Cosmic expansion calculations may be wrong - Max Planck Institute for Astronomy

[Matteo]

Astronomers led by Maria Bergemann (Max-Planck-Institute for Astronomy) have performed chemical measurements on stars that could markedly change the way cosmologists measure the Hubble constant and determine the amount of so-called dark energy in our universe. Using improved models of how the presence of chemical elements affects a star’s spectrum, the researchers found that so-called supernovae Type Ia have different properties than previously thought. Based on assumption about their brightness, cosmologists have used those supernovae to measure the expansion history of the universe. In light of the new results, it is now likely those assumptions will need to be revised.

A puzzle piece from stellar chemistry could change our measurements of cosmic expansion

www.mpia.de

And the original article: https://www.mpg.de/14550374/original_article.pdf

 

[Brian G Turner]

The assumptions behind "Dark Energy" look increasingly flimsy:

Dark Energy proven not to exist?

I've always though the original observations claiming the existing of Dark Energy were deeply flawed and rested on false assumptions. Latest research suggests this is exactly the case: https://phys.org/news/2020-01-evidence-key-assumption-discovery-dark.html Simply put, the original science...

www.sffchronicles.com

 

[Foxbat]

So, is it the case that the speed of expansion of the universe has been based on flawed data given that the supernovae redshift appear to have been measured incorrectly? Or have I missed something?

 

[Brian G Turner]

So, is it the case that the speed of expansion of the universe has been based on flawed data given that the supernovae redshift appear to have been measured incorrectly? Or have I missed something?

Basically:

Original experiment: A certain type of supernova is always the same brightness, but we observed some that were dimmer than expected - therefore we must invent the concept of Dark Energy pushing the universe apart.
Recent studies: Um, no, this type of supernova is not always the same brightness.

 

[Foxbat]

It seems that it doesn’t discount or discredit the theory of dark energy, only the way we use assumptions in brightness measurement.

My interpretation: we don’t know how it works but we do know that this current method is not the right way to measure it.

One step forward, one step back.

 

[tegeus-Cromis]

As I've said more than once, we are only, at best, 0.1% closer to understanding the universe than Thales and Anaximander were 2500+ years ago.

 

[hitmouse]

As I've said more than once, we are only, at best, 0.1% closer to understanding the universe than Thales and Anaximander were 2500+ years ago.

Nonsense. Our understanding is far from complete, but it immeasurably better and more rigorous than the superficial explanations proposed by the pre-Socratics.

 

[tegeus-Cromis]

Nonsense. Our understanding is far from complete, but it immeasurably better and more rigorous than the superficial explanations proposed by the pre-Socratics.

Because our explanations are so much less superficial? Yes, I took into account all the progress since. Hence the (quite optimistic, I should add) 0.1% estimate. This is not to say that a lot hasn't been learned, but that what is not known is still huge. Do we know anymore than them whether the universe is finite or infinite? We know (presumably) the mechanism of the big bang, but do we know what caused it -- if anything? Do we know whether there was anything before it or not? Etc etc. On all the fundamental questions we are as clueless as they were.

 

[Foxbat]

We may well find that if somebody can find a way to compensate for the light variance and the calculations are redone that the universe is still expanding faster than it should relative to its mass. I hope that this is the case because a finite universe scares me more (for some strange reason) than my own finite life.

 

[tegeus-Cromis]

We may well find that if somebody can find a way to compensate for the light variance and the calculations are redone that the universe is still expanding faster than it should relative to its mass. I hope that this is the case because a finite universe scares me more (for some strange reason) than my own finite life.

But a finite universe can still be expanding faster than it should. As a matter of fact, inflation models usually apply to a finite universe.

Philosophically, if the universe is finite, we are each a minuscule portion of it. If it is infinite, we are literally nothing by comparison. I'd rather be something.

 

[Robert Zwilling]

I think for the amount of stuff we can now see, sense and detect, that we are not much farther along, percentage wise, about understanding what is going on in the star crossed heavens.

 

[hitmouse]

Because our explanations are so much less superficial? Yes, I took into account all the progress since. Hence the (quite optimistic, I should add) 0.1% estimate. This is not to say that a lot hasn't been learned, but that what is not known is still huge. Do we know anymore than them whether the universe is finite or infinite? We know (presumably) the mechanism of the big bang, but do we know what caused it -- if anything? Do we know whether there was anything before it or not? Etc etc. On all the fundamental questions we are as clueless as they were.

The key difference is that we have scientific method. Hypotheses and theories which are potentially disprovable through observation and experiment, and subject to peer review. We accept that what we know is not concrete fact, but the best explanation going, and this may be disputed, modified, or change as new knowledge comes along. There is not a finite amount of knowledge in, or about the universe. The more one looks, the more things there are to question and explain. There have been philosophical questions about the nature of reality, the elements, and the cosmos, since ancient times. These have become nuanced and far more complex, and have moved from pure philosophy into the realm of science, with significant advances. What we do have are many big and interesting questions, which have arisen as a result of science, which the pre-Socratics did not dream of, and indeed what pre-20th century phsicists did not really consider.

We do have (for example):
Mathematics
Newtonian mechanics, thermodynamics
Modern physics, including: general and special relativity, quantum physics and lots of good astrophysics and observational astronomy.
Quite a good understanding of how stars work, physical geography, chemistry

 

[tegeus-Cromis]

The key difference is that we have scientific method. Hypotheses and theories which are potentially disprovable through observation and experiment, and subject to peer review. We accept that what we know is not concrete fact, but the best explanation going, and this may be disputed, modified, or change as new knowledge comes along. There is not a finite amount of knowledge in, or about the universe. The more one looks, the more things there are to question and explain. There have been philosophical questions about the nature of reality, the elements, and the cosmos, since ancient times. These have become nuanced and far more complex, and have moved from pure philosophy into the realm of science, with significant advances. What we do have are many big and interesting questions, which have arisen as a result of science, which the pre-Socratics did not dream of, and indeed what pre-20th century phsicists did not really consider.

We do have (for example):
Mathematics
Newtonian mechanics, thermodynamics
Modern physics, including: general and special relativity, quantum physics and lots of good astrophysics and observational astronomy.
Quite a good understanding of how stars work, physical geography, chemistry

Precisely what I said. 0.1%. I'm glad that we agree.

 

[Ray Zdybrow]

Because our explanations are so much less superficial? Yes, I took into account all the progress since. Hence the (quite optimistic, I should add) 0.1% estimate. This is not to say that a lot hasn't been learned, but that what is not known is still huge. Do we know anymore than them whether the universe is finite or infinite? We know (presumably) the mechanism of the big bang, but do we know what ca3used it -- if anything? Do we know whether there was anything before it or not? Etc etc. On all the fundamental questions we are as clueless as they were.

We all hit the ground running, and hope that the people who came before us had a clue what was going on. To paraphrase Rumsfeld, we don't know what we don't know - 0.1% IS optimistic!

 

[mosaix]

By its very definition I would have thought it’s not possible to provide any information about something “we don’t know” - even how much there is of it.

 

[tegeus-Cromis]

By its very definition I would have thought it’s not possible to provide any information about something “we don’t know” - even how much there is of it.

That's true. And you don't know all the zeroes I deleted before I posted "0.1%." I was trying not to be too negative.

 

[mosaix]

That's true. And you don't know all the zeroes I deleted before I posted "0.1%." I was trying not to be too negative.

And I could be trying not to be too positive, tC, when I suggest the figure could be (* plucks random figure out of thin air *) 5.23%

We just don’t know.

 

[tegeus-Cromis]

You know the expression "figure of speech," right?

 

[mosaix]

There used to be a popular poster called Devil’s Advocate here on Chrons, tC, perhaps he should have posted my remarks?

 

[tegeus-Cromis]

There used to be a popular poster called Devil’s Advocate here on Chrons, tC, perhaps he should have posted my remarks?

Sadly, he was probably named after the Keanu Reeves movie.