This Friday, asteroid 2014 YB35 will hurtle past Earth. Despite the scaremongering of some news outlets, the passage won't be incredibly close, but 2014 YB35 is extremely large and its recent discovery raises questions of what else is lurking undiscovered in the darkness.
Asteroids large enough to be observed by sky surveys frequently make close approaches to Earth. In the last year, we have seen a 20-meter-wide (65.5 ft) asteroid pass closer than the moon. In January, the 500-meter-wide (1,640 ft) 2004 BL 86 passed by at three times the distance of the moon. And the same night that 2014 YB35 makes its pass, a much smaller asteroid will be passing slightly closer to Earth.
2014 YB35 will not be getting closer than 4.5 million km (2.8 million miles), which is 11.7 times the distance of the moon. However, with a diameter estimated at up to 1,000 m (3,000 feet), it is the sort of thing that could do serious damage if it did collide with Earth. Asteroids this size wouldn't cause a global catastrophe on the scale of the dinosaur-killer, but the damage would still be devastating for hundreds of kilometers around, releasing energy equivalent to a thousand of the largest nuclear bombs. Depending on location, we could be treated to an earthquake similar to the largest ever recorded. Tsunamis, firestorms, acid rain and dust-induced winters are at least possible bonus extras.
This isn't the last we will see of 2014 YB35 either. In 2033, it will be back for a pass nine moon distances away, with another approach in 2128.
Passes like this offer astronomers an opportunity to learn more about asteroids; in January, we discovered that 2004 BL 86 is accompanied by a moon. This time the Goldstone Observatory, California and Arecibo telescopes will be watching.
The disturbing aspect to 2014 YB35 lies in the first part of its name. It was only last year, December 27 to be precise, that the Catalina Sky Survey detected it. This is so recent that it has yet to be assigned an asteroid number and size estimates still vary. Although 2014 YB35's orbit takes it out past Mars, it is not some long period object whose arrival we cannot predict.
In 1998, NASA took on the goal of discovering 90% of the near-Earth asteroids larger than 1 kilometer (0.6 miles) across. While we are thought to be approaching this goal—if it has not already been achieved—new discoveries serve as reminders that we are still short of 100%. Meanwhile, smaller objects capable of doing serious local damage continue to be detected at a rate of around a thousand a year.
If this sort of thing bothers you, you can help by using the recently released software app that allows amateurs to assist in the discovery of potentially hazardous objects.