AST Ch 2-1 Part 1
List the major bodies of the solar system
The sun and the planets that revolve around it.
The model in which Earth is at the center of the system of planet is called the
geocentric
Meteoroids usually come from
comets or asteroids
The main characteristics used to classify stars are
size,
temperature
brightness
Isaac Newton concluded that there were two factors that keep the planets in orbit. The factor that pulls planets towards each other is
gravity
Planets differ in size, surface features, and
composition
How does Earth’s sun rate in comparison to other stars in the universe?
Earth’s Sun is an average-size star
Chunks of ice and dust that usually have long elliptical orbits are called
comets
The apparent brightness of a star depends upon which three things?
size
color and temperature
distance from Earth
Isaac Newton concluded that there were two factors that keep the planets in orbit. The factor that keeps planets moving forward is?
inertia
Describe the shape of the orbit in which planets move around the sun
elliptical
The central and largest body in the solar system is the ______, which is also the closest _______ to the Earth
sun
star
A meteoroid that hits Earth’s surface is called a
meteorite
A light-year is ____________________________, or about 9.5 million million kilometers.
the distance that light travels in one year
Astronomers measure space in
light years
Name all the objects planets can have orbiting them:
moons
rings of particles
other satellites
The sun is more than __________ times greater in volume than the Earth.
one million
Another name for “shooting star” is
meteor
The sun looks very bright, yet it does not give off more light than all other stars. Why do other stars look like points of light in the sky? What is this called?
The sun looks so bright simply because it is so close to Earth. Other stars are much farther away. Apparent magnitude is a star’s brightness as seen from Earth.
Use the planet table to answer the following question. Name planets 8, 9, and 10 in correct order.
8. Venus
9. Earth
10. Mars
The modern heliocentric model of planetary motion states that the planets travel around the _______ in slightly __________ orbits.
Sun
elliptical
A sun-centered system of planets is called the _____________ system.
heliocentric
Few comets pass near Earth because their _________ are so elliptical.
orbits
The ___________ is a giant flat structure, called a __________, that contains ____________ of stars. There are billions of ___________ in the _________, which astronomers define as all of space and everything in it.
Milky Way
galaxy
hundreds of billions
galaxies
universe
Use the planet table to answer the following question. Name objects 17, 16, 15, 14 in this order.
17. a comet
16. the Sun
15. Neptune
14. Uranus