Fireballs that Produce
Meteorites
- Fireballs in the sky are caused by interplanetary debris crashing
into Earth's atmosphere. Some fireballs result in showers of
meteorites, rocks or metal that fall from the sky.
This page follows an international team as they put these two
phenomena together to learn the composition, structure, and paths
of these objects.
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Iridescent Clouds
- Have you ever seen clouds near the sun shimmering with pearly
colors? This effect is produced by a different optical
process than the more familiar rainbow. This page helps you
to see iridescent clouds yourself, and to understand what causes
them.
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Building Planets at PSI
- At PSI, theoretical computer models are used to investigate
how the planets formed.
This page shows how we can learn about the early history of
our solar system by using physics to create computer models and
comparing them with observations of the real solar system.
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The Origin of the Moon
- In 1975, two PSI scientists were first to suggest the leading
modern hypothesis of the moon's origin. This page shows how
the moon is believed to have formed, as well as showing the
process of science, the formation and testing of a hypothesis,
and the roles of observation and theory in advancing scientific
knowledge.
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Introduction to Martian Cratering
Studies - By measuring the distribution of craters on
the surface of a planet, much can be learned about the age of the
surfaces, the volcanic and erosional processes occurring there, and
even about the planet's atmosphere. This page is an introduction
to cratering studies on the planet Mars.
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Siberia Explosion
- In 1908, a large meteorite exploded over a remote area of Siberia.
PSI scientist and artist William K. Hartmann used the eyewitness
accounts of this event to attempt to reconstruct what happened and to
create paintings showing what it may have looked like to observers.
This page presents his results and explores the significance
of asteroid impacts to our planet.
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The KT-Boundary Impact
- According to abundant geological evidence, an asteroid roughly
six miles across hit the earth about 65 million years ago. The
impact made a crater over 100 miles across, severely altering
the climate of the whole planet and causing the extinction of
three-fourths of the species then existing. This page explores
what we know about this impact, how we know it, and the implications
for future impacts.
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The Coronado Expedition - In the 1530s
and 1540s, the first European exploration of the American Southwest
included a large expedition led by the Spanish explorer Coronado.
This page describes the circumstances of the expedition, the route,
the people who carried it out, and the archeological investigations
that revealed the details and route of the expedition.
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