plasma
- Thread starter sculptor
- Start date
...try ddg...
https://science.nasa.gov/science-news/science-at-nasa/1999/ast07sep99_1/ : "99.9 percent of the Universe is made up of plasma," says Dr. Dennis Gallagher, a plasma physicist at NASA's Marshall Space Flight Center. "Very little material in space is made of rock like the Earth."
https://www.livescience.com/54652-plasma.html : " Plasma makes up the sun and stars, and it is the most common state of matter in the universe as a whole. "
https://www.plasma-universe.com/99-999-plasma/ : "The visible universe is 99.999% plasma."
All of course held together by gravity.
sculptor
Valued Senior Member
or
electromagnetism?
Yes, as per the links dmoe gave.
In essence a plasma is actually matter where the electrons have been stripped. This not only occurs in stars, but are also the result of lightening, and even neon signs that we see in big cities.
Also the Earth's Ionosphere is ionised.
exchemist
Valued Senior Member
Good point (same point as made by mathman) . Most of the normal matter seems to be plasma, in stars, but if it is the case that 85% of matter in the universe is dark matter, then that is not plasma, or not as we know it, Jim.
In which case the answer to the OP question becomes "no".
exchemist
Valued Senior Member
Plasma, like the other states of matter, is only defined for normal matter.
Since we have no idea what dark matter is, we cannot make any comment about what states of matter may apply to it. Plasma is defined as partly or fully ionised matter, which presupposes it is made of atoms that can be ionised by pulling electrons off them. Dark matter is not made of atoms, apparently. So all bets are off.
Since WE DO NOT KNOW what Dark Matter is and honestly, WE DO NOT KNOW if it even exists, then like you stated "we cannot make any comment about what states of matter may apply to it."
So... IF we allow that this Mythical Dark Matter exists, then wouldn't the only honest answer to the question posed in the OP be...WE HONESTLY DO NOT KNOW?
Good point. Earlier posts in this thread talk about the percentage of visible matter that is plasma.
Since nobody knows for sure what dark matter is, yet, we don't know whether it is plasma or not, as several other posters have already said.
We do actually. DM cannot be a plasma (defined as a gas of electrically ionized particles), for the obvious reason a plasma interacts with and scatters/refracts EM radiation. Hence is not 'dark' as in utterly transparent to light or other EM radiation. DM has only ever been 'observed' via its gravitational influence, in particular lately via gravitational lensing.
Excuse my ignorance, but doesn't Normal Matter in any of it's states(solid, gas, plasma, etc) interact with EM radiation?
So...following that line of thought, couldn't it be said that DM cannot be in any state that we currently recognize in Normal Matter?
Again, please excuse my ignorance, but if DM was exactly like Normal Matter and followed/obeyed all of the properties of said Normal Matter...it would not be DM, would it?
So, since we have NO physical sample of this mythical DM...how can we possibly rule out the possibility that DM may indeed manifest in a plasma state as well as the other states that we recognize for Normal Matter?
Okay, Normal Matter, ionised or not, interacts with EM radiation.
Is that correct?
Yet this Mythical DM supposedly does NOT interact with EM radiation.
Is that correct?
So, if we cannot explain why this DM does NOT interact with EM radiation, how can we possibly KNOW that a gas of ionised DM particles WOULD interact with EM radiation?
Is that correct?
Yet this Mythical DM supposedly does NOT interact with EM radiation.
Is that correct?
So, if we cannot explain why this DM does NOT interact with EM radiation, how can we possibly KNOW that a gas of ionised DM particles WOULD interact with EM radiation?
Wikipedia is a great source of info on DM:
https://en.wikipedia.org/wiki/Dark_matter
The overwhelming preponderance of observational data accords with DM being uncharged.