They are made up of hydrogen and helium because of which they produce heat & light.
The Sun is a Star!
Yes, the Sun is the biggest Star that is closest to the Planet Earth’s surface.
Relative Motion
As the Earth’s motion is towards the east (at 1K miles per hour), the Stars look like rising in the east and setting in the west.
Stars are always present in the sky both during the daytime and at night. But since the Earth rotates on its own axis, just like the Sun, we see that stars also rise and set.
Presence of Stars
Appearance of Stars
We know that the Sun is closer to the Earth and it is brighter than any other Star. Due to their less intense brightness compared to the Sun, Stars cannot be noticed during the daytime.
Why are Stars Visible Only at Night
During nighttime, due to the absence of the Sun, the sky becomes darker. This is when we can visualise the brightness of different Stars located miles away from the Earth.
Stars Not Visible at Night?!
Yes, sometimes we cannot see Stars in the nighttime also. The reason could be because of the clouds.
How intense are the clouds?
The thinnest cloud is enough to hide a less intense Star, where as thicker clouds can even hide the Moon in the sky.
Count the Stars
Though there are about 5,000 Stars that can be seen from the naked eyes, Earth’s rotation limits their visibility to us.
Twinkling Star
If the sky is clear enough at night, the Stars twinkle due to the effect of winds in the atmosphere, temperature difference and the change in areas with densities.
Stargazing
Since Moon’s brightness can also hide the stars, we can see an many as possible stars if there is no Moon in the sky.
Actual Count
It is believed that there are around 200 billion trillion Stars in the universe as of 2021. But we can only see the Stars that are about 4000 light years away or less than that from us.