299, play in measuring universe expansion. Credit: NASA

How much light does a supernova shed on the history of universe?

New research by cosmologists at the University of Chicago and Wayne State University confirms the accuracy of Type Ia in measuring the pace at which the universe expands. The findings support a widely held theory that the expansion of the universe is accelerating and such acceleration is attributable to a mysterious force known as dark energy. The findings counter recent headlines that Type Ia supernova cannot be relied upon to measure the expansion of the universe.

Using light from an exploding star as bright as entire galaxies to determine cosmic distances led to the 2011 Nobel Prize in physics. The method relies on the assumption that, like lightbulbs of a known wattage, all Type Ia supernovae are thought to have nearly the same maximum brightness when they explode. Such consistency allows them to be used as beacons to measure the heavens. The weaker the light, the farther away the star. But the method has been challenged in recent years because of findings the light given off by Type Ia supernovae appears more inconsistent than expected.

"The data that we examined are indeed holding up against these claims of the demise of Type Ia supernovae as a tool for measuring the universe," said Daniel Scolnic, a postdoctoral scholar at UChicago's Kavli Institute for Cosmological Physics and co-author of the new research published in Monthly Notices of the Royal Astronomical Society. "We should not be persuaded by these other claims just because they got a lot of attention, though it is important to continue to question and strengthen our fundamental assumptions."

One of the latest criticisms of Type Ia supernovae for measurement concluded the brightness of these supernovae seems to be in two different subclasses, which could lead to problems when trying to measure distances. In the new research led by David Cinabro, a professor at Wayne State, Scolnic, Rick Kessler, a senior researcher at the Kavli Institute, and others, they did not find evidence of two subclasses of Type Ia supernovae in data examined from the Sloan Digital Sky Survey Supernovae Search and Supernova Legacy Survey. The recent papers challenging the effectiveness of Type Ia supernovae for measurement used different data sets.

A secondary criticism has focused on the way Type Ia supernovae are analyzed. When scientists found that distant Type Ia supernovae were fainter than expected, they concluded the universe is expanding at an accelerating rate. That acceleration is explained through dark energy, which scientists estimate makes up 70 percent of the universe. The enigmatic force pulls matter apart, keeping gravity from slowing down the expansion of the universe.

Yet a substance that makes up 70 percent of the universe but remains unknown is frustrating to a number of cosmologists. The result was a reevaluation of the mathematical tools used to analyze supernovae that gained attention in 2015 by arguing that Type Ia supernovae don't even show dark energy exists in the first place.

Scolnic and colleague Adam Riess, who won the 2011 Nobel Prices for the discovery of the accelerating universe, wrote an article for Scientific American Oct. 26, 2016, refuting the claims. They showed that even if the mathematical tools to analyze Type Ia supernovae are used "incorrectly," there is still a 99.7 percent chance the is accelerating.

The new findings are reassuring for researchers who use Type Ia supernovae to gain an increasingly precise understanding of , said Joshua A. Frieman, senior staff member at the Fermi National Accelerator Laboratory who was not involved in the research.

"The impact of this work will be to strengthen our confidence in using Type Ia supernovae as cosmological probes," he said.

Explore further: Collaboration uncovers the origin of extraordinary supernovae

More information: David Cinabro et al. Search For Type Ia Supernova NUV-Optical Subclasses, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw3109

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julianpenrod
1 / 5 (3) Jan 04, 2017
But, again, the claim of the universe exp[anding is based on faulty "reasoning".
Perlmutter said they looked at a galaxy. They derived the Doppler shift in the light and, from that, calculated the speed the galaxy is moving away. Using the Hubble Constant, they then derived the distance as 5 billion light years. But, they claim the supernova !a they saw is dimmer than it should be, so the galaxy must be further away. So it must be moving faster. But the Doppler shift is still for a galaxy moving away at a modest speed! They're raying the galaxy is moving away faster than it is moving!
Note, if the universe began accelerating in the past, it would be accelerating now, so there couldn't be a Hubble Constant. Also, if the speed of expansion of the universe was increasing, there should be a "pile up" of numbers of observed galaxies at a certain velocity level as images of newer accelerated galaxies attain the speeds of older galaxies at their old speeds.
RNP
5 / 5 (7) Jan 04, 2017
@julianpenrod
You have missed the point. What Permutter et al. found was that, based on redshift AND THE ASSUMPTION THAT THE UNIVERSE IS NOT ACCELERATING, the galaxy would be at a distance of 5 billion light years. The fact that the SNae in the galaxy were dimmer than expected for this distance therefore suggests that the universe IS accelerating.

No such "pile up" of galaxies is predicted in an accelerating universe, so I do not know where you got that idea.

RealityCheck
1 / 5 (6) Jan 04, 2017
Hi RNP, julianpenrod, everyone. :)

Best wishes for safe, intellectually fruitful, New Year!

@RNP.

Mate, it is exactly this kind of hack 'science' and 'publications', employing/reinforcing naive/simplistic models/assumptions made moot by newer discovery/reviews of the actual cosmos, that the following PO article is addressing:

http://phys.org/n...lse.html

You perfectly demonstrate 'brainwashing' effect of repeated regurgitations of naive/simplistic interpretations/assumptions.

These hack 'researchers' doing exactly what Bicep2 'team' did: applying incorrect models etc to 'confirm' naive assumptions/models etc INPUTS!

They use GIGO to produce GIGO which bears NO relation to the reality being discovered NOW!

Light types/intensities 'seen' from supernovae increasingly found to be affected/determined by their ACTUAL LOCAL system content/dynamics AND local/intervening space materials/distributions etc)!

They have NO idea!

RETHINK. :)
jonesdave
4.5 / 5 (8) Jan 04, 2017
@julianpenrod
You have missed the point. What Permutter et al. found was that, based on redshift AND THE ASSUMPTION THAT THE UNIVERSE IS NOT ACCELERATING, the galaxy would be at a distance of 5 billion light years. The fact that the SNae in the galaxy were dimmer than expected for this distance therefore suggests that the universe IS accelerating.

No such "pile up" of galaxies is predicted in an accelerating universe, so I do not know where you got that idea.



Again, as I've said before, this requires the intellectually challenged to actually read the paper. And understand it. Never going to happen.
Da Schneib
5 / 5 (2) Jan 04, 2017
Bah, the second paragraph of the article claims that "...all Type Ia supernovae are thought to have nearly the same maximum brightness when they explode." This is incorrect. In fact, what they're all thought to have is nearly the same relation between brightness and the time it takes them to dim. This is called the "brightness curve."

Oh and BTW dark energy isn't a "substance." It's a characteristic of spacetime. See the Einstein Field Equations and the Theory of General Relativity.

However, this does not change the fact (which the article gets right) that the only "problem" with this was that there appeared to be two populations of Type 1as, with a slightly different relation between brightness and the curve. What has been done here is to show that in fact there are not two populations.

That wasn't what I expected, but it'll do.
Whydening Gyre
5 / 5 (4) Jan 05, 2017
Another double post caused by an edit. Bah, fix your system.

Quit clickin' on the "Quote" button...;-)
RNP
5 / 5 (7) Jan 05, 2017
@RealityCheck
@RNP.

Mate, it is exactly this kind of hack 'science' and 'publications', employing/reinforcing naive/simplistic models/assumptions made moot by newer discovery/reviews of the actual cosmos, that the following PO article is addressing:

http://phys.org/n...lse.html

You perfectly demonstrate 'brainwashing' effect of repeated regurgitations of naive/simplistic interpretations/assumptions.

These hack 'researchers' doing exactly what Bicep2 'team' did: applying incorrect models etc to 'confirm' naive assumptions/models etc INPUTS!...

They have NO idea!


You realize that these "hack researchers" won the Nobel Prize for these "naive/simplistic interpretations/assumptions."

The discovery was also completely new and unexpected. So, your reference to the publication bias article is completely irrelevant.

From your post, we can safely conclude that it is YOU who has no idea.
RealityCheck
1 / 5 (5) Jan 05, 2017
Hi RNP. :)

Assessing Nobel Prizes in Cosmology/Astronomical 'theoretical physics', depends on BB etc 'group-think' furphy 'reinforced' by 'passed peer review' WRONG/NAIVE assumption/interpretation/model etc; 'built-into' the 'professionliterature/peer review publication/awards system over many decades; treated as 'accepted' by 'peer reviewers' inculcated in the SAME BB 'group-think' furphy!

RNP, are you aware of recent bollocking Prof Paul Steinhardt gave his 'peers' regarding "Inflation" model?

It was treated as 'fact' for so many decades; prompting innumerable 'hack' papers/acceptances based on nothing but flawed beliefs/models etc having NO scientifically tenable evidence at any stage!

YET how long did "Inflation" last in the 'professional' BB literature/modeling assumptions/interpretations 'belief' system?!

TOO LONG, according to Steinhardt (and me)!

RNP et al, realize: MOST of what you 'believe' re BB, DM etc is based on NAIVE, SIMPLISTIC crap from the 60s! :)
RNP
4.4 / 5 (7) Jan 06, 2017
@RC
Assessing Nobel Prizes in Cosmology/Astronomical 'theoretical physics', depends on BB etc 'group-think' furphy 'reinforced' by 'passed peer review' WRONG/NAIVE assumption/interpretation/model etc; 'built-into' the 'professionliterature/peer review publication/awards system over many decades

Are you saying that you understand science better than the Nobel committee? I have seen NO evidence to support this. In fact, scientifically, you seem almost illiterate.

[inflation] was treated as 'fact' for so many decades

No it was not. It was, and is, a THEORY. N.B. In scientific discussions you are not allowed to alter history to suit your argument.

are you aware of recent bollocking Prof Paul Steinhardt gave his 'peers' regarding "Inflation" model?

AGAIN with the misrepresentation. I've seen the video. There was no "bollocking". Also, what do you say to those that have disagreed with Steinhardt's analysis? What are your thoughts about THEIR arguments?
RealityCheck
1 / 5 (5) Jan 06, 2017
Hi RNP. :)

Oh, come on, mate. Stop trying to deny what has been happening with all BB related assumptions/models/interpretations being treated as 'givens' when experiments/exercises are designed and papers written/published based on ongoing baseless pseudoscience/metaphysics crap which hack mathematicians and researchers keep exploiting in order to 'pass peer review' and enhance their citation/funding 'status' within the 'professional peer review/publishing' ratrace.

Prof Steinhardt's admission/bollocking to his professional peers said it all.

Similar situation has obtained for practically all cosmological/astronomical 'studies and claims' for DECADES now, despite increasing evidence that there was NO tenable supporting evidence for MOST of the 'peer reviewed/passed/awarded' claims/interpretations built into BB related literature/theory 'edifice'; which keeps ignoring the real objective discoveries/reviews since those 'early-days' naive/metaphysical BB 'furphies'. :)
Uncle Ira
4 / 5 (8) Jan 06, 2017
@ Really-Skippy. How you are Cher? I am good me, thanks for asking.

Steinhardt-Skippy told me in the nice email he answered me with that you are a crankpot, and not even a very good one too.

Oh yeah, I almost forget. It is bad enough that you come around disrespecting the humans and scientists, but this is a family oriented place so you got to lay off of the gratuitous "furphiesing".
Whydening Gyre
5 / 5 (7) Jan 06, 2017
@ Really-Skippy. How you are Cher? I am good me, thanks for asking.

Steinhardt-Skippy told me in the nice email he answered me with that you are a crankpot, and not even a very good one too.

Oh yeah, I almost forget. It is bad enough that you come around disrespecting the humans and scientists, but this is a family oriented place so you got to lay off of the gratuitous "furphiesing".

Hey Ira. Hope the New year is going well for you. What the heck is "furphiesing"...?
And I thought I'd point out - RC is still King of conjugizing with "/"...:-)
del2
5 / 5 (6) Jan 07, 2017
@Whydening Gyre: "A furphy is Australian slang for an erroneous or improbable story that is claimed to be factual." - Wikipedia. And @Ira, don't worry, mon cher, it's not obscene.
RNP
5 / 5 (6) Jan 07, 2017
@RealityCheck
Oh, come on, mate. Stop trying to deny what has been happening with all BB related assumptions/models/interpretations.....


There is nothing for me to deny because, as usual, your post provides no scientific justifications for any of its ridiculous claims. Nor does it contain suitable references supporting your position. Finally, and worst of all, when you HAVE referenced an external source, you have deliberately misrepresented it. These are not the actions of a scientific literate engaged in honest scientific discourse.

Until you mend your ways, your posts achieve nothing but you stroking your own ego.
RealityCheck
1 / 5 (3) Jan 07, 2017
Hi RNP. :)

Mate, you're in denial; looking for excuses to 'kill the messenger' to avoid shock to your ego that would ensue once you took off your biased denial//ego 'blinkers' to the unfolding reality being discovered/reviewed by mainstream itself: which is increasingly confirming me correct all along on many fronts.

The most recent example involves the plasmon/near-field 'common factor" in all results/dynamics involved in 'slit-experiment' setups.

I have been pointing out this real physical scientifically supportable physical fact which mainstream experimenters are NOW finally addressing, and finding I was correct all along! For relevant evidence/background on that issue, please see following two threads/discussions:

http://phys.org/n...ent.html

http://phys.org/n...lit.html

RNP et al, it's way past time for you to finally 'get it': RealityCheck was correct all along on the science. Catch up. :)

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