How many stars

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Learn about the Moon in a great new book New book chronicles the space program. Dave's Universe Year of Pluto. Groups Why Join? Astronomy Day. The Complete Star Atlas. Scientists have a good estimate on the staggering number of stars in the universe. Exactly how many stars are in space? Note the spiral arms. The universe, galaxies, stars Yet astronomers like me have figured out how to estimate the total number of stars in the universe, which is everything that exists.

Like people, galaxies are diverse. They come in different sizes and shapes. Counting the galaxies Before calculating the number of stars in the universe, astronomers first have to estimate the number of galaxies. That number is then multiplied by the number of pictures needed to photograph the whole sky.

Each galaxy contains billions of stars. About two-thirds of the stars in the Milky Way are red dwarfs. Exoplanet is the name for worlds outside our solar system.

Yet astronomers like me have figured out how to estimate the total number of stars in the universe, which is everything that exists. Scattered throughout the universe are galaxies — clusters of stars, planets, gas and dust bunched together.

Other galaxies are elliptical — kind of egg-shaped — and some are irregular , with a variety of shapes. Before calculating the number of stars in the universe, astronomers first have to estimate the number of galaxies. To do that, they take very detailed pictures of small parts of the sky and count all the galaxies they see in those pictures. But we can make a good guess at the number of stars in our own Milky Way. Those stars are diverse, too, and come in a wide variety of sizes and colors.

Our Sun, a white star, is medium-size, medium-weight and medium-hot: 27 million degrees Fahrenheit at its center 15 million degrees Celsius. Bigger, heavier and hotter stars tend to be blue, like Vega in the constellation Lyra. Smaller, lighter and dimmer stars are usually red, like Proxima Centauri. Red, white and blue stars give off different amounts of light. By measuring that starlight — specifically, its color and brightness — astronomers can estimate how many stars our galaxy holds.

Now the next step. Since you can only see half the sky at any time, that means there are as many as 4, stars visible in your sky tonight. And as we continue to learn, all of these stars seem to have planets.

Might on one what happened on Earth also have happened? Meaning the development of intelligent life? Log in to Reply. Some very intelligent videos are posted on Youtube by Prof. David Kipping of Columbia University regarding the search for exoplanets and the likelihood that any will have life evolving on them.

Community Leaders: Notable Astronomers. By: Richard S. Wright Jr. November 9, Imaging Foundations with Richard Wright.