Facts About Solar System Planets

Help for Science Projects and Reports

Jul 8, 2007 Denise Oliveri

Here are some facts to help you out when teaching or learning about the planets in our solar system. There may even be a 10th planet coming soon!

There are currently nine planets in our solar system. Each planet orbits around the Sun. When a planet makes a complete path around the Sun, it is called a revolution. Our planet, Earth, takes approximately 365.25 days to make a revolution. Planets that are farther away from the Sun take longer to make a revolution. Planets spin on an axis, which is an imaginary line that goes through the center of the planet. The time it takes Earth to rotate on its axis equals one day or 24 hours.

Here are some interesting facts about each of the planets:

(Day = midday to midday)

Mercury

• Distance from Sun: 36 million miles
• Diameter: 3,032 miles
• Average Temperature: 333° F
• Surface: Silicate rock
• Revolution: 88 days
• Day: 175.94 days
• Number of moons: 0
• Neat Fact: Closest planet to the Sun.

Venus

• Distance from Sun: 67 million miles
• Diameter: 7,521 miles
• Average Temperature: 867° F
• Surface: Silicate rock
• Revolution: 224.7 days
• Day: 116.75 days
• Number of moons: 0
• Neat Fact: Rotates in the opposite direction from the other planets.

Earth

• Distance from Sun: 93 million miles
• Diameter: 7,926 miles
• Average Temperature: 59° F
• Surface: Water, basalt, and granite rock
• Revolution: 365.25 days
• Day: 24 hours
• Number of moons: 1
• Neat Fact: Travels around the Sun at a speed of >66,000 miles per hour.

Mars

• Distance from Sun: 142 million miles
• Diameter: 4,213 miles
• Average Temperature: -81° F
• Surface: iron-rich basaltic rich
• Revolution: 687 days
• Day: 24 hours 39 minutes 35 seconds
• Number of moons: 2
• Neat Fact: The largest volcano in the Solar System is on Mars. It is called Olympus Mons.

Jupiter

• Distance from Sun: 484 million miles
• Diameter: 88,732 miles
• Average Temperature: -162º F
• Surface: Liquid hydrogen
• Revolution: 11.9 years
• Day: 9 hours 55 minutes 30 seconds
• Number of moons: 63
• Neat Fact: The four largest moons were found by Galileo in 1601; the others were discovered in 2003.

Saturn

• Distance from Sun: 887 million miles
• Diameter: 74,975 miles
• Average Temperature: -218º F
• Surface: Liquid hydrogen
• Revolution: 29.5 years
• Day: 10 hours 39 minutes 23 seconds
• Number of moons: 47
• Neat Fact: Galileo discovered the rings around Saturn with a simple early telescope.

Uranus

• Distance from Sun: 1.8 billion miles
• Diameter: 31,763 miles
• Average Temperature: -323º F
• Surface: Liquid hydrogen and helium
• Revolution: 84 years
• Day: 17 hours 14 minutes 23 seconds
• Number of moons: 27
• Neat Fact: Its north pole stays dark for 42 years at a time.

Neptune

• Distance from Sun: 2.8 billion miles
• Diameter: 30,603 miles
• Average Temperature: -330º F
• Surface: Liquid hydrogen and helium
• Revolution: 164.8 years
• Day: 16 days 6 hours 37 minutes
• Number of moons: 13
• Neat Fact: Neptune can have winds up to 2400 miles per second.

Pluto

• Distance from Sun: 3.6 billion miles
• Diameter: 1,485 miles
• Average Temperature: -369º F
• Surface: Rock and frozen gases
• Revolution: 247.7 years
• Day: 6 days 9 hours 17 minutes
• Number of moons: 3
• Neat Fact: Some scientists do not consider Pluto to be an actual planet.

More Planet Facts

• Largest Planet: Jupiter
• Smallest Planet: Pluto
• Fasting Orbiting Planet: Mercury
• Slowest Orbiting Planet: Pluto
• Hottest Planet: Venus
• Coldest Planet: Pluto
• Shortest Day: Jupiter
• Longest Day: Mercury

New Planet Coming Soon

Xena was discovered in 2003. Astronomers in 2006 stated that it is an object that is bigger than Pluto and located about 9 billion miles from the Sun. Could this one day be considered the 10th planet? Time will tell.

The copyright of the article Facts About Solar System Planets in Homeschooling is owned by Denise Oliveri. Permission to republish Facts About Solar System Planets in print or online must be granted by the author in writing.

The nine planets

17 Comments

Comments

May 16, 2008 2:42 AM

Guest :

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Jun 8, 2008 3:14 PM

Guest :

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Aug 25, 2008 11:27 AM

Guest :

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Aug 25, 2008 4:41 PM

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Dec 17, 2008 2:06 PM

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Dec 29, 2008 12:51 PM

Guest :

Pluto is no longer considered a planet. The International Astronomical Union (who decides on these things) reclassified it in 2006 as a "dwarf planet". Therefore, Neptune is now the slowest-orbiting planet. Please update your site for your students. Thanks.

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Oct 19, 2009 8:56 PM

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17 Comments