Selenologists study the Moon, as geologists study Earth.

The planet Venus does not tilt as it goes around the Sun, so consequently, it has no seasons. On Mars, however, the seasons are more exaggerated and last much  longer than on Earth.

Scientists believe that hydrogen comprises approximately 90 to 99 percent of all matter in the universe.

45% of Americans don't know that the sun is a star.

The sun's surface can reach 9,980 degrees Fahrenheit, but at its core, it can reach 27 million degrees.

It takes eight minutes for sunlight to reach Earth

The sun burns off the equivalent in weight of 12 ocean liners every second.

When Voyager 2 visited Neptune it saw a small irregular white cloud that zips around Neptune every sixteen hours or so now known as "The Scooter".

The Sun travels at a speed of 155 miles per second, but it still takes 230 million years for it to complete a single revolution of the galaxy.

If it were possible to drive through space at 75mph (120 km/h), you could reach the sun in a little over 142 years. But at that same speed it would take more than 38 million years to reach the stars of the Alpha Centauri system, the closest to ours. Source: "Reader's Digest Book of Facts"

A cumulonimbus cloud can be enormous: six miles across and eleven miles high, and twice as high as Mount Everest.  

The name of the asteroid that was believed to have killed the dinosaurs was named Chixalub. (Pronounced Sheesh-uh-loob)

If a baseball-sized piece of a supernova star (known to astronomers as a pulsar) were brought to Earth, it would weigh more than the Empire State building.

The temperature on the Moon reaches 243 degrees Fahrenheit  
  at midday on the lunar equator. During the night, the  
  temperature falls to -261 degrees Fahrenheit.

An area of the Sun's surface the size of a postage stamp  
  shines with the power of 1,500,000 candles.

Temperature variations on Mercury are the most extreme in  
  the solar system, ranging from 90 K to 700 K.

The moons of Mars are called Phobos and Deimos after two mythical horses that drew the chariot of Mars, the Roman god of war.

The Moon weighs 81 billion tons.

The first person to report a finding on an attempt to measure the distance to the Sun was a Greek astronomer, Aristarchus, who lived in the 3rd century B.C. Unfortunately, the number he came up with was completely wrong, some 20 times too small. It wasn't until the past 100 years that scientists have made more accurate measurements.

Phobos, one of the moons of Mars, is so close to its parent  
  planet that it could not be seen by an observer standing at  
  either of Mars poles. Phobos make three complete orbits  
  around Mars every day.

All the moons of the Solar System are named after Greek and  
Roman mythology, except the moons of Uranus, which are named  
after Shakespearean characters.

M.V.E.M.J.S.U.N.P.  

To remember the order of the planets use the phrase 'My Very Eager Mother Just Served Us Nine Pizzas' - the capital letters give the order of planets, beginning with closest to sun - Mercury, Venus, Earth, Mars Jupiter, Saturn, Uranus, Neptune, Pluto.  (Oops - take out pizza. "My very eager mother just served us nine Napoleons" - Pluto has been demoted!)

  Dog Days  

Meaning: The hottest days of summer.  

The Ancient Romans believed that there was a period during the summer when "the brightest star in the heavens, the dog star 'Sirius,' added its heat to the sun's, making these days veritable inferno."  

Halley`s Comet passes by the Earth approximately  
every 76 years.  

On a clear night in the Northern Hemisphere the naked  
eye can discern some 5000 stars.  

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Olympus Mons on Mars is the largest volcano in our  
solar system.  

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The first American satellite in orbit, Explorer I, was  
launched February 1, 1958.  

Always old, sometimes new, never sad,  
sometimes blue. Never empty, sometimes  
full, never pushes, always pulls.  
What am I?  

Answer = The Moon