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Exploratour - Life on Earth


Corel Photography

At one time or another, we've probably all wondered how life first got started. This is not an easy question! There are at least three kinds of explanations for how life on Earth began:

1) Life was created. Some people believe that life on Earth was created by a supreme being or spirit. These ideas have been around for a very long time and differ among different cultures and religions. We can't use science to test these ideas, so we leave it to each person to decide for him- or herself.

2) Life began somewhere else in the universe, then arrived on Earth later. This idea got some new attention with the recent discovery of a meteorite from Mars. The meteorite showed some signs that ancient forms of life may have existed on Mars a long time ago, but more research is needed before we can reach any conclusions.

3) Life began on Earth by chance. Many scientists believe that life began as the result of complex chemical reactions that took place in the Earth's atmosphere 3.5 billion years ago. When chemicals in the atmosphere interacted with the electricity from lightning, certain substances formed that were necessary for early forms of life. In the 1950's, two biochemists conducted an experiment which showed how this could happen in the laboratory.



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ExploraTour - Looking at the World in a Different Light

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ExploraTour - Looking at the World in a Different Light

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ExploraTour - Looking at the World in a Different Light

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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

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ExploraTour - Looking at the World in a Different Light

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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