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Science, Evolution, and Creationism, by the National Academies, focuses on teaching evolution in today's classrooms. Check out the other publications in our online store.

ExploraTour - Looking at the World in a Different Light


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NASA / Smithsonian Astrophysical Observatory

The awesome power of a giant black hole was revealed by looking at this galaxy in three different types of light. The picture that you see is of Centaurus A, a very peculiar galaxy.

A galaxy is just a large group of stars that are moving together through space. Centaurus A is different because something violent is happening there. At the center of Centaurus A, scientists believe there is a very large black hole.

When stars quit burning because they use up their fuel, the gas in their outer layers falls inward on top of the gas at the center. This falling gas crushes everything below it. Soon the star has been smashed into a very small object. But this object has such strong gravity that not even light can get away from it. This object is called a black hole because it is totally black -- we cannot see it.

Other stars can fall into the black hole and also be crushed. When this happens, the black hole gets bigger and more powerful.

The black hole at the center of this galaxy is spinning and making a big jet of gas squirt out of the top and bottom. This gas jet is very hot and so it emits x-rays. Electrons moving near the black hole give off radio waves.


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Traveling Nitrogen Classroom Activity Kit

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

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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

The awesome power of a giant black hole was revealed by looking at this galaxy in three different types of light. The picture that you see is of Centaurus A, a very peculiar galaxy. A galaxy is just a...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