The answers are as follows:
1. C
In physics, time in space is measured by using the speed of light. The speed of light in a vacuum has been recorded to be 186,282 miles per seconds and in miles per hour, the speed of light is 670,616, 629 miles per hours. It is believed that no other thing can travel as fast as light.
2. D
The milky way, which is the earth galaxy is the galaxy that contains the earth solar system and is made up of billions of stars. An estimate of 100 billion stars has been attributed to the milky way. Some of these stars are either smaller or bigger than the sun.
3. A.
There are three major types of galaxy, these are irregular galaxy, spiral galaxy and elliptical galaxy. Random galaxy is not a type of galaxy. The mostly widely used classification for galaxy is based on the work of Edwin Hubble which used these three main types.
4. D
There is a theory of earth evolution which is generally acceptable by all scientists, this theory is called Bing Bang theory. This theory explains that, about 15 billion years ago there was a big explosion which marks the beginning of the universe.
