NASA is sounding the alarm over several incoming space rocks, one of which is due to pass within a third of the distance between the Earth and the moon.

To kick things off amid yet another rocky month for Earth and its asteroid hunters, on Tuesday, asteroid 2009 PQ1, measuring 110 meters in diameter, will come within 4.1 million kilometers of Earth. This will be followed just days later by asteroid 2020 OL4 (diameter: 37m) at a distance of 3.6 million km, on Saturday August 8.

But wait, there’s more! The end of August will see another flurry of asteroidal activity, with three space rocks, ranging in size from a family car to a passenger plane, will skim past us.

On August 23 and 26, 2020 FA1 (19m) and 2016AH164 (3.9m) will fly past the earth at distances seven and six million kilometers respectively. All perfectly safe.



However, on September 1, 2011 ES4 (28m) will pass between us and the moon at a risky 121,000 kilometers, or roughly a third of the distance between us and the moon (384,400 km). Too close for comfort, by many people’s standards, but still far enough away that it is unlikely to impact the orbit of any man-made satellites in High Earth Orbit (35,786 km and beyond).

These close flybys serve as yet another reminder that our planetary defenses need to be bolstered, ahead of more serious threats in future, for example Asteroid 29075 1950.

According to previous simulations by scientists at the University of California, Santa Cruz (USCS), if 29075 1950 were to strike Earth, it could generate tsunami waves 120m high across the Atlantic, obliterating the eastern seaboard of the US and wreaking havoc across the pond as well.