'Potentially Hazardous' Asteroid Expected to Fly by Earth on March 4

An asteroid was detected to fly by Earth on March 4, at 03:00 a.m. ET (local time).

The asteroid is called 138971 (2001 CB21) and its size is up to 1.3 kilometers (0.81 miles) in diameter, approximately four times as wide as the Eiffel Tower and comparable to the size of the Golden Gate Bridge.

Discovery of 2001 CB21 Asteroid

Gianluca Masi, an astronomer at the Virtual Telescope Project in Italy, detected the 2001 CB21 asteroid on Jan. 30 when the asteroid was over 21.5 million miles away from Earth.

The National Aeronautics and Space Administration (NASA)'s Center for Near Earth Object Studies (CNEOS) classified the asteroid as a "Potentially Hazardous Asteroid (PHA)," as per the Space Reference organization.

Also classified as a Near Earth Asteroid (NEA), the classifications on 2001 CB21 are based on its predicted relative closest distance, 4,911,102 million kilometers (3,051,617 miles), when it passes on Earth.

To put into perspective, the distance of the asteroid when it passes Earth is about 13 times between Earth and the moon.

The asteroid has been categorized as a small Apollo-class Asteroid (APO) since its orbit will cross Earth's orbit.

Further categorization of APOs is also based on the asteroid's size.

2001 CB21 makes an orbit around the sun once every 384 days (1.05 years), as per Space Reference.

Other Asteroids: Apophis and the 1994 PC1

The classifications of asteroids as PHAs are not rare.

In fact, an asteroid flyby occurred last month. A large PHA-classified asteroid called 1994 PC1 safely passed by Earth on Jan. 18.

The asteroid has an estimated size of 1 kilometer (0.6 miles) and with a height more than twice of the Empire State Building, as per the Earth Sky organization.

The said asteroid was first discovered in 1994.

Another asteroid called 99942 Apophis, with the size of 1,120 feet (0.34 kilometers) will make a close encounter with Earth on April 13, 2029.

Discovered in 2004, Apophis will pass by Earth with only a distance of 31,000 kilometers (19,000 miles) from our planet.

The Apophis is considered to be one of the most dangerous asteroids that might strike Earth due to the estimated close distance when it passes Earth in 2029.

Measures Against a Possible Asteroid Strike

There have been no planet-killing asteroids that struck Earth since the Chicxulub crater asteroid that caused the fifth mass extinction around 66 million years ago.

The asteroid left its crater off the coast of Mexico, where its impact brought an end to the dinosaurs and the majority of other animal and plant species living on Earth at that time, as per The Harvard Gazette.

However, NASA is preparing measures against a possible asteroid strike on Earth in the future.

Currently, NASA is engaging in a program called the Double Asteroid Redirection Test (DART) mission with the primary objective of deflecting an incoming asteroid away from Earth.

Launched on Nov. 24, 2021, the DART mission is a test designed to evaluate the kinetic impact technique by hitting an asteroid with a spacecraft and observing any changes in the asteroid's orbit before and after, as per NASA.

The space agency will conduct the test by flying the DART spacecraft at a high relative velocity to the binary near-Earth asteroid called 65803 Didymos and its moonlet.

The DART spacecraft is expected to intercept Didymos' moonlet in late September 2022, as per NASA's Planetary Defense Coordination Office.