Will the Asteroid 1997 XF11 collide with the Earth? The Center for Near-Earth Object Studies (CNEOS) of NASA has been answering this query for quite a few years now.

NASA was trying to oblige to a Congressional request made in 1998 when the researchers encountered an asteroid (1997 XF11) which indicated that a kilometer-wide object could smash into the Earth in 2028. The Congress wanted the space agency to detect and catalogue at least 90% of all Near-Earth Objects (NEOs) that are larger than a kilometer in size. Those comets and asteroids that bring themselves into the inner solar system are referred to as the NEOs in the astronomical world. Statistically, for an object to be considered a NEO, it should orbit within 195 million kilometers of the Sun and within 50 million kilometers of the Earth’s orbit.

NASA was given 10 years to achieve the immensely important goal mentioned above. The Jet Propulsion Laboratory (JPL) was instructed to establish a new office and make use of the data from the Minor Planet Center, an organization which was sanctioned by the International Astronomical Union for submission of all observations of asteroids and comets. They were also advised to get help from different observatories around the country. Similarly, they coordinated with the space surveillance of the U.S. Air Force as well for this mission.

The Minor Planet Center informed the authorities at the JPL about the possible clash on 11^th March 1998. Despite the fact that the news was meant to reach only that portion of the astronomical community which is linked with the hunting and tracking of asteroids, this announcement went public. The Earth was never in danger of a clash with 1997 XF11 but Don Yeomans, who was the Leader of the Solar System Dynamics at JPL, performed a thorough orbit analysis before giving any statement. Paul Chodas, who is serving as the Director of CNEOS these days, accompanied him in that examination. He concluded the matter by saying,

“The 2028 impact was essentially impossible. To this day we still get queries on the chances of XF11 impacting in 2028. There is simply no chance of XF11 impacting our planet that year, or for the next 200 years.”

NASA has been relying heavily on CNEOS for the last 20 years in its quest to map the orbits of all the known NEOs, accurately. Other than that, CNEOS has been assessing their chances of impact to the Earth, predicting their upcoming close approaches, and has delivered this information effectively to the astronomers as well as general public. Chodas acknowledged that the achievements of CNEOS have played an integral role in making NASA the leader of the world in the field of asteroid hunting and tracking. He said,

“We compute high-precision orbits for all asteroids and comets and map their positions in the Solar System, both forward in time to detect potential impacts, and backward to see where they’ve been in the sky. We provide the best map of orbits for all known small bodies in the Solar System.”

In order to assess the impact risk of an asteroid or a comet, the first thing that needs to be done is to figure out whether the orbit of that object will coincide with Earth’s path or not. JPL has the ability to provide the most accurate information about the orbits and current positions of these heavenly objects. Observatories from different parts of the world feed the data, they collect, to the Minor Planet Center. Once this observational data is received, the scientists of CNEOS work on it to calculate the orbit and futuristic motion (for many years) of that NEO. In addition to that, the researchers try to investigate the probability of potential impacts with the Earth, other planets, and the Moon.

Talking about impacts, ‘Sentry’ is a designated system of CNEOS which analyzes which NEOs can possibly hit the Earth over the next 100 years. The results of Sentry are stored online and it uses the latest CNEOS-generated orbit models to ensure the best possible outcome. Steve Chesley, the Main Developer of the Sentry who is also a member of the CNEOS team, explained the working mechanism in the following words:

“If Sentry finds potential impacts for an object, we add it to our online ‘impact risk’ table, and asteroid observers can then prioritize that object for further observation. The more measurements made of the object’s position over time, the better we can predict its future path. In most cases, the new measurements mean the object can be removed from the risk list because the uncertainties in the orbital path are reduced and the possibility of impact is ruled out.”