Asteroids pose a serious potential threat to our planet. There have been cases in history when the fall of a large space object completely changed the course of events on Earth. If you don’t believe me, ask the dinosaurs. It is therefore not surprising that scientists have long been racking their brains over how to avoid a collision if an asteroid suddenly takes a course straight for our planet again. The most varied solutions have been proposed, for example, an asteroid explosion like in “Die Hard” or simply an impact similar to the one we observed during the DART mission. According to a new study by scientists, at a critical moment we can be saved by X-rays, which are capable of changing the trajectory of even a very large object.
Scientists have come up with a way to protect the Earth from asteroids. Source: inosmi.ru
How to Save the Earth from an Asteroid
The threat from an asteroid may be more real than many of us assume. For example, according to some scientists, there is a high probability that the asteroid Apophis will crash into the Earth in 2029. But even if it flies past, sooner or later the Earth will definitely collide with a large object capable of causing serious damage to life on the planet.
Scientists have already proposed many ideas on how to avoid such a threat. It would seem that a solution already exists – you can destroy a dangerous object with a nuclear explosion. However, the approach in the spirit of the Bruce Willis hero does not solve the problem, since all the debris of the asteroid will still fall on our planet and cause serious damage.
A more effective solution is to deflect the asteroid's trajectory so that it does not intersect with the Earth's trajectory. The aforementioned DART mission has proven that this can be done. However, the effectiveness of this solution is still questionable, since it is not that easy to move a large and heavy asteroid.
There is still no effective way to deflect an asteroid. Photo source: iflscience.com
Employees of the Sandia National Laboratory (USA) have proposed an alternative – a shot of X-ray pulses at the surface of an asteroid. They even tested this technology in practice, albeit on a very small scale. The pseudo-asteroids in a vacuum, at which they shot X-rays, had a diameter of only 12 mm. Nevertheless, the technology has proven its effectiveness.
How X-rays can change the trajectory of an asteroid
X-rays alone cannot deflect the trajectory of even a very small object, but they can vaporize two of the most common minerals found in asteroids. This has been shown to give the object a boost. On a larger scale, this approach could shift the asteroid so that its trajectory is deflected and it flies past Earth.
To understand how this works, it is enough to pay attention to comets. When they fly past the Sun, the ice heats up and some of it turns into gas. At some point, this gas breaks out under pressure, forming a tail. At the same time, the comet itself receives momentum. This is the reason why comets can accelerate and change their trajectory. A similar phenomenon is observed with some asteroids.
Asteroid Oumuamua changes its flight path due to gas escaping from its surface. Photo source: universemagazine.com
A striking example of this is the asteroid Oumuamua. At first, scientists could not understand why it changed speed and direction, but later it turned out that the reason was the gas escaping due to heating of the surface.
Why X-rays are more effective than lasers
Vaporizing rock is much more difficult than evaporating ice. Scientists initially considered using powerful lasers focused on the approaching threat. However, X-rays contain much more energy than visible light.
In the experiment, the researchers fired a 1.5 megajoule X-ray pulse at artificial quartz “asteroids” suspended in a vacuum. This heated them up so much that they released a cloud of steam. This created a shock wave that allowed the objects to deflect and accelerate to speeds of about 70 meters per second, the authors report in Nature Physics. These figures even exceeded the researchers’ expectations.
The technology developed by scientists needs to be tested in real conditions. Source: www.ixbt.com
Of course, making a small stone deviate is not the same as changing the trajectory of a large asteroid. However, according to the researchers, the technology can be scaled up, which will allow changing the trajectory of objects up to 4 kilometers in size. Such an asteroid, if it crashes into the Earth, could well put an end to civilization.
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Unfortunately, it is very difficult to predict how powerful an impulse the X-ray impact will give to an asteroid, since it depends on the composition of the asteroid and a number of other factors. Using an impact object, as in the case of DART, provides a more predictable result. In order to consider the technology effective, it is necessary to conduct an experiment with a real asteroid, which is quite a difficult task. But it is quite possible that sooner or later it will still be possible to solve it.