Why is Cygnus X-1 considered such a good black hole candidate?
What will be an ideal response?
The massive visible star is pulled around by an invisible massive companion in a 5.6 day orbit. If the visible star is a giant of 30 solar masses, then the companion must be close to 10 solar masses, well over the 3 solar mass limit for black holes. Also, the matter pulled off the visible star is seen to be flowing toward the dark companion, where it generates much X-rays in the accretion disk.
You might also like to view...
The most recent ice age ended
A) about 1000 years ago. B) about 10,000 years ago. C) about 100,000 years ago. D) about one million years ago. E) hundreds of millions of years ago.
Grandfather clocks are designed so they can be adjusted by moving the bob at the bottom of the pendulum up or down. Suppose you have a grandfather clock at home that runs slow
Which of the following adjustments of the bob would make it more accurate? (There could be more than one correct choice.) A) Raise the bob. B) Lower the bob. C) Add more mass to the bob. D) Remove some mass from the bob. E) Increase the amplitude of swing by a small amount.
The temperature scale that places zero at the point where all atomic and molecular motion ceases is:
A) Fahrenheit. B) Celsius. C) Kelvin. D) centigrade. E) Ransom.
The electric field of a point charge has an inverse _____ behavior
a. r3 c. r b. r2 d. r1/2