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| Plasma, the state that matters! | Jun 02, 2012 5:57 AM PDT | url |
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Added 1 new A* page:A few days ago I posted about the new finding of what appears to be fairly solid evidence that our galaxy's central supermassive black hole, Sgr A*, shot out a galaxy-spanning beam of plasma some tens or thousands of years ago, the result of swallowing something like the equivalent of 10,000 Suns. Well that reminded me that I wasn't too sure what exactly is covered by the term "plasma," so I went and looked it up!
According to Wikipedia, plasma "is a state of matter similar to gas in which a certain portion of the particles are ionized." Oh! Well, that's pretty easy. Like a gas, it doesn't have a definite shape, BUT--unlike a gas--plasma, being ionized (positive or negative ions, or electrons), can be shaped or guided by magnetic fields.
You've probably manipulated plasma with the magnetic field of your body, in fact, by touching the outside of one of these babies:
image by Luc Viatour / www.Lucnix.be (source)
But you can get plasma all over the place! For instance, the Space Shuttle Atlantis left a trail of plasma as it plunged through the atmosphere to come in for its last-ever landing last July:
image by NASA/ISS Expedition 28 (source)
And in fact, plasma is the most common state of matter (as opposed to solids, liquids, or gasses) in the visible universe! It's plasma that makes for much of the cool glowy stuff I do so love to post in space photos. Let's review some of A*'s greatest plasma hits!
You see a big ball of plasma in the sky probably nearly every day. That's right, we call that plasma the Sun! Stars are fusion-powered plasma:
image by NASA (source)
Powerful magnetic fields in stars like our sun shape the plasma into all sorts of shapes: tube-like structures in sunspots
image by SST, Royal Swedish Academy of Sciences / NASA (source)
and into huge leaping arcs called "coronal loops":
image by NASA (source)
Of course we already know that plasma can be shaped into huge jets by the incredibly powerful magnetic fields generated by supermassive black holes, like this 5000 light-year-long (!!), near-light speed jet coming out of the center of galaxy M87, one of the most massive galaxies in our little corner of the universe (~53 million light years away, and maybe 200 times as massive as the Milky Way):
image by NASA/ESA (source)
And on a more local scale, you're seeing plasma when you see lightning. And it can be generated for space travel purposes, as with the slow-but-efficient Hall Effect ion thruster ("Over 240 thrusters have flown in space since that time [of the Soviet "Meteor" satellite in 1971] with a 100% success rate")
image by NASA (source)
or to impress people with your scientific and commercial ideas, Tesla-style:
image by Dickenson V. Alley (source)
(Mind you, not even the ambitious Nikola Tesla liked the idea of sitting that close to such a powerful electrical field, so he had his photographer use a double-exposure to *appear* to capture him alongside that raging plasma in his Colorado lab in 1899.)
Fun stuff, that plasma!
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