What Would Happen if Asteroid 2004 BL86 Hit Earth?

Over the last few months, the attention of the scientific world has been dominated by asteroids. Back in November of last year, the Rosetta Mission successfully landed a probe on a moving asteroid in a feat of spectacular engineering. To learn more about the benefits of the venture, see this article: The Rosetta Mission is Over: Was it Worth the Wait?

Meanwhile, in just a few days’ time, the asteroid 2004 BL86 will pass close by the Earth’s atmosphere, as we discussed in this update: Will Asteroid 2004 BL86 Hit Earth?  In the early hours of the morning of January 27th (GMT), the asteroid will afford amateur stargazers a rare treat and scientists an ideal opportunity to observe and learn more about these intergalactic rocks as it hurtles past our planet.

Fortunately, the 680m-wide rock will pass us at a safe distance of 745,000 miles; but what would happen if it were to impact the Earth?

The Consequences of Asteroid Impact

According to the chief administrator of NASA, our prospects in the event of a collision with such an asteroid wouldn’t be good. Charles Bolden recently claimed that our best hopes in such an instance would be, quite simply, to pray.

Were the impact to occur in a city, the devastation would be felt for miles around and, depending on the size of the projectile, could potentially affect all life on Earth. While the initial crater it would cause would be monumental and the shockwaves it sent out far-reaching, the real danger would lie in the pollution that would ensue.

Massive clouds of dirt and dust would be sent up into the Earth’s atmosphere, potentially blocking out the sunlight we so desperately need to cultivate our plant and animal life. With no sun, life on Earth simply cannot exist – and therein lies the main danger of an asteroid impact. Indeed, it was exactly such a cause which hypothetically ended the life of dinosaurs on Mexico’s Yucatan peninsula around 65 million years ago – the last time a sizable asteroid collided with the Earth.

On the other hand, were the impact to occur in the ocean (which, due to the ratio of water to land on the Earth’s surface, would prove far more likely), massive tidal waves or tsunamis would occur which would decimate the coastlines of our continents.

An Unlikely Probability – with Catastrophic Consequences

The science advisor to the White House, John Holdren, has stressed the need for effective planning in the (admittedly unlikely) event of impact with an asteroid.

“The odds of a near-Earth object strike causing massive casualties and destruction of infrastructure are very small, but the potential consequences of such an event are so large it makes sense to takes the risk seriously,” Holdren told a Science Committee hearing back in 2013. Indeed, the inauguration of Asteroid Day this June 30^th is intended to be a signal of our increasing devotion towards tackling this conundrum and ensuring such a catastrophic collision never comes to pass – whether that’s through the use of nuclear bombs in diverting or disintegrating the asteroid, or simply effective evacuation of endangered areas based upon predicted knowledge of asteroid orbits.

In any case, we have nothing to fear from asteroid 2004 BL86, whose trajectory will not come as close to the Earth again for another 200 years. It does make sense to have a Plan B, though, just in case a collision course with another flying rock threatens our very existence in the future.