AN asteroid named 2021 RS2 became the closest space rock to pass Earth this year as it whizzed by on September 7. 

Travelling at 39,355 miles per hour, 2021 RS2 flew by our planet just hours after its discovery. 

The asteroid, measuring at estimated 11.5 feet (3.5 meters) in diameter, was spotted by astronomers at Mount Lemmon in Arizona with trajectory information revealing that it would skim the Earth in the coming hours. 

2021 RS2 came just just 9,532 miles (15,340 kilometres) from Earth’s surface and while the asteroid would have burned up in the atmosphere upon entry, the rock is just one more example of how close the Earth sometimes comes to being struck by cosmic debris.


2021 RS2 is the 81st known asteroid to fly by Earth inside one lunar distance since the start of 2021. 

As of September 10, according the European Space Agency, there are 1196 Near-Earth Objects on their 'Risk List', those meriting some possibility of striking the Earth in the future.

The discovery follows another record breaking asteroid. Named 2021 PH27, this asteroid is unique in so much as it has an extremely small orbit, rounding the Sun in less than four months (115 days to be precise), surpassed only by planet Mercury with its 89 days.