Two Asteroids to Pass by Earth

According to Nasa reports two rocks in the space are whizzing by the earth! There won’t be any clashes. For India unfortunately this event can not be seen as it is occurring during the day.

Asteroids are rocky and metallic objects that orbit the Sun but are too small to be considered planets. These are objects that have a near-Earth orbit, yet far enough from the Sun so that the surface material never evaporates, having a diameter over 50 metres. Various dynamical groups of asteroids have been discovered orbiting in the inner Solar System.

Significant populations include:

  • Main asteroid belt
  • Trojans
  • Near-Earth asteroids

The Main asteroid belt (white) and the Trojan asteroids (green)

Those NEOs (Near Earth Objects) that are asteroids (NEA) have orbits that lie partly between 0.983 and 1.3 AU astronomical units away from the Sun.  When an NEA is detected it is submitted to the Harvard Minor Planet Center for cataloging. Some near-Earth asteroids’ orbits intersect that of Earth’s so they pose a collision danger.  The United States, European Union and other nations are currently scanning for NEOs in an effort called Spaceguard.

Asteroid Vesta  (left) and dwarf planet Ceres (center), with  Earth's Moon (right) shown to scale

Objects in the main asteroid belt vary greatly in size, from almost 1000 kilometres for the largest down to rocks just tens of metres across. The dwarf planet Ceres is the largest object in the asteroid belt, with a diameter of 975 km (610 mi). The next largest are the asteroids 2 Pallas and 4 Vesta, both with diameters of just over 500 km (300 mi). Normally Vesta is the only main belt asteroid that can, on occasion, become visible to the naked eye. However, on some rare occasions, a near-Earth asteroid may briefly become visible without technical aid.

Two asteroids sped toward Earth but just missed humanity’s home planet by what amounts to a cosmic hair’s breadth on Wednesday, NASA said.

Top view: Two small asteroids in unrelated orbits will pass within the moon's distance of Earth on Wed. Both should be observable with moderate-sized amateur telescopes. Image credit: NASA/JPL-Caltech

Top view: Two small asteroids in unrelated orbits will pass within the moon’s distance of Earth on Wed. Both should be observable with moderate-sized amateur telescopes. Image credit: NASA/JPL-Caltech

Near-Earth asteroid 2010 RX30 is estimated to be 32 to 65 feet (10 to 20 meters) in size and will pass within 0.6 lunar distances of Earth (about 154,000 miles, or 248,000 kilometers) at 2:51 a.m. PDT (03:21:00 p.m. Wednesday September 8, 2010 in Asia/Calcutta) Wednesday. At time of closest approach for 2010 RX 30, it will be approximately 154,000 miles (about 248,000 kilometers) above the North Pacific, south of Japan.

The second object, 2010 RF12, estimated to be 20 to 46 feet (6 to 14 meters) in size, will pass within 0.2 lunar distances (about 49,088 miles or 79,000 kilometers) a few hours later at 2:12 p.m. PDT (02:42:00 p.m. Wednesday September 8, 2010 in Asia/Calcutta), the asteroid will be approximately 49,088 miles (about 79,000 kilometers) above Antarctica.

Impact rate

Objects with diameters of 5-10 metres impact the Earth’s atmosphere approximately once per year, with as much energy as the atomic bomb dropped on Hiroshima, approximately 15 kilotonnes of TNT. These ordinarily explode in the upper atmosphere, and most or all of the solids are vaporized. Objects of diameters of the order of 50 meters strike the Earth approximately once every thousand years. Objects with a diameter of one kilometer hit the Earth an average of twice every million year interval. Large collisions with five kilometer objects happen approximately once every ten million years.

The rate of impacts of objects of at least 1 km in diameter is estimated as 2 per million years. Assuming that this rate will continue for the next billion years, there exist at least 2,000 objects of diameter greater than 1 km that will eventually hit Earth. However, most of these are not yet considered Potentially Hazardous Objects because they are currently orbiting between Mars and Jupiter. Eventually they will change orbits and become NEOs. Objects spend on average a few million years as NEOs before hitting the Sun, being ejected from the Solar System, or (for a small proportion) hitting a planet.

As NASA said “Both asteroids should be observable near closest approach to Earth with moderate-sized amateur telescopes. Neither of these objects has a chance of hitting Earth”.

Future Impacts

Radar image of Asteroid 1950 DA.

Radar image of Asteroid 1950 DA.

Although there have been a few false alarms, a number of objects have been known to be threats to the Earth. (89959) 2002 NT7 was the first asteroid with a positive rating on the Palermo Technical Impact Hazard Scale, with approximately one in a million on a potential impact date of February 1, 2019.

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