Category 1
The sun appears so bright from Earth. Why is this?
Because it is the closest star to Earth.
The most massive body in the solar system is what?
A large object composed of rock particles, ice, and frozen gases.
Comet.
The burning up of the meteors produces a light in the sky during a what?
Meteor shower.
Describe the planets' orbits.
It is elliptical.
This model places the sun in the center of the solar system, with all the other planets orbiting around it.
Heliocentric Model.
Small pieces of rock from comets, along with particles from other sources.
Meteoroids.
The sun makes one orbit around the center of the Milky Way every ____________ years.
240 million.
The unit used to measure distances between stars; one light-year is equal to the distance that light travels in one year.
Light-year.
Relate a star’s color to its temperature.
A star’s color is a clue to its surface temperature.
ex. Blue-white stars are the hottest, while red stars are the coolest.
The force of attraction that keeps planets in their orbits.
Gravity.
A piece of rock made of minerals similar to those that formed Earth.
Asteroid.
The sun and its solar system are part of a large, spiral galaxy. What is that galaxy called?
Milky Way.
The measure of a star’s brightness.
A star's magnitude.
Relate a meteoroid to a meteor and a meteorite.
When a meteoroid crosses Earth’s path and enters its atmosphere, it begins to burn up (meteor). If a meteor is large enough, it might not burn up completely as it enters Earth’s atmosphere. A meteorite=meteor that has landed on Earth’s surface.
Identify the two factors that affect the shape and speed of a planet's orbit.
The sun’s gravity and the planets distance from the sun.
The asteroid belt is located between which two planets?
Mars and Jupiter.
Galaxies are huge clusters of stars, gas, and dust held together by gravity. Do small or enormous distances separate them?
Enormous.
What type of galaxy has an indistinct shape?
Irregular.
A huge cloud of dust, ice, and gas rotated slowly. Part of the cloud collapsed inward. Its core become hot and dense, becoming the sun. Matter outside the core began to clump together. Gravity pulled in more matter. Large clumps of matter became the planets. Smaller clumps became moons.
This all explains what?
The formation of the solar system.
Explain why some planets are mostly rock.
As planets formed closer to the sun, only matter that did not vaporize to become gases, such as rocks and minerals, remained.
Identify one similarity between the universe and the galaxies.
The number of stars in each.
What discovery was made by Edwin Hubble?
He discovered that everything in the universe is moving away from everything else; the universe is expanding.
Which planet travels at the highest speed around the sun?
Mercury is the planet that travels the fastest at a speed of 47.5 km/s.
It suggests that the universe was once a massive, dense, hot ball. About 15 billion years ago, an enormous explosion sent materials in the ball flying in all directions. It marked the beginning of the universe.
What does this explain?
The big bang theory.