
Scientists uncover exotic matter in the sun's atmosphere - dnetesn
https://phys.org/news/2019-05-scientists-uncover-exotic-sun-atmosphere.html
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SAI_Peregrinus
The "exotic matter" is plasma. Since the entire atmosphere of the sun (the
corona) is plasma the headline is about as relevant to the study as saying
that scientists studying hydrology have found water.

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ncmncm
At least some people are willing to use the word, now. Until recently you
would be ostracized by other astronomers for mentioning it. (Thus, "hot gas".)

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SAI_Peregrinus
Astronomers consider Nitrogen and Carbon to be metals. Their jargon is very
particular to astronomy, and they seem to love using words in ways different
from how the rest of the scientific community uses them.

~~~
ncmncm
While that is true (anything not H or He is "metal") they have long had a sort
of guild requirement that every phenomenon must be explained with nothing but
heat and gravitation; if a magnetic field is invoved it has to be generated by
a massive body. Anything that can't is not to be discussed, because plasma
dynamics is too hard.

The wall is starting to crack, though.

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ncmncm
> ... plasma remains a mystery, mainly due to its scarcity in natural
> conditions on Earth ...

I guess a candle flame isn't strictly natural, but a forest fire is. I don't
encounter forest fires every day, but I daresay more than one is burning
somewhere right now.

Tornadoes also tend to plasma, although you won't find a meteorologist who
will discuss it.

But, yes, we generally try to stay clear of plasma events. They tend,
inherently, to unpredictability.

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saagarjha
Is fire plasma?

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sq_
Any of our resident scientists are welcome to correct me if I'm wrong, but I
believe that most plasmas require _much_ higher temperatures and pressures
than a regular fire like a candle can create.

The light we see from flames is mostly just photons emitting from the hot
gases and other products of the combustion reaction, as far as I know.

~~~
ncmncm
Yes, light is 100% photons, or your money back.

Considering that the overwhelming majority of the plasma in the universe is in
interstellar space: no, extreme pressures and temperatures are not necessary.

The absolute requirement is an ionization rate of more than 0.01%: more than
one ion per 10000 neutral atoms. (Above that, regular gas dynamics don't work,
and you need plasma dynamics.) This can be achieved by high-ish temperatures,
or ionizing radiation, or various physical processes involving strong and
varying electric and magnetic fields.

Plasma dynamics are interesting because positive ions are at least 2K more
massive than electrons. Any field that pushes the positive cores one way
pushes the electrons 2k times faster in the other direction. Which, of couse
generates other fields, and likely x-rays, too.

Whenever you see some astronomy source claiming that x-rays imply a weirdly
high temperature, you can be smug knowing that plasma is happy to emit x-rays
at any temperature.

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sq_
Thanks for the rundown on plasmas there, that's super interesting. I always
enjoy being taught new things, especially about physics!

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andrewflnr
I'm, maybe, unreasonably angry about that headline. I sort of knew phys.org
was not a top quality science publication, but _holy shit_.

~~~
sq_
I don't think it's unreasonable at all. When I read "exotic matter", I
immediately think of things like negative mass, not comparatively run-of-the-
mill solar plasma.

Something tells me phys.org cares more about clicks than accuracy...

