Asteroid 2020 ND

• 27 Jul 2020

Why in News

Recently, the National Aeronautics and Space Administration (NASA) has issued a warning that a huge “Asteroid 2020 ND” will move past Earth on 24^th July.

Key Points

• Description: The asteroid, about 170 metres-long, will be as close as 0.034 Astronomical Unit (AU- Astronomical Unit is the distance between the Earth and the Sun and is roughly 150 million km) to the Earth, and is travelling at a speed of 48,000 kilometres per hour.
• It is a Near-Earth Objects (NEO) and its distance from Earth has placed it in the Potentially Hazardous Asteroids (PHA) category.
• 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.
• Solutions
  
  • Deflecting Asteroids: Blowing up the asteroid before it reaches Earth, or deflecting it off its Earth-bound course by hitting it with a spacecraft may ward off the threat.
  • AIDA: The measure undertaken so far is the Asteroid Impact and Deflection Assessment (AIDA), which includes NASA’s Double Asteroid Redirection Test (DART) mission and the European Space Agency’s (ESA) Hera.
    • DART: In 2018, NASA announced that it had started the construction of DART, which is scheduled to launch in 2021 with an aim to slam into the smaller asteroid of the Didymos system at around 6 km per second in 2022. Didymos, is a binary near-Earth asteroid, that could pose the most likely significant threat to Earth.
    • Hera: It is scheduled to launch in 2024, and will arrive at the Didymos system in 2027 to measure the impact crater produced by the DART collision and study the change in the asteroid’s orbital trajectory.
  • Monitoring of PHAs: It is not necessary that asteroids classified as PHAs will impact the Earth. It only means there is a possibility of a threat.
    
    • By monitoring these PHAs and updating their orbits as new observations, it is possible to predict the close-approach statistics and thus their Earth-impact threat.

Significance

• The scientific interest in comets and asteroids is largely due to their status as relatively unchanged remnant debris from the solar system formation process over 4.6 billion years ago. Therefore, they offer clues about the chemical mixture from the planets formed.
• Significantly, among all the reasons that will eventually cause the extinction of life on Earth, an asteroid hit is widely acknowledged as one of the likeliest.

Asteroids

• Asteroids orbit the Sun and are small bodies in the solar system.
• They are made up of metals and rocks.
• They tend to have shorter and elliptical orbits.
• They do not produce a coma or tail atmosphere.
• The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars.

Comet

• Comets also orbit the Sun and are relatively small bodies of the solar system.
• They are made up of ice and hydrocarbons.
• Comets have an eccentric orbit.
• When comets approach the sun, some part of their ice melts and the other materials vapourise due to the heat of the sun. This results in a glowing halo that extends outwards through space.
  
  • Therefore, a thin atmospheric tail is formed when close to the Sun.

Source: IE