comets
It reach when your mother had sucked your dads dick
Burns up before entering the Earths atmosphere
meteorites
The Earth's shield that protects it from space debris is called the atmosphere. The atmosphere acts as a protective layer, burning up most incoming objects before they reach the Earth's surface.
Its called friction. When the rock enters the atmosphere it can be travelling at thousands of miles and hour. In space there is nothing to slow it down, when it comes to the Earths atmosphere there is resistance as the air tries to slow it down, this creates heat and the tempretures can reach thousands of degrees, rock melts at about 1200ºC.
No, a bullet cannot reach the Earth's atmosphere because it is already on Earth's surface. Bullets are fired from guns on the ground and do not have the velocity or trajectory to escape the planet's gravitational pull and reach space.
Meteors
Meteorites are meteoroids that survive their journey through Earth's atmosphere and reach the surface without completely burning up. They can be composed of rock, metal, or a combination of both and provide valuable information about the early solar system.
A meteor IS a what you call a body of matter when it enters earth's atmosphere. A meteoroid is what you call a body of matter in space that hasn't entered earth's atmosphere. Source: Dictionary.com http://dictionary.reference.com/browse/meteor
The air becomes less dense, the higher you go. And generally, the temperature gets colder until you reach the thermosphere, which is the hottest part of Earths atmosphere.
Pieces of stone that enter the Earth's atmosphere are commonly referred to as meteoroids. When they burn up upon entering the atmosphere, they create a streak of light known as a meteor or shooting star. If any fragments of the meteoroid reach the Earth's surface, they are called meteorites.
It takes around 8 minutes for a rocket to reach space and escape Earth's atmosphere. This can vary slightly depending on the specific rocket and its speed.