PowerPoin t Wong Kam Man 2D (36)

MASS When astrophysicist Vera Ruban looked at Galaxies, she noticed a curious problem. She expected that the outer parts of a galaxy would move slower than the inner parts. But she found that this is not the case. The rotation curves of galaxies (a graph of the radius of a galaxy versus rotational speed) is flat, meaning that the outer parts move at the same speed as the inner parts. Large amounts of mass would account for the unexpected speed, but we don't see the mass that should be there. When astrophysicist Vera Ruban looked at Galaxies, she noticed a curious problem. She expected that the outer parts of a galaxy would move slower than the inner parts. But she found that this is not the case. The rotation curves of galaxies (a graph of the radius of a galaxy versus rotational speed) is flat, meaning that the outer parts move at the same speed as the inner parts. Large amounts of mass would account for the unexpected speed, but we don't see the mass that should be there.

Dark mass- MASS To aid your understanding of this, think of how planets revolve around the Sun in our solar system. Mercury (the closest planet to the Sun) zips around the Sun in 88 days, but it takes the furthest planet, Pluto, 248 years to orbit the Sun. If there were a solid sphere of mass between the Sun and Pluto, than Pluto's orbital period would be the same as Mercury's. No one is suggesting that galaxies are actually solid spheres of matter, but there must be more mass in these galaxies then we can see. Because we can't see it, the mass is called dark matter. To aid your understanding of this, think of how planets revolve around the Sun in our solar system. Mercury (the closest planet to the Sun) zips around the Sun in 88 days, but it takes the furthest planet, Pluto, 248 years to orbit the Sun. If there were a solid sphere of mass between the Sun and Pluto, than Pluto's orbital period would be the same as Mercury's. No one is suggesting that galaxies are actually solid spheres of matter, but there must be more mass in these galaxies then we can see. Because we can't see it, the mass is called dark matter.

Baryonic matter -MASS Dark matter may account for up to 90% of the Universe's total mass. Bernard Sadoulet, who leads a search for dark matter at theCenter for Particle Astrophysics has stated that "Not only can we not see what most of the Universe is made of, we aren't even made of what most of the Universe is made of!" What did he mean by this? Scientists tend to categorize everything and matter is no different. The matter you are familiar with, matter composed of neutrons and protons, is called baryonic matter. Dark matter may account for up to 90% of the Universe's total mass. Bernard Sadoulet, who leads a search for dark matter at theCenter for Particle Astrophysics has stated that "Not only can we not see what most of the Universe is made of, we aren't even made of what most of the Universe is made of!" What did he mean by this? Scientists tend to categorize everything and matter is no different. The matter you are familiar with, matter composed of neutrons and protons, is called baryonic matter.

WIMP -MASS Non-baryonic matter also exists, but is generally difficult to detect. Professor Sadoulet's experiment is looking for exotic, non-baryonic particles called WIMPs. WIMP stands for Weakly Interacting Massive Particle. There is a great deal of theoretical work which suggests that WIMPs exist and probably account for a large fraction of dark matter. Non-baryonic matter also exists, but is generally difficult to detect. Professor Sadoulet's experiment is looking for exotic, non-baryonic particles called WIMPs. WIMP stands for Weakly Interacting Massive Particle. There is a great deal of theoretical work which suggests that WIMPs exist and probably account for a large fraction of dark matter.

MAIN POINT Large amounts of mass would account for the unexpected speed, but we don't see the mass that should be there. Large amounts of mass would account for the unexpected speed, but we don't see the mass that should be there. The outer parts of a galaxy would move slower than the inner parts The outer parts of a galaxy would move slower than the inner parts No one is suggesting that galaxies are actually solid spheres of matter, but there must be more mass in these galaxies then we can see. No one is suggesting that galaxies are actually solid spheres of matter, but there must be more mass in these galaxies then we can see. Dark matter may account for up to 90% of the Universe's total mass. Dark matter may account for up to 90% of the Universe's total mass.

MAIN POINT The matter you are familiar with, matter composed of neutrons and protons, is called baryonic matter. The matter you are familiar with, matter composed of neutrons and protons, is called baryonic matter. Looking for exotic, non-baryonic particles called WIMPs. Looking for exotic, non-baryonic particles called WIMPs. There is a great deal of theoretical work which suggests that WIMPs exist and probably account for a large fraction of dark matter. There is a great deal of theoretical work which suggests that WIMPs exist and probably account for a large fraction of dark matter.

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