NASA has released a public announcement about an asteroid that could one day be headed for Earth. As of Wednesday the 24th of November, a rocket was launched by NASA which is now on route to intentionally hit the asteroid off its potential course. The asteroid does not pose a current risk to Earth; however, NASA wants to ensure there will be no future collision risk with our planet, from this asteroid, or any other space object over time.
Asteroids are small chunks of minerals that orbit the Sun, usually made from rocky materials that form the main planets. As a result, asteroids can also be described as minor planets. This sounds a little dramatic when we think of a ‘minor planet’ hurtling towards our full-sized one, but asteroids can come in a variety of sizes. The asteroid in question has been named Dimorphos and is 160m in size. The technical term to describe Dimorphos is a ‘moonlet’ as it orbits a larger asteroid system named Didymos which has a diameter of 780m. Although 160m is about the size of a playing field, this is within the common size range of the asteroids currently known by NASA. The size of the asteroid isn’t an issue until it’s pointing at Earth. We know that objects speed up when entering the Earth’s atmosphere, so even the smallest of space pebbles could pack quite a punch on the Earth’s surface, never mind a rock the size of a sports field.
The most well-known asteroid incident is the Chicxulub event, the major impact that led to the global extinction of the dinosaurs. When someone mentions comets or meteors this is usually the example that comes to mind. However, other asteroids have struck since then. In 1908 in Siberia near Tunguska, an asteroid of approximately 30m exploded above the ground, knocking down an estimated 80 million trees. No casualties or deaths were reported at the time, but because the explosion happened over 100 years ago in rural forest land, we cannot be certain. The first expedition to successfully reach the remote impact zone did not take place until 1927 and was led by Leonid Kulik who photographed the central damage in a series of unnerving images.
The asteroid in Tunguska exploded above ground, leaving no crater in the earth, just a mass graveyard of trees. A similar event took place in 2013 in Chelyabinsk in Russia when an asteroid was seen blazing across the sky. Many pictures and videos capture the asteroid’s descent, which luckily exploded 30km above ground, avoiding direct impact. However, from the explosion came a strong shockwave, injuring 1,500 people and damaging buildings across six cities. These in-air asteroid explosions are referred to as ‘air blasts’ and according to NASA, an object like the Chelyabinsk meteor of 2013 can impact the Earth every 10 to 100 years on average.
Interestingly, the 2013 Chelyabinsk meteor hasn’t been talked about much since. An asteroid shoots into our atmosphere and brings with it the realisation of our tiny existence in a vast universe that is out of our control. When it doesn’t hit the ground and nobody is killed, we think “huh, that was close” and we move on with our earthly lives.
To NASA, this impending threat of a meteorite collision is everyday talk over breakroom coffee mugs. NASA started tracking asteroids because of their activity in recent decades. The possibility that one big enough could cause substantial damage to the Earth and large loss of life became a more pressing subject and so careful tracking of NEO’s (Near Earth Objects) became a priority. Because of such tracking, NASA was able to inform people of the asteroid before it entered the Earth’s atmosphere in Chelyabinsk 2013, most casualties came from people trying to catch a video or photo of it on their phones. Even more recently on November 19th of this month another asteroid reportedly the size of the Great Pyramid of Giza passed peacefully by Earth, an occurrence we were informed of in advance.
Coinciding with their NEO tracking, NASA has now developed a programme titled DART (Double Asteroid Redirection Test) which was launched Wednesday the 24th of November. The test aims for the DART spacecraft to purposefully crash into an asteroid to change its predicted course, which is currently set towards Earth. If successful, this technology could prevent instances such as the 1908 Tunguska and the smaller 2013 Chelyabinsk meteor air blasts. Potentially, DART could even go as far as protecting the Earth from another ‘global destruction’ resulting in a mass extinction like that of the prehistoric age. We could be witnessing the making of an effective ‘Earth defence system’, a term only otherwise heard in sci-films and TV shows. Reflecting on the rapid pace of technological advancements, it’s likely that redirecting an asteroid in another hundred years’ time will be comparable to casually swatting a fly.
But what does it mean to be so closely involved with space situations? Could an increase in intervening backfire? Multiple questions have been raised following Nasa’s latest lift-off. The DART spaceship’s collision with the asteroid could accelerate its speed instead of its intended redirection, leading not only to the predicted asteroid collision but that of even greater impact. If Dimorphos is successfully redirected, there’s no telling if it will simply drift back into its original path toward Earth. The hit from the DART spacecraft could cause the Dimorphos to break into separate pieces – smaller individual meteors all with just as much chance of making it to the Earth’s atmosphere. This could cause multiple air blasts and even direct impacts on the Earth’s surface. Considering that the DART spaceship will be travelling in space for 10 months before Dimorphos is close enough for it to infiltrate, tells us that it would be quite a task to target and redirect multiple asteroids at once in such a situation. In the event of another airburst occurring without loss of life, there remains the real risk of shockwaves causing tsunamis, landslides, avalanches and even volcano eruptions if the meteor collided in the wrong place. We live in a highly reactive and fragile climate within our planet, which is as unpredictable as the space we float in.
Keeping up with purely Earth surface environmental news can be overwhelming enough, being in the ongoing climate change crisis. Talk of a meteor on track for our planet feels like the cherry on top of a crumbling cake. This begs the question, is asteroid collision risk another natural disaster we need to keep track of and prevent or should we be more focused on researching the wounded world we are standing on and healing it while it’s still here?
An impending asteroid impact is quite a jarring announcement; with such warnings only usually heard in fictional futuristic contexts. Naturally, the thought of a potential comet collision causes quite a bit of concern. It’s easy to forget that we’re living on a floating planet, surrounded by other objects that could theoretically hurtle into us at any minute. Hence why these announcements are challenging to process, they aren’t our usual Earth-only updates, they are news flashes from the surrounding unforeseeable universe. As ambitious as NASA’s DART mission sounds, it does sum up what humankind has come to be about, turning the tide in our favour wherever possible. Whether that turn of tide benefits the actual Earth itself will only be seen in time. Deflecting asteroids such as Dimorphos will not solve the devastating impact our own civilisation has had on this planet.