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NASA's 2017 asteroid flyby helps defend Earth from Armageddon

A very strange series of memos arrived in the White House in autumn 2017, detailing a nightmare scenario: an asteroid apparently on course to hit Earth . But these memos were covered with bright red warnings indicating that they were just part of an exercise. Humanity had no other reason than normal to fear the end of civilization.

The memos were part of a surreal, sophisticated exercise that allowed NASA and the scientific community to practice the existential threat posed by an asteroid and seems to be on the right path to hit Earth – all based on one real asteroids. Now, the team involved in the exercise has published a final set of findings on how the project went and what people can do to better prepare for this possible scenario of the apocalypse.

"The most important thing was [that] when we tested the entire system for the first time, including notifying the White House," said Vishnu Reddy, a planetary expert at the University of Arizona and co-author of the new paper, at the annual Lunar and Planetary Science Conference held at The Woodlands, Texas. "It was a really fantastic experience for us to test with a true asteroid."

Related: Humanity beats a spaceship into an asteroid in a few years' time to save us ]

In early 201

7, scientists decided to carry out such an exercise. So they were looking for an asteroid that was not actually risky, but close enough to get realistic data on how an actual risk could impact. This would allow planetary defense specialists, who deal exclusively with the asteroid threat, to test their observation, assessment and reaction procedures .

A space rock known as 2012 TC4 fits the bill. When the object was first discovered in 2012, observations of its path through the solar system indicated that it would approach Earth in October 2017, but not dangerously, although the researchers did not know which way to go. [19659002] So the asteroid has earned its role as guinea pig for the end of the world, as we know it.

"We knew it was not a threat … we wanted it to be an exercise, but TC4 was a good candidate," said Michael Kelley, NASA scientist in the Planet Defense Program and co-author of the briefing paper during a presentation on the same Conference. "It was an asteroid with a little uncertain orbit within the time frame we wanted to do this exercise, we knew it was outside, we knew roughly where to look into the sky, but we did not know Exactly where To align the telescopes, we would have to search a little to find it. "

This search began in July 2017, when a team that used the Very Large Telescope in Chile tried to spot TC4. They had finally settled in August when they expected them to. Another telescope, Pan-STARRS in Hawaii, also proved separately that the scientists had not yet discovered the data in 2012 about two weeks before the next approach from 2017.

As TC4 As they approached, the scientists aimed the telescopes around the globe at the object. First, they wanted to follow the path. Observers and orbiting specialists worked together to update their expectations of where the Rock would travel exactly, one of the main tasks of planetary defense. As this picture developed, the team brought the data to government officials to discuss how the situation would be handled in real life.

The good news is that you've never heard of a big asteroid hit Earth in the fall of 2017. The intricate finding is that the team's calculations at one time gave rise to the assumption that this was a real possibility was, said Kelley. On September 24 of this year TC4 gave a 1 to 180 chance to hit Earth. "This is far below the threshold to trigger any triggers for an emergency situation," Kelley said.

Fortunately, the splinter of a chance had evaporated within a few days . The uncertainty leads to a risky situation, he added, as the team never wants to act prematurely and panic. But somebody who does not follow the whole process could one day purposely take the data out of context.

"You have to be very, very careful when you have a lot of measurements and are waiting to be seen. What suits the pattern and what does not fit the pattern," Kelley said. "You can get to the point where you make the wrong conclusion when you stop at a certain point or just take a snapshot image."

At the end of the exercise, the team had completely eliminated the likelihood of impact in the foreseeable future of TC 4.

But the scientists were not content to simply predict the way of the asteroid; They also wanted to collect as much data as possible about the rock itself. In particular, they examined how it weakened and brightened when it turned in outer space . This information is not only scientifically interesting in the context of a potential impactor. In addition, details about the rotation and composition of an asteroid can influence the potential disaster and affect how much of the initial mass penetrates the destructive atmosphere of the Earth.

Again, it was a bit shaky. The team had set up a number of facilities they wanted to use before, but fate intervened. The scientists wanted to use the massive radio set in Arecibo, Puerto Rico to repel light waves from the surface of the asteroid and see how they rebounded. But Hurricane Maria devastated the island only a few weeks before the next approach of the asteroid, and the telescope was unwilling to help. To compensate for the absence of Arecibo, the scientists had to catch up with two other radio telescopes, Goldstone and Green Bank.

The team wanted to use NASA's infrared telescope facility in Hawaii to better understand the composition of the object. The telescope had a window for three nights to catch TC4. It watched the asteroid the first night and was put on another task on the second night. On the third night the electricity went out.

"It turns out someone fell a tree and the tree fell on the power line," said Reddy. "And so the fate of the world will end in 19459018. A person with an ax in his hand trying to cut down a tree in the evening."

There is no reason to assume that the same profane things would be patient Wait for a real threat. "There are real problems that can emerge even in an emergency situation," Kelley said. "Bad timing is always there."

Despite the challenges of observing, scientists are quite satisfied with what they learned about TC4. It seems to be very bright, about 10 meters in diameter, with an uneven surface. "This could be a fragment of a very bright white rock in space," Kelley said. It seems to resemble an unusual type of meteorite – a species that accounts for only 1% of the space rock we have here on Earth – Aubrite.

Now that the results of the TC4 Drill have been released The team is ready to apply the lessons learned during the exercise to a new exercise. This team has selected a different asteroid, which in turn is based on the orbit of the object. "We can not plan the asteroid [s] We have to wait somehow for cooperation," Kelley said.

This exercise will be smaller in size than the TC4, with the goal of learning so much about the space rock itself – although scientists already have a good sense of what it is.

"We know a lot, but we pretend we do not know," said Reddy. "Imagine, when this asteroid hits us, say 15, 20 years, and this is the last and best flyby, if we can characterize it, to know what in the next 15, 20 years before the impact What can we learn? "

This kind of preparation is not just about sailing distant space rocks through the solar system . It also means learning about deeply earthly, deeply human factors, such as how to be ready to fake the wrong tree on the wrong day.

"This exercise was actually a good lesson in reality, so to do in a practical sense," Kelley said. "Real events had an impact on the campaign, but we worked with them and worked through them." Man should therefore be better prepared for the next approach.

"Luckily, the fate of the earth did not depend on this thing, so we're fine," he said.

The project described in a work published in March in the journal Icarus .

Mail to Meghan Bartels at mbartels@space.com or follow her @meghanbartels ]. Follow us on Twitter @SpaceTotcom and Facebook .

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