AST Lec 2: Solar System and Planetary Orbits

The plane in which all the planets orbit the sun.

Ecliptic Plane

The shape of the orbits of the planets around the sun.

Elliptical Orbits

Closest planet to the Sun with no atmosphere and a highly cratered surface.

Mercury

About the same size as Earth, with a thick CO2 atmosphere and a runaway greenhouse effect.

Venus

About the same size as Venus, with a large moon and significant life presence.

Earth

Has a thin CO2 atmosphere, extinct volcanoes, and two small moons.

Mars

Small, rocky planets with relatively thin or no atmosphere and few moons.

Terrestrial Planets

Largest planet in the solar system with a thick gaseous atmosphere and many moons.

Jupiter

Second largest planet known for its spectacular rings and many moons.

Saturn

Coldest planet with a thick atmosphere and a rotation axis tilted 98 degrees.

Uranus

Furthest planet from the Sun with the strongest winds in the solar system.

Neptune

Large gas and liquid planets including Jupiter, Saturn, Uranus, and Neptune.

Jovian Planets

Nine identified, including Pluto and Ceres, with high ice content.

Dwarf Planets

Contains around a million asteroids larger than 1km in diameter.

Asteroid Belt

A vast collection of small icy bodies beyond Neptune's orbit.

Kuiper Belt

Smaller icy bodies from the outer solar system that emit tails when close to the sun.

Comets

Launched in 1977 to visit all four Jovian planets using gravity assists.

Voyager Probes

One of Jupiter's moons, known for being the most geologically active in the solar system.

Io

One of Jupiter's moons, known for its high ice content.

Europa

One of Jupiter's moons, larger than Mercury.

Ganymede

One of Jupiter's moons, heavily cratered and old.

Callisto

Neptune's largest moon, known for its frozen nitrogen surface.

Triton

All planets orbit the sun in the same direction.

Planetary Orbits

The sun rotates in the same direction that the planets orbit.

Planetary Rotation

Temperature of Venus

Always 460 C everywhere due to the greenhouse effect.

Mars' Orbital Tilt

25.2 degrees

Earth's Rotational Tilt

23.4 degrees

Has over 60 known moons, with 5 over 1000 km diameter.

Saturn

Has over 60 known moons, with 4 over 1000 km diameter.

Uranus

Has 14 known moons, with only one over 1000 km diameter.

Neptune

The planets all orbit the sun on the same…

Plane

The planets all have ____ orbits.

Elliptical Orbits

The planet with no atmosphere, a highly cratered surface, a rocky exterior and huge iron core, fluctuating temperatures, and no moons.

Mercury

The planet that was visited by the probes Mariner 10 and MESSENGER.

Mercury

The planet with lots of volcanoes, a thick CO2 atmosphere that causes an intense greenhouse effect, rains acid, has no moons, rotates backwards slowly, and has been visited by many probes and landers.

Venus

The planet with lots of volcanoes, an O2 and N2 atmosphere, large oceans that regulate CO2, a surface heavily effected by Life, 1 large moon, and significant seasons.

Earth

The rotational tilt of the Earth which produces significant seasons.

23.4 degrees

The planet with lots of extinct volcanoes, a very thin CO2 atmosphere, evaporated oceans, 2 small moons, polar-/dry ice caps, planet-wide dust storms, significant seasons, and has been visited by many probes and landers.

Mars

The rotational tilt of Mars which produces significant seasons.

25.2 degrees

Terrestrial Planets have relatively _____ atmospheres and ____ moons.

Thin, few

The Terrestrial Planets are made from…

Heavy Elements

The planet with a thick gaseous atmosphere surrounding a giant ball of liquid hydrogen, very faint rings, more than 60 moons, and has been visited by several probes.

Jupiter

The planet with a structure much like Jupiter’s, noticeable rings, more than 60 moons, and has been visited by several probes.

Saturn

The planet with the coldest temperature, a small rocky core, a mantle of thick water, Ammonia and Methane, a thick H2/He atmosphere, a rotational tilt >90 degrees, thin rings, and lots of moons.

Uranus

The planet with a structure much like Uranus’ though with more surface features, a rotational tilt of 28 degrees, and the strongest winds in the solar system.

Neptune

The Jovian Planets are ____, made of ____ and ____, and have ____ moons.

Large, gas, liquid, many

The Jovian Planets are made from…

Light elements

The moon with no atmosphere, a rocky cratered surface, and no geological activity.

Earths’s Moon

The planet with over 60 known moons, 4 being over 1000 km in diameter, of high ice content, and the most geologically active moon in the solar system.

Jupiter

The planet with over 60 known moons, 5 being over 1000 km in diameter, of high ice content, which orbit in the same plane and direction as that planet’s rings.

Saturn

The planet with over 60 known moons, 4 being over 1000 km in diameter, of high ice content, which orbit on the same plane as its rotation: at 97 degrees from the Ecliptic Plane.

Uranus

The planet with 14 known moons, 1 being over 1000 km in diameter, which orbits on a different plane and direction than the planet’s and has a surface of frozen Nitrogen.

Neptune

Most major moons orbit in the plane of their planet’s equator—except ____ around ____.

Triton, Neptune

The only 2 Dwarf Planets to have been visited by probes.

Pluto, Ceres

The Dwarf Planet with very high ice content.

Pluto

The collection of around 1 million asteroids larger than 1 km in diameter that float between Mars and Jupiter, whose total mass is ~3% of the moon’s.

Asteroid Belt

The asteroid in the Asteroid Belt that is 330 m in length and was visited by the Hayabusa space probe in 2005, which took samples for study.

25143 Itokawa

The collection of small icy bodies beyond the orbit of Neptune that includes several Dwarf Planets and whose total mass is around the Earth’s moon’s.

Kuiper Belt

The object in the Kuiper Belt that is 36×20×10 km, is 6 light-hours from Earth, and was visited by the New Horizons probe in 2019.

Arrokoth

The smaller, icy bodies found in the outer solar system that have highly elliptical orbits and emit tails when they come near to the Sun.

Comets

The 2 probes that were launched in 1977 at just the right time to visit all 4 Jovian Planets by sling-shotting off of each planet’s gravitational pull to accelerate and change trajectory.

Voyager 1 and Voyager 2