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Ready, Set, SCIENCE!, by the National Research Council, focuses on K-8 science classsrooms. Check out the other publications in our online store, as well as classroom materials.

The Planets and Space Exploration

The four rocky planets at the center of the solar system Mercury, Venus, Earth, Mars, are known as the inner planets. Jupiter, Saturn, Uranus, and Neptune are all composed primarily of gas and are known as the outer planets.

There are thousands of smaller, icy not-quite-planets in the space beyond Neptune. They include the dwarf planets Pluto, Haumea, Eris, and Makemake.

The asteroid belt, between Mars and Jupiter, is made of thousands of chunks of rock which travel around the Sun. The largest asteroid, Ceres, is also a dwarf planet. Comets are small icy bodies that travel past the Sun and give off gas and dust each time they pass by.

Unmanned spacecraft have travelled to all the planets in the solar system (except Pluto) and taken pictures of the planets and many of their moons. They have also taken measurements that tell us what the planets are like inside.

Big, Bigger, Biggest

A Solar System Model Builders Guide

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The Summer 2010 issue of The Earth Scientist, available in our online store, includes articles on rivers and snow, classroom planetariums, satellites and oceanography, hands-on astronomy, and global warming.

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Cool It! Game

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

Trans-Neptunian Objects (TNO)

The outer edge of our Solar System is not empty. There are many huge spheres of rock and ice out near Pluto's orbit and beyond. Astronomers have a name for everything further out than the planet Neptune....more

Dwarf Planets

In 2006 the International Astronomical Union (IAU) approved a new classification scheme for planets and smaller objects in our Solar System. Their scheme includes three classes of objects: "small solar...more

Pluto

Pluto is a frigid ball of ice and rock that orbits far from the Sun on the frozen fringes of our Solar System. Considered a planet, though a rather odd one, from its discovery in 1930 until 2006, it was...more

Eris - a dwarf planet

Eris is a dwarf planet in our Solar System. Eris was one of the first three objects classified as a dwarf planet, along with Pluto and Ceres. Eris was first spotted in January 2005. Eris is a large sphere...more

Makemake: a Dwarf Planet

Makemake is a dwarf planet in our Solar System. Makemake was discovered in March 2005 by a team of astronomers led by Mike Brown. Makemake officially became a dwarf planet in July 2008. There were three...more

The Solar System

The solar system is made up of the Sun, the // Call the planets count function defined in the document head print_planet_count('planets'); planets and // Call the planets count function defined in the...more

Solar System Formation

Scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (called a supernova). This explosion made waves in space...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