Outskirts of Shrewd'm / Science, Technology, Engineering and Mathematics
No. of Recommendations: 5
https://phys.org/news/2024-08-analysis-webb-univer...But new measurements from the powerful James Webb Space Telescope seem to suggest that there may not be a conflict, also known as the "Hubble tension," after all.
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One major approach involves studying the remnant light from the aftermath of the Big Bang, known as the cosmic microwave background. The current best estimate of the Hubble constant with this method, which is very precise, is 67.4 kilometers per second per megaparsec
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In the past, measurements with this method [measure the expansion of galaxies in our local cosmic neighborhood directly, using stars whose brightnesses are known] returned a higher number for the Hubble constant—closer to 74 kilometers per second per megaparsec.
This difference is large enough that some scientists speculate that something significant might be missing from our standard model of the universe's evolution.
No. of Recommendations: 7
This difference is large enough that some scientists speculate that something significant might be missing from our standard model of the universe's evolution.
Oh I’m sure there’s “something” missing. In fact most of something, if the “dark matter” proponents are to be believed.
My theory is that there are trillions of dead galaxies and stars floating around, and with a black hole at the center we simply can’t see them because they’re, well, black. Not just the center: Including all the stars that circle and planets which circle them. They’re dead, you see. In space “dead” = “black”, at least at distance. Unobservable, unmeasurable.
Shortly after the Big Bang as energy accreted into matter it was still close together relatively speaking. Gravitational attraction would have formed stars, then galaxies *much* faster than we are used to today, and that led to billions or trillions of proto-galaxies forming within a few tens or hundreds of millions of years. They also burned out quickly because they were mostly gigantic, massive stars which can burn through their fuel in just a few million years, meaning it would be entirely possible for whole galaxies to have lived and died quickly and which would be unaccounted for (except by indirect gravitational measurements) in our “sighted” (visual, infrared, etc.) observations.
Get enough of those, impossible to see, not emitting any kind of radiation, and you have a huge source of matter which accounts for “the standard model” which is having trouble accounting for all manner of stuff.
Speaking of which, the edge of the universe isn’t really the edge, and our inference of how old the universe is is wrong, too. It’s been around a lot longer, and some things past “the edge” just aren’t measurable because they’re moving too fast, their radiation/energy is beyond our ability to see. But that’s for another post someday.
No. of Recommendations: 3
My related, half baked theory is that virtual particles/antiparticles arising from zero point energy interact with light vanishingly rarely. But over universe size distances, the absorptioin/re-emissions add up, red shifting the light and distorting our perception of the age and size of the universe. This would work with regular old matter like burned out stars, too.
I don't know how that agrees with the the cluster and galaxy level observations, or dark energy.
https://en.wikipedia.org/wiki/Fritz_Zwicky, who coined the term dark matter, also talked about "tired light" which is like this. There is also fun anecdote in his wikipedia entry:
"He is remembered as both a genius and a curmudgeon.[15] One of his favorite insults was to refer to people whom he did not like as "spherical bastards", because, as he explained, they were bastards no matter which way one looked at them."I am not a physicist, though, so I'm probably wrong and several grad students have researched and disproved my idea.
No. of Recommendations: 1
"My theory is that there are trillions of dead galaxies and stars floating around, and with a black hole at the center we simply can’t see them because they’re, well, black. Not just the center: Including all the stars that circle and planets which circle them. They’re dead, you see. In space “dead” = “black”, at least at distance. Unobservable, unmeasurable.
Shortly after the Big Bang as energy accreted into matter it was still close together relatively speaking. Gravitational attraction would have formed stars, then galaxies *much* faster than we are used to today, and that led to billions or trillions of proto-galaxies forming within a few tens or hundreds of millions of years. They also burned out quickly because they were mostly gigantic, massive stars which can burn through their fuel in just a few million years, meaning it would be entirely possible for whole galaxies to have lived and died quickly and which would be unaccounted for (except by indirect gravitational measurements) in our “sighted” (visual, infrared, etc.) observations.
Get enough of those, impossible to see, not emitting any kind of radiation, and you have a huge source of matter which accounts for “the standard model” which is having trouble accounting for all manner of stuff."
Seems plausible.
Next step would be designing a set of observations in an attempt to bolster or detract from what is heretofore to be known as the Goofy Dark Matter Hypothesis.
Perhaps keep a directed search going in distant, dark areas for luminous bodies which geometrically accelerate, redshift, then vanish?
-- sutton
No. of Recommendations: 4
I'm not a cosmologist, but that is almost a restatement of the dark matter hypothesis, except concentrating it into black holes. One problem is that black holes evaporate over time (Hawking). Another is that we've learned how to see them if they are anywhere near matter because the matter accelerating towards the black hole emits radiation (detectable).
The latest scholarship on galaxy formation is that the first galaxies appeared after about 100-200M years.
And then there's dark energy...
Lots to discover. We appear to be living at a time when that is still possible. In the far future, things may have expanded so much that we wouldn't be able to see much because it will be too far away, moving faster than it's light can ever get to us. We see that phenomenon now, distant objects winking out of our view.
