Near Earth Asteroid 163348 (2002 NN4) to Pass Earth
Top Current Affairs 6th June 2020
Source | Indian Express
GS Paper III: Awareness in Space.
- The gaint near-earth object named 163348 (2002 NN4) was discovered in July 2002 and is expected to approach the earth in June 2020. The asteroid is estimated to be between 250-570 meters in diameter.
- By convention, a Solar System body is a NEO if its closest approach to the Sun i.e., perihelion is less than 1.3 astronomical units (AU). [where 1 AU = 1.495978707×1011 m]
Read More: 1998 OR2 | POTENTIALLY HAZARDOUS ASTEROID
Context: According to an announcement made by NASA, a giant Near Earth Asteroid called as 163348 (2002 NN4), is expected to pass Earth on 6th June 2020.
- NASA has also speculated that the passing of this gaint near-earth asteroid will be within the safe limit of distance.
What you need to know about Near Earth Asteroids and 163348 (2002 NN4)?
The gaint near-earth object named 163348 (2002 NN4) was discovered in July 2002 and is expected to approach the earth in June 2020. The asteroid is estimated to be between 250-570 meters in diameter.
According to the scientists, this asteroid is a Near-Earth Object and classified as a Potentially Hazardous Asteroid (PHA).
Read More: New Trojan Asteroid discovered near Jupiter
A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun i.e., perihelion is less than 1.3 astronomical units (AU). [where 1 AU = 1.495978707×1011 m]
- There are over 20,000 known near-Earth asteroids (NEAs), over a hundred short-period near-Earth comets (NECs), and a number of solar-orbiting spacecraft and meteoroids large enough to be tracked in space before striking the Earth.
- Two scales namely, the Torino scale and the more complex Palermo scale, rate a risk which is based on how well constrained the orbit calculations of identified NEOs are and on how bad the consequences of a putative impact would be.
- NEOs have low surface gravity, and many have Earth-like orbits making them easy targets for spacecraft.
- As of January 2019, five near-Earth comets and five near-Earth asteroids have been visited by spacecraft.
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When does a NEO designated as potentially hazardous?
- If a NEO’s orbit crosses the Earth’s orbit, and the object is larger than 140 meters (460 ft) across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets.
- They are defined as having a minimum orbital intersection distance with Earth of less than 0.05 astronomical units (19.5 lunar distances) and an absolute magnitude of 22 or brighter.
- 98% of the known potentially hazardous objects are not an impact threat over the next 100 years.
Minimum Orbit Intersection Distance is a method for calculating the minimum distance between two almost overlapping elliptical orbits.
The Astronomical Unit (AU) is the distance between the Earth and the Sun and is roughly 150 million km.
The absolute magnitude is a measure of the star’s luminosity i.e. the total amount of energy radiated by the star every second.
What is the difference between an asteroid and a comet?
- The main difference between asteroids and comets is their composition, as in, what they are made of.
- Asteroids are made up of metals and rocky material, while comets are made up of ice, dust and rocky material.
- Both asteroids and comets were formed early in the history of the solar system about 4.5 billion years ago.
- Asteroids formed much closer to the Sun, where it was too warm for ices to remain solid.
- Comets formed farther from the Sun where ices would not melt.
- Comets which approach the Sun lose material with each orbit because some of their ice melts and vaporizes to form a tail.
- Hence the tail of the comet that we see is nothing but the ice which melts and vaporizzes as the comet approaches the sun.
Most Recent Asteroid Passby
On 29 April 2020 at 09:56 UTC (3:26 P.M. in India), the 1998 OR2 asteroid safely passed at 0.042 AU (6.3 million km; 16 LD) from Earth. With observations as recent as April 2020 and a 32-year observation arc, the 2020 close approach distance was known with an accuracy of roughly ± 6 km.
What you need to know about 1998 OR2?
- 1998 OR2, is an asteroid on an eccentric orbit, classifed as a near earth object and potentially hazardous asteroid of the Amor group, with a diameter of 2 kilometers (1.2 mi).
- It was discovered on 24 July 1998, by astronomers of the NEAT program at the Haleakala Observatory, Hawaii.
- There are precovery images from 1987 and 1996.
- It is one of the brightest and therefore largest potentially hazardous asteroids known to exist.
- With an observation arc of 32 years, the asteroid has a well-determined orbit, and its trajectory is well known through the year 2197.
- The asteroid’s orbit is only potentially hazardous on a time scale of hundreds, if not thousands, of years.
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