Thanks to Observations, a Potentially Dangerous Asteroid was Found to be Harmless

The discovery of a potentially hazardous asteroid took astronomy on a roller coaster ride.

Astronomers at the Mount Lemmon Observatory in Arizona discovered an asteroid that was roughly 70 meters across. It appeared that this object could hit Earth on July 4, 2023.

Astronomers at several different observatories scrambled to make follow-up observations of the asteroid after it was discovered, which usually rule out any future impacts.

The chance of impact appeared to increase based on the first seven nights of observations. The asteroid was flagged for a potential impact by the Asteroid Orbit Determination (AstOD), an automated system that is used to assess the asteroid risk. One of the highest rankings on the Palermo Scale was given to the asteroid. Anyone interested in astronomy can take a look at the information on the websites of NASA and the European Space Agency.

The following week, no observations could be made because the full Moon blocked out any views of the asteroid.

The accumulating data on the asteroid's path showed that the chance of impact was decreasing over time. It has been confirmed that there will be no impact on Earth in the foreseeable future.

MarcoMicheli, astronomer at the Near-Earth Object Coordination Centre, said that he had never seen such a risky object.

How did astronomer be able to rule out a threat that seemed certain?

A single dot of light in the sky is the only data point that can be used to observe an asteroid. It is not clear what it is or where it is going. At least three observations are needed to determine where the object is going and how fast it is moving. Astronomers can't be sure of where it won't go until they're sure of where Earth is.

Astronomers use computer simulations to calculate the future path of the asteroid, and input randomly chosen initial positions and velocities that fall within the margin of error of the observations so far. Calculating the probability that a particular path will hit Earth is done by creating a large number of simulations. The odds of the asteroid hitting Earth are a million to one if one million different possible orbits are used.

With more data and observations, the hazard zone narrows and the corridor of the asteroid's future path moves away from Earth. With the network of observatories around the world that are focused on planetary defense, you can look for incoming asteroids and comets and quickly rule out any space rocks that aren't a threat.

The team moved after one observation showed that the risk level had crashed and was close to zero.

The data was clear, confirmed the next morning by our counterparts at NASA, said Laura Faggioli, near-Earth object dynamicist in the NEOCC. We didn't need to follow it anymore after it was removed from the risk list.

The asteroid will fly by Earth at a distance of ten million kilometres, more than 20 times the distance from the moon, in early July of 2023.

Even though the odds of an asteroid hitting Earth are low, it is still possible that we will see a large airburst event like the Chelyabinsk meteor. Calculating the rate of asteroid impacts, the current estimate is that one will hit Earth every 100 million years or so. Both professional and amateur astronomer continue to look at the skies.

On the evening of January 19th, the Calar Alto Schmidt telescope in Spain was used to observe a asteroid. The credit is given to the European Space Agency.

The Planetary Defense Office is a source of information.