It was all misrouted luggage at the world's airports.
First detection of the missing half of normal matter in our universe
91–100 of 131 posts
Re: First detection of the missing half of normal matter in our universe
#92Earlier quoted context omitted.
>things in motion tend to stay in motion comes to mind
Motion is relative though. And just because something is moving relative to another thing does not necessarily mean it is hot.
temperature, in my simple understanding, is brownian motion. What ever that means in the end, we know that vacuum is a pretty good thermal isolator, so the counter question should be, why should it cool down? Sure, heat can be given off as radiated photons which is messured coming from the filaments, but you probably don't even begin to understand why, ie. why the T is hot, I sure don't, so the question seems like stabbing in the dark (puns not intended).
Re: First detection of the missing half of normal matter in our universe
#93Can I just check - my understanding is that we can only see 5% of the expected mass in the universe - so we have just found another 5%? meaning dark matter needs to account for 90%? plus, how awesomely beautiful is the idea of tendrils of has connecting the galaxies through space.
Tendrils between galaxies is mind-blowing. Aren't galaxies very very far apart? And there is basically nothing in between? How are subatomic particles - baryons - able to survive the constant expansion? Do the tendrils keep getting thinner? Can they be a medium to transmit intergalactic information someday?
Also, to expand on that (I have no knowledge, just making assumptions), the space between galaxies would need to either create new matter, or the matter would get infinitely spread out over time?
So, if the stretching thing is true, would there be areas with absolutely no matter or anything at all?
Re: First detection of the missing half of normal matter in our universe
#94Earlier quoted context omitted.
The universe expands. Things bound by gravity tend not to expand that much. As a result, most of the space that expands is vacuum.
'The universe expands' in what? I thought everything was the universe, as meant by the term 'universal'.
Imagine you have a meter-stick. It has uniform graduation markings to show you centimeters and millimeters.
Now imagine that it is getting longer. No matter how hard you look at it, the stick is still one meter long. That's what the markings on it say, anyway. It's actually getting longer at the same rate as all the other meter-sticks. That's the expansion of the universe.
Now imagine you balanced two marbles on the stick. They bow the stick ever so slightly, and roll together at the 50 cm mark. They are not expanding--or at least not expanding like the meter-stick expands. But they will continue to roll together. They are detectable masses acting under the effect of gravity. If you look closely, they appear to be shrinking. But it's actually the meter-stick expanding.
When you expand this out to galaxy scale, two galaxies that are not moving with respect to each other are getting further apart. The mass in the galaxies have enough intra-galactic gravitational attraction to keep themselves from flying apart along with the vacuum, but not enough the keep their neighbor galaxies close. The inter-galactic gravitation doesn't pull hard enough to overcome the expansion. So they surf away from each other, becoming further apart.
At least, that's how I understand it. I could be wrong.
Re: First detection of the missing half of normal matter in our universe
#95Ok, it seems like a lot of people here think dark matter is a “thing” but it’s not. Dark matter is simply unaccounted for mass in the universe. When we discover mass that we didn’t know about before, the amount of “dark” matter decreases. The word “dark” here merely means “known unknown” because we observe the effect but not the cause. This discovery has unveiled some of the dark matter as baryon particles in a plasm…
>This discovery has unveiled some of the dark matter as baryon particles in a plasma. So some of that dark matter is now known.
The article clearly points out that this is not the case. The amount of dark matter is still the same.
>Dark matter is simply unaccounted for mass in the universe.
The article clearly points out that this is not the case.
Re: First detection of the missing half of normal matter in our universe
#96Re: First detection of the missing half of normal matter in our universe
#97> At the largest size, Google image search tells me that it looks exactly like foam rubber. Foam rubber is created by combining a chemical agent that glomps together through the wonder of polymerization with another chemical agent that delivers lots of gas bubbles to make space between the polymers. Universes are created by rapidly expanding a superdense plasma that glomps together through the wonders of gravity, whi…
Why should vacuum expand? Is it due to gravity of the filament molecules pulling those molecules together into larger 'strings' or 'planes' which leave 'holes'? Or some other mechanism?
Don't think of a "vacuum" as nothing. Space-time is a real substance with properties.
Re: First detection of the missing half of normal matter in our universe
#98The title is effectively click-bait because of: https://www.reddit.com/r/space/comments/75944s/half_the_univ...
Ok, we've debaited it.
Re: First detection of the missing half of normal matter in our universe
#99Oh where would we be without these geniuses!?
Would you please not post unsubstantive comments like this?
Re: First detection of the missing half of normal matter in our universe
#100It was all misrouted luggage at the world's airports.
Please don't do this here.