Related topics: planets · nasa · earth · orbit · asteroid

Harvard astronomer argues that alien vessel paid us a visit

Discovering there's intelligent life beyond our planet could be the most transformative event in human history— but what if scientists decided to collectively ignore evidence suggesting it already happened?

First image of a multi-planet system around a sun-like star

The European Southern Observatory's Very Large Telescope (ESO's VLT) has taken the first ever image of a young, sun-like star accompanied by two giant exoplanets. Images of systems with multiple exoplanets are extremely rare, ...

Giant methane storms on Uranus

Most of the times we have looked at Uranus, it has seemed to be a relatively calm place. Well, yes its atmosphere is the coldest place in the solar system. But, when we picture the seventh planet in our solar system invariably ...

How strong is gravity on other planets?

Gravity is a fundamental force of physics, one which we Earthlings tend to take for granted. You can't really blame us. Having evolved over the course of billions of years in Earth's environment, we are used to living with ...

Mass anomaly detected under the moon's largest crater

A mysterious large mass of material has been discovered beneath the largest crater in our solar system—the Moon's South Pole-Aitken basin—and may contain metal from the asteroid that crashed into the Moon and formed the ...

What percent of Earth is water?

The Earth is often compared to a majestic blue marble, especially by those privileged few who have gazed upon it from orbit. This is due to the prevalence of water on the planet's surface. While water itself is not blue, ...

Researchers crack Newton's elusive three-body problem

It's been nearly 350 years since Sir Isaac Newton outlined the laws of motion, claiming "For every action, there is an equal and opposite reaction." These laws laid the foundation to understand our solar system and, more ...

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Solar System

The Solar System[a] consists of the Sun and those celestial objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The Sun's retinue of objects circle it in a nearly flat disc called the ecliptic plane, most of the mass of which is contained within eight relatively solitary planets whose orbits are almost circular. The four smaller inner planets; Mercury, Venus, Earth and Mars, also called the terrestrial planets, are primarily composed of rock and metal. The four outer planets, Jupiter, Saturn, Uranus and Neptune, also called the gas giants, are composed largely of hydrogen and helium and are far more massive than the terrestrials.

The Solar System is also home to two main belts of small bodies. The asteroid belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal. The Kuiper belt (and its subpopulation, the scattered disc), which lies beyond Neptune's orbit, is composed mostly of ices such as water, ammonia and methane. Within these belts, five individual objects, Ceres, Pluto, Haumea, Makemake and Eris, are recognised to be large enough to have been rounded by their own gravity, and are thus termed dwarf planets. The hypothetical Oort cloud, which acts as the source for long-period comets, may also exist at a distance roughly a thousand times beyond these regions.

Within the Solar System, various populations of small bodies, such as comets, centaurs and interplanetary dust, freely travel between these regions, while the solar wind, a flow of plasma from the Sun, creates a bubble in the interstellar medium known as the heliosphere, which extends out to the edge of the scattered disc.

Six of the planets and three of the dwarf planets are orbited by natural satellites, usually termed "moons" after Earth's Moon. Each of the outer planets is encircled by planetary rings of dust and other particles.

This text uses material from Wikipedia, licensed under CC BY-SA