NEAR EARTH COLLISIONS

By Xavier Ramana Henry Park Pri Sch 5r1 (18)

Near earth collisions are collisions that almosthappened. They are space objects which madean orbit near the earth. On the next few slidesthere are facts about some Earth shakingimpacts.

• Chicxulub impactor

• It was an asteroid or comet at least ten kilometres in diameter which impacted a few miles from the present-day town of Chicxulub in Mexico, after which the impactor and its crater are named.

• Chicxulub impactor

• It is the asteroid which is supposed to have wiped out the dinosaurs. The impactor's crater is more than 180 km in diameter, making it one of the largest known impact craters on Earth.

Chicxulub crater

• Shiva crater

• Shiva crater was created around 65 million years ago, about the same time as a number of other impact craters and the Dinosaurs extinction event . It is not confirmed that it is a crater.

• Shiva crater• Although the site has shifted since its

formation because of sea floor spreading, the formation is approximately 600 kilometres long by 400 km wide. It is estimated that this proposed crater would have been made by an asteroid or comet approximately 40 km in diameter.

Shiva Crater

• Tunguska event

• The Tunguska event was an enormously powerful explosion that occurred near the Podkamennaya Tunguska River in what is now Krasnoyarsk Krai, Russia, on June 30 1908.

• Tunguska event

• The explosion, having the epicentre is believed to have been caused by the air burst of a large meteoroid or comet fragment at an altitude of 5–10 kilometres above the Earth's surface

Tunguska event

• Shooting star is a common name for the visible path of a meteoroid as it enters the atmosphere, becoming a meteor. As it enters the atmosphere the meteor burns and vaporizes. They hit the earth’s atmosphere almost everyday, so they create an unimportant, small, near earth collision.

• The Torino Scale is an asteroid impact measuring scale. It uses a colour code scale: white, green, yellow, orange, red. Each colour code has an overall meaning. On the next slide there is the explanation for the colour codes.

• Dying because of Dying because of a

an asteroid: Plane crash while flying

1 in 24,000 in it once a year:

1 in 66,000

N 1 in 66,000

99942 Apophis is a near-Earth asteroid thatcaused a brief period of concern inDecember 2004 because initialobservations indicated a probability that itwould strike the Earth in 2029.

It got a Torino scale rating of 4. Newerobservation changed its rating to 1.On thenext page you can compare its height withsome of the tallest buildings in the world.

Adapted from:

http://en.wikipedia.org/wiki/99942_Apophis

• When a asteroid hits the earth it would create a gigantic cloud of dust. When the dust goes up it will cover the sunlight. When the sunlight is covered plants cannot make food and die. When the plants die the animals that eat plants die too and so the cycle continues. When this happens it will result in a mass extinction.

• There is a program called ‘Star Wars”. It is an organisation that deflects asteroids. Almost any deflection effort requires years of warning, allowing time to prepare and carry out a collision avoidance project. It has been estimated that a slight change of one millimetre is needed to successfully deflect a body on a direct collision trajectory.

We need to learn about near earth collision as weare the next generation to protect earth. If we learnabout asteroids and other outer space objects now ,we will have a better chance of keeping earth safe.Thank You for your kind understanding!

• These may be a warning for us to protect our earth from these deep space intruders. We need to prepare ourselves to push these rocks away or we may face the deadly effects. That is the reason why we should learn about near earth collisions. Thank you for your kind understanding