The Solar System
How many dwarf planets does the IAU recognize?
5
How far is Earth from the sun?
93 million miles away (about 150 million kilometers)
What is a dwarf planet?
A celestial body that orbits the sun, has enough mass to give it a round shape, is not a moon orbiting another planet, but has NOT cleared a path through the region around its orbit.
How long can a comet's tail be?
A comet's tail may be millions of miles long.
What is a crater?
A large hole in the ground shaped like a bowl
What is a space probe?
A spacecraft designed to gather information
What is the Oort Cloud?
A spherical cloud of comets beyond our furthest planet from the sun, Neptune.
How old is the sun?
It is believed to be more than 4.5 billion years old
Why does the sun appear to be the largest star in the sky?
It is the closest star to Earth
How are Jovian planets different from terrestrial planets?
Jovian planets are cold, much larger, they are made of gases and liquids (not water), they have no real surface to stand on, with very small cores, and they all have rings similar to Saturn, and they all have moons
What are the four outer planets called?
Jovian planets or gas giants
What is the largest planet in the solar system? It is 10 times larger than Earth.
Jupiter
What are the four Jovian planets and why are they called "Jovian"?
Jupiter, Saturn, Uranus, and Neptune, because they all resemble Jupiter
What is called the red planet? It also has the largest volcano in the solar system and has two moons.
Mars
What is the fastest moving planet in the solar system?
Mercury
What are the terrestrial planets?
Mercury, Venus, Earth, Mars
How do the planets orbit the sun? In what order?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune
Which is smaller an asteroid or meteoroid?
Meteoroids are among the smallest types of space debris. Usually meteoroids are small pieces of asteroids.
How is Earth different from the other planets?
Mostly covered with water, only planet with a lot of oxygen in its atmosphere, an atmosphere that keeps the temperature inhabitable, and only planet to support life
What are three examples of dwarf planets?
Pluto, Ceres, and Eris
When a comet is far away from the sun, its nucleus is frozen. What happens when it gets close enough to the sun?
Radiation from the sun releases some of the gases and dust particles and the comet may appear to have a fuzzy, very thin atmosphere and a long tail.
Why was Pluto dropped from the list of major planets?
Scientists discovered another body very similar to Pluto and instead of expanding the solar system from 9 planets, scientists created a new classification, dwarf planets.
What is the IAU?
The International Astronomical Union is the official body that sets definitions and verifies identifications for planetary science.
From what you have learned so far, which do you think came first, the Milky Way Galaxy or the sun and our solar system? Why?
The Milky Way because as the dust and gas in the Milky Way became denser, after a long time, stars began to form from the material in the galaxy.
What is a light year?
The distance light travels in one year. (Traveling at the speed of light, it would take one hundred thousand years to cross our galaxy.
What is the relationship between the sun and the eight major planets?
The eight planets orbit the sun.
The name Earth is from an old English word meaning what?
The ground we walk on
What is accretion?
The growth of massive objects by gravitational attraction which formed our planets.
What of these is NOT part of the solar system? the sun eight planets Milky Way galaxy asteroids
The milky way galaxy
How is the Milky Way Galaxy different from the solar system?
The solar system is a very small part of the Milky Way, which is made up of billions of stars
What is the sun?
The sun is a medium sized yellow star.
What is called Earth's twin? It is also the hottest planet in the solar system.
Venus
What is a meteorite?
a chunk of a meteoroid that hits Earth's surface
How many moons are included in our solar system?
almost 200
How many major planets are there in the solar system?
eight
What do terrestrial planets all have?
hard, rocky surfaces, dense, and have solid cores with relatively thin atmospheres and relatively small diameters with few or no moons.
List 3 characteristics of Jovian planets.
no solid surface; thick, dense atmosphere; many moons
What are two ways in which comets are different from other celestial bodies?
nucleus of dust, rocks, and ice; may have a long, gaseous trail
What are examples of celestial bodies?
planets, moons, dwarf planets, cosmic dust, asteroids, comets, and meteroids
What is the nucleus of a comet made of?
rocky material, dust particles, and ice.
What are small orbiting bodies?
satellites
What is the Milky Way galaxy?
spiral shaped and one hundred thousand light years in diameter
What is the solar system?
the collection of planets (including Earth), moons, asteroids, and other celestial bodies that orbit the sun.
What is at the center of our solar system?
the sun
What is the largest object in the solar system?
the sun, more than 1.3 million Earths could fit inside of it!
What is another name for comets?
Dirty snowballs
What is the main difference between a dwarf planet and a major planet?
Dwarf planets have not cleared other bodies out of their orbital paths.
What is the largest of the inner planets?
Earth
What is the third planet from the sun?
Earth
What does terrestrial mean?
Earth like
What is the name of the comet visible to the naked eye that swings around the sun once every 76 years?
Halley's Comet
About how many stars exist in our Milky Way?
200 billion
When do scientists believe the story of our solar system began?
10 to 15 billion years ago
What kinds of objects are smaller than dwarf planets?
Asteroids, comets, and meteoroids, but far more numerous
In which direction does a comet's tail point?
Away from the sun
What is the big bang theory?
Condensed matter exploded and began expanding equally in all directions
