What evidence supports the existence of a black hole at the ...

[nmorano1]

What evidence supports the existence of a black hole at the center of our galaxy?
 
  A) The motions of the gas and stars at the center indicate that it contains 4 million solar masses within a region only 3 light-years across.
  B) We observe a large, dark object that absorbs all light at the center of our galaxy.
  C) We can see gas falling into an accretion disk and past the event horizon of a black hole.
  D) We observe an extremely bright X-ray source at the center of our galaxy.
  E) All of the above

Question 2

The Tully-Fisher relation uses the ________ of the spiral to find its luminosity.
 
  Fill in the blank(s) with correct word

[ryrychapman11]

Answer to Question 1

A

Answer to Question 2

rotation

[nmorano1]

Excellent

[phuda]

Thanks for the timely response, appreciate it