New estimate for Hubble constant differs from previous and also conflicting results
The uncertainty of science: Using microlensing effects scientists have measured a new estimate for the Hubble constant, the rate in which the universe is expanding, and have come up with a number that is different from previous results.
Using adaptive optics technology on the W.M. Keck telescopes in Hawaii, they arrived at an estimate of 76.8 kilometers per second per megaparsec. As a parsec is a bit over 30 trillion kilometers and a megaparsec is a million parsecs, that is an excruciatingly precise measurement. In 2017, the H0LICOW team published an estimate of 71.9, using the same method and data from the Hubble Space Telescope.
The new SHARP/H0LICOW estimates are comparable to that by a team led by Adam Reiss of Johns Hopkins University, 74.03, using measurements of a set of variable stars called the Cepheids. But it’s quite a lot different from estimates of the Hubble constant from an entirely different technique based on the cosmic microwave background. That method, based on the afterglow of the Big Bang, gives a Hubble constant of 67.4, assuming the standard cosmological model of the universe is correct.
An estimate by Wendy Freedman and colleagues at the University of Chicago comes close to bridging the gap, with a Hubble constant of 69.8 based on the luminosity of distant red giant stars and supernovae.
So five different teams have come up with five different numbers, ranging from 67.4 to 76.8 kilometers per second per megaparsec. Based on the present understanding of cosmology, however, the range should have been far less. By now the physicists had expected these different results to be close to the same. The differences suggest that either their theories are wrong, or their methods of measurement are incorrect.
The most likely explanation is that we presently have too little knowledge about the early universe to form any solid theories. These measurements are based on a very tiny amount of data that also require a lot of assumptions.
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The uncertainty of science: Using microlensing effects scientists have measured a new estimate for the Hubble constant, the rate in which the universe is expanding, and have come up with a number that is different from previous results.
Using adaptive optics technology on the W.M. Keck telescopes in Hawaii, they arrived at an estimate of 76.8 kilometers per second per megaparsec. As a parsec is a bit over 30 trillion kilometers and a megaparsec is a million parsecs, that is an excruciatingly precise measurement. In 2017, the H0LICOW team published an estimate of 71.9, using the same method and data from the Hubble Space Telescope.
The new SHARP/H0LICOW estimates are comparable to that by a team led by Adam Reiss of Johns Hopkins University, 74.03, using measurements of a set of variable stars called the Cepheids. But it’s quite a lot different from estimates of the Hubble constant from an entirely different technique based on the cosmic microwave background. That method, based on the afterglow of the Big Bang, gives a Hubble constant of 67.4, assuming the standard cosmological model of the universe is correct.
An estimate by Wendy Freedman and colleagues at the University of Chicago comes close to bridging the gap, with a Hubble constant of 69.8 based on the luminosity of distant red giant stars and supernovae.
So five different teams have come up with five different numbers, ranging from 67.4 to 76.8 kilometers per second per megaparsec. Based on the present understanding of cosmology, however, the range should have been far less. By now the physicists had expected these different results to be close to the same. The differences suggest that either their theories are wrong, or their methods of measurement are incorrect.
The most likely explanation is that we presently have too little knowledge about the early universe to form any solid theories. These measurements are based on a very tiny amount of data that also require a lot of assumptions.
The support of my readers through the years has given me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Four years ago, just before the 2020 election I wrote that Joe Biden's mental health was suspect. Only in this year has the propaganda mainstream media decided to recognize that basic fact.
Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Even today NASA and Congress refuse to recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
Please consider supporting my work here at Behind the Black.
You can support me either by giving a one-time contribution or a regular subscription. There are five ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation:
5. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.
You know, I can’t get terribly excited over a 10% disagreement; I’m old enough to remember when it was war to the death over 50 km/s/Mpc vs. 100 km/s/Mpc.
Hmmm, so the Hubble Constant isn’t…..
Those who truly understand the propagation of error and significant figures are with Call Me Ishmael.
I could give many examples but have done that before here.
The biggest discrepancies (and they seem not that great) are between methods that use the “cosmic microwave background-early cosmic history” theories whose ABSOLUTE accuracy is easily questionable, and those methods using more direct measurements. When error bars are taken into consideration, the consistency of the latter methods is remarkable. Rather than saying the theories are “wrong”, it is amazing how “right” they seem to be.
Most theories or models (perhaps all) and all experiments AND their error bars are not ABSOLUTELY exact (ie “wrong”)…That is not a useful question; the question is how useful are they.
A nice review of methods/results is given here:
https://en.wikipedia.org/wiki/Hubble%27s_law#Measured_values_of_the_Hubble_constant
The Cosmic Distance Ladder and the Hubble Controversy.
Dr. Laird Whitehill Fun with Astronomy
https://youtu.be/A_XW-cMgfgc
54:15
“There is stuff we didn’t know that we didn’t know. Now we know what we don’t know. And we don’t understand it. Why do different researchers get different results about the expansion rate of the Universe (the Hubble Constant). By now we have to admit that both groups are right. So something is wrong, not with their conclusions, but with our understanding of the universe.”