Wednesday, February 24, 2016

100-Foot Asteroid Could Hit Earth In 2017


An asteroid measuring 100 feet in length will make its closest approach to Earth on March 5, 2016 and NASA scientists aren't sure just how close the asteroid will come to our home planet.


During the upcoming March 5 flyby, asteroid 2013 TX68 could fly past Earth as far out as 9 million miles (14 million kilometers) or as close as 11,000 miles (17,000 kilometers), scientist say. The variation in possible closest approach distances is due to the wide range of possible trajectories for the asteroid because it was tracked for only a short time after discovery.

Although they are not sure how close the asteroid will near Earth, scientists at NASA's Center for NEO Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California have assured the public that there is no possibility that this object could impact Earth during the flyby next month. 

However, astronomers have identified an extremely remote chance that this asteroid could impact the Earth next year on September 28, 2017, with odds of no more than 1-in-250-million. Flybys in 2046 and 2097 have an even lower probability of impact.

"The possibilities of collision on any of the three future flyby dates are far too small to be of any real concern," said Paul Chodas, manager of CNEOS. "I fully expect any future observations to reduce the probability even more."

Asteroid 2013 TX68 is estimated to be about 100 feet (30 meters) in diameter. By comparison, the asteroid that broke up in the atmosphere over Chelyabinsk, Russia, three years ago was approximately 65 feet (20 meters) wide. If an asteroid the size of 2013 TX68 were to enter Earth's atmosphere, it would likely explode with an air burst with about twice the energy of the Chelyabinsk event, according to NASA's Planetary Defense Coordination Office.

The asteroid was discovered on Oct. 6, 2013 as it approached Earth on the nighttime side. After three days of tracking, the asteroid passed into the daytime sky and could no longer be observed. Because it was not tracked for very long, scientists cannot predict its precise orbit around the sun, but they do know that it cannot impact Earth during its flyby next month.

"This asteroid’s orbit is quite uncertain, and it will be hard to predict where to look for it," said Chodas. "There is a chance that the asteroid will be picked up by our asteroid search telescopes when it safely flies past us next month, providing us with data to more precisely define its orbit around the sun."

What's the difference between an asteroid, a meteor and a meteorite? 

NASA defines shooting stars or meteors as bits of material falling through Earth's atmosphere; they are heated to incandescence by the friction of the air. The bright trails as they are coming through the Earth's atmosphere are termed meteors, and these chunks as they are hurtling through space are called meteoroids. Large pieces that do not vaporize completely in the atmosphere and reach the surface of the Earth are termed meteorites.

Simply put, the name of the space material depends on where it is located:  

Asteroid - A relatively small, inactive, rocky body orbiting the Sun in outer space.
While in space - a meteoroid;  
While traveling through the Earth's atmosphere - a meteor (also called a shooting star); and
After hitting the Earth's surface - a meteorite.