Earth getting hit by an asteroid someday is one of the biggest "end of the world" fears that people have. Now a new study conducted by NASA researchers have revealed that there are more than 15,000 asteroids and comets that could potentially collide with Earth.

The threats to Earth from asteroids and comets passing by or hurtling towards it have increased in the recent years. At the same time, the possibility of detecting these near-Earth celestial objects has also increased.

According to researchers at NASA, the number of near-Earth objects (NEO), which includes asteroids and comets have increased drastically in the last few years. The number has certainly crossed 15,000 in 2016 and on an average, there are 30 new discoveries being made each week.

The 15000th asteroid named 2016 TB57 was discovered on Oct 13th by a team of scientists at the Mount Lemmon Survey. The same asteroid flew past Earth, safely, on Oct. 31.

However, the growing number of NEO have raised concerns that some of them could pose a serious threat to Earth. But thanks to the special asteroid detection programs, these celestial bodies can be tracked and their path can be mapped with the help of a specialized software.

The good news is that more than 90 percent of larger NEOs have already been identified by the researchers. This has been made possible with the help of upgraded telescopes and NEO surveys dedicated to the identification of such celestial objects near Earth.

There are several asteroids detection techniques in place that can predict whether an asteroid would fly past Earth safely or whether there is any risk of collision. One such system is NASA's Scout early warning system, the Tech Times reports.

While Scout only hunts for small asteroids, NASA's Sentry program identifies biggest objects, asteroids and comets that have the capacity to wipe out entire cities on Earth. The program has already identified over 600 big objects that could pose a danger to Earth if they collide.