Planets
By the current count of astronomers, our solar system includes 8 planets and 5 dwarf planets. The planets were formed during the process of solar system formation, when clumps began to form in the disk of gas and dusk rotating about our young Sun. Eventually, only the planets and other small bodies in the solar system remained. 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. Find out more about the planets through the links below.
What's New on the Site?
When Nature Strikes - Earthquakes
When Nature Strikes - Volcanoes
When Nature Strikes: Tsunami Classroom Activity
When Nature Strikes: Wildfires - Why are they a challenge to stop?
Windows to the Universe Community | |
News | Opportunities |
Explore Planets
What is a Planet?
Do you know what a planet is? If so, you are doing better than professional astronomers! Right ...Read more
Mercury
Mercury, the planet nearest the Sun, is the second smallest planet in the solar system. Only ...Read more
Venus
Fair but inhospitable Venus, a "Sister" planet to the Earth that is very different from our ...Read more
Mars
Mars, Earth's outer neighbor, is the fourth planet from the Sun. Mars' bright appearance and ...Read more
Jupiter
Jupiter is the largest planet in the solar system. When approached from afar, its fantastic ...Read more
Saturn
Saturn, the sixth planet from the Sun, has the most spectacular set of rings in the solar system. ...Read more
Uranus
Uranus, the seventh planet from the Sun, has its spin axis almost in the plane of its orbit ...Read more
Neptune
Neptune, the eighth and furthest planet from the Sun, is a very cold place. Its bluish color ...Read more
Dwarf Planets
In 2006 the International Astronomical Union (IAU) approved a new classification scheme for ...Read moreMore about Planets
- Planets Around Other Stars
- Tours
Global locations of visitors using this page right now
Historical Events
Full Earth and Space Science History Calendar (Members only)
Teacher Opportunities
Full Teacher Events Calendar (Educator Members only)
Did you know?
Did you know that there are no seasons on Venus?Do you know how Neptune was discovered?
Earth and Space Science Concept of the Day
Do you know what this word or phrase means?Alluvium
xAlluvium : Alluvium is loose gravel, sand, silt, or clay deposited by streams.
Click on the word to find out!
Research Highlights
“Missing” Heat May Affect Future Climate Change
As greenhouse gases build up in the atmosphere, more of the energy that gets to Earth from the Sun sticks around the planet. This means that the amount of energy coming to Earth is greater than the amount...Read more
Please log in
Science Blogs
Real Climate: climate science from climate scientists
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.
