Astronomers See Evidence of Something Unexpected in the Universe

Astronomers See Evidence of Something Unexpected in the UniverseIt will be interesting to see what is discovered in the course of trying to understand why these results disagree.

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

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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

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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.

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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.

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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.EnjoyLinks and Information Forum please.

Thread copied here from the Astronomers See Evidence of Something Unexpected in the Universe thread in the Proposed New Topics forum.

One of these days they will discover an unexpected BIG eyeball staring right back at them! Seriously though, its always exciting to progress our understanding (and lack thereof) Godidit is boring. (Though he may well have done it!

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?There were two independent research efforts based on different principles that established the accelerating expansion. I'd like to see something similar for this time-variable finding.--Percy

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

That was a long time ago now, I don't recall the details, so I went to Wikipedia and it makes it seem like the two efforts used the same techniques. They both observed Type 1a supernova, but not in the same way. High-Z Supernova Search Team, Supernova Cosmology Project gives some details:

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The High-Z team observed a large area near the celestial equator so they could observe both hemispheres for follow-up details. They aimed for a limiting magnitude (the faintest magnitude visible from Earth) that is slightly fainter than the expected maximum brightness (Schmidt, Suntzeff, et al).

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The Supernova Cosmology Project Team calibrated the maximum magnitudes of supernovae to use as standard candles in their redshift measurements. They observed seemingly empty sky until they found a dozen or so supernovae. This method increases the chances of finding the supernovae before max magnitude, so they could easily measure the max (Perlmutter).

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Supernovae, an accelerating universe and the cosmological constant also characterizes some of the differences:

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Meanwhile, the Supernova Cosmology Project (SCP) continued to search for high redshift supernovae. By 1997, the SCP had a preliminary result (14). Based on seven supernovae discovered in 1994 and 1995, the Caln/Tololo low redshift sample, and a variant of the luminosity-light curve relation, they concluded that the evidence favored a high matter density universe, Ωm = 0.88 0.6. They argued that the supernova data at that point placed the strongest constraint on the possible value of the cosmological constant, with their best estimate being ΩΛ = 0.05.

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Another group, the High-Z Supernova Team (of which I am a member) introduced a number of new developments, including custom filters, which help minimize the effect of redshift on interpreting the observed fluxes, and ways to use observations in two colors to estimate the absorbing effects of interstellar dust on the supernova light by measuring the reddening it produces. The High-Z team found its first supernova, SN 1995K, in 1995 (15) and now has detected more than 70 events. Fig. ​Fig.22 illustrates some of the high redshift supernovae discovered by the High-Z Team that have been observed with the Hubble Space Telescope (HST). The supernovae are, in general, found and studied from ground-based observatories, but the HST provides much better separation of the supernova from the background galaxy, which leads to more precise measurements of the supernova’s light curve.

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This refresher doesn't really sound familiar. What I recall from when I read the Scientific American article from 20 years ago (they don't make the archives available for free and I'm a cheapskate) is how greatly the different techniques employed by the two teams increased our confidence in the results, and it described the key differences.
What I quoted above doesn't seem to do that. You can tell they took different approaches, but not what it was about those differences that contributed to the confidence in the results.--Percy

This is interesting, but not unexpected.I should clarify that. I am not say that I expected what they are seeing. Rather, I am say that I expected that evidence would show up suggesting something unexpected.Some folk will remember that I have expressed some doubts about big bang cosmology. Percy didn't like that, as I recall.I have agreed all along that there is cosmological red shift. I have questioned the big bang view, that cosmological red shift is due to expansion. I think it more likely that cosmological red shift is cosmological. That is to say, the red shift we see has to do with the nature of the cosmos, and is not simply a matter of expansion.Talk of "the expanding universe" implicitly assumes that there is a yardstick (for measuring distance) which can be used throughout the cosmos and for all time. I cannot see any reason to believe that. We use a local yardstick defined in terms of local features. And it may well be that every location can have a local yardstick. But I cannot see any certainty that we can put these together to have a cosmos-wide yardstick. It might be that there are local distance functions at every location, but no single distance function that can be used across the entire cosmos. And there could be similar issues with the measurement of time and with the measurement of other physical properties.It is standard physics, that entropy is increasing. We hear of the heat death of the universe. But maybe entropy is not increasing. If we fix our yardsticks (and other measuring standards) for today, and project, we see reasons to believe entropy is increasing. But if we could time-travel to 1000 years into the future, we might find that the yardstick has also changed over that time, and that the total amount of entropy as measured by the new measuring standards of 1000 years in the future is the same as the total amount of entropy as measured by our own standards at this time. That is to say, maybe entropy can only be a localized property localized to a time and place, and maybe there isn't any single standard for entropy that can be extended throughout the cosmos.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 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. 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.

We are mainly restricted by the limits of our access.Our main mistake is in our understanding of "objective". People take it for granted that there is an objective human-independent world. But everything that we know about is a projection from our subjective experience. What we call "objective" is really those aspects of subjective experience that humans can share with one another. And we project that to what we take to be a human independent cosmos. But perhaps it is not nearly as human independent as we like to think that it is.

I don't recall this now, but I hope my focus was on the lack of anomalous evidence pointing in the direction of your doubts, which seem based more on the general kind of concerns that can be raised about any field of science, i.e., a) the limitations of human knowledge; and b) knowledge is revised over time as we learn more.--Percy

The yardstick is the speed of light, spectra, and type Ia supernovae. To use another example, we measure the distance to the Moon using the time it takes for a laser to bounce off of the Apollo reflector on the Moon and return to Earth.Type Ia supernovae have very similar brightness because they explode with the same mass (E=mcc), so the distance can be determined by luminosity. Next, you have the amount of redshift as determined by the shift in spectral lines which is ultimately determined by the speed of light. When you plot luminosity vs. redshift you get this wonderful correlation: Another factor to consider is that if redshift is due to relative differences in velocity due to expansion then high redshift type Ia supernovae should brighten and dim at slower rates due to relativistic effects. That is also seen. A cosmological redshift unrelated to expansion should not do this, and yet it is there. Also, there is no other known mechanism that would redshift all wavelengths by the same amount. Other mechanism are wavelength dependent and will shift some wavelengths more than others.

Two scientists can independently measure redshift and type Ia supernovae luminosity without ever communicating with one another and still produce data sets that agree with one another. I would call that objective.

I think Nwr's objection is more epistemological. He might agree that on one level what you describe is objective while seeing that objectivity dissolve into mere human consensus and assumptions on deeper levels. The best example I can think of is that we still haven't defined mass in terms of fundamental constants - there's still a standard kilogram kept in a vault outside Paris.--Percy

You might be interested in the new proposed standard that is defined in terms of fundamental constants. It is a polished sphere of crystalline silicon-28. They can very precisely measure the volume of the sphere, and from there they can accurately calculate the number of atoms in the sphere due to the consistent nature of crystals formed from silicon-28. Once you have the number of atoms you have the kilogram. This gets around the issues of the old kg standard changing in weight over time due to accumulation of oxidation and other such issues. Using this standard you could travel to an entirely new planet with no standards from Earth and still be able to very accurately produce a kg standard that agrees with the one on Earth.Page not found | NIST

To use the speed of light as a yardstick, you need a fixed clock. But we don't have one.