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fandomhigh2011-05-20 08:10 am
notawoodwind.livejournal.com) wrote in fandomhigh2011-05-20 08:10 am
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Advanced Astrophysics (and Arts & Crafts), Friday, 3rd Period - 5/20
Class today featured a large assortment of tubes of glitter in different shades, sturdy paper and glue waiting for the students when they arrived. Because glitter art would never stop being amazing, right kids? Right? Oh, just go with it because Reed wasn't very good at that part of it, okay?
"Good morning, class!" he said cheerfully, passing out the materials before starting on his lecture. And trying not to get glitter on himself. Somehow he was almost sure he'd never live that down if anyone back home caught wind of it. "Today, we'll be discussing dark matter. What we can see or detect around us is only a fraction of the matter in our universe. Far more of it is something that we're only made aware of by the affect it has on the gravity of the visible matter around it."
"While we are unsure just what this so called dark matter is comprised of because there has yet to be a device about to truly study it--" Get to work, Reed! "--there are ideas of just what they might be."
Writing on the board, Reed continued, "It could consist of already existing matter within the universe that we're aware of..."
Brown dwarfs -- These large objects formed in the same way as stars but never accumulated enough gas and dust to reach the critical mass to start hydrogen fusion. Brown dwarfs are about 5 percent of the sun's mass, i.e. usually larger than a planet, but not as large as a star. Astronomers call these and similar objects MACHOs, which stands for Massive Compact Halo Objects. MACHOs can be detected by gravitational lensing. Astronomers think that brown dwarfs are not numerous enough to account for dark matter in the galaxy.
White Dwarfs -- These are the remnants of the cores of dead small to medium-size stars. Although large numbers of white dwarfs exist, there are not enough to account for dark matter (there should be large amounts of leftover helium from them, but this has not been observed).
Neutron stars/black holes -- These are the last remnants of the cores of large stars after supernovae explosions. While they do have large gravitational effects and are invisible because they can even prevent light from escaping (black holes), they are far too rare to account for dark matter.
"...or, it could be something else entirely. Something we call extraordinary matter. This is matter that consists of subatomic particles that very weakly interact with normal matter. That would probably be why they are referred to as WIMPs." Oh, his grin at that was so horribly nerdy. "Or, Weakly Interacting Massive Particles."
Neutrinos -- Subatomic particles that move near the speed of light, but have little mass. These particles probably make up little dark matter within galaxies because they move fast enough to escape even a galaxy’s pull of gravity. However, they may constitute some dark matter between galaxies. So, it is doubtful that they make up much dark matter.
New subatomic particles -- There could be many of these proposed particles. Many come from the theory of supersymmetry, which doubled the number of particles from the standard model. They move relatively slowly and are relatively cold (i.e. undetectable by infrared and X-ray telescopes). Particle physicists are actively trying to find evidence for these theoretical particles to explain dark matter.
Neutralinos (massive neutrinos) -- hypothetical particles that are similar to neutrinos, but heavier and slower. Although they have not been discovered, they are a leading candidate for extraordinary dark matter.
Axions -- small, neutral, low-mass (less than a millionth of an electron) particles
Photino -- similar to photons, but have a mass that is 10 to 100 times greater than a proton. Photinos are uncharged and interact weakly with matter.
Wow, weren't you all glad you took this class now?
Reed smiled again, trying to encourage the kids along. "Now, next week we will be doing pottery, so please wear something you won't mind getting dirty."
"Good morning, class!" he said cheerfully, passing out the materials before starting on his lecture. And trying not to get glitter on himself. Somehow he was almost sure he'd never live that down if anyone back home caught wind of it. "Today, we'll be discussing dark matter. What we can see or detect around us is only a fraction of the matter in our universe. Far more of it is something that we're only made aware of by the affect it has on the gravity of the visible matter around it."
"While we are unsure just what this so called dark matter is comprised of because there has yet to be a device about to truly study it--" Get to work, Reed! "--there are ideas of just what they might be."
Writing on the board, Reed continued, "It could consist of already existing matter within the universe that we're aware of..."
Brown dwarfs -- These large objects formed in the same way as stars but never accumulated enough gas and dust to reach the critical mass to start hydrogen fusion. Brown dwarfs are about 5 percent of the sun's mass, i.e. usually larger than a planet, but not as large as a star. Astronomers call these and similar objects MACHOs, which stands for Massive Compact Halo Objects. MACHOs can be detected by gravitational lensing. Astronomers think that brown dwarfs are not numerous enough to account for dark matter in the galaxy.
White Dwarfs -- These are the remnants of the cores of dead small to medium-size stars. Although large numbers of white dwarfs exist, there are not enough to account for dark matter (there should be large amounts of leftover helium from them, but this has not been observed).
Neutron stars/black holes -- These are the last remnants of the cores of large stars after supernovae explosions. While they do have large gravitational effects and are invisible because they can even prevent light from escaping (black holes), they are far too rare to account for dark matter.
"...or, it could be something else entirely. Something we call extraordinary matter. This is matter that consists of subatomic particles that very weakly interact with normal matter. That would probably be why they are referred to as WIMPs." Oh, his grin at that was so horribly nerdy. "Or, Weakly Interacting Massive Particles."
Neutrinos -- Subatomic particles that move near the speed of light, but have little mass. These particles probably make up little dark matter within galaxies because they move fast enough to escape even a galaxy’s pull of gravity. However, they may constitute some dark matter between galaxies. So, it is doubtful that they make up much dark matter.
New subatomic particles -- There could be many of these proposed particles. Many come from the theory of supersymmetry, which doubled the number of particles from the standard model. They move relatively slowly and are relatively cold (i.e. undetectable by infrared and X-ray telescopes). Particle physicists are actively trying to find evidence for these theoretical particles to explain dark matter.
Neutralinos (massive neutrinos) -- hypothetical particles that are similar to neutrinos, but heavier and slower. Although they have not been discovered, they are a leading candidate for extraordinary dark matter.
Axions -- small, neutral, low-mass (less than a millionth of an electron) particles
Photino -- similar to photons, but have a mass that is 10 to 100 times greater than a proton. Photinos are uncharged and interact weakly with matter.
Wow, weren't you all glad you took this class now?
Reed smiled again, trying to encourage the kids along. "Now, next week we will be doing pottery, so please wear something you won't mind getting dirty."