The order of the planets in the solar system, starting nearest the sun and working outward is the following: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and then the possible Planet Nine. If you insist on including Pluto, it would come after Neptune on the list.
List of exoplanets in the conservative habitable zone
| Object | Star | Radius (R⊕) |
|---|
| Earth | Sun (Sol) | 1.00 |
| Proxima Centauri b | Proxima Centauri | 0.8 – 1.1 – 1.4 |
| Gliese 667 Cc | Gliese 667 C | 1.1 – 1.5 – 2.0 |
| Kepler-442b | Kepler-442 | 1.34 |
Gas planet facts
- The gas planets are Jupiter, Saturn, Uranus and Neptune.
- They are the furthest planets from the Sun.
- They each have many moons.
- They are much bigger than the rocky planets.
- They're balls of hydrogen and helium - you couldn't stand on the surface of the planet because it's not solid.
Missions – NASA Solar System Exploration. More than 250 robotic spacecraft—and 24 humans—have ventured into space since we first began exploring beyond Earth's atmosphere in 1958. This section focuses on U.S. missions with science goals to study planets, moons, asteroids and comets beyond Earth orbit.
The inner planets are much smaller than the outer planets and because of this have relatively low gravity and were not able to attract large amounts of gas to their atmospheres.
A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
Venus' density and internal structure are similar to Earth's. But in other ways, Venus and Earth are very different. Venus rotates from east to west, the opposite direction from most other planets and moons. The pressure of Venus's atmosphere is 90 times greater than the pressure of Earth's atmosphere.
The Sun is a yellow dwarf star, a hot ball of glowing gases at the heart of our solar system. Its gravity holds the solar system together, keeping everything – from the biggest planets to the smallest particles of debris – in its orbit.
1.) Ganymede: Jupiter's largest moon is the largest non-planet in the Solar System. With a diameter of 5,268 km (3,271 miles), it's 8% bigger than the planet Mercury, although it has less than half the mass of our Solar System's innermost planet, being made of mostly ices and silicate minerals.
Saturn has overtaken Jupiter as the planet with the most moons, according to US researchers. A team discovered a haul of 20 new moons orbiting the ringed planet, bringing its total to 82; Jupiter, by contrast, has 79 natural satellites. The moons were discovered using the Subaru telescope on Maunakea, Hawaii.
So inconspicuous that it was not discovered until 1930, Pluto is not a gas giant planet like all the others in the outer solar system. Instead it is a small, rocky world about the size of Earth's Moon.
The temperature of the early solar system explains why the inner planets are rocky and the outer ones are gaseous. As the gases coalesced to form a protosun, the temperature in the solar system rose. In the inner solar system temperatures were as high as 2000 K, while in the outer solar system it was as cool as 50 K.
A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars. These planets are located between the Sun and the asteroid belt.
When the solar system settled into its current layout about 4.5 billion years ago, Mars formed when gravity pulled swirling gas and dust in to become the fourth planet from the Sun. Mars is about half the size of Earth, and like its fellow terrestrial planets, it has a central core, a rocky mantle and a solid crust.
So inconspicuous that it was not discovered until 1930, Pluto is not a gas giant planet like all the others in the outer solar system. Instead it is a small, rocky world about the size of Earth's Moon.
The Solar System has four terrestrial planets: Mercury, Venus, Earth and Mars.
They are called the inner planets. The inner planets are made up mostly of rock. The outer planets are Jupiter, Saturn, Uranus, and Neptune.
| The Inner Planets | The Outer Planets | Dwarf Planets |
|---|
| Mercury | Jupiter | Pluto |
| Venus | Saturn | Ceres |
| Earth | Uranus | Eris |
| Mars | Neptune | Haumea |
On average, Mercury is the closest planet to the Earth, and it is the closest planet to each of the other planets in the Solar System.
The tradition of naming the planets after Greek and Roman gods and goddesses was carried on for the other planets discovered as well. Mercury was named after the Roman god of travel. Venus was named after the Roman goddess of love and beauty. Mars was the Roman god of War.
The International Astronomical Union (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria the IAU uses to define a full-sized planet. Essentially Pluto meets all the criteria except one—it “has not cleared its neighboring region of other objects.”
The outer planets are planets in the Solar System that are beyond the asteroid belt. The four planets; Jupiter, Saturn, Uranus and Neptune are gas giants. All four of these planets have planetary rings which are made up of dust and other particles.
When the solar system settled into its current layout about 4.5 billion years ago, Venus formed when gravity pulled swirling gas and dust together to form the second planet from the Sun. Like its fellow terrestrial planets, Venus has a central core, a rocky mantle and a solid crust.
Because it has not cleared the neighborhood around its orbit, Pluto is considered a dwarf planet. It orbits in a disc-like zone beyond the orbit of Neptune called the Kuiper belt, a distant region populated with frozen bodies left over from the solar system's formation.
There are about 170 moons in our Solar System. Most of them are in orbit around the gas giants Jupiter and Saturn. Small planets tend to have few moons: Mars has two, Earth has one, while Venus and Mercury do not have any. Earth's Moon is unusually large compared with the planet.
There are hundreds of moons in our solar system — even a few asteroids have been found to have small companion moons. In the outer solar system, the gas giants Jupiter and Saturn and the ice giants Uranus and Neptune have dozens of moons.
Four the planets in the Solar System have rings. They are the four giant gas planets Jupiter, Saturn, Uranus, and Neptune. Saturn, which has by far the largest ring system, was known to have rings for a long time. It was not until the 1970s that rings were discovered around the other gas planets.
