Asteroid
Asteroid Pixabay

Aside from NASA's main asteroid-tracking systems such as Sentry and the Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE), the agency also relies on another option that provides last-minute warnings against impact events.

NASA's Sentry and NEOWISE mainly work by identifying asteroids that are expected to fly close to Earth. The aim of these systems is to detect a hazardous asteroid long before it collides with Earth.

Through early detection, the space agency will have enough time to plan and execute planetary defense solutions. One such plan is to deflect asteroids away from Earth to prevent a collision. However, these systems are not effective hundred percent. As previously reported by NASA, some asteroids can still slip through its monitoring systems. These asteroids could approach Earth completely undetected until it's too late.

Fortunately, there is another system in place that's specifically designed to track asteroids that are already very close to Earth. Named as the Atlas Terrestrial-Impact Last Alert System (ATLAS), it tracks and identifies asteroids that are just days or weeks from hitting Earth.

ATLAS was developed by the University of Hawaii with help from NASA. It mainly uses two telescopes that are situated 160 kilometers from each other. These telescopes regularly scan the sky several times a day to search for near-Earth objects. The data collected by ATLAS' telescopes is submitted to NASA's Center for Near Earth Object Studies for analysis.

As a last-minute warning system, ATLAS provides notices for near-Earth asteroids based on their sizes. For example, the system will release a warning a day before the predicted impact of a 30-kiloton asteroid, which is big enough to destroy an entire town. For larger asteroids that can take out cities and countries, ATLAS will provide respective warnings a week and three weeks before they arrive.

Warning people about an asteroid impact a day or week before it happens may not seem too helpful. However, Dr. Natalie Starkey, a cosmochemist who is not involved with ATLAS, noted that this system is designed to alert governments and other organizations so they can carry out mass evacuations in areas that will be hit by the approaching asteroid. She said that it is similar to warning systems that predict volcanic eruptions.

The early warning system, reminiscent of the siren during the world wars, may not work in all countries and regions alike. Depending on the preparedness of each individual nation and its citizens, the evacuation will provide succour to those who want to escape. Otherwise, it may turn into another system that remains in the pipeline forever.

But brimming with confidence, Starkey says:"Of course, it's unlikely we could do much about these objects in time to divert or destroy them, but it would allow us to instead work on evacuating and preparing the forecasted target region in the same way we would for a predicted volcanic eruption," reports Express.