Let’s imagine the following common Hollywood scenario. Some brilliant scientific, most likely unnoticed, discovers the presence of a humongous meteor. The space body is in direct trajectory to collide with the Earth globe. Somehow it was never detected before. It is a big asteroid, and its collision with Earth will, without any doubt, put an end to life on our planet. At least life as we know it, with all the perks of a sized developed civilization, with drive-ins and all that. After a fair share of disbelief and a few passionate presentations, NASA decides to take cards in the matter. Gathering a task force for the last effort to save all (human) life on our planet.
Does it ring a bell? It roughly describes the basic plot of numerous space catastrophe movies. Disaster films like “Judgement day” (1999), “Asteroid Final impact” (2015) or Michael Bay’s “Armageddon” (1988), to mention some. Well, apparently, the answer is the threat is more real than is looks and not a delusion out of a screenwriter mind.
Movie poster of “Asteroid Final Impact”, one of the numerous movies with the meteor impact as the main topic
In the Planetary Defense Conference, held in Washington D.C some weeks ago, the NASA administrator Jim Bridenstine, cautioned about the risk of a meteor impact with the planet Earth (here is the link to the complete YouTube video). Pointing out that, perhaps because of all the Hollywood movies about it, governments have not done enough to prepare us for an issue of that nature. As species, we tend to focus on the immediate risks. Dismissing the problems that have a low probability of occurring or seem to be far off into the future.
What is The Risk?
According to Mr. Bridenstine, the frequency of such events is far from having such a low probability of occurring. “I wish I could tell you that these events are exceptionally unique, but they are not”, “These events are not rare — they happen. It’s up to us to make sure that we are characterizing, detecting, tracking all of the near-Earth objects that could be a threat to the world”. During the conference, he was not shy about the potential impact it could have. “This is about ultimately protecting the only planet we know right now to host life.”
A Meteor Impact? Did It Happen Before?
It is generally agreed that the impact of a massive asteroid, 6 to 9 miles width, was the most likely cause of a massive extinction 66 million years ago. According to the Alvarez hypothesis, the impact left behind a 112 miles wide crater. A thin layer of sediments all over the surface of the globe (caused by the debris ejected to the atmosphere) and triggered what is known as an impact winter. The event meant effectively the death of three-quarters of all life on planet Earth, plants and animals. We are aware of that risk, at least in popular culture. But such a devastating event is also hard to grasp in our minds. Because of the scale as well as the fact that it happened far away in our timeline.
Chicxulub crater, aerial picture
Although we have more recent examples of asteroids impacting our solar system. The impact reported in Brazil in 1930 and the Tunguska Event of 1908, in a remote area of Siberia. This one had such a powerful blast as to knock down from his chair a man sitting forty miles away from the point of impact of the meteor.
Bridenstine referred as well to an even more recent event, the Chelyabinsk event. In 2013, an approximately 20 m near-Earth asteroid entered Earth’s atmosphere over Russia. Quickly becoming visible over the southern Ural region. Unlike other historic events, this time the strike was recorded by modern technology. There is satellite footage of the impact. Security and personal video cameras recorded its path across the sky. Checking YouTube, we can find more than a few videos of the sky that day. Including official videos from NASA covering the meteor impact. “It was brighter in the sky than the sun at that point when it entered Earth’s atmosphere. And people could feel the heat from this object from 62 kilometers away,” Bridenstine recounts.
Image of a vapor trail left by the meteor. It was captured about 125 miles (200 kilometers) from the Chelyabinsk meteor event, about one minute after the house-sized asteroid entered Earth’s atmosphere. Credits: Alex Alishevskikh
What is NASA Doing to Prevent It?
NASA proactively works on the detection and developing of scientific modeling systems to protect our planet. Bridenstine said meteorites with such destructive power as the Chelyabinsk should be expected about once every 60 years. NASA is working to detect and track asteroids measuring 140 meters or larger.
As a result, NASA scientists have already discovered more than 90% of those potential civilization-enders. The impact of a meteor of those characteristics would be enough to wipe out a state or even a whole country. NASA is considering launching a dedicated asteroid-hunter, the Near-Earth Object Camera. Its mission will be to discover and characterize most of the potentially hazardous asteroids that are near the Earth. Scanning in infrared light, spotting their heat signatures in the darkness of the space. The effort in detection, plus global coordination, would allow us to launch initiatives to change the trajectory. Avoiding the impact is, of course, the final goal.
“We know for a fact that the dinosaurs did not have a space program,” Bridenstine added. “But we do, and we need to use it.”. One more reason to love the Space Agency, remember, they are keeping an eye out there for all the potential menaces to our beloved planet Earth. Home, nothing less.
Mars as seen by the Hubble Space Telescope during Opposition. Credit: NASA/Hubble Telescope