5 ms·

If I understand this correctly, couldn't this explain dark matter? The article didn't say how dense this cloud was, but if it was still a cloud it couldn't be

by fooqux 5y ago

If I understand this correctly, couldn't this explain dark matter? The article didn't say how dense this cloud was, but if it was still a cloud it couldn't be that dense right? Surely something that could exist in the cold vastness of space.

gpm 5y ago
Near absolute zero states of matter don't really work the same way. I wouldn't read too much into them saying "cloud".
ben_w 5y ago
The cosmic microwave background is 136000 times hotter, so I don’t think so, no.
- fooqux 5y ago
  Fair, but the article implied that it's a somewhat linear effect- you don't need absolute zero for it to make the cloud dim. The article didn't do a great job of saying what temps they were testing at. Still, I'm not surprised. I doubt some armchair scientist is going to solve the riddle of dark matter. I was curious and got some good answers. Thanks!
- dtgriscom 5y ago
  "136000 times hotter" sounds a lot more impressive than "2.72546 degrees hotter"...
  - BobbyJo 5y ago
    That was fun to read. Even funner to realize that the huge relative number is actually more useful too. Saying 2.72 degrees sounds small, but a difference that large on average throughout the universe would be absolutely insane And break basically all of physics
- toxicFork 5y ago
  Is that temperature uniformly spread?
  - checkyoursudo 5y ago
    The temperature variance across the CMB is incredibly small. It depends on what you mean by uniformly spread, of course, but the fancy colorful images you often see are showing variance out to like 4 or 5 decimal places, if I recall. Like thousandths or ten-thousandths of a degree K.
jwuphysics 5y ago
No. The experimentalists used lasers to condense the atoms to high densities.
- klyrs 5y ago
  Sounds like a fun conspiracy. Aliens using space lasers to hide, what, 25% of the matter in the universe from us?
  - ben_w 5y ago
    85%, not that it would matter for a conspiracy theory.
    - GordonS 5y ago
      Nice pun :)
  - GuardianCaveman 5y ago
    Yeah the 25% coolest parts too.
  - denton-scratch 5y ago
    Would that be the 25% that isn't "Dark Matter"? Ergo, nothing in the Universe is observable ... wait.
  - mleonhard 5y ago
    They're saving it to use as fuel to survive until the next big bang.

by fooqux 5y ago

gpm 5y ago

Near absolute zero states of matter don't really work the same way. I wouldn't read too much into them saying "cloud".

ben_w 5y ago

The cosmic microwave background is 136000 times hotter, so I don’t think so, no.

fooqux 5y ago
Fair, but the article implied that it's a somewhat linear effect- you don't need absolute zero for it to make the cloud dim. The article didn't do a great job of saying what temps they were testing at. Still, I'm not surprised. I doubt some armchair scientist is going to solve the riddle of dark matter. I was curious and got some good answers. Thanks!
dtgriscom 5y ago
"136000 times hotter" sounds a lot more impressive than "2.72546 degrees hotter"...
- BobbyJo 5y ago
  That was fun to read. Even funner to realize that the huge relative number is actually more useful too. Saying 2.72 degrees sounds small, but a difference that large on average throughout the universe would be absolutely insane And break basically all of physics
toxicFork 5y ago
Is that temperature uniformly spread?
- checkyoursudo 5y ago
  The temperature variance across the CMB is incredibly small. It depends on what you mean by uniformly spread, of course, but the fancy colorful images you often see are showing variance out to like 4 or 5 decimal places, if I recall. Like thousandths or ten-thousandths of a degree K.

jwuphysics 5y ago

No. The experimentalists used lasers to condense the atoms to high densities.

klyrs 5y ago
Sounds like a fun conspiracy. Aliens using space lasers to hide, what, 25% of the matter in the universe from us?
- ben_w 5y ago
  85%, not that it would matter for a conspiracy theory.
  - GordonS 5y ago
    Nice pun :)
- GuardianCaveman 5y ago
  Yeah the 25% coolest parts too.
- denton-scratch 5y ago
  Would that be the 25% that isn't "Dark Matter"? Ergo, nothing in the Universe is observable ... wait.
- mleonhard 5y ago
  They're saving it to use as fuel to survive until the next big bang.