As many as four potentially hazardous asteroids went past the Earth late on Tuesday, The Indian Express reported.

Three out of four of these celestial rocks were barely discovered a few hours before zipping past the Earth-Moon system, the Daily Express reported. One asteroid called 2019 SM8 was seen by space researchers at the Mount Lemmon Observatory in Arizona on Monday, which flew by our planet hours later, according to NASA.

The asteroid 2019 SM8 at its closest was approximately 99,000 miles (159,000 kilometres) away from Earth, which is a little less than half of the average distance between the Moon and our planet, a report by Space.com said. According to NASA’s estimate, this particular asteroid was about 16 feet (4.8 metres) in diameter, which is approximately the size of an SUV.

Around an hour later, another asteroid was discovered, however, this celestial rock named asteroid 2019 SE8 flew from a little distance. This particular asteroid flew from a distance of approximately 674,000 miles (1.1 million kilometres) from the Earth and hence did not prove to be a threat. In terms of size, this asteroid was comparatively bigger than the previous one. It was estimated to be around 47 feet (14 metres) in size.

Apart from these, two more celestial rocks named asteroid 2019 SD8 and asteroid 2018 FK5 were detected by the US space agency, which passed approximately 331,000 miles (532,000 kilometres) and 3 million miles (5 million kilometres) away from the Earth respectively.

Even though none of these asteroids had much chance of hitting our planet, however, these rocks are classified by NASA as potentially hazardous asteroids as they pose a threat in their future course when their orbits intersect that of our planet, the report said.

In the past, some key space researchers and entrepreneurs have pointed out fears regarding asteroids hitting the Earth. In August, Space X and Tesla CEO Elon Musk had pointed out on  Twitter that the Earth presently has no defence against “killer” asteroids.

Responding to a tweet about the asteroid Apophis — dubbed as the “God of Chaos” that is expected to scrape past Earth in 2029, Musk pointed out that there is, currently, no defence system to protect our planet.

Prior to Musk, a famous astrophysicist Neil deGrasse Tyson had also warned about the Apophis 99942 hitting the Earth, causing a major tsunami that can wipe out the entire west coast of North America.