Lecture 15
Pulsars, Gamma-ray bursts, and black holes
Monday July 28, 2008
Slides on Angel
Concepts:
- Neutron star: Incredibly dense, size of large city, rapid rotation, strong magnetic fields, made of tightly packed neutrons
- Gamma-ray burst: Core-collapse of very massive star, forming black hole; jet blasts through outer layers of star
- Black hole: object with density so high that it folds spacetime in on itself: once past the event horizon, nothing can get out
- Special relativity: Speed of light is maximum obtainable velocity, constant for any observer (leads to time dilation, length contraction, etc)
- General relativity: Matter tells spacetime how to curve, and spacetime tells matter how to move
Vocabulary:
- Pulsar: Rotation of neutron star can sweep beam of radiation (at magnetic pole) across line of sight, producing very regular pulses
- Event horizon: Point at which escape velocity from black hole is equal to speed of light; anything closer than this to black hole never escapes
- Gravitational redshift: Photons climbing out of gravitational well lose energy, are shifted to longer wavelengths
Activity:
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Random link:
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