Slashdot Mirror
Milky Way Is Surrounded By Halo of Hot Gas
New submitter kelk1 writes "If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the 'missing baryon' problem for the galaxy [...] a census of the baryons present in stars and gas in our galaxy and nearby galaxies shows at least half the baryons are unaccounted for [...] Although there are uncertainties, the work by Gupta and colleagues provides the best evidence yet that the galaxy's missing baryons have been hiding in a halo of million-kelvin gas that envelopes the galaxy."
Iiiii'm the CAT!
Seriously, we're not going to get out of this galaxy alive.
A feeling of having made the same mistake before: Deja Foobar
Excuse me.
that envelopes the galaxy
Surely you meant to use the verb, i.e. "envelops".
retain it's 1,000,000K for 14,000,000 years?
"I don't know, therefore Aliens" Wafflebox1
http://en.memory-alpha.org/wiki/Galactic_barrier
more cowbell
...I think you guys just like saying the word "baryon".
/* No Comment */
"... a few hundred times hotter than the surface of the sun." That's very warm.
It's relative warmth in the 100,000 K and up club it's rather difficult to keep track because once you've boiled away Tungsten, there's not much meaning in additional units of heat.
It does give me the impression the galaxy is actually protecting us from all this hot matter, it gets too close and gets blown away by a star or attacted to cooler matter. I imagine, however, this halo should be generating some serious amounts of IR. Need that ol' James Webb telescope to explain more about it.
A feeling of having made the same mistake before: Deja Foobar
Hold on a second... so they just discovered the Galaxy is surrounded by gas that's the same temperature as the surface of the sun, and is 300,000 lightyears across... possibly extending far into other galaxies... I'm going to take a wild stab here and say that, if that's true it probably pervades the entire universe... Isn't this the biggest scientific discovery in the past decade? What effect does this have on Dark Matter, Dark Energy, etc... etc...
Sorry, that was me. BIG burrito last night.
Where No Man Has Gone Before
As a plasma physicist, I'm not bothered or concerned about them calling it gas. When interacting with the general public to discuss plasma related research, sometimes you find yourself having to make a choice between trying to teach a person what a plasma is, or teaching them what you are doing with it. Attention spans, and time/space are sometimes limited with such interactions and you have to choose your priorities.
Of course every time a story comes up about missing matter being found, people want to know the impact on the need for dark matter. There is evidence that suggest how much matter in the universe is made out of baryonic matter (protons and neutrons... essentially anything made of atoms), and how much is made out of non-baryonic matter. The latter category is dark matter. In addition to the missing non-baryonic matter, there is also a bunch of missing baryonic matter, which what is being found by studies like this. That wasn't counted as part of dark matter in the first place. It is not like every bit of new baryonic matter we find cuts into the dark matter slice of the pie, they are still trying to fill up the normal matter slice,
This just accounting for regular own (baryonic) matter. The Halo is still mostly "Dark" matter, which is non-interacting. (It may be WIMPs, i.e., non-baryonic, or it may be quark nuggets, i.e., baryonic, but either way it is non-interacting.)
...has Rush Limbaugh really gotten that big?
No, no more than the incredibly hot solar corona / wind bothered the Apollo astronauts. The energy density is just way too low.
Aren't we all supposed to have learned about solid, liquid, gas and plasma back in grade school? I seem to recall having the concept explained over and over again from before high school and right through it. I can see the people who pass through school without learning to read having trouble with it, but it's a depressing thought that the ones who managed to become journalists missed the entire concept.
It's hot, but it's also a hard vacuum. For a spacecraft travelling through it, it's probably better to just think of it as radiation.
The previous story is the Romney-Ryan Space Policy.
There is a barrier surrounding the galaxy!
Same AC you replied to...
Although many people do learn that in school, they either don't remember it or never learned anything about what a plasma actually is other than it is some mysterious hot stuff, and can't see how it is pretty similar to gas in a lot of situations.
If anything, I've run into more trouble with people who paid attention to such things in school and not much else. They get stuck with this notion that everything has to be pigeon-holed into one of those categories (which makes it even worse if they were taught only three states). There seems to be a bit of lack of sense of how the different states relate to each other, and that the boundary between them can be fuzzy in many cases. This is especially so with plasma, since in some cases the electrical properties don't matter much and it acts just like a gas. Other times you can have partially ionized plasmas where the electrical effects are there, but not dominant (or even see such effects in things like semiconductors or conducting liquids, which sometimes get referred to as plasmas when speaking analogously, but are also different).
For stories like this though, the difference probably doesn't matter much. I think they could have easily called it plasma, and the number of people it would have confused would have been minimal, although I don't know if it would have added anything.
It's relative warmth in the 100,000 K and up club it's rather difficult to keep track because once you've boiled away Rhenium, there's not much meaning in additional units of heat.
https://en.wikipedia.org/wiki/Rhenium :)
The more you know...
Do what thou wilt shall be the whole of the Law
Everyone knows a Milky Way is surrounded by a halo of milk chocolate.
I spent 30min on Wikipedia because of you...
ics
Let's see. At the average thermal velocity of
What's the escape velocity of a particle in this halo?
Somewhere close to the airspeed velocity of an unladen swallow (European)
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
Surrounded by a halo of hot gas... The Milky Way Galaxy and Washington D.C.
Aren't we all supposed to have learned about solid, liquid, gas and plasma back in grade school?
Considering how many comments ON A NERD SITE say "loose" instead of "lose", aliterate things like "there cars are over their" and "The tomato's are in season", I think the fact that they don't know what a plasma is is pretty understandable.
Free Martian Whores!
I'll take you at your word (I'm a chemist, not a particle physicist, though I do know enough about Boltzman distributions that I could probably work it out).
Agreed that the velocity distribution might not be right - initially this stuff all started out as a mostly uniform cloud of gas with particles falling towards the nearest clump of mass, with particles that are farther picking up more speed - should be possible with some assumptions and calculus to work out what the distribution is assuming no collisions at all, and then it would move from that to a Boltzman distribution as collisions happen. That said, I'm sure there is SOME interaction among particles. The mean free path could be rather long though - and all of the particles are moving fast so collisions will shoot off some X-Rays and then everything is still moving along.
Again, I'm not a physicist, though I might be if I had the time. :) One lifetime just isn't enough.