Our Solar System

Our solar system is filled with a wide assortment of celestial bodies - the Sun itself, our eight planets, dwarf planets, and asteroids - and on Earth, life itself! The inner solar system is occasionally visited by comets that loop in from the outer reaches of the solar system on highly elliptical orbits. In the outer reaches of the solar system, we find the Kuiper Belt and the Oort cloud. Still farther out, we eventually reach the limits of the heliosphere, where the outer reaches of the solar system interact with interstellar space. Solar system formation began billions of years ago, when gases and dust began to come together to form the Sun, planets, and other bodies of the solar system.

Have you ever seen the <a href="/earth/Magnetosphere/aurora.html">Southern or Northern Lights</a>? Earth isn't the only planet that puts on these beautiful light shows, which are also called the "<a href="/earth/Magnetosphere/aurora.html">aurora</a>". Aurora have been seen at both <a href="/saturn/saturn_polar_regions.html">poles of Saturn</a>, too, as well as at the poles of <a href="/jupiter/magnetosphere/jupiter_aurora.html">Jupiter</a>. These "<a href="/earth/Magnetosphere/tour/tour_earth_magnetosphere_09.html">curtains of light</a>" sometimes rise 1,200 miles (2,000 km) above the <a href="/saturn/atmosphere/S_clouds_overview.html">cloud tops</a> near Saturn's poles. The <a href="/space_missions/HST.html">Hubble Space Telescope</a> took this picture in 2004.<p><small><em>Image courtesy of NASA, ESA, J. Clarke (Boston University), and Z. Levay (STScI)</em></small></p>Comets are <a href="/comets/comet_nucleus.html">lumps</a> of ice and dust that periodically come into the center of the solar system from its <a href="/comets/Oort_cloud.html">outer reaches</a>. Some comets make <a href="/comets/perihelion_pass.html">repeated trips</a> to the inner solar system. When comets get close enough to the Sun, heat makes them start to <a href="/comets/sublimation.html">evaporate</a>. Jets of gas and dust form long <a href="/comets/tail.html">tails</a> that we can see from Earth. This photograph shows <a href="/comets/comets_table.html">Comet Kohoutek</a>, which visited the inner solar system in 1973. It has an <a href="/physical_science/physics/mechanics/orbit/orbit_shape_interactive.html">orbit</a> of about 75,000 years!<p><small><em>Image courtesy of NASA</em></small></p>Lunar eclipses are special events that only occur when certain conditions are met. First of all, the Moon must be in <a href="/the_universe/uts/moon3.html">full phase</a>. Secondly, the <a href="/sun/sun.html">Sun</a>, <a href="/earth/earth.html">Earth</a> and <a href="/earth/moons_and_rings.html">Moon</a> must be in a perfectly straight line. If both of these are met, then the Earth's shadow can block the Sun's light from hitting the Moon. The reddish glow of the Moon is caused by light from the Earth's limb scattering toward the Moon, which is reflected back to us from the Moon's surface.<p><small><em>Image credit - Doug Murray, Palm Beach Gardens, Florida</em></small></p>This historic image is the first ever taken from a spacecraft in orbit about <a href="/mercury/mercury.html">Mercury</a>, the innermost planet of the solar system. Taken on 3/29/2011 by <a href="/space_missions/robotic/messenger/messenger.html">MESSENGER</a>, it shows numerous craters across the <a href="/mercury/Interior_Surface/Surface/surface_overview.html">surface</a> of the planet. Temperatures there can reach over 800°F because Mercury is so close to the Sun and rotates so slowly. MESSENGER entered orbit around Mercury earlier in March 2011.<p><small><em>NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington</em></small></p>This dramatic view of Jupiter's <a href="/jupiter/atmosphere/J_clouds_GRS.html">Great Red Spot</a> and its surroundings was obtained by <a href="/space_missions/voyager.html">Voyager 1</a> on Feb. 25, 1979, when the spacecraft was 5.7 million miles (9.2 million kilometers) from Jupiter. Cloud details as small as 100 miles (160 kilometers) across can be seen here. The colorful, wavy cloud pattern to the left of the Red Spot is a region of extraordinarily complex end variable wave motion.<p><small><em>Image courtesy of NASA</em></small></p><a href="/asteroids/asteroid_lutetia.html">Lutetia</a> is a medium-sized <a href="/our_solar_system/asteroids.html">asteroid</a>. It orbits the <a href="/sun/sun.html">Sun</a> in the main asteroid belt between the planets <a href="/mars/mars.html">Mars</a> and <a href="/jupiter/jupiter.html">Jupiter</a>. This lumpy object is about 96 km (60 miles) in diameter. It isn't a perfect sphere, though. Lutetia is 132 km (82 miles) across one way, but only about 76 km (47 miles) long in another direction. The European space probe <a href="/space_missions/robotic/rosetta_flyby_asteroid_lutetia_july_2010.html">Rosetta flew past Lutetia</a> in July 2010, and gave us our first good look at the asteroid.<p><small><em>Image courtesy of ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA.</em></small></p>

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Explore Our Solar System

Solar System Formation

Solar system formation began billions of years ago, when gases and dust began to come together ...Read more

Sun

The Sun is the closest star to Earth and is the center of our solar system. A giant, spinning ...Read more

Planets

By the current count of astronomers, our solar system includes 8 planets and 5 dwarf planets. ...Read more

Dwarf Planets

In 2006 the International Astronomical Union (IAU) approved a new classification scheme for ...Read more

Asteroids

Asteroids are small bodies that are believed to be left over from the beginning of the solar ...Read more

Meteors, Meteoroids, and Meteorites

Meteors are streaks of light, usually lasting just a few seconds, which people occasionally ...Read more

Comets

Not long ago, many people thought that comets were a sign that something bad was about to ...Read more

Poles in Space

The areas around the North and South Poles of planets, moons, and even the Sun are often interesting ...Read more

Culture, Myth, and Arts

Make important cultural connections about the Sun, planets, and the Moon. ...Read more

Solar System Discoveries

Who discovered the planets? For many of the planets in the solar system, we'll never know! ...Read more

More about Our Solar System

Did you know?

Did you know that the physics of a spinning dancer and the formation of the solar system have something in common?

Did you know that our solar system now has eight planets and five dwarf planets, according to the International Astronomical Union?

 

Earth and Space Science Concept of the Day

Do you know what this word or phrase means?

Tide
xTide : A tide is the regular rising and falling of the ocean's surface caused by the gravitational pull of the Moon and the Sun on the ocean and the Earth's rotation.

Click on the word to find out!

Research Highlights

Caribbean Coral Reef Protection Efforts Miss the Mark

Conservation efforts to protect endangered corals in the Caribbean focus on the areas that have the largest variety of species. Ann Budd of the University of Iowa and John Pandolfi of the University of...Read more

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