NASA annually discovers over 3,000 asteroids; Here's how space agency tracks them all

An asteroid twice size of Empire State Building made its closest approach to Earth on January 18, making it newest celestial body to skim past our planet this month. Dubbed 1994 PC1, this asteroid is about one kilometre wide and flew by at a staggering speed of 69,200 kilometres per hour from a safe distance of 1.93 million kilometres from Earth, as per NASA. This was fifth asteroid that came close to our planet this month, adding to list of rocks that NASA identifies and warns us about. Among an uncountable number of such asteroids hurtling through universe, keeping an eye on m must be rar hectic. NASA still does it anyway through software that runs on a special algorithm for tracking se lingering bodies. 

Here’s how NASA keeps track of asteroids

ncy states that survey telescopes have discovered as many as 28,000 near-Earth asteroids (NEAs), as of w. This number, when broken down, equates to about 3,000 discoveries each year. Until w, NASA has kept an eye on each of its discoveries through Center for Near-Earth Object Studies (CNEOS), which is mand by Jet Propulsion Laboratory (JPL). According to ncy, astromers have been able to track asteroids through CNEOS which monitors risk posed by same through software called ‘Sentry’. Developed by JPL in 2002, w-outdated Sentry was based on ‘smart mamatics’, which was capable of determining impact probability for a newly discovered asteroid over next 100 years. 

NASA upgrades to Sentry-II

Since Sentry became a techlogy of past, NASA has w developed a newer and improved version of software and has named it Sentry-II. ncy states that with upgraded version, astromers will be able to monitor asteroids and calculate ir impact probabilities even of those special cases that were left out by Sentry. Interestingly, Sentry-II would allow assessment of all potential impacts with odds as low as a few chances in 10 million. Ar advant offered by this newer techlogy is that it eliminates drawbacks of its predecessor. 

Sentry’s limitation was that it was unable to assess Yarkovsky effect, which is responsible for changing path of an asteroid over decades or centuries. This effect is created when sun rays heat one side of asteroid and when asteroid turns, its heated side cools down and releases infrared energy which produces a thrust to change asteroid’s path. 

How does software work?

To understand working of Sentry-II it is important to te that each asteroid has its uncertainty region which may evolve over time. According to NASA, what ir new software algorithm does is that it selects random points throughout entire uncertainty region and is t limited by any assumptions about how uncertainty region may evolve. It n predicts  possible orbits within  entire region of uncertainty that could hit Earth thus allowing astromers to zero in on more very low probability impact scenarios, which might have been missed by its predecessor.

(Im: NASA)