Assignment 3 - Due 3/5/2002

Please answer in complete sentences!

 
Read the smaller article first, and answer the following questions:

1. Name two parts of the electromangnetic spectrum.  Tell me which one has a shorter wavelength.

2. How massive does a star have to be to become a Black Hole?

3. In what parts of the electromagnetic spectrum does the gas falling into a black hole radiate most strongly?

Now, read the larger article.  You don't need to memorize it all: just skim it, and summarize the following
questions:

4. John Wheeler described searching for Black Holes as a "Great Waltz", or a dance.  Describe what he
means by this.

5. Astronomers measure velocities of stars and other objects using the Doppler effect.  If the light is
coming from gas orbiting around a Black Hole, describe what an astronomer might observe.

6. There are three Black Hole candidates described in the article.  Name them, tell me when they were first studied, and give me your opinion about which one is the best case for a black hole.  Back up your opinion
with facts!

7. Go to the following web site:  http://www.badastronomy.com/bitesize/accrete1.html  Also, look at http://antwrp.gsfc.nasa.gov/apod/ap010508.html and http://antwrp.gsfc.nasa.gov/apod/ap991219.html

Describe what an accretion disk so that your parents could understand it.