This URL is a stub, and the full article can be read at https://www.esa.int/Science_Exploration/Space_Science/Webb/W...
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Webb and Hubble confirm Universe's expansion rate
21–30 of 380 posts
Re: Webb and Hubble confirm Universe's expansion rate
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Re: Webb and Hubble confirm Universe's expansion rate
#23[flagged]
Almost all claims any serious scientist makes concern the observable universe.
Also, these are very smart people. You'd be surprised what we can work out with a few very reasonable assumptions and the observations we made. The dismissiveness really isn't warranted.
Re: Webb and Hubble confirm Universe's expansion rate
#24What are the implications?
Basically it means that we can't regard the Hubble result as a mismeasurement and the age of the universe seems to be different depending on how you measure it. From the article: "The bottom line is that the so-called Hubble Tension between what happens in the nearby Universe compared to the early Universe’s expansion remains a nagging puzzle for cosmologists. There may be something woven into the fabric of space tha…
Sounds like they don't want to spoil everyone's research grants!
Re: Webb and Hubble confirm Universe's expansion rate
#25Unbelievable how much we can work out from just the odd photon hitting us from somewhere in the great unknown.
Occam's Razor does a lot of heavy lifting.
Re: Webb and Hubble confirm Universe's expansion rate
#26This sort of brushes on it but for a long time there was hope at resolving the Hubble Tension by saying that Hubble telescope’s measurements were incorrect, because that would be the most simple explanation. This was not the case, so if anything, the mystery deepens. I don’t know for certain but I believe Hubble’s estimation has been widely accepted for a while though, because we’ve been using the 13.8 billion cosmol…
> we’ve been using the 13.8 billion cosmological age estimate ever since I started brushing up my layman's understanding of the subject. I remembered the age of the universe as as 13.7 billion years, but I wasn't sure why that was. Well, the initial WMAP results in 2003 supported an age of 13.7 billion years. Later results nudged this upwards to 13.8 billion years. Of course, all the results have error bars.
> Of course, all the results have error bars.
Not to mention the underlying philosophical assumptions, such that the "rate of time" has been constant across all of... time.
Aka: How do we know a "year" 13 Billion "years" ago bears any resemblance to one now? What would it mean for it not to?
Re: Webb and Hubble confirm Universe's expansion rate
#27Unbelievable how much we can work out from just the odd photon hitting us from somewhere in the great unknown.
It's astounding to me that space is so empty that in the billions of light years from here to the edge of the universe, there's orders of magnitude less total interference than what you get from a small cloud.
It's also astounding that celestial objects emit enough photons that thousands per second travel within the arc that goes the distance from the star to somewhere inside the radius of your pupil.
And if this wasn't the case, then we'd never even be aware of any of this.
Re: Webb and Hubble confirm Universe's expansion rate
#28A little background based on a few articles about this plus my recollection of PBS Space Time videos on this: There are at least two ways to try to figure out the rate of expansion of the universe (which is called the Hubble Constant).
• From variations in the cosmic microwave background (CMB) which are the result of certain conditions in the early universe it is possible to figure out what the expansion rate should be now.
• From looking at very distant galaxies and noting how far away they are and how fast they are receding from us the expansion rate can be calculated.
Theory says that these should give the same expansion rate. When the rates were first found using those two methods they gave different results, but the error bars on both were large enough to overlap. People expected then that further refinement of both methods to decrease the error bars would converge to some common value.
That did not happen. Refinement of the CMB measurements got to 67 +/- 0.5, and refinement of the galaxy distance/speed method got to 73 +/- 1. Those do not overlap.
This non-overlap between the possible ranges given by the two methods is called the Hubble tension, and it is one of the most irksome problems in cosmology.
Possible explanations include:
• Some sort of error in how we measure the variations in the CMB.
• Some sort of error in the distant galaxy distance or speed measurements, which until the James Webb telescope were almost entirely Hubble telescope measurements.
• We're missing something in our understanding of the physics.
These new results add a bunch of data from the James Webb telescope, which observes in different wavelengths than Hubble. These results fit with the Hubble measurements.
They do not resolve the Hubble tension. What they do is remove most doubt that the distant galaxy results involve some sort of Hubble measurement error. I believe cosmologists are pretty confident of the CMB measurements, and so this will be interpreted as telling us that the Hubble tension is not just a problem with our measurements. There is either physics that we got wrong or physics we need to discover.