A rare event will take place on Saturday, as the European Space Agency (ESA) reports that a large asteroid will safely pass between Earth and the Moon. The asteroid, named 2023 DZ2, is estimated to be 40 to 70 meters (130 to 230 feet) wide, roughly the size of the Parthenon. Though it is large enough to wipe out a major city if it were to collide with Earth, it poses no threat during its flyby. The asteroid’s proximity presents a unique opportunity for planetary defense training and analysis.
At 19:49 GMT on Saturday, 2023 DZ2 will come within a third of the distance from Earth to the Moon. According to Richard Moissl, head of the ESA’s planetary defense office, this is “very close,” but there is no cause for concern. While small asteroids fly past Earth every day, an asteroid of this size passing so close to our planet only occurs approximately once every 10 years.
The asteroid will travel 175,000 kilometers (109,000 miles) from Earth at a speed of 28,000 kilometers per hour (17,400 miles per hour). It was first spotted by an observatory in La Palma, one of Spain’s Canary Islands, on February 27. The UN-endorsed International Asteroid Warning Network (IAWN) recently decided to use this event as an opportunity to conduct a “rapid characterization” of 2023 DZ2.
Astronomers worldwide will utilize a range of instruments, such as spectrometers and radars, to analyze the asteroid. The goal of this exercise is to determine how much information can be gathered about such an asteroid in only a week. This analysis will also serve as training for how the network would respond to a future asteroid threat.
Preliminary data suggests that 2023 DZ2 is a “scientifically interesting object,” possibly an unusual type of asteroid. However, more data is needed to determine its composition. The asteroid is scheduled to pass by Earth again in 2026 but poses no impact threat for at least the next 100 years, based on its calculated trajectory.
Earlier this month, another similarly sized asteroid, 2023 DW, was initially given a one-in-432 chance of impacting Earth on Valentine’s Day 2046. Subsequent calculations eliminated the possibility of an impact, and 2023 DW is now expected to miss Earth by around 4.3 million kilometers.
In the event of a future asteroid threat, Earth is not defenseless. Last year, NASA’s DART spacecraft successfully collided with the pyramid-sized asteroid Dimorphos, altering its course in the first test of our planetary defenses. The upcoming analysis of 2023 DZ2 will contribute valuable knowledge and experience to our ongoing efforts to protect Earth from potential asteroid impacts.