An asteroid that zipped past Earth in 2016 has returned and will fly much closer to the planet today. Scientific experts warned that returning asteroids could endanger Earth due to gravitational factors that can alter their courses.

NASA’s Center for Near Earth Object Studies (CNEOS) first noticed that asteroid 2019 LB2 was approaching Earth this year on May 21. Following their observations, NASA’s scientists predicted that the asteroid will fly by Earth on June 20 at 12:35 am ST.

Data collected on the near-Earth object revealed that it has a diameter of 82 feet, making it about as long as the distances of baseball bases. Currently, the asteroid is travelling at a speed of 7,500 miles per hour.

Once it makes its approach, 2019 LB2 is expected to be about 0.01653 astronomical units or roughly 1.5 million miles from the Earth’s center.

2019 LB’s upcoming visit will mark the third time the asteroid approached Earth in the past decade. In November of 2009, the asteroid flew past Earth from a distance of 0.47122 astronomical units or about 44 million miles away.

On Feb. 18, 2016, the asteroid came closer to Earth by approaching from 0.46456 astronomical units or around 43 million miles away.

Based on the data collected by CNEOS from 2009 to 2019, it can be seen that the asteroid is getting closer to Earth each time it passes by. The change in its trajectory path can be caused by a number of factors but probably the most common one is a gravitational keyhole.

According to astronomers, gravitational keyholes are specific regions in space that are affected by the gravitation pull of a nearby large object, such as a planet.

Each time an asteroid passes through a keyhole, it gets pulled by the gravitational forces, causing it to deviate from its original course. Both slight and major changes to its path could lead to an impact event.

In the case of 2019 LB2, it seems was affected by a gravitational keyhole because of the drastic changes to its distance from Earth. According to NASA, 2019 LB2 is expected to make its next pass on Earth in 2022. Hopefully, it will still be travelling on a safe path to avoid a direct collision with Earth.

The asteroid that wiped out the dinosaurs millions of years ago also caused a worldwide tsunami. Pictured: An image mosaic of the asteroid Eros, with sunlight coming from the northeast, taken by the robotic NEAR Shoemaker space probe March 3, 2000 from a distance of 204 kilometers, or 127 miles. After a year of circling and taking pictures, NEAR will touch down on asteroid Eros February 12, 2001, to capture surface details, which will be the first time any craft has tried to land on a tumbling space rock. Getty Images/NASA/Newsmakers