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Cathy Plesko, Ph.D., is a researcher at National Laboratory Los Alamos in New Mexico. She contributed to this article The voices of Space.com expert: Op-Ed & Insights.
In a few weeks, at the Global Defense Conference, just outside of Washington, DC, I will be taking part in one of the most ambitious role-playing games on the planet: an exercise in defense. emergency response where astronomers and emergency management experts, planetary scientists (like me), meteorologists, rocket specialists and other experts work together to put our response into practice if a large asteroid or a comet was heading towards us. In the manner of a fire drill, we practice our roles and test new technologies and new scientific data to see how this would change what we think is the best answer.
Even though asteroids and comets large enough to be dangerous do not hit the Earth very often, they hit randomly. It is therefore possible that an extinction level event (such as what happened to the dinosaurs) could happen to us. It would be like winning the worst lottery prize of all time. It is therefore important to provide a way to protect ourselves.
Related: Potentially dangerous asteroids (Images)
Fortunately, we come to the point where we can see these potentially dangerous objects happen and maybe even do something. Astronomers using terrestrial and space telescopes have discovered nearly 20,000 objects close to Earth to date and the pace of discovery is accelerating. Like a new pair of glasses, future telescopes such as the future NeoCam Space Telescope have the potential to show us dangers that we could not see before.
Once the telescopes reveal what an object is and where it is going, we can simulate its orbit for hundreds of years in the future. If this orbit crosses the path of our planet at any time, the United Nations International Asteroid Alert Network inform member governments and act as a clearinghouse for information on this topic.
If the object has a chance to hit the Earth – say, one out of a few thousand in the next 20 years – NASA's space mission planning group will coordinate among governments working on a defense plan so that everyone is on the same length of action. is required. A threatening object will probably not be kept secret because all the information about it will be published and the object will be visible by telescopes of many countries.
Most items are announced with estimated impact probabilities similar to Vegas betting odds. As more observations arrive, the probability is zero, because we find that their orbit and that of the Earth do not intersect. If, on the contrary, the data indicate to us that the object is more likely to offend than we thought, the Space Mission Planning Group will coordinate all space missions for close examination, deflection or destruction.
Using science to answer the question "What if?
As a researcher at Los Alamos National Laboratory, I study what happens in the atmosphere and the Earth's crust when an asteroid or comet strikes and possible ways to stop that. I use the Los Alamos supercomputers, some of the fastest in the world, to run high fidelity simulations to accurately model the physics of an impact. These simulations are constantly updated with state-of-the-art data from NASA missions and laboratory experiments conducted on Earth.
I am working on a team of scientists from national laboratories and NASA centers studying particular hypothetical scenarios, and reporting the results to the Global Defense Coordination Office.
Our first hypothetical case study focused on asteroid Bennu, target NASA mission OSIRIS-REx. Bennu is about as wide as the Empire State Building and weighs up to 800 aircraft carriers. It approaches the Earth every six years, so that astronomers can study it and even use the Arecibo and Goldstone radio telescopes to create a 3D model of its shape. Fortunately, Bennu only has a 2700 chance of touching the Earth in about 100 years.
Related: OSIRIS-REx: the mission to return NASA's asteroid samples in images
We used computer models to study two ways to push Bennu off course to avoid any negative impact: breaking it down with a kinetic impactor in the shape of a cannonball or roasting from one side to the other. # 39; other. detonate a nuclear explosive device from some football fields. We have incorporated the best estimates of Bennu's shape, composition, mass, and strength into our computer models and predicted what would happen in each scenario. Then we designed a spaceship that could do the job.
We learned that moving Bennu would be a big challenge if it consisted of the type of rock that NASA meteorologists have hypothesized. It would be necessary to launch this spacecraft 10 to 25 years before the intended impact to make it deviate from its trajectory. And we would need not just one, but a complete fleet of kinetic impactors of cannonballs – more than we could currently launch in time.
Last year, we published our forecasts in a scientific journal, before OSIRIS-REx reached Bennu. For the global defense conference exercise, the OSIRIS-REx team provides us with everything that it is learning in orbit around the asteroid. Soon, they will use a robotic arm on the spacecraft to take a sample and send it back to Earth for analysis. We will integrate this data into our models and rerun it to see what difference it makes.
While waiting for OSIRIS-REx to send this sample of space rock to Earth, we are studying another asteroid, Didymos B or Didymoon, which is the smallest member of a binary asteroid system. NASA is designing the double asteroid redirection test, or DART mission, to test what really happens when we hit an asteroid with a kinetic impactor with cannonball. They aim Didymoon to alter its orbit around another asteroid in the system, Didymos A, without changing the orbit of one or the other asteroid around the sun. This experiment will allow them to test the deviation process of the kinetic impactor without Didymoon being accidentally projected onto a collision course with the Earth.
I am happy that we are conducting this research now, so that we can take the time to carefully study the problem and check our models three times without the pressure of a specific, potentially dangerous object happening to us. If we prepare well, our species could, for the first time, avoid a major natural disaster. We can not fend off a hurricane, bind a volcano, or lock a earthquake-prone fault, but in a few years we might be ready to stop a comet in its tracks.
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