"For now, cosmology is safe."
For now....
Scientists have confirmed that the universe is very likely the same in every direction, showing that the assumption of the universe being isotropic can be safely used in cosmology. The results, published in Physical Review Letters show that there is only a 1 in 121,000 chance that the universe is non-isotropic. On small …
How convenient.... the Universe is expanding, and the Milky Way is in the MIDDLE...
BUT....in a Time magazine interview, "Shift on Shift", Dec 14, 1936....the father of Big Bang....
said that it is a HOAX....see the Cosmology tab at FauxScienceSlayer....
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left over from the energetic blast of the Big Bang
The Big Bang wasn't a blast. You can look at it as more of a cooling event. And as the CMB dates from 380,000 years later, it's more a snapshot of the early universe than anything. Though I suppose you could also say that we're all leftovers from the Big Bang.
Sorry, but I did warn you. Friday morning pre-pub mood.
I get what you're trying to get at. But think it through a bit more.
Once the detonation is over, any explosion will cool as it expands. So that's nothing special.
The normal definition of a detonation is a supersonic chemical reaction in which molecules release energy as they go from a high energy state to a low energy one. Again the big bang took matter from a high energy state to a low energy state at superluminal rates, releasing energy.
The only real differences between the big bang and a regular explosion is that regular explosions don't create spacetime and the temperatures were so high molecules couldn't form.
(Well, I say molecules couldn't form. Really I mean temperatures were so high the laws of physics couldn't form.)
The normal definition of a detonation is a supersonic chemical reaction in which molecules release energy as they go from a high energy state to a low energy one
Raising the pedantry level a bit, there are also entropic explosives (like TATP) which release little if any energy when they go bang. It's the massive increase in entropy that drives the explosion.
Raising the pedantry level a bit, there are also entropic explosives (like TATP) which release little if any energy when they go bang. It's the massive increase in entropy that drives the explosion.
I don't understand this.
The above statement applies to little kids but rather less to TATP. If you blow tops off buses, there sure is energy being released.
It was a time of magic.
If the laws of physics had not yet formed, things do not fall under natural laws - they are "supernatural."
Not only that, but if the laws of physics don't apply, you can't use the laws of physics to study it.
"Here be dragons" as the old maps say.
>CMB dates from 380,000 years later,
Hopefully someday we can accurately map the CNB. That will give us a picture of what the universe looked like 1 to 2 seconds after the Big Bang (with very little distortion due to matter). Pretty impressive z at that age lol.
Edit: forgot about the GWB. That one might actually be doable (probably not in my lifetime though) before the CNB and it gives a picture of the universe a tiny fraction of second after the big bang.
The 'CMB' does not exist!
The Herouni Antenna - The Death of the Big Bang!
https://www.youtube.com/watch?v=p8lKQMEYYLw
Herouni's telescope, Big Bang Theory, and Ian Gillan's only question,
https://www.mediamax.am/en/news/special-report/33818/
The Life and Work of Professor Paris Herouni: A Documentary, https://photos.app.goo.gl/fVCCCf3HCSijVeoE7
P. Herouni, Measured Parameters of Large Antenna of ROT-54/2.6 Tell about Absence of Big Bang Journal of Astrophysics: Reports. — National Academy of Sciences of Armenia 2007, v. 107, no. 1. 73-78. http://rnas.asj-oa.am/2542/1/73.pdf
P. Herouni, About Self Noises of Radio-Optical Telescope ROT-54/2.6 Antenna. Journal of Applied Electromagnetism. Athens. 1999, v. 2, No. 1, 51-57.
http://jae.ece.ntua.gr/archive/1999/vol2no2_June1999.zip
If it was really like the Barbican it would have a helpful yellow line running through it for people to follow until it randomly disappeared into a stairwell or brick wall.
American readers had to be told that Asda was like Walmart a few days ago. They're really going to struggle with the Barbican, so for their benefit, it's like Lincoln Centre. Sorry, Center.
Totally off topic... I dimly recall visiting London in the early 1980ies. We went to the Barbican Centre (can't remember why) early on a saturday or sunday morning (can't remember why either) and for some reason we walked through a couple of blocks of 'The City' which were totally deserted. I was like in one of those desaster movies where the hero wakes up one day and finds that he is the last man o earth or something.
No: it's the same in every direction wherever you are. One of the most important assumptions in cosmology is that we aren't at some special place in the universe.
It is, unfortunately, hard to give a good picture of what the universe looks like that can make this be true. One way of thinking of it is to think of an ant on a balloon: wherever the ant is, the balloon looks the same. This is, inevitably, not a completely useful model.
"...come back around on yourself?"
The standard FLRW solution for a matter-gas filled isotropic expanding Einstein Gravity universe says:
... yes if it's "closed" (akin to a sphere surface everywhere)
... no if it's "open" (aking to the centre of a saddle surface everywhere), then you just keep going
But it may have more complicated shapes, too. You may even hit a "domain wall" if it's divided into various areas of distinct physics (or not, you will probably never reach the wall due to worsening expansion)
You can still have a flat or even negatively curved space which "repeats", like in Pacman. The technical term is a non-simply connected space. There have been searches for that, too, but it now appears that if we live in such a space, then the distance to go "around" the universe must be larger than we can look, i.e. greater than the size of the observable universe.
> "Go outside and point in any random direction. What happens if you keep going, and going, and going (forever). Where do you end up? Is there no end, or do you somehow come back around on yourself? Or something else?"
It doesn't matter, because you'll take so long to get there that by the time you do, it'll have moved off elsewhere anyway...
A possible void nearly 2 billion light years across (Wikipedia's listed estimate is wrong on this according to some other articles about its size) especially when the universe was 11 billion years old (well aware of comoving distance) is not as easily dismissed as it seems to be.
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Yeah, but the "5-sigma" does not really apply here. You need it when you pretend to have found a new unicorn and run repeated experiments to make sure that the unicorn does indeed appear in your setup.
Here, you just check whether the unique greyness is indeed rather uniformly grey. Then you can state "yep, it's uniformly grey" with pretty good assurance.
I guess I'm sort of in the habit of treating all claims as an - in your context - unicorn. After all it's not so long ago that science was pretty sure gorillas didn't exist or that we believed in the big bounce.
If you accept currently popular theories with a much lower certainty threshold than new theories then you run into a problem of potentially valid theories being edged out by popular, but ultimately incorrect, theories because they seem like they should be right. The benchmark for certainty needs to be the same for every theory. Otherwise why even have a benchmark?
"On small scales, the universe appears clumpy."
How do we know what counts as small, maybe beyond the 'tiny' limit of the observable universe it's also clumpy and what we see is a mere isotropic clump. Isn't there infinite light years in every direction?
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