Energy & Green Tech

When the sun switches off the solar panels

The more the sun shines in the southern German town of Aurach, the more likely it is that Jens Husemann's solar panels will be disconnected from the grid—an exasperating paradox at a time when Germany is navigating an energy ...

Energy & Green Tech

Converting solar energy to electricity on demand

The researchers behind an energy system that makes it possible to capture solar energy, store it for up to 18 years and release it when and where it is needed have now taken the system a step further. After previously demonstrating ...

Energy & Green Tech

Record solar hydrogen production with concentrated sunlight

Hydrogen will play a key role in reducing our dependence on fossil fuels. It can be sustainably produced by using solar energy to split water molecules. The resulting clean energy can be stored, used to fuel cars or converted ...

Energy & Green Tech

Good news for rooftop solar, not for home batteries

The energy produced over the lifetime of typical rooftop solar panels more than makes up for the energy it takes to make, mount and then eventually recycle them. But adding a home battery usually lowers those dividends, according ...

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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