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Become a nitrogen atom in the nitrogen cycle in our Traveling Nitrogen Classroom Activity Kit/Game. See all our games, activity kits and classroom activities.

ExploraTour: A Peek into the Lives of the Stars

What Happens to Stars Much Heavier Than The Sun?

STAGE 4b: Black Hole

If the central core, that remains after the supernova blast, is greater than 3 times the sun's mass, the internal pressure cannot halt the gravitational collapse. The core will continue to collapse to form a black hole.

In a black hole, there is so much mass compressed into such a small volume that gravity prevents even light from escaping. Since no light can ever reach your eyes from the collapsed core, it appears black, hence the name.

The apparent surface of the black hole is the radius at which light just manages to escape. It is called the event horizon.

For example, a black hole with 3 times the solar mass would have a circumference of 55.5 kilometers (the size of a town). The Earth as a black hole would only be a couple of centimeters in diameter (about the size of a marble)!

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Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

ExploraTour - Looking at the World in a Different Light

Even though the sleeping man is no longer on the bed, you can still see where he was lying down. The heat from his body warmed up the bed sheets which are now radiating infrared light toward your eyes....more

ExploraTour - Looking at the World in a Different Light

All warm objects (not just people) radiate in the infrared. Warmer objects give off more infrared radiation. Very hot objects radiate other types of light in addition to infrared. Click on the picture...more

ExploraTour - Looking at the World in a Different Light

Your eye is a wonderful detector of visible light. Different frequencies of light produce different sensations in the eye which we interpret as colors. Our eyes detect light by using light sensitive components...more

ExploraTour - Looking at the World in a Different Light

Imagine you found a pair of special glasses that not only gave you telescopic vision but gave you the ability to see all forms of radiant energy. The universe in visible light contains all the familiar...more

ExploraTour - Looking at the World in a Different Light

This is a volcano on the island of Miyake in Japan. It has erupted, sending hot lava and ash into the air, a total of ten times. The time after one eruption until the next occurred was about twenty years...more

ExploraTour - Looking at the World in a Different Light

This is a picture of a galaxy in visible light. A galaxy is a large number of stars, some like our sun, some bigger, some smaller and all moving together through space. This galaxy is called Centaurus...more

ExploraTour - Looking at the World in a Different Light

This is a plant in Gary, Indiana where power is made. We use power to run things like television sets, radios, lights, and microwave ovens. The picture looks very strange because it was taken in infrared....more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA