Asteroids and Meteoroids and Comets :
Asteroids are pieces of rock and iron that orbit the Sun.
Meteoroids are smaller bits of material that fly through space.
Comets orbit the Sun and are made of ice, dust and rock.
Asteroids are known as minor planets although they can range in size from a few metres across to the largest – Ceres - which is almost 1000 km wide. Many asteroids are found orbiting in a belt between Mars and Jupiter.
Meteoroids travel at great speed. When they enter Eorth's atmosphere, they bum up due to friction with the air. These streaks of light ore called meteors or shooting stars. If meteors don't burn up completely, due to their large size, they hit Earth's surface. These are called meteorites. The Barrington Crater in Arizona, USA, was formed when a 30-50
metre iron meteorite hit Earth about 50000 years ogo. It is one of about 120 impoct craters on Earth.
There are billions of comets orbiting the Sun. A comet doesn't have a tail for most of its
orbit. As a comet moves closer to the Sun, it begins to warm up. Gas and dust from the nucleus or solid icy centre of the comet begin to form a cloud or a coma around the nucleus. The Sun and its solar wind blow the coma into two tails - one of gas and one of dust. As the comet moves away from the Sun, the tails shrink.
Halley's comet is the best known periodic comet with the first recorded sighting being in China in 240 BC. It returns to Earth every 75-76 years. Its next visit to the inner solar system will be the summer of 2061.
AMAZING FACTS about Our Solar System :
The inner solar system is separated from the outer by the asteroid belt.
The solar system is port of the Milky Way galaxy which is a barred-spiral galaxy.
There were 9 planets in the Solar System until 2006 when the International Astronomical Union decided that Pluto could no longer be considered a plonet due to its size being smaller than our moon.
If all the planets were joined together, the Sun would still be more than 700 times bigger.
It contains over 99% of the solar system's mass.
It takes two million years for gamma rays produced in the core of the Sun to reach its surface.
The Sun is the largest object the solar system. It is about 332 950 times more mossive
The relationship between the Sun and the Earth drives the seasons, currents in the ocean, weather and climate.
The Sun has been burning for about five billion years and will bum for another five billion.
If you stood on Venus, the atmospheric pressure would be the same as if you were 900 metres underneath an ocean on Earth.
Much of the surface of Venus, including craters, has been covered in lava from previous
Mercury and Venus are the only two planets in our solar system that don't have moons.
Mercury has the greatest variation in surface temperature of any planet in the solar system — can be over 600 degrees Celsius.
Because there is no wind or rain on the Moon, any footprints left by the astronauts should remain for millions of years.
It is thought that Earth was hit by a lorge object and the debris that was ejected into space joined together to form the Moon.
The official Latin name for planet Earth is Terra. It is named after the Roman goddess of fertility and growth - Terra Mater.
The Moon is the only other planet or satellite in the solar system that humans
hove set foot upon.
The length of each Martian season is almost twice as long as a season on Earth.
Mars has the least hostile environment of all the other planets in the solar system.
The surface area of Mars is approximately equal to that of Earth's dry land as Mars does not have any oceans.
Mars has two small moons. They have uneven shapes and may originally have been asteroids.
After the Sun, the Moon and Venus, Jupiter is usually the fourth brightest object in the sky.
Saturn is almost exactly the same as Jupiter, just smaller. The only striking difference is the rings around Saturn.
Saturn's rings are thought to be particles of an old moon which was smashed to pieces in a collision million of years ago.
Jupiter is made of hydrogen and helium gases which also make up the Sun. If Jupiter
had been any bigger, it could have become a star.
It takes 84 Earth years for Uranus to complete one full orbit around the Sun.
The Kuiper Belt contains many comets, asteroids and other small bodies made largely of ice.
As its orbit is so for from the sun, Neptune receives very little heat - in fact the uppermost regions of its atmosphere are -218 degrees Celsius.
A comet's tail can be millions of kilometres long.
Over 9 000 asteroids hove been located and named.
An asteroid, colled Ido, has its own moon called Dactyl.
Halley's comet lost visited Earth in 1986
Asteroids and Meteoroids and Comets :
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