Science & Technology

Why 2018 Was the Year of the Asteroid

What did our solar system use to look like, long before the Earth and the planets were a thing? The answer lies in asteroids — little space rocks that still float around our neighborhood some 4.5 billion years after the sun formed. This year, two space missions arrived at their target asteroids, and they plan to pick up some precious samples to return back to Earth.

Related Video: How to Protect Earth From Space Rocks

Tiny Targets

This year was a really exciting one for asteroid visits because not one but two crafts visited some space-rock neighbors. The Japanese Hayabusa2 spacecraft arrived at its destination of Ryugu while NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) got to asteroid Bennu in late 2018.

Each of these spacecraft have different missions as they learn more about the asteroid beneath them — for example, Hayabusa2 plans to send a fleet of tiny hoppers and rovers on to the surface, something that OSIRIS-REx will not attempt. But what unites the two missions is sample return. In other words, both Hayabusa2 and OSIRIS-REx will attempt to bring scoops of asteroid material back to Earth for analysis.

Sample return has been done before, but only by a handful of missions. This literally makes every grain of asteroid dust precious, because researchers all over the world will want to get their hands on the material. Using high-tech instruments on Earth, we can unlock a ton of information about asteroid history. One example could be tracing the origins of water in our solar system as scientists continue the debate about how Earth got all of its water in the first place.

Why Should You Care?

There are plenty of reasons why asteroids are important. On the selfish side, we really want to figure out how to deflect one if, "Armageddon" style, we find it on a catastrophic trajectory toward Earth. We've already seen the effects of even very small asteroids when they slam into our atmosphere. In 2013, for example, a space rock the size of a six-story building exploded over Chelyabinsk, Russia. The shock wave shattered glass in the buildings below and injured more than 1,000 people.

Watch the Chelyabinsk Meteor Fall

But there is also the angle of trying to figure out our origins. The solar system used to be filled with rocks and gas and dust and not much else. Planets grew up when all of this stuff began to combine. While we really enjoy planets (after all, it's thanks to Earth that we're living and breathing and using the Internet to read Curiosity) the downside is that a big world has geological processes that erase any trace of our tiny ancestors.

So if we fly to a distant space rock, there are a couple of benefits. The first is better learning about the asteroid's composition and path through space so that we can protect Earth in case of emergency. And the second is learning more about how this particular asteroid compares to all the other asteroids we know, to build up a scientific database of asteroid types and histories and origins.

It's a rewarding field of research and if you have a small telescope, you can even participate yourself in watching asteroids as they fly across space. Here are some guides to help you get started. Meanwhile, don't forget to follow the two asteroid missions as they share their adventures on Twitter @OSIRISREx and @haya2e_jaxa.

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Can't get enough space rocks? Check out "Asteroid Hunters" by Carrie Nugent, an asteroid hunter herself. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Elizabeth Howell December 20, 2018

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