A shooting star.

GUESS WHAT!

A "shooting star" is not a shooting star! It's actually a broken fragment of a comet (Ice, dust, and rock,) that travels through space, orbiting the sun. When this piece of debris is in outer space it is called a meteoroid. Gravity will eventually pull the meteoroid into Earth's atmosphere, making it a meteor. As these fragments of rock fall into Earth's atmosphere, they will experience a buildup of frictional heat. The heat makes the particles of the meteor glow brightly as it continues to fall. Most meteors will burn up before they hit the Earth, but if they are large enough and make it to the ground, they are called a meteorite. When you are staring into the beautiful night sky and notice a streak of light pass by, you are looking at a "shooting star."

The largest meteorite was discovered in 1920 by a farmer in Namibia. It is nine feet long, nine feet wide, and three feet thick. "Hoba" weighs 66 tonnes, and is composed of 84% iron, 16% nickel. It currently resides in its original location of discovery.

The Sun.

98% of our total solar systems mass is taken up by the Sun, making it the largest object in the solar system. The Sun is around 70% Hydrogen, and 28% Helium. The last 2% is made up of "metals". This can slowly change over time as the Sun converts Hydrogen to Helium in its core (The inner 25% of its radius). The Sun produces power by Nuclear Fussion Reactions.

The Sun is approximately 4.5 billion years old, and has used up to half of the Hydrogen in its core. For the next 5 billions years it will continue to radiate, and it's luminosity will double in that time. Eventually, the Sun will run out of Hydrogen fuel and be forced into radical changes. This means that through commonplace by stellar standards, it will result in the total destruction of the Earth.

R136a1

R136a1 is a newly discovered star, founded by a group of British astronomers. This star is outside of the milky way in star cluster R136. It is believed that R136 contains tens of thousands of stars within a few light-years of space. Hundreds of it's stars, which are rare and massive, are so bright that any planet orbiting a star in the middle of it's cluster does not experience darkness at night. R136a1's mass is said to be around 265 times larger than the sun. Even though this star is only a little over a million years old, it has already lost around a fifth of it's initial mass.

As of July 2010, this star has the highest known stellar luminosity. The temperature at the surface of this star reaches up to 50 thousand degress celsius, which is almost 8 times more heat than the sun. It is ten million times brighter than the sun, and 165,000 light-years away from Earth. Sadly, this star will only live for approximatlely 3 million years.


http://www.theepochtimes.com/n2/content/view/39587/