The solar system
Our solar system contains planets, comets and asteroids all of which travel around our star, the Sun.
Between 1801 and 1807 small starlike objects were discovered in the solar system. These small bodies became known as Minor Planets or asteroids.
Different theories account for the formation of the solar system.
The diameter of the Sun is 1,400,000 km (840,000 miles) which is more than 100 times the diameter of the Earth.
Sunspots are a phenomenon that has been known about for at least several thousands of years.
An eclipse occurs when a body cuts off the light from a light source so that we can no longer see it shining.
The Aurora Borealis and Aurora Australis are seen in the northern and southern hemispheres respectively.
The Moon is the closest astronomical object to the Earth.
Four times smaller in diameter than the Earth, our Moon was probably formed shortly after the rest of our solar system, about 4500 million years ago.- The phrase 'once in a blue Moon' is a familiar one meaning once in a very long interval of time. The phrase goes back to at least 1824 when an explanation of its meaning appears as a footnote attached to its use.
The main difference between planets and stars is that stars shine with their own light, and planets shine by reflected light.
Mercury is the closest planet to the Sun. With a diameter of 4880 km, it is the second smallest.
Venus is the second closest planet to the Sun. It has no moon. With a diameter of 12,104 kilometres it is the closest in size to the Earth.
Mars is the fourth planet from the Sun and there has been much speculation over the years about the possibility of other life forms existing there.
Saturn is probably the best known and most beautiful planet in the solar system.
Jupiter is the largest planet in the solar system. Its diameter is 11 times that of the Earth, its mass twice the sum of all the other planets.
Uranus is the seventh planet of the Solar System, with a diameter of about 52,400 km. It orbits the Sun every 84 years.
Neptune is the eighth planet from the Sun, orbiting the Sun every 165 years at a mean distance of 30.1 times that of the Earth (Astronomical Units).
Pluto has been recategorised as a 'dwarf planet' and is no longer recognised as a full planet.
The furthest object was probably a comet which passed the Sun many years ago, returning to the furthest limits of the solar system.
The solar system information gives tables of data relating to the orbits of planets, the globes of planets, and the satellite distances from planets.- An icy planetary body has been discovered orbiting the Sun beyond Neptune.
- Until Isaac Newton formulated his Laws of Motion it was generally thought that to keep a body in motion it was necessary to use a force to push or pull it
In 2006 Pluto was relegated to the new category of ‘dwarf planet’.
Tides are created by the gravitational attraction of one massive body on another.
The surface temperatures of the planets vary from more than 400 degrees on Mercury and Venus to below -200 degrees on the distant planets.
One of the four units of ESO’s Very Large Telescope was used to take ground-based images of the lunar surface.- In 1999 'Galileo' gave clear views of Callisto, revealing a landscape of ice and dust on one of the oldest surfaces in the Solar system.
In 2001 the Hubble Space Telescope was able to take a detailed image of Mars.
In May 2003, a transit of Mercury was observed from the Royal Observatory, Greenwich.
During May 2003 both a lunar and solar eclipse were visible across the UK.
In October 2004 British astronomers watched the year's second total eclipse of the moon.
In 2003 Astronomers in Europe and the Americas observed the annual Leonid meteor shower.- In 2003 astronomers found a companion in collision with our galaxy, the Milky Way.
The British-made probe Beagle 2 was declared lost in January 2004. The probe was due to land on Mars on Christmas morning 2003.
The last total lunar eclipse visible until 2007 took place in October 2004.
On 8 June 2004 the transit of Venus was visible across the UK.
A year after its discovery, the newly designated ‘dwarf planet’ 2003 UB313 was named Eris.
In 2006 the space probe Mars Odyssey found geysers of carbon dioxide gas erupting from the Martian south pole.
The Cassini-Huygens mission to Saturn found lakes near the north pole of the largest moon, Titan.
The European Space Agency (ESA) spacecraft Mars Express has discovered a layer of water ice deep beneath the surface of Mars.
On 3 January 2006 the annual Quadrantid meteor shower took place in the northern hemisphere.- Amateur astronomers in the United States watched in July 2006 as a mountain-sized asteroid raced past the Earth.
In 2006 Jupiter's 350-year-old Great Red Spot was overtaken by its younger sibling which formed in the late 1990s.
After a 2-year mission to the Moon, the SMART-1 probe crashed into the lunar surface at 0642 BST on 3 September 2006.
In 2006 the Mars Express probe imaged the Cydonia region of Mars solving the mystery of the legendary ‘face’.
Images from the Cassini probe show a previously unknown ring of icy material around Saturn.
In 2006 the NASA probe Mars Reconnaissance Orbiter imaged the robotic rover Opportunity on the edge of the Victoria Crater on Mars.