Issues: Near Earth Objects

Near Earth Objects are objects from space, asteroids, meteors and comets that pass dangerously close to the the Earth on their orbits around the Sun.

In the summer of 1994, the Comet Shoemaker-Levy 9 broke up into pieces and dove into Jupiter leaving scars the size of our own planet. Had this comet been on a track to Earth, our planet would have been destroyed. Scientists have since received more funding for identifying and preparing plans to deal with this natural threat. We are the only creatures on Earth who have the capability to divert these dangerous bodies from a collision with our home world. These collisions have happened in the past and these bodies will continue to present themselves in the future.

Scientists are currently mapping the sky to find the NEOs. According to NASA's Near Earth Object Program, there are currently about one thousand known PHAs (Potentially Hazardous Asteroids).

In February 2008 an asteroid named "2008 CT1" flew past the Earth only 72,000 miles away. That is 0.3 lunar distances or stated another way - 1/3 the distance to our Moon. This was a very close approach. It was not large, however, only about the size of a large school bus - 13 meters wide. If it had struck the Earth, it would have probably exploded into fragments in the atmosphere and sent small shards across the Earth, doing little damage.

Asteroid 2007 TU24 made its closest approach to Earth at 12:33 am UT on Jan. 29 2007. At its closest point, the asteroid was 554,209 kilometers (344,370 miles) from Earth, or roughly 1.4 times the distance between the moon and Earth.

An asteroid around 1.2 km in width and promptly named 2003QQ47 was discovered on August 24, 2003 by the Lincoln Near Earth Asteroid Research Project (an MIT Lincoln Laboratory program funded by the US Air Force and NASA) in New Mexico. 2003 QQ47 was initially classified as a #1 threat on the Torino scale of impact hazards. Due to visit near Earth in March 2014, the asteroid has since been downgraded from a potential impact threat to a safe passage.

A historically close visit by a large asteroid named Apophis (210-330 meters / 690-1080 feet) is expected in April of 2029 and it is expected to return in 2036. In 2029, Apophis is expected to pass by close to our communication satellites, about 29,470 km, 18,300 miles or 4.6 Earth radii from the surface of our planet. This would be a very close passage. It may be visible as a spot of light crossing the sky.

Scientists are calling for international cooperation to develop the capability to divert these bodies into stable non-threatening orbits when necessary. See the links below for lists of NEOs and PHA monitored by NASA and other organizations.




Quotes

"Until then, no one had seen a comet so completely disrupted with its fragments all lined up and in orbit about a planet; no one had ever seen the impact upon a planet of a comet or an asteroid. This comet was nature's grand experiment for man to learn about the structure and makeup of comets, impact dynamics, the chemistry of Jupiter's clouds and, most importantly, to gain the awareness that, yes, objects can fall out of the sky and impact planets, including ours. The discovery of 31 other comets and of many near-Earth asteroids was also important as a foundation for our understanding of our solar neighbourhood and the origin of our solar system."

"How does one stand back and evaluate themselves? I would like to think that I made an important contribution in planetary astronomy with my pursuit of comets, planet-crossing asteroids, and impact craters and with a role in the education of others as to the importance of these bodies. Because my work preceded that of all but a small group involved in the search for near-Earth objects, it served to call more attention to them and to provide a base knowledge about the origin of our solar system and its solid bodies." Carol Shoemaker




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