Revolve: When a smaller object circles a larger one.
Rotate: When an object spins on its own axis.
8 Planets were discovered in our solar system
Inner Planets: Mercury, Venus, Earth, Mars
Outer Planets: Jupiter, Saturn, Uranus, Neptune
Inner planets have more craters because they were constantly hit by asteroids at their first 600 million years.
Orbit : A path that a celestial body follows
3 Requirements to become a Planet:
Must orbit the sun
Have enough mass to become spherical (caused by own gravity)
Made its orbit path clear of any objects similar in size.
Dwarf planets are not considered planets because they fulfill the first 2 requirements, but didn’t pass for the third.
The three dwarf planets are: Pluto, Ceres, Eris
Inner and Outer planets
The difference between inner and outer planets is that…
Inner planets are between the sun and asteroid belt and the planets are constantly being hit by asteroids (at the beginning, on their first 600 million years)
Outer planets are outside the asteroid belt
Inner planets were made of sphere shaped rocks while Outer planets are gaseous spheres.
Outer planets have rings.
Our Solar System Asteroid Belt Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Sun
Mercury’s extra-thin atmosphere of helium and sodium is caused because Mercury is very close to the sun and most of the gases get boiled down. Thin gas will make Mercury cooler since it traps less heat.
Two elemenets in Mercury’s atmosphere are sodium and helium
Mercury’s surface is shaped by:
Other objects crashing into Mercury (causing craters)
Lava flooding on its surface
Crusts moving (tectonic movement)
Venus is also called the Evening Star because it appears very bright in the sky when seen from earth
Its atmosphere contains carbon dioxide and sulfuric acid
Retrograde rotation: Rotating clockwise on axis (opposite to every other planet)
A day in Venus = 225 earth days
A year in Venus = 243 earth days
A day > A year
If you were on Venus, the sun would appear to rise in the west and set in the east. This is because Venus rotates clockwise, so the sun appears from the west side first.
Venus is the hottest planet in our solar system because it’s atmosphere acts like a greenhouse and traps all the heat from the sun.
Earth’s atmosphere is made out of:
0.1% water vapor, carbon dioxide, neon, sulphur dioxide, hydrogen, helium...
Our atmosphere protects us from harmful radiation from the sun and meteors.
Rotational tilt: 23.5 Degrees
Spinning of Earth’s liquid iron core produces a magnetic field around Earth.
One natural satellite of Earth is the Moon.
Obviously the most beautiful planet
Some meteors that crash on Earth are pieces of Mars, and there may have been ancient bacteria on it, signaling life on Mars
Mars’s atmosphere is mostly carbon dioxide.
It appears red because it has soil rich in iron
Olympus Mons is a volcano, 600km wide and 26km tall.
Mars’s two natural satellites are Phobos and Deimos
Jupiter is bulged at the equator and flattened at the poles like Earth. This is because Jupiter spins so fast.
Hydrogen, Helium, Sulfer and Nitrogen make up Jupiter’s atmosphere.
The Great Red Spot is a circular hurricane wind
Jupiter has about 50 named natural satellites and 13 other ones.
Io, one of Jupiter’s natural satellites happens to be the hottest celestial body in our solar system! It has volcanic eruptions very frequently too.
Saturn’s atmosphere is made of helium and hydrogen.
Saturn’s rings may have been caused by natural satellites breaking down
The rings are made of water, ice and dust.
Saturn could float in water because its density is so low!
Seasons in Saturn last for 7 earth years!
Uranus’s rotation looks like it is rotating on its side because its tilt is 98 degrees!
Hydrogen, Helium and Methane make up Uranus’s atmosphere (Methane gives it its blue-green color)
Uranus has 27 known natural occurring satellites.
Ammonia, Helium and Methane make up Neptune’s atmosphere
Neptune has 13 known natural satellites!
Triton is the largest satellite of Neptune. Scientists think that Triton used to be another body, but it was captured by Neptune’s gravitational pull and became a satellite.
Pluto’s 3 moons are called :
They have detected that Pluto has methane, in the form of frost! Also, Charon, a satellite has water frost!
Charon is about half the size of Pluto (very big for a moon!)
A revolution for Ceres takes 4.6 Earth years!
Ceres used to be considered an asteroid because other objects were also found to be orbiting near Ceres
Its surface is made of water ice, carbonate and clay!
Eris used to be called “Xena”, following the show about a warrior princess.
Eris takes 557 Earth years to orbit the sun.
Dysnomia is Eris’s moon.
Eris is not considered a planet because it doesn't fulfill ALL the three requirements to be a planet. It didn’t clear its orbit of any other celestial bodies.