The Last of the Universe’s Ordinary Matter Has Been Found

Post by Baeocystin » Mon, Sep 10, 2018, 9:58 PM UTC

coldtea wrote: post #18

TomMckenny wrote: post #8

Slightly related, I wonder if anyone has figured out the density of interstellar comet or asteroid like objects. I notice that Oumuamua happened to pass within some 20 million km of earth within a decade or so of having systems in place to spot it. Wouldn't this imply there are an awful lot of them?

> I notice that Oumuamua happened to pass within some 20 million km of earth within a decade or so of having systems in place to spot it. Wouldn't this imply there are an awful lot of them? Finding one in a decade's span within 20 million km would imply there are "an awful lot of them"?

Post by Baeocystin » Mon, Sep 10, 2018, 10:02 PM UTC

aikah wrote: post #19

sandworm101 wrote: post #15

Earlier quoted context omitted.

Who is telling you that the universe is infinite? Astronomers/cosmologists generally all agree that our current universe (the matter-containing 4 dimensions bit we live in) had a defined beginning from which is has grown. There is an outer edge,. defined by the rate of expansion starting from the big bang.

Then what do physicists call what is beyond the edge of the universe? edit: excuse my french ;)

Post by eridius » Mon, Sep 10, 2018, 10:05 PM UTC

nfc wrote: post #9

gcbw2 wrote: post #6

The hypothesis is they should see CMB distortion between galaxies, which is hidden by the distortion caused by the galaxies themselves. The solution was to assume they were removing the distortion caused by the galaxy halo, and what was left was the original distortion they were looking for. sounds like the work to rule out false-positives would be huge. This is putting a lot of weight on a technique that is not full…

I'm not really sure of what you mean by false positives. After my understanding of the stacking technique as used in other contexts in astrophysics and without going into too much details : The problem they were facing is that the signal to noise of the images of the filaments was too low to say that they had detected anything in any individual images. However by stacking (adding) images they were able to detect it b…

Post by AnimalMuppet » Mon, Sep 10, 2018, 11:02 PM UTC

thisismyswamp wrote: post #26

sandworm101 wrote: post #15

Earlier quoted context omitted.

Who is telling you that the universe is infinite? Astronomers/cosmologists generally all agree that our current universe (the matter-containing 4 dimensions bit we live in) had a defined beginning from which is has grown. There is an outer edge,. defined by the rate of expansion starting from the big bang.

The Big Bang supposedly encompassed all of space and had no edges.

Post by nfc » Mon, Sep 10, 2018, 11:21 PM UTC

gcbw2 wrote: post #10

nfc wrote: post #9

Earlier quoted context omitted.

I'm not really sure of what you mean by false positives. After my understanding of the stacking technique as used in other contexts in astrophysics and without going into too much details : The problem they were facing is that the signal to noise of the images of the filaments was too low to say that they had detected anything in any individual images. However by stacking (adding) images they were able to detect it b…

Think like that: there are two bright lights in front of you. There will always be a halo between those two bright lights. Now, my hypothesis is that "between all two bright lights, there is third, dimmer one, hidding". And then i prove it by filtering X from the two bright light halo, and prove that Y is left proving that the third light is there. Now, how can i be sure Y is really a third dimmer light? and not just…