If the Earth is in the path of a giant asteroid, can we save our planet? And How? We present the opinion of three scientists on what we can really do.
The earth is constantly bombarded from space. In most cases, we are talking about dust or small stones that burn up in the atmosphere before reaching the Earth's surface. We see them at best as beautiful stars falling from the night sky.
But sometimes something bigger appears.
And what do we do then? Do we have a plan? Our reader Silas Kristensen really wants to know the answer, and we understand him well.
“What happens if the asteroid heads for Earth? What will governments do and how can we stop it? Do we have a group of scientists called Earth Defenders who are tasked with saving the Earth if it is in danger? " - he wrote in our "Ask a Question" column.
Multiple answer question
The answer to Silas' question concerns, shall we say, many, so we immediately turned to scientists working in this field to get an idea of how prepared we really are.
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Since the question itself consists of several smaller questions, the answer in the article is also divided into several parts:
1. First we will understand what would happen if we learned that some asteroid headed for Earth right now.
2. Next, we find out that governments and academics will purely practically do each in their respective fields.
3. Finally, we will look at what options we have in stock if an incident is inevitable.
4. "Right now we couldn't do anything at all."
The answer to the first question, unfortunately, is that today we most likely will not be able to prevent a collision.
“Right now, we couldn't do anything at all,” says Distinguished Associate Professor of Physics at the Niels Bohr Institute, Malte Olsen.
“The problem is, even if we find it, what can we do? It will take us years to build a rocket for such a mission, and today we usually cannot predict that an asteroid will pass near the Earth earlier than in a few weeks."
Reaction speed is the main problem today, according to Michael Linden-Vørnle, astrophysicist and leading consultant at the DTU Space Institute for Space Research.
“Early warning is key. If there is enough time, then we will have a chance, we have the basic technologies that should be enough to solve the problem. But it doesn't matter if we just aren't prepared,”he says.
The necessary work is already underway
Fortunately, the necessary work is already underway, said Line Drube, a doctor of astronomy, who studies asteroids at the Institute for Planetary Research in Berlin.
She herself participates in several joint international projects, which are aimed specifically at developing an action plan in the event of the approach of dangerous asteroids, which among scientists are called "Near Earth Objects" (NEOs).
“It all started with the NEOSHIELD 1 project, when the European Commission first announced that we needed a plan in case of an asteroid impact threat. We are now working on a continuation of the project, the NEOSHIELD 2 program. Our team consists of scientists, engineers and other experts who carefully study and compare asteroids and look for ways to avoid collisions,”she says.
Problem statement: when what should be done?
In addition, the joint work of the UN member states in the framework of the Space Mission Planning Advisory Group (SMPAG) is ongoing in parallel and continuously. Dane Line Drube also takes part in it.
“The point is that scientists around the world can work together to assess risks and make recommendations, which are sent further to the UN and on the basis of which a decision will be made later on what to do,” she says.
So, in fact, we have a group of scientists "Earth Defenders", which our reader Silas Christensen was looking for, and she is working on the search, research and observation of asteroids, as well as finding ways to solve the problem, in case they head for us …
Since it is difficult to determine the trajectory of an asteroid with absolute precision, a team of scientists is working on various risk scenarios and time frames, said Lina Drube.
“We are trying to outline a scheme for when and what we will do. If, for example, there are five years left before an asteroid collision, what methods do we use in this case? It makes a very big difference when there is information that it will hit the Earth in thirty years or in five years. If we have thirty years, we can do much more and calmly find a good solution, but if there are only five years left, the plan must be ready immediately.”
USA initiated
In addition, the White House just published an asteroid collision strategy, which was also part of a joint UN work, says Lina Drube. This is a good sign, she thinks.
“This will serve as an incentive. Over the past 10 years, people have become aware of the threat posed by asteroids. So I think that we can create everything, test and plan the actions, we can handle it."
Mikael Linden-Wörnle also sees the White House strategy as a positive measure, although it essentially only presents a list of problems and tasks to be solved.
“This strategy is essentially very general, and now it must be complemented by a specific plan of action and measures. But as a starting point, it serves as a recognition that something needs to be done and that this issue should be taken seriously, which is, of course, very positive."
Raise your head and hope for the best
International cooperation is aimed especially at detecting asteroids that may approach the Earth, says Mikael Linden-Wörnle.
“The goal is to capture at least 90% of asteroids that are larger than 140 meters. The very large ones are quite easy to control because they are just easier to see, but the smaller ones are very difficult to find,”he says.
Many people probably remember the photos and videos taken in Russia in 2013, when a 20-meter asteroid exploded over the city of Chelyabinsk. The outbreak was visible 100 kilometers around, and more than 1,000 people were affected by the blast.
Nobody expected him
“It appeared in broad daylight, when the sky was naturally bright, and it was also incredibly difficult to see such a small object moving at a speed of 66,000 kilometers per hour. They simply could not fix it,”explains Lina Drube.
“Therefore, we cannot expect to predict the emergence of absolutely all small, but still potentially deadly threats to us,” says Mikael Linden-Wörnle.
“When it comes to smaller asteroids, we often have little choice but to raise our heads and hope for the best,” he says.
Bruce Willis' last resort method
“Fortunately, scientists have determined the orbits of most of the largest asteroids, called 'global killers', because it is believed that they can cause global harm to the planet,” says Line Draube.
But in case, all the same, now from blue skies we are threatened by the "killer of the world", scientists have already developed a number of different anti-asteroid projects.
And yes, they also include Bruce Willis's method of exploding an atomic bomb on an asteroid, as was done in the movie "Armageddon".
“But this would probably be the most extreme case, because the use of atomic weapons from a political point of view is generally a very difficult issue. So this could only be discussed in the case of a very large asteroid, and only if there was very little time left before the impact,”explains Line Draube.
In addition, this option may create more problems than it solves, says Malte Ohlsson.
“If you detonate an atomic bomb on an asteroid, it is very likely that 10,000 smaller asteroids will appear in place of the large one, which will constantly pose a threat and whose trajectory will be even more difficult to calculate. So it will be like a modified suicide."
Solutions: Ionic Shepherd or Gravity Tractor
In general, there are two approaches to the problem, says Mikael Linden-Wörnle:
"You can either destroy the object or change its trajectory."
Today there are the following two proposals, which seem to be real, say three of our scientists.
Launch a spaceship at high speed directly into the asteroid and thereby knock it off the trajectory directed towards the Earth. This method has been described, for example, in NASA's Deep Impact project and the AIDA space project, which consists of the two programs DART and AIM, a collaboration between ESA and NASA. The AIDA project, however, was denied further funding, and scientists are now working on a similar, but cheaper version of the mission.
Launch a heavy spacecraft with a large mass and place it near the asteroid so that it drags the asteroid off its trajectory for some time due to gravitational action. But this can only work for small asteroids and if there is a lot of time left. This NASA project is also called the "Gravity Tractor".
Launch an ion cannon near the asteroid so that it bombarded the "cobblestone" with radiation and eventually forced it to change its original trajectory. This ESA project is called the Ion Beam Shepherd and may also be used to propel space debris.
Controversial idea: paint the asteroid white
In addition, Malte Ohlsson and Mikael Linden-Wörnle also mention a variant based on the so-called Zharkovsky effect. Line Drube, however, does not consider it a serious decision and calls it an "idiotic method."
However, it is based on the following principle.
You can use the so-called Zharkovsky effect, which was also studied in the framework of the NASA OSIRIS Rex project. The effect occurs when a rotating asteroid is heated by the sun. When the warm side is in the shadow, it emits heat radiation, which works as a motor and changes the trajectory of the asteroid. If, for example, one side of an asteroid is painted white, it will be possible to influence the trajectory, since the reflectivity of the colored side, and therefore its heating capacity, will change. In theory, anyway.
But none of these methods are among the mundane things that we have done a hundred times, says Mikael Linden-Wörnle.
“In principle, it can work, but theory and practice are completely different things. We need to build device systems, test them, and then launch them. Whether all this will function effectively, whether it will be in the right place - it will only be clear when the decisive day comes,”he says.
Unlike earthquakes, it is really possible to do something here
“Although the task of keeping an eye on the flying boulders of the entire solar system, and one fine day taking off and changing their trajectory or exploding, may seem impossible, we practically have no other alternative,” says Line Draube.
But unlike other natural disasters, such as earthquakes, it is really possible to do something here, and this, she believes, obliges us to something:
"If one day the news comes that an asteroid is flying towards us, I'm sure people would like to know that we have some kind of ready-made plan that can save everyone."
Thanks for the question
So Silas Christensen should be content this time with such an ambiguous answer. We don't have a plan yet, but fortunately we are already working on it.
Well, if while your mood has soured a little and wanted to see what might happen if a huge asteroid collides with the Earth, you can play with the fate of the planet for free using the Impact Earth stimulator.
Thanks to Silas Christensen for the good question, and also thanks to the scientists for their answers and for working on our plan of salvation.
Johanne Uhrenholt Kusnitzoff