The observations show that the motion of the individual star is governed by the gravitational field of the cluster as a whole, rather than the pull of any one galaxy. In other words, they are truly …

In 1912, Henrietta Swan Leavitt noted that 25 stars, called Cepheid stars, in the Magellanic cloud would brighten and dim periodically. Leavitt was able to measure the period of each star by …

Here is a star chart to help you find the Andromeda Galaxy. Note that the top of the image is north and east is to the left side of the image. Think about what you are really seeing: It is a whole …

A star is a big ball of gas which gives off both heat and light. So where do stars come from? What happens to them as they grow older? A galaxy contains clouds of dust and gas, as well as …

Una estrella es una esfera de gas caliete que brilla intensamente cuya energía es producida por un proceso interno de fusión nuclear. Las estrellas se encuentran en galaxias. Una galaxia no …

The International Astronomical Union is the only OFFICIAL agency which names stars and other celestial objects. There are standardized rules for how objects get their names. None of these …

What is the solar system? It is our Sun and everything that travels around it. Our solar system is elliptical in shape. That means it is shaped like an egg. The Sun is in the center of the solar …

Centaurus A, An Elliptical Galaxy Centaurus A (or Cen A for short) is a typical elliptical galaxy. Its unusual name comes from radio astronomy; Centaurus A was the first source of radio waves …

Galileo Galilei was an Italian physicist and astronomer. He was born in Pisa on February 15, 1564. Galileo's father, Vincenzo Galilei, was a well-known musician. Vincenzo decided that his …

This result surprised many scientists who thought that it would have taken much longer for gravity to pull enough matter together to make a star. This animation (5.0 MB) shows how the …