# 22 - Today Announcements: HW#9 is due Friday April 16 at...

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ISP209s10 Lecture 22 -1- Today • Announcements: – HW#9 is due Friday April 16 at 8am – Exam 3 on April 29 (Thursday) Final exam will be on LONCAPA • Black holes, Worm holes, and White holes • New topic: Life in the universe, are we alone?

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ISP209s10 Lecture 22 -2- Large Mass in a small region What is the escape velocity for an object with the mass of the Sun and a radius of 10 km? M sun =1.99E+30 kg G=6.67E-11 Nm 2 /kg 2 s m E E R GM v 8 10 5 10000 31 99 . 1 11 67 . 6 2 2 ! = " # " = = This is greater than the speed of light! Nothing can go faster Than the speed of light. What does this mean?
ISP209s10 Lecture 22 -3- Einstein Equations predict “Black holes” A hole so deep that even light can not escape. www.ifa.hawaii.edu/~barnes/ast110_06/bhaq.html A huge mass in a tiny spacetime region warps it so strongly that it has “infinite curvature” aka a “spacetime singularity” develops. Einstein didn’t believe in them. He thought it was an “artifact” of the mathematics.

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ISP209s10 Lecture 22 -4- Parts of a black hole G = 6.673E-11 N m 2 / kg 2 c = 3.0E+8 m/s M = mass of the black hole Nothing, not even light, can escape the black hole once it comes inside the “Event Horizon”, which is given by R sch The equation for R sch Tells us how small we Have to smoosh some Mass M to create a Black hole (I.e., where The escape velocity = c)
ISP209s10 Lecture 22 -5- Black Holes Black holes act as a lens and we see light from stars behind. They don’t necessarily look “black”. They range from 3 solar masses to more than a billion solar masses. – Small ones are formed by the collapse of a large star

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## This note was uploaded on 12/05/2011 for the course ISP 209 taught by Professor Sherrill during the Fall '07 term at Michigan State University.

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22 - Today Announcements: HW#9 is due Friday April 16 at...

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