Today, at approximately 20:59 GMT, a rock so big that it has its own moon safely flew past Earth. It’s name is 1998 QE2, an asteroid that is roughly 500,000 times larger than the one which made that near-Earth flyby back in February. But of course, scientists had been letting the public know well in advance that this one would miss us to, and by a much wider margin.

In fact, whereas the last rock missed us by a mere 27,700km (17,200mi), this one passed at a much safer distance of about 5,800,000 km (3,600,000 miles). Good news for anyone who’s been caught up in all the asteroid/meteoroid frenzy of late. And while it might seem that a lot more stellar objects have been hurling towards us lately, a simple review of our Solar Systems turbulent history will confirm that this is pretty much business-as-usual.

What’s more, this most recent flyby provided scientists and astronomers with yet another opportunity to study an asteroid as it passed close to Earth. Using radar telescopes, they were due to record a series of high-resolution images, the purpose of which was to study what the asteroid was made of and where exactly in the Solar System it came from.

Prof Alan Fitzsimmons, an astronomer at Queen’s University Belfast, said:

It’s a big one. And there are very few of these objects known – there are probably only about 600 or so of this size or larger in near-Earth space… We already know from the radar measurements, coupled with its brightness, that it appears to be a relatively dark asteroid – that it’s come from the outer part of the asteroid belt.

What’s more, the curious nature of the asteroid – in that it has its own moon – is something which makes it a scientific curiosity. Approximately 15% of asteroids have the mass that they are capable of supporting their own satellite, but rarely does one fly this close to Earth. Early observations of this “moon” indicated that it is roughly 600m in diameter, and would have been visible during the flyby to amateur astronomers with a sufficient enough telescope.

After this, asteroid 1998 QE2 will hurtle back out into deep space where it will stay for some time. In fact, Friday’s visit was the closest it has been to Earth for at least two centuries. And not surprisingly, researchers are becoming increasingly interested in potential hazards in space. So far they have counted more than 9,000 near-Earth asteroids, and they spot another 800 new space rocks on average each year.

And given the potential for harm if one made contact with Earth, as they have been known to do in the past, the information gleamed from observation and study is sure to come in handy as far as planetary defense is concerned. As Fitzsimmons himself pointed out about this particular asteroid:

…if something this size did hit us one day in the future, it is extremely likely it would cause global environmental devastation, so it is important to try and understand these objects.

Source: bbc.co.uk