Solar System Exploration: Planet Selector: Sun

PLANET SELECTOR

ABOUT THE SUN

The Sun is a star, a hot ball of glowing gases at the heart of our solar system. Its influence extends far beyond the orbits of distant Neptune and Pluto. Without the Sun's intense energy and heat, there would be no life on Earth. And though it is special to us, there are billions of stars like it scattered across our galaxy.
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Featured Mission: SOHO
The international Solar and Heliospheric Observatory (SOHO) has been keeping a steady watch on the Sun since April 1996.
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VITAL STATISTICS

Distance to Nearest Star:	39,900,000,000,000 km (24,800,000,000,000 miles)
Diameter:	1,391,000 km (864,300 miles)
Volume:	1,412,200,000,000,000,000 km³ (338,800,000,000,000,000 miles³)
Mass:	1,989,000,000,000,000,000,000,000,000,000 kg (332,965 x Earth's)
Number of Planets:	8

SIZE & DISTANCE

If the Sun were as tall as a typical front door, Earth would be about the size of a nickel.

Average Distance from Earth: 149,597,890 km (1 A.U.)

EXTREME SPACE

Solar Sizzle
The super hot center of the Sun blazes at 15,700,000°C (18,000,000°F) - more than 40,000 times as hot as boiling water. The surface of the Sun - the part we can see - is a relatively cool 5,500°C (9,900°F) - more than 15 times as hot as boiling water.

What a Blast
You'd need to explode 100,000,000,000 tons of dynamite every second to match the energy produced by the Sun.

Long Arm of the Sun
Even though it is about 13,500,000,000 km (8,200,000,000 miles) out, NASA's Voyager 1 spacecraft is still within our Sun's sphere of influence. It has been more than 13 years since it passed the farthest point in the orbit of Pluto, our solar system's most distant known planet.

Long Ride
The Sun seems small when we look at it because it is 150,000,000 km (93 million miles) from Earth. If you could somehow fly an airplane to the Sun, it would take 26 years. Even super fast particles of light take eight minutes and 19 seconds to get from the Sun to Earth.

Cosmic Calculation
Our Sun is one of about 70,000,000,000,000,000,000,000 (that's 70 sextillion) stars in the universe. Even though most are too faint to see, there are more stars out there in space than there are grains of sand on Earth.

That's All, Folks...
When the Sun starts to die, it will swell so big that it will almost engulf the Earth. Vast magma oceans will make our home planet a very unpleasant place to live. Fortunately, scientists predict the Sun is a little less than halfway through its lifetime. We have about 6.5 billion years to find a new home.

TIMELINE

150 A.D. - Greek scholar Claudius Ptolemy launches a 1,000-year misconception when he writes that the Sun and planets revolve around the Earth.

1507-1515 - Polish astronomer Nicolaus Copernicus determines that the planets revolve around the Sun - launching a new age of astronomy.

1645-1715 - Sunspot activity declines to almost nothing on the Sun - possibly causing what is known as the ''Little Ice Age'' here on Earth.

1845 - French physicists Luis Fizeau and Leon Focault use the fairly new technology of photography to take the first snapshot of the Sun.

1860 - Observers of a total solar eclipse on July 18, 1860 see a massive burst of material from the Sun - the first recorded coronal mass ejection.

1994 - The Ulysses spacecraft makes history as it begins the first observations of the Sun's polar regions, which are not visible from Earth.

SLIDE SHOW

First Photograph of the Sun (1845)
A Massive Plasma Eruption
Sunspot Activity
Hot Coronal Loops
Light Bulb-Shaped Eruption
Spacewalker in Sunlight
The Sun's Corona
Solar Eclipse
Earth During Solar Eclipse
X-ray View of the Sun

MOONS

The Sun has no moons. Moons are natural satellites which orbit planets and, in a few cases, smaller objects such as asteroids. Planets orbit stars such as the Sun. Our Sun's gravitational grip holds four ''terrestrial'' planets (Mercury, Venus, Earth and Mars), four gas giant planets, (Jupiter, Saturn, Uranus and Neptune), Pluto and thousands of asteroids, comets and other debris in orbit.