Asteroid 163348 can make threatening close approaches to our planet. (Representational image)

Near-Earth Asteroid: On June 6, a giant asteroid was expected to fly past the Earth at a safe distance. The asteroid, estimated to be larger than the Empire State Building in New York with its diameter ranging between 250 and 570 metres, has been named Asteroid 163348 (2002 NH4) by NASA’s Jet Propulsion Laboratory. The Near-Earth Object (NEO) has been categorised as a potentially hazardous asteroid (PHA) by the space agency.

An NEO is defined by NASA as asteroids and comets which are moved by the gravitational force of planets into an orbit which brings them to near-Earth space. According to an IE report, these NEOs are usually made of water ice with dust particles embedded into it. NEOs occasionally come close to the Earth and NASA’s Centre for Near-Earth Object Study (CNEOS) determines when the object will approach the Earth and how close it will get.

According to the IE report, asteroids and comets are an interesting field of study because these bodies have remained relatively unchanged since they were formed of remnant debris during the formation of the solar system more than 4.6 billion years ago. These bodies, therefore, clue in the scientists regarding the chemical mixtures from the planets formed, the report added.

Moreover, an asteroid collision is also thought to be one of the likeliest causes for the extinction of life on Earth, which is also thought to be the cause for the extinction of dinosaurs, as per National Geographic. Now, scientists are proposing that one way to avert such extinction is by destroying the incoming asteroid before it collides with Earth, or by deflecting the body of its path by hitting it with a spacecraft.

The NASA Near-Earth Object Observations Programme discovers, tracks and characterizes more than 90% of the NEOs which are equal to or larger than 140 metres in size. As per the IE report, objects of this size or bigger than these are a cause of concern because of the devastation they can cause upon any collision. The report further adds that no asteroid larger than this has any significant chance of colliding with Earth anytime soon. However, so far only less than half of the estimated 25,000 NEOs equal to or larger than 140 metres have been discovered.

Asteroid 163348 can make threatening close approaches to our planet, which is why it has been categorised as a PHA. PHAs are those asteroids which have a minimum orbit intersection distance or MOID of about 0.05 AU, or 74.8 lakh km or less and an absolute magnitude of 22 or less, or smaller than about 150 m.

However, PHAs will not necessarily impact the Earth. According to NASA, classifying an asteroid as PHA only means that there is a possibility that such a threat might crop up. Classifying these as PHA puts NASA in a better position to predict the close-approach statistics.