Near-Earth-Objects
Near-Earth-Objects :
Near-Earth-Objects (NEOs) are small objects in the solar system. They have struck Earth in the past and will definitely hit again, but are we in danger of Near-Earth-Objects?
The Earth has been hit by asteroids, comets and meteorites in the past. Scientists believe that when a large asteroid collided with Central America 65 million years ago, the dinosaurs became extinct. The collision threw up water and rock which hid the Sun and covered the Earth in darkness for months. Dinosaurs could not survive in the cooler climate.
Of the Near-Earth-Objects, Most meteors are tiny and burn up in Earth's atmosphere. Even the ones that do get through and land as meteorites are mostly very small. The Earth's atmosphere protects us from all objects up to about 40 metres across. Asteroids pose a much bigger threat to Earth as they tend to be much larger objects.
If an asteroid with a diameter of more than two kilometres hit the Earth, it would cause a catastrophic planetary event. Many people would die as a result of the impact and of the Earth entering a long cold winter where most crops die. The good news is that an asteroid of this size only collides with Earth about once every 100 million years. The Spaceguard survey scans the skies looking for any dangerous NEOs. As yet, none that are on a collision course with Earth, have been discovered.
When a bigger object does head our way, we should have the advance warning and technology to deal with it.
AMAZING FACTS about Our Solar System :
The solar system includes the Sun, the nine planets and their 158 presently known moons. It also includes asteroids, meteoroids, comets and interplanetary dust. Come on a journey and travel through our solar system. Visit all nine planets and discover if NEOs are a threat to Earth.
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 than Earth.
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 eruptions.
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
Astronomers look in space for asteroids or meteorites that might be headed towards Earth.
Today, in the United States and Australia, we can still see craters that are the result of meteorites hitting Earth.
Huge asteroids like the one that caused the extinction of the dinosaurs collide with Earth about once every 100 million yeors. That asteroid was 15 km wide.
When small fragments of cosmic debris, often left over from a passing comet, enter Earth's atmosphere at high speed we get a meteor shower.
Near-Earth-Objects :
