The National Aeronautics and Space Administration (NASA) has recently alerted the global community about “Asteroid 2020 ND”. This massive asteroid is expected to fly by Earth on 24th July.
The Asteroid’s Profile
This enormous celestial body, measuring approximately 170 meters in length, will approach as close as 0.034 Astronomical Units (AU) to our planet. For reference, an AU represents the average distance between Earth and the Sun and equates to nearly 150 million kilometers. Traveling at a speed of around 48,000 kilometers per hour, this asteroid has been classified as a Near-Earth Object (NEO) and falls into the Potentially Hazardous Asteroids (PHA) category due to its proximity to Earth.
Understanding Potentially Hazardous Asteroids
The term PHA is used to describe asteroids that could pose a significant threat to Earth due to their close approaches. Specifically, all asteroids with a Minimum Orbit Intersection Distance (MOID) of 0.05 AU (roughly 7,480,000 Km) or less and a diameter of roughly 150 meters (an Absolute Magnitude (H) of 22.0) are considered Potential Hazardous Asteroids. The MOID indicates the smallest distance between two elliptical orbits that almost overlap, while the absolute magnitude refers to the star’s total radiated energy per second.
Solutions for Asteroid Deflection
Strategies to divert the trajectory of asteroids include detonating the asteroid before it reaches Earth or redirecting it from its path towards Earth using a spacecraft. A notable effort in this regard is the Asteroid Impact and Deflection Assessment (AIDA), a project involving NASA’s Double Asteroid Redirection Test (DART) mission and the European Space Agency’s (ESA) Hera.
The DART and Hera Missions
In 2018, NASA initiated the construction of the DART mission, which aims to collide with the smaller asteroid of the Didymos system at a speed of about 6 km per second in 2022. The Didymos system is a binary near-Earth asteroid and has the potential to pose a significant threat to Earth. On the other hand, Hera is set to launch in 2024 and will reach the Didymos system in 2027 to examine the impact crater caused by the DART collision and assess the change in the asteroid’s trajectory.
Monitoring Potentially Hazardous Asteroids
Although an asteroid may be classified as a PHA, it does not necessarily mean it will hit Earth. This classification simply indicates a potential risk. By closely monitoring these PHAs and updating their orbits based on new findings, scientists can forecast their approach patterns and evaluate the threat they might pose to Earth.
Significance of Studying Asteroids and Comets
These celestial bodies are remnants from the formation of the solar system over 4.6 billion years ago and have remained largely unchanged. Hence, they provide valuable information about the chemical composition of the original planetary mix. Furthermore, an asteroid hit is widely recognized as one of the most plausible causes of potential mass extinction on Earth.
Characteristics of Asteroids and Comets
Asteroids, small bodies orbiting the sun mainly composed of rocks and metals, generally have shorter and more elliptical orbits and lack a coma or tail atmosphere. An asteroid belt, situated approximately between the orbits of Jupiter and Mars, contains masses of these celestial bodies. Comets are small icy and hydrocarbon bodies also orbiting the Sun. They have eccentric orbits, and as they near the Sun, part of their ice melts and other materials vapourise, resulting in a glowing halo extending out into space, forming a thin atmospheric tail when close to the Sun.