Author Question: Why are black holes called black? What will be an ideal ... (Read 71 times)

PhilipSeeMore · **on:** Jul 27, 2018

Why are black holes called black?

What will be an ideal response?

Question 2

Explain why Copernicus' hypothesis, where the Sun was the center of the planetary system, became known as the Copernican Revolution.

What will be an ideal response?

todom5090 · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

The escape velocity of a celestial object is the speed that an object on its surface needs to escape the gravitational field. A black hole is so dense that the escape velocity is greater than the speed of light, so light cannot escape the black hole; hence, the term black.

Answer to Question 2

It became known as the Copernican Revolution because it was not just the adoption of a new idea but a total change in the way astronomers, and, in fact, all of humanity, thought about Earth and its place in the Universe. In fact, our modern use of the words revolution and revolutionary to describe philosophical, political, and social upheavals comes from the title of Copernicus's book, De Revolutionibus, which means On Revolutions.