Chapter 3 Lesson 2 Flashcards
What makes up our solar system?
Sun, planets, moon, and a variety of smaller objects.
From what did the solar system form?
A cloud of hydrogen, helium, rock, ice and other materials pulled together by gravity.
When was the solar system formed?
4.6 billion years ago
Dwarf planet
Object that orbits the sun, is spherical , but has not cleared the area of its orbit.
Astronomical unit
Used to measure distances within the solar system.
1 AU is equal to 15 million km
Planetesimal
A small body that combined with like bodies to form all the other objects in our solar system
Planet
Object that orbits the sun, is round, and has cleared the area of its orbit.
What percent of the solar system is our sun?
99.85
Where is the largest gap between planets?
Uranus & Neptune
What happens when a planet is farther from the sun?
It get colder, and it’s ellipse becomes larger.
Which planets don’t have any moons?
Mercury & Venus
Which planets have the most moons?
Jupiter & Saturn
60+
How many moons does Neptune have?
13+
How many moons does Uranus have
20+
