Outer space is full of large and small bodies, while some are light years away from us and we never have to worry about them, other space rocks are within our solar system that can pose an extinction-level threat to our existence. There are meteoroids, that are pebble-sized objects that regularly enter our atmosphere but are burnt away being too small. Then there are asteroids, though their size range varies greater, we are talking about the larger ones here that can end life on our planet. After all, it was a massive asteroid that collided with Earth and wiped the dinosaurs completely. So are we equipped to stop such a catastrophic event from happening?
What is an Asteroid?
Asteroids are basically rocks from space. Asteroids are rocky objects that have both spherical and irregular shapes that orbit the Sun much like planets, however, they are significantly smaller than a planet. Asteroids are basically the leftovers or waste materials from the formation of our solar system that happened approximately 4.6 billion years ago. Though asteroids sometimes wander off and fall onto planets, in our solar system they are found in the space between Mars and Jupiter, the distance among these two averages 550,390,000 km, plenty of room for asteroids to exist, still they decide to bombard other bodies from time to time.
A photograph of an asteroid.
To put their impact into perspective, it said that an asteroid just about 30 meters across is enough to wipe out an entire city and when their size increases so do its impact. Around 120-meter big asteroid would destroy an entire mid-sized country. When it reaches the size of 500 meters, it can kill half the planet.
Preventing the Collision
In order to stop an asteroid from hitting the Earth, it is vital that we must be able to recognize and find if an asteroid is about to hit the Earth. The first thing would be to use the Massive telescopes, though these are quite capable of at looking objects that far away and can even detect fast-moving asteroids, however, when we would be able to detect something like that approaching our planet it’d be too late. Even if 1000 meter big asteroid was to be rushing towards us, it is still small compared to the grand scale of objects in our solar system. Another option would be to have detecting instruments that observe heat and infrared waves in space and be able to tell us about an asteroid years before the impact. Let’s say we did happen to find one and we have about 8-10 years to stop it or change its trajectory, how do we do it?
- Bombing Rockets: This shouldn’t come as a surprise that rockets would be involved in changing the course of these humungous asteroids. However, unlike movies where it is basically nuked and the hero saves the day, in reality, we just do not have enough ammunition to cause a similar effect and even if we did a tremendous amount of fuel would be required to propel that rocket into space. So what do we do? We deflect it. The pro of this approach is that we only need to change its path by a few centimeters for it to avoid hitting the Earth, but the con being it would require extreme amounts of force. As the mass of the 4 Vesta, an asteroid of about 550km is about 2.589 × 10^20 kg, therefore even to deflect it by few centimeters, a nuclear bomb that can deliver over a million tons of energy is required. Additionally, these have to be remotely controlled obviously, but exact calculations must be done in order to pinpoint the asteroid’s exact location to precisely hit it at an angle that yields the most deflection. This sounds like a great plan, however, if the asteroid was to be composed of thousands of smaller rocks, it would end up showering onto Earth causing a catastrophe. In order to find if it is possible, NASA is preparing to crash a rocket into a non-threatening asteroid to see if they can divert the trajectory, this project is known as DART (Double Asteroid Redirection Test).
A representation of NASA’s DART program.
- Gravity Tractor: Unlike the previous method where we explode it while hoping to deflect it, here we try to do something different. In this approach, a goliath of a rocket would have to be built and of course, it would require extreme amounts of fuel. But let’s say we did manage to build one how will it work? In this option, this gigantic rocket would be flown towards the asteroid but wouldn’t crash into it. Instead, it would come just close to the asteroid so that a gravitational pull is generated on the asteroid. Minuscule may be, it may just do the trick to divert it from the Earth. It basically works on the principle of Gravity, as two objects exert their gravity onto each other, in theory, a rocket will do the same on the asteroid. But like the previous method, it has some flaws. Firstly, it would take over weeks to do this process which means a way to refuel the rocket must be designed, and of course, the fueling rocket would require its own fuel as well. So overall it would be too much fuel consumption to carry this out. Secondly, what if rocket malfunctions in between? It will be of no use and Earth will be colliding with that asteroid.
- Lasers: As laser technology is advancing rapidly, scientists have proposed that this method could be our best bet when it comes to stopping giant space rocks from hitting our planet. With lasers that can reach over 1 million degrees celsius, these can in theory just vaporize the asteroid’s outer layers into tiny particles. These particles will simply fly off away from the Earth and the constant barrage of lasers will shrink the asteroid into a size that wouldn’t be much of a threat. One obstacle for this method would be to find a way to operate these lasers at their maximum capacity while traveling at about 10kms/s as that is the average speed of an asteroid.
A representation of High-powered lasers shooting an asteroid.
So can we stop an asteroid from hitting the Earth? Yes, we can. Only if we have ample time to build adequate measures against this catastrophe. Thankfully as of today, no asteroid big enough has been detected that is approaching Earth, but will there be in the future? We don’t know.
