Solar system - Regions of the solar system

The solar system comprises our Sun and the retinue of celestial objects gravitationally bound to it. Traditionally, this is said to consist of the Sun, nine planets and their 158 currently known moons; however, a large number of other objects, including asteroids, meteoroids, planetoids, comets, and interplanetary dust, orbit the Sun as well. Although the term "solar system" is frequently applied to other star systems and the planetary systems which may comprise them, it should strictly refer to our system specifically: the wor ...

Including:

• Solar system - Structure and layout of the solar system
• Solar system - Origin and age of the solar system
• Solar system - Regions of the solar system
• Solar system - Interplanetary medium
• Solar system - The inner planets
• Solar system - The asteroid belt
• Solar system - The outer planets
• Solar system - The trans-Neptunian region
• Solar system - And beyond
• Solar system - Galactic orbit of the solar system
• Solar system - Planetary system formation
• Solar system - Discovery of the solar system
• Solar system - Exploration of the solar system
• Solar system - Attributes of major planets
• Solar system - Attributes of the largest minor planets
• Solar system - Other facts

Read more here: » Solar system: Encyclopedia - Solar system

According to their location, the objects in the solar system are divided into three zones: Zone I or the inner solar system, including terrestrial planets and the Main belt of asteroids; Zone II, including the giant planets, their satellites and the centaurs, and Zone III, or the outer solar system, comprising the area of the Trans-Neptunian objects including the Kuiper Belt, the Oort cloud, and the vast region in between.

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Regions of the solar system

The total surface area of the solar system's objects that have solid surfaces and a diameter greater than 1 km is ~1.7×109 km2 —about 11 times the area of the Earth's land masses. It has been suggested that the Sun may be part of a binary star system, with a distant companion named Nemesis. Nemesis was proposed to explain some timing regularities of the great extinctions of life on Earth. The hypothesis says that Nemesis creates periodical perturbations in the Oort cloud of comets surrounding the solar system, ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Other facts

The Sun (astronomical symbol ☉) is a main sequence G2 star that contains 99.86% of the system's known mass. Its two largest orbiting bodies, Jupiter and Saturn, account for 91% of the remainder (the Oort Cloud might hold a substantial percentage, but as yet its existence is unconfirmed). In broad terms, the charted regions of our solar system consist of the Sun and its planetary system: the eight bodies in relatively unique orbits (commonly called planets or major planets) and two belts of smaller objects (which can be called minor ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Structure and layout of the solar system

The current hypothesis of solar system formation is the nebular hypothesis, first proposed in 1755 by Immanuel Kant and independently formulated by Pierre-Simon Laplace. It states the solar system was formed from a gaseous cloud called the solar nebula. It had a diameter of 100 AU and was 2-3 times the mass of the Sun. Over time, a disturbance, possibly a nearby supernova, sent shock waves into space, which squeezed the nebula, pushing more and more of its matter inward until gravitational forces overcame its internal gas pressure and it beg ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Origin and age of the solar system

The largest minor planets are smoothly rounded, like planets, because their gravity overcomes material strength that keeps smaller bodies in non-spherical shapes. Before the discovery of 2060 Chiron and the trans-Neptunian objects, the term "minor planet" was a synonym for asteroid, but many people now prefer to restrict the use of "asteroid" to refer to rocky bodies of the inner solar system. Most trans-Neptunian objects are icy, like comets, al ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Attributes of the largest minor planets

The solar system is located in the Local Fluff of the Milky Way galaxy, a spiral galaxy with a diameter of about 100,000 light years containing approximately 200 billion stars, of which our Sun is rather large and bright. (The vast majority of stars are red dwarfs; our Sun is placed near the middle of the Hertzsprung-Russell diagram, but stars larger and hotter than it are rare, whereas stars dimmer and cooler than it are very common, although we can observe on ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Galactic orbit of the solar system

Since the start of the space age, a great deal of exploration has been performed by unmanned space missions that have been organized and executed by various space agencies. The first probe to land on another solar system body was the Soviet Union's Luna 2 probe, which impacted on the Moon in 1959. Since then, increasingly distant planets have been reached, with probes landing on Venus in 1965, Mars in 1976, the asteroid 433 Eros in 2001, and Saturn's moon Titan in 2005. Spacecraft have also made close approa ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Exploration of the solar system

The current hypothesis of solar system formation is the nebular hypothesis, first proposed in 1755 by Immanuel Kant. It states the solar system was formed from a gaseous cloud called the solar nebula. It had a diameter of 100 AU and was 2-3 times the mass of the Sun. Over time, a disturbance, possibly a nearby supernova, sent shock waves into space, which squeezed the nebula, pushing more and more of its matter inward until gravitational forces overcame its internal gas pressure and it began to collapse. As the nebula collapsed, it decreased ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Origin and age of the solar system

The Sun (astronomical symbol ☉) is a main sequence G2 star that contains 99.86% of the system's known mass. Its two largest orbiting bodies, Jupiter and Saturn, account for 91% of the remainder (The Oort Cloud might hold a substantial percentage, but as yet its existence is unconfirmed). In broad terms, the charted regions of our solar system consist of the Sun and its planetary system: the eight bodies in relatively unique orbits (commonly called planets or major planets) and two belts of smaller objects (which can be called minor ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Structure and layout of the solar system

The solar system is part of the Milky Way galaxy, a spiral galaxy with a diameter of about 100,000 light years containing approximately 200 billion stars, of which our Sun is rather large and bright. (The vast majority of stars are red dwarfs; our Sun is placed near the middle of the Hertzsprung-Russell diagram, but stars larger and hotter than it are rare, whereas stars dimmer and cooler than it are very common, although we can observe on ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Galactic orbit of the solar system

For many years, our solar system had the only planetary system known, and so theories of planetary formation only had to explain one system to be plausible. The discovery in recent years of many extrasolar(exo) planets has uncovered systems very different to our own, and theories have had to be revised accordingly. Exoplanets have not been seen by astronomers yet, however we know they exist because of the gravitational tug the planets induce on the star, and hence making the star ‘wobble’. Astronomers can calculate how massive the ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Planetary system formation

The planets out to Saturn were known to ancient astronomers, who observed the wandering of these objects against the apparently fixed pattern of stars. Venus and Mercury were each identified as single objects despite the difficulty of connecting "evening" and "morning stars". It was also identified that the two non-pointlike objects, the sun and the Moon, moved across the same fixed background. However knowledge of the nature of these cele ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Discovery of the solar system

All attributes below are measured relative to the Earth: Of the other objects, Ganymede has the largest mass (0.02). Note: Although 2003 UB313 is a minor planet, it is being considered as possibly being a major planet (the tenth in the solar system). For a more comprehensive table, see table of planets in the solar system. ...

See also:

Solar system, Solar system - Structure and layout of the solar system, Solar system - Origin and age of the solar system, Solar system - Regions of the solar system, Solar system - Interplanetary medium, Solar system - The inner planets, Solar system - The asteroid belt, Solar system - The outer planets, Solar system - The trans-Neptunian region, Solar system - And beyond, Solar system - Galactic orbit of the solar system, Solar system - Planetary system formation, Solar system - Discovery of the solar system, Solar system - Exploration of the solar system, Solar system - Attributes of major planets, Solar system - Attributes of the largest minor planets, Solar system - Other facts

Read more here: » Solar system: Encyclopedia II - Solar system - Attributes of major planets