Scintillation, or the 'twinkling' we see of stars in the sky, is due to motions in the earth's atmosphere. Sometimes the sky is very clear and you can see fainter stars, while other times it is a little hazy and you can see only the brighter stars. I'm not sure why you see stars on some nights where there were none before. How come some nights we see stars where there were none before? Most of them are too faint to see except through a big telescope. So the total number of stars in space is HUGE!!!! Of course you can't see them all. There are billions of other galaxies, too. We think that there are about 200 billion stars in our galaxy, the Milky Way.

If you put Betelgeuse into our solar system, it would swallow up Mercury, Venus, Earth, and Mars!!! Also it is about 10,000 times brighter than our sun (because a larger star is brighter). It is about 500 times bigger than our sun. That is why it is red - red stars are cooler than the sun, blue-white stars are hotter.īetelgeuse is, however, much bigger and brighter. The sun's surface temperature is about 5,800° Kelvin (about 10,000° Fahrenheit), and Betelgeuse is roughly half that, about 3,000° Kelvin (about 5,000° Fahrenheit). How many times hotter, brighter, and larger is Betelgeuse than the sun?īetelgeuse is actually cooler than our sun. If the sun were a red supergiant, it would swallow up Mercury, Venus, Earth, Mars, and some asteroids! That would be about 300 million miles across, which is over three times the distance between Earth and the sun. If you plopped Betelgeuse into the middle of our solar system, it would fill it out to roughly the orbit of Jupiter! Red supergiants are about 400 times larger than our sun. The biggest stars are known as 'red supergiants.' The star Betelgeuse (which is in the constellation Orion) is one. The funny thing is that a baby star is BIGGER than an adult star! It takes about 20 million years for the new star to get to this point. Finally the center becomes so hot that the hydrogen gas starts to undergo nuclear reactions to become helium, which provides the energy for the star to keep shining for billions of years.

Then the rest of the cloud of gas and dust either falls into the star or gets blown away, and the star gets hotter and smaller due to gravity.

That takes about a million years, if the star is about the mass (weight) of our sun.

Then the center of the blob becomes hot enough to give off visible light and most of the cloud of gas and dust has fallen into it.

First the cloud of gas and dust comes together, due to gravity, to form a 'protostar' (a hot blob that is not quite a star but will eventually become a star) that takes thousands of years.

There are several steps in the formation of a star: Cathy Imhoff of the Space Telescope Science Institute. The following questions were answered by astronomer Dr.

Mass effect black blob