AST 2002 Lecture Notes - Lecture 34: Inertial Frame Of Reference, Length Contraction, Time Dilation
Document Summary
After a massive star supernova, if the core has a mass greater than 3 times the sun, the force of gravity will be too strong for even neutron degeneracy to stop further collapse. This is what we call a black hole. Since 3 times the mass of the sun or more are compressed into an infinitely small space, the gravity of the star is huge. Ne(cid:449)to(cid:374)"s la(cid:449) of gra(cid:448)it(cid:455) is (cid:374)o lo(cid:374)ger (cid:448)alid. Laws of physics are the same in any inertial reference frame. The speed of light is the same for all observers all the time. Length contraction: moving things shrink in the direction they are moving. Time dilation: time runs more slowly the faster you are going. Ei(cid:374)stei(cid:374)"s (cid:374)e(cid:454)t (cid:271)ig idea (cid:455)ou (cid:272)a(cid:374)"t tell the differe(cid:374)(cid:272)e (cid:271)et(cid:449)ee(cid:374) u(cid:374)ifor(cid:373) a(cid:272)(cid:272)eleratio(cid:374) a(cid:374)d a gravitational field. Mass (energy) bends space-time, which in turn affects the motion of objects. For very large gravitational fields, for objects accelerating very quickly.
