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Crash Course Astronomy

Galaxies, part 2: Crash Course Astronomy #39

Crash Course Astronomy

Galaxies, part 2: Crash Course Astronomy #39

15m 20s

Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy.

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12m 42s

Neutron Stars: Crash Course Astronomy #32

In the aftermath of a 8 – 20 solar mass star’s demise we find a weird little object known as a neutron star. Neutrons stars are incredibly dense, spin rapidly, and have very strong magnetic fields. Neutrons stars with the strongest magnetic fields are called magnetars, and are capable of colossal bursts of energy that can be detected over vast distances.

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12m 2s

Low Mass Stars: Crash Course Astronomy #29

Today we are talking about the life -- and death -- of stars. Low mass stars live a long time, fusing all their hydrogen into helium over a trillion years. More massive stars like the Sun live shorter lives. They fuse hydrogen into helium, and eventually helium into carbon. When this happens they expand, get brighter, and cool off, becoming red giants.

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11m 49s

Exoplanets: Crash Course Astronomy #27

Phil explains that YES, there are other planets out there and astonomers have a lot of methods for detecting them. Nearly 2000 have been found so far. Exoplanets appear to orbit nearly every kind of star, and weÕve even found planets that are the same size as Earth. We think there may be many billions of Earth-like planets in our galaxy.

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