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Author Topic:   Astronomers See Evidence of Something Unexpected in the Universe
Tanypteryx
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Posts: 2578
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.9


(3)
Message 1 of 86 (828780)
02-23-2018 10:44 PM


Astronomers See Evidence of Something Unexpected in the Universe

It will be interesting to see what is discovered in the course of trying to understand why these results disagree.

quote:
The team’s new study extends the number of stars analyzed to distances up to 10 times farther into space than previous Hubble results.

quote:
But Riess’s value reinforces the disparity with the expected value derived from observations of the early universe’s expansion, 378,000 years after the big bang — the violent event that created the universe roughly 13.8 billion years ago. Those measurements were made by the European Space Agency’s Planck satellite, which maps the cosmic microwave background, a relic of the big bang. The difference between the two values is about 9 percent. The new Hubble measurements help reduce the chance that the discrepancy in the values is a coincidence to 1 in 5,000

quote:
Planck’s result predicted that the Hubble constant value should now be 67 kilometers per second per megaparsec (3.3 million light-years), and could be no higher than 69 kilometers per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it is moving 67 kilometers per second faster. But Riess’s team measured a value of 73 kilometers per second per megaparsec, indicating galaxies are moving at a faster rate than implied by observations of the early universe.

quote:
The Hubble data are so precise that astronomers cannot dismiss the gap between the two results as errors in any single measurement or method. “Both results have been tested multiple ways, so barring a series of unrelated mistakes,” Riess explained, “it is increasingly likely that this is not a bug but a feature of the universe.”

The disagreement in these results could possibly indicate an expected new (to us) property of the Universe.

I find this article interesting not just because it is reporting results that are exciting on their own, but because it is reporting the disparity in results and shows scientists trying understand what is happening rather than covering it up, an accusation aimed at science that has been seen being made by the anti-science conspiracy nutjobs.

Enjoy

Links and Information Forum please.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


Replies to this message:
 Message 3 by Phat, posted 02-24-2018 3:06 PM Tanypteryx has acknowledged this reply
 Message 4 by Percy, posted 02-24-2018 3:30 PM Tanypteryx has responded
 Message 7 by nwr, posted 02-26-2018 8:47 PM Tanypteryx has responded

  
Tanypteryx
Member
Posts: 2578
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.9


Message 5 of 86 (828819)
02-24-2018 5:47 PM
Reply to: Message 4 by Percy
02-24-2018 3:30 PM


First there was the static universe, then an expanding universe slowing due to gravity, then an accelerating expansion, and now possibly a time-variable accelerating expansion?

It is good to know that cosmology, astrophysics and particle physics are not finished. Still lots of questions to answer.

Did you notice that the chart shows a significant increase in the distances that can be measured using parallax?

There were two independent research efforts based on different principles that established the accelerating expansion.

Ok, I guess I thought it was two teams, but both looking at Type 1a supernovae at increasing distances from us. What were the different principles?

I'd like to see something similar for this time-variable finding.

There is a team looking at cosmic microwave background and a team looking at supernovae and cepheid variables.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


This message is a reply to:
 Message 4 by Percy, posted 02-24-2018 3:30 PM Percy has responded

Replies to this message:
 Message 6 by Percy, posted 02-25-2018 7:19 PM Tanypteryx has acknowledged this reply

  
Tanypteryx
Member
Posts: 2578
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.9


Message 8 of 86 (828910)
02-26-2018 9:53 PM
Reply to: Message 7 by nwr
02-26-2018 8:47 PM


Some folk will remember that I have expressed some doubts about big bang cosmology

I had forgotten that. I guess I accepted the expansion and red shift as a consequence of that, but it always felt that there was more involved than we had figured out yet. This is from a layman who loves reading and studying and thinking about this stuff, but without a deep understanding of it. If red shift can't work as a standard candle for distance and time measurement it would be disappointing, mostly because we might not ever discover a new technique for those parameter measurements.

If we are mistaken about the Big Bang and red shift will it make a difference or limit the chances of future discoveries? Will we be able to figure out that we are wrong and that we are stuck in an illusion?

When I first started hearing about Dark Matter I wondered if it would turn out to be the gravitational effect of particles that are not in this universe at all, but the effect of mass or gravitation leaked from a "parallel" universe or "hidden" dimension.

To say all of this differently, it may well turn out that what know about the nature of the cosmos is miniscule in comparison to what we do not know about the nature of the cosmos.

I suspect all physicists would agree, but I could be wrong. I love what we do know and that we are continuing to strive to learn more about the cosmos and that I have lived to see so much. It's a great time to be alive. I can't wait to see what we find with the Webb.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


This message is a reply to:
 Message 7 by nwr, posted 02-26-2018 8:47 PM nwr has responded

Replies to this message:
 Message 9 by nwr, posted 02-26-2018 10:26 PM Tanypteryx has acknowledged this reply

  
Tanypteryx
Member
Posts: 2578
From: Oregon, USA
Joined: 08-27-2006
Member Rating: 5.9


Message 17 of 86 (829048)
03-01-2018 2:16 PM


Strongly Lensed Type Ia Supernovae
Can strongly lensed type Ia supernovae resolve one of cosmology's biggest controversies?

quote:
In 1929 Edwin Hubble surprised many people – including Albert Einstein – when he showed that the universe is expanding. Another bombshell came in 1998 when two teams of astronomers proved that cosmic expansion is actually speeding up due to a mysterious property of space called dark energy. This discovery provided the first evidence of what is now the reigning model of the universe: "Lambda-CDM," which says that the cosmos is approximately 70 percent dark energy, 25 percent dark matter and 5 percent "normal" matter (everything we've ever observed).

quote:
Until 2016, Lambda-CDM agreed beautifully with decades of cosmological data. Then a research team used the Hubble Space Telescope to make an extremely precise measurement of the local cosmic expansion rate. The result was another surprise: the researchers found that the universe was expanding a little faster than Lambda-CDM and the Cosmic Microwave Background (CMB), relic radiation from the Big Bang, predicted. So it seems something's amiss – could this discrepancy be a systematic error, or possibly new physics?

quote:
The farther away an object is in space, the longer its light takes to reach Earth. So the farther out we look, the further back in time we see. For decades, Type Ia supernovae have been exceptional distance markers because they are extraordinarily bright and similar in brightness no matter where they sit in the cosmos. By looking at these objects, scientists discovered that dark energy is propelling cosmic expansion.

But last year an international team of researchers found an even more reliable distance marker – the first-ever strongly lensed Type Ia supernova. These events occur when the gravitational field of a massive object – like a galaxy – bends and refocuses passing light from a Type Ia event behind it. This "gravitational lensing" causes the supernova's light to appear brighter and sometimes in multiple locations, if the light rays travel different paths around the massive object.

Because different routes around the massive object are longer than others, light from different images of the same Type Ia event will arrive at different times. By tracking time-delay between the strongly lensed images, astrophysicists believe they can get a very precise measurement of the cosmic expansion rate.


The solution to the disparity in the results of the rate of cosmic expansion found using CMB and Type 1a Supernovae, may be comparison of several strongly gravitational lensed images of the same supernovae. Only two of these supernovae have been discovered so far and they are much rarer than usual type 1a supernovae. Another new tool to help us understand the Universe.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


  
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