ASTEROID APOPHIS

ASTEROID APOPHIS

Subject : Science & tech

Context : Recently, the USA’s NASA space agency has ruled out the possibility of the dreaded asteroid Apophis causing any damage to the Earth for the next 100 years.

Concept :

Asteroid Apophis

• It is named after the ancient Egyptian god of chaos and darkness.
• It was discovered in 2004, after which NASA had said that it was one of the asteroids that posed the greatest threat to Earth.
• It measures 340 metre across which is comparable to the size of the huge ship that has currently blocked the Suez Canal.
• The astronomers used the 70-metre radio antenna at the Deep Space Network’s Goldstone Deep Space Communications Complex near Barstow, California in order to track Apophis’ motion.
• They also used the 100-metre Green Bank Telescope in West Virginia which showed imaging of Apophis.
• The two systems were used together in a “bistatic” experiment that doubled the strength of the received signal.
• Apophis is categorised as a potentially hazardous asteroids (PHAs).

Potentially Hazardous Asteroids:

• It means that an asteroid has the potential to make threatening close approaches to the Earth.
• Specifically, all asteroids with a Minimum Orbit Intersection Distance (MOID) of 0.05 AU (which is about 7,480,000 Km) or less and an Absolute Magnitude (H) of 22.0 (about 150 mt in diameter) or less are considered PHAs.
• MOID is a method for calculating the minimum distance between two almost overlapping elliptical orbits.
• The absolute magnitude is a measure of the star’s luminosity i.e. the total amount of energy radiated by the star every second.