The Earth in Space

Collision Course - NEO 's When looking at the Earth in the Solar System , there are many fascinating objects , and also many dangerous ones . NEO 's , or Near Earth Objects are constantly being studied to determine the actual possibility of collision with the Earth . Most NEO 's consist of meteors , meteorites comets and asteroids . Though most of the objects are too small to cause any sort of substantial damage , there are a few that are capable of causing the next major extinction . In for an object to be considered a NEO , it must

be within 1 .3 AU 's (or astronomical units from the Sun . 1 .3 AU is the same as about 93 million miles . The NEO 's are objects that have been bumped by the gravity of other planets which let them get close to the Earth 's orbit

One of the major groups of NEO 's are meteoroids . The term meteor is actually used to describe the streak of visible light after it 's trip through the Earth 's orbit . One of the most famous craters , which is like a giant scar caused by a NEO hitting the Earth , is in Arizona Meteor Crater , or Barringer Meteorite Crater as it is also known as , is a jarring reminder of what kind of damage a NEO can do upon impact . Most meteors are small enough that once they are pulled in by the Earth 's orbit and hit the atmosphere , they burn up and disintegrate before they ever get the chance to actually hit the Earth 's surface

Another group of NEO 's are asteroids . One of the largest asteroids that astronomers keep their eyes on is Apophis . This giant is due to hit the Earth in 2036 . The size of Apophis is estimated to be a bit larger then the Rose Bowl , and if it were to hit the Earth would cause global damage . If it hits the ocean , the damage occurring from the huge tsunamis by themselves would be catastrophic

Another class of objects that are visible to the naked eye are comets When speaking of them as NEO 's , then they are considered to be old comet nuclei whose perihelia are less then 1 .3 AU from the Sun . One comet in particular that has been known through history is Halley 's Comet . Also the trail of cosmic dust , or tail of the comet can also be passed through by the Earth

In conclusion , NASA is taking steps to try and diminish the risk of being hit by a NEO by continually watching and cataloging the orbits and behaviors of NEO 's . What remedies that have been looked at so far to try and deal with the risk of being hit is to explode nuclear weapons near the object to try and change it 's course . Other considerations that have been looked at is sending high-speed ballistic missiles towards the object to make an impact , or to send a hovering spacecraft to pull the object into a different orbit , thereby allowing it to miss the Earth altogether . The future for watching NEO 's is strongly backed now more then ever before . Washington has allowed a 4 million dollar budget for listing potential and real threats to the Earth , and sent a new report to congress in March 2007 . Considering the probability that the Earth will be hit again , as it has been hit in the past requires that the scientific community take heed of the risk , and not only be able to prepare the world for such a catastrophe , but be able to prevent it as well

References

HYPERLINK "http /www .jpl .nasa .gov /multimedia /neo /index .cfm http /www .jpl .nasa .gov /multimedia /neo /index .cfm

HYPERLINK "http /www .nasa .gov /centers /hq /home /index .html http /www .nasa .gov /centers /hq /home /index .html

HYPERLINK "http /newton .dm .unipi .it /cgi-bin /neodys /neoibo ?info :0 faq \l "nea " http /newton .dm .unipi .it /cgi-bin /neodys /neoibo ?info :0 faq nea ...