Astronomy U4 - Solar System

Terrestrial planets

Close to sun, close orbits, small, rocky, high density, no rings, few moons, slow rotation

4 examples of terrestrial planets

Mercury, Venus, Earth, Mars

Jovian Planets

Similar in size to Jupiter, interior = hydrogen & helium, rocky core, far from sun, wide orbits, big, gaseous, low density, rings, moons, fast rotation

4 examples of jovian planets

Jupiter, Saturn, Uranus, Neptune

Retrograde rotation

Object that spins in opposite direction of orbit (EX: Venus)

Nebula

Enormous cloud of gas and dust

Protostar

Contracting Mass of gas - early stage of star formation (before nuclear fusion, temperature sorts materials)

Planetesimals

Small clumps of dust/gas, no bigger than small moon

Accretion

Growth of object’s Mass with accumulation of matter (surrounding gas, dust, particles) due to gravitational pull

Nebular hypothesis

1. Starts with nebula

2. Nebula contracts/flattens

3. Protostar forms

4. Nebula picks up mass (accretion)

5. Planetesimals form

6. Jovian Planets form

7. Protoplanets form

8. Sun ignites

What and how much of it is in the solar system?

8 planets, 5 dwarf planets, 214 planetary & dwarf planet moons, asteroids, comets, and more

What percentage of the solar system is the sun

99%

Age of solar system

4.6 billion years old

What are the requirements to become a planet?

1. In orbit with sun

2. Is large enough to be a sphere

3. Is more massive than other objects in its orbit and can clear out orbital neighborhood of other objects

What are the requirements to be a dwarf planet (Pluto)?

1. In orbit with sun

2. Has enough Mass to be round

3. Cannot clear its orbit of debris

Which planet has the largest diameter?

Jupiter

Which planet has the largest mass?

Jupiter

Which planet has the largest orbital speed?

Mercury

Which planet has the largest orbital period?

Neptune

Which planet has the largest gravitational Acceleration?

Jupiter

Which planet has the largest temperature?

Venus

Which planet has the largest number of moons?

Saturn

Which planet has the largest axial tilt?

Venus

Planets in order

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

Trend for temperature

Temperature gets colder as the distance from the sun increases.

Trend for orbital period

As you get farther away, the orbital period of the planets increases.