Even as threats to Earth from asteroids' collision have increased, the good news is that early detection capability on approaching near-Earth asteroids has also increased. Both asteroids and comets are covered under the term near-Earth objects, or NEOs.
According to estimates, there is a huge surge in the number of near-Earth asteroids detected and the number has crossed 15,000 in 2016. There is an average of 30 new discoveries a week, at the rate of four in a night.
This marks a 50 percent increase in the number of NEAs spotted since 2013. According to experts, this jump in NEO tracking is thanks to NASA's Near-Earth Object Observations Program, which is very effective and accounts for more than 90 percent of the new NEO discoveries.
The most recent NEO detected was 2016 TB57. It was the 15,000th near-Earth asteroid, discovered on Oct. 13 by scientists at the Mount Lemmon Survey. This small asteroid of 50 to 115 feet in size will pass Earth on Oct. 31 safely.
Already, more than 90 percent of the estimated population of the large NEOs - those bigger than 0.6 miles wide - has been discovered by scientists.
"The rising rate of discovery is due to dedicated NEO surveys and upgraded telescopes coming online in recent years," said NASA's NEO Observations Program Manager Kelly Fast.
Asteroid Detection Programs
Vestiges of collisions between planetary objects are plenty. It is believed that the right eye of the "Man on the Moon" was the result of a cosmic collision that happened 3.8 billion years ago. The fallen asteroid must have been 150 miles in length and struck the moon to form the mysterious structure, Imbrium Basin.
Newly developed asteroid detection techniques like NASA's Scout early warning system have been a boon in early identification and foretelling when an asteroid would get past Earth with or without a collision threat.
"Objects can come close to the Earth shortly after discovery, sometimes one day, two days, even hours in some cases," NASA Jet Propulsion Lab's Davide Farnocchia said.
Take the case of asteroid 2016 UR36, which made a close encounter with the Earth on Sunday, Oct. 30. It was first detected on Oct. 25 by a telescope in Hawaii. Soon, the information was uploaded to NASA's Scout as an intruder alarm, and within 10 minutes the software mapped out its potential flight paths.
Scout is now in the test phase and can define threat levels and ways to mitigate them. Asteroid 2016 UR36 was its first case study. Among the NASA asteroid programs, the Sentry program deserves special mention.
Unlike Scout that tracks small NEOs, Sentry is on the lookout for bigger objects that have the potential to wipe out big cities.
Bigger NEOs with a length larger than 140 meters (460 feet) can finish off any city. Remember the way dinosaurs were wiped out by the collision of a 10-kilometer-long (6-mile-long) asteroid.
According to NASA, Sentry has already listed 655 near-Earth objects that are too risky and have the potential to cause large-scale damage to Earth.