Most comets are found in 2 regions of the solar system: _______________ and _____________.
Kuiper belt- A __________-shaped region that extends beyond ________ orbit to about 100 times ___________distance from the sun.
Oort cloud- A ____________region of comets that surrounds the ________ system out to more than 1,000 times the distance between _________ and the _________.
A _______ and _______ space object. Most asteroids are found in the __________ belt. The asteroid belt is located between the orbits of _______ and __________.
There are about 40,000 known asteroids that are over 0.5 miles (1 km) in diameter in the asteroid belt. About 3,000 asteroids have been cataloged. There are many smaller asteroids (100,000).
Asteroids are made of _______, silicate, ______, nickel, and carbon. The first one discovered (and the biggest) is named _________; it was discovered in 1801. Asteroids range in size from tiny pebbles to about 578 miles (930 kilometers) in diameter (Ceres).
Asteroids can be pulled out of their solar orbit by the ___________ pull of a planet. They would then orbit that ________ instead of orbiting the Sun. Astronomers theorize that the two moons of _______, Phobos and Deimos, are captured asteroids.
Scientists hypothesize that one or more large asteroids hit Earth 65 million years ago and caused extinction of the ___________. Scientists also hypothesize that the largest mass extinction, 250 million years ago, killing off 90% of all species was also caused by a large asteroid
Meteoroid-A _______ of _______ or ________ in space. Meteoroids come from ______ or ___________.
When a meteoroid enters Earth’s atmosphere, ____________ with the air creates heat and produces a _________ of light that you can see in the ______. A __________is a meteoroid that enters Earth’s atmosphere and burns up.
Meteorites: Meteoroids that pass through the atmosphere and hit Earth’s ____________.
Classified by composition: stony, iron ,or stony-iron.