Education Activities To Accompany Chandra Data Analysis Software Cas A
Activity 2: What is the distance to Cas A and when did it explode?
Since this remnant has been expanding for over 300 years at incredibly high speed, by now it is quite large.
Distances to Supernova Remnants are very difficult to
determine. The best estimates come from the fast moving knots of
material that we can actual SEE moving outward through the sky over a
period of years. (View a fantastic black and white photo that shows the
Crab Nebula
expanding through space over a ten year period). The bright spots in
Cas A are examples of some of these knots. If we know how fast the
knots are moving through space, and we know how far they move in angle
across the sky, we can compute the distance to them....
