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Exploratour - Evolution of the Solar System

This is a schematic showing the forming solar system.
Click on image for full size
C. Alexander

As the cloud contracted, it rotated faster and faster, just like an ice skater that spins faster as she pulls in her arms. The momentum of the rotation flattened the originally round cloud into a disk, somewhat the way a ball of pizza dough can be made flat by spinning it in the air. As it flattened, gaseous material condensed, then collected together to form more solid material. Eventually, the cloud grew hotter and denser in the center, with a disk of gas and dust surrounding it such that it was hot in the center but cool at the edges.

The little particles of condensed, solid material were warm, soft and sticky, and whenever they touched each other, further clumped together to form larger balls of solid material somewhat the way pieces of "silly putty" would stick together if they came into contact. The hot and dense part in the center we call a proto-sun, meaning that it was a forming sun. The large balls of clumpy stuff, which could be boulder sized to asteriod sized, we call "planetismals", meaning that they were miniature planets. Eventually only a few large clumps of this material remained in the forming solar system, and they became the core of "proto-planets".

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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 radiate in the infrared. The warmer the object, the higher the frequency and intensity of the radiation. Very hot objects give off other types of radiation in addition to infrared. Click...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

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