Asteroid 2014 HQ124, aka 'The Beast', makes Earth flyby this weekend
Friday, June 6, 2014, 2:57 - A newly-discovered asteroid, which astronomers have nicknamed 'The Beast', is flying by the Earth at a little over three times the distance to the Moon this weekend. While it poses no danger to us on this close-pass, it does demonstrate the sobering fact that Earth flies through a 'cosmic shooting gallery' on its yearly journey around the Sun.
Asteroid 2014 HQ124 was discovered on April 23, 2014, by NASA's NEOWISE infrared space telescope. This 325-metre-wide rock was spotted while it was over 50 million kilometres away from Earth, well below the planet's orbital path around the Sun. Computations of its orbit quickly showed that it was going to make a very close pass by us on the night of June 7 through early morning of June 8 - at least on an interplanetary scale - as it comes within 1.3 million kilometres (roughly 3.3 times the distance to the Moon). Tracing 2014 HQ124's orbit over time, this is actually the third time that it's made this close of a pass by us since the start of the 20th century, and it's apparently the last time it will come this close until at least the 23rd century. This is due to the fact that its year is only around 286 days long, compared to our 365 days. So, it's a bit like having a friend who's work schedule is different enough from yours that you just can't seem to meet up on a regular basis. It works out once in awhile, but most of the time you just aren't in the same place at the same.
On Thursday night, the astronomers running the Slooh Space Camera locked on to 2014 HQ124 and streamed their view live on the internet (which you can watch below):
2014 HQ124 is harmless to us, because it's not going to come close enough to hit Earth. However, if it were to hit us at some point, the impact would be devastating - ten times more powerful than the largest nuclear weapon humanity has ever detonated (Tsar Bomba, at around 50 megatons). We all saw ample footage of the 20-metre-wide asteroid that exploded over Chelyabinsk, Russia in February 2013. That explosion was estimated at around 500 kilotons. A 500 megaton meteor strike wouldn't be on the scale of the one that wiped out the dinosaurs (that one was likely around 10 kilometres wide), but it would be enough to wipe out a city, leaving behind a crater over 3.5 kilometres wide and over 400 metres deep.
So, while we don't have anything to worry about from this particular asteroid, near-Earth objects are something we should be concerned about, simply to protect ourselves from harm.
The image below is a map of the inner solar system (click here for the full version). The orbits of Mercury, Venus, Earth and Mars are shown (with Earth's in light blue), along with the current location of each planet along their orbit. Besides the Sun (in the middle), every other dot on the map is a known asteroid. Green are ones that stay far enough away from our orbit to never pose a threat to us. Yellow ones come close enough to Earth orbit to be of concern, but do not cross. Red ones are definitely a concern to us, since they cross our orbit and can come close enough to pose a risk to us.
Zooming in on Earth, this is a 3D perspective map of the space around us today (full version here), showing all the known asteroids that are closest to us. The red circle, with a radius of 10 times the distance to the Moon, is for reference. Vertical lines connect each object to the plane of Earth's orbit (objects at the top of the line are above our orbit, objects at the bottom of the line are below our orbit). Arrows indicate the direction the object is travelling. If an object were within the distance of the red circle, it would also be coloured red.
So, it's pretty crowded out there in space, and astronomers are discovering new asteroids all the time. 2014 HQ124's name indicates that, just in the week of April 16-23, there were 3,108 asteroids discovered! Not all of these end up on the list of potentially-hazardous asteroids, but that's an awful lot of stuff flying around out there and the best estimates of astronomers say that there are still millions left to find!
The one thing that helps us is the fact that space is so big. Recall that, from side to side, the red circle in the above image is 20 times the distance to the moon - some 7.69 million kilometres wide. That's a lot of space! 2014 HQ124 will pass through this circle, but it's still no threat to us. One big danger to us, though, is that our methods of detecting asteroids are dependent on us looking away from the Sun. Ground-based surveys need darkness (and clear skies). If NEOWISE caught the direct rays from the Sun on its detectors, it would likely burn them out completely. That leaves us with a big blind spot, which is exactly where the Chelyabinsk asteroid came at us from before it entered the atmosphere.
Fortunately, since we're well aware of the blind spot, there are efforts to do something about it. The B612 Foundation wants to get their Sentinel mission off the ground sometime in 2017 or 2018. This video from the B612 Foundation discusses the mission and how it will work:
What happens if we do detect an asteroid that's about to hit us?
Back in January, the very first asteroid discovered this year - 2-metre-wide 2014 AA - was one that burned up in our atmosphere only hours after it was detected. The bigger an asteroid is, the further away it can be spotted, though. At the moment, we don't have anything in place to protect us from incoming asteroids. There's always the possibility of using nuclear weapons. This wouldn't be like we've seen in the movies, though. Armageddon had the right idea, although the plan would be to use the explosions to push the asteroid off course, rather than split it in two (since that would probably make things even worse). The better ideas are far more subtle, but they'd take time - such as painting one side of the asteroid so that the Sun's rays act to push it off course, or parking a small spacecraft next to the rock and letting gravity act like a 'tractor beam' of sorts. One of the best ideas might be for us to send out tiny ships to start grabbing these rocks and towing them back to us. This not only eliminates the threat, but provides us with valuable resources as we mine them. Check out Planetary Resources, as they are at least one of the companies looking to start this very effective (and undoubtedly profitable) method of planetary defense.