Solar System is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest are the eight planets, with the remainder being smaller objects, the dwarf planets and small Solar System bodies.
Mercury is the smalles planet in our Solar System. It is the closest planet to the Sun at a distance of about 36 million miles (58 million kilometers) or 0.39 AU. Temperature on the surface can be vary from 430 degrees Celsius (800 degrees Fahrenheit) to -180 degrees Celsius (-290 degrees Fahrenheit).
Standing on Mercury's surface at its closest approach to the Sun, our star would appear more than three times larger than it does on Earth.
The second planet from the Sun, Venus is the only palnet that spins backwards. Due to greenhouse effect the planet’s surface temperature is about 465 degrees Celsius (900 degrees Fahrenheit). Venus and Earth are about same size.
Venus’ extreme temperatures and acidic clouds make it an unlikely place for life as we know it.Many scientists believe water once existed on the surface. Future Venus explorers will search for evidence of an ancient ocean.
The third planet from the Sun, Earth is the only planet (so far) inhabited by humans. Has only moon named Luna. A day on Earth is 24 hours. Earth makes a complete orbit around the sun (a year in Earth time) in about 365 days. Only planet that has liquid water on it's surface.
Our atmosphere protects us from incoming meteoroids, most of which break up in our atmosphere before they can strike the surface.
The fourth planet from the Sun, Mars is a dusty, cold, desert world with a very thin atmosphere. One day on Mars takes a little over 24 hours. Mars makes a complete orbit around the Sun (a year in Martian time) in 687 Earth days.
Mars has a thin atmosphere made up mostly of carbon dioxide (CO2), argon (Ar), nitrogen (N2), and a small amount of oxygen and water vapor.
Mars has two moons named Phobos and Deimos.
The fifth planet from the Sun, Jupiter is a gas-giant planet. Eleven Earths could fit across Jupiter’s equator. It has more than 75 moons. Jupiter's atmosphere is made up mostly of hydrogen (H2) and helium (He). Jupiter rotates once about every 10 hours (a Jovian day), but takes about 12 Earth years to complete one orbit of the Sun (a Jovian year).
The sixth planet from the Sun, Saturn is a gas-giant planet, it takes about 10.7 hours to rotate on its axis once—a Saturn “day”—and 29 Earth years to orbit the sun.
Saturn has 53 known moons with an additional 29 moons awaiting confirmation of their discovery—that is a total of 82 moons.
Saturn has the most spectacular ring system, with seven rings and several gaps and divisions between them.
The seventh planet from the Sun, Uranus is an ice-giant planet and it was discovered in 1781 by William Herschel. It's the first planet found using a telescope. Uranus is known as the “sideways planet” because it rotates on its side.
It's four times larger than Earth, has 27 known moons, most of which are named after literary characters. Additionally, Uranus has rings.
The eighth planet from the Sun, Neptune is an ice-giant about four times wider than Earth. Most of its mass is a hot, dense fluid of "icy" materials – water, methane and ammonia – above a small rocky core. Neptune takes about 16 hours to rotate once (a Neptunian day), and about 165 Earth years to orbit the sun (a Neptunian year).
Neptune has 14 known moons which are named after sea gods and nymphs in Greek mythology. Neptune has at least five main rings and four more ring arcs, which are clumps of dust and debris likely formed by the gravity of a nearby moon.