June 30 is Asteroid Day, a United Nation sanctioned event designed to raise awareness about asteroid risks and shine a spotlight on the people working to spot near-Earth objects in the sky. This year more than 700 events are planned in 190 countries, with participation from agencies like NASA, the European Space Agency (ESA), and Japanese Aerospace Exploration Agency (JAXA). along with a 24-hour livestream online. If the above scenario ever does occur, we may have Asteroid Day to thank for our preparedness.
“The ultimate goal is to protect our planet from future asteroid impacts.”
“The ultimate goal is to protect our planet from future asteroid impacts,” Asteroid Day co-founder Grig Richters told Digital Trends. “This can only be achieved when the global community works together to fund the science and the space missions.”
In 2014, Richters and his co-founders — including Queen guitarist Brian May whom, you may not know, is also an astrophysicist — gathered more than 200 signatures from renowned scientists and artists for the Asteroid Day declaration. In December 2016, the United Nations approved International Asteroid Day “to raise public awareness about the asteroid impact hazard.”
The sky is falling!
Asteroid risks have been known for some time. June 30 marks the anniversary of the Tunguska event, an impact event that occurred in 1908 and flattened 770 square miles of forest in Siberia.
And the current threat is very real. Just four years ago, a meteor entered Earth’s atmosphere undetected before illuminating the sky and exploding over the Russian city of Chelyabinsk. The event, which was captured on numerous dashboard cameras, caused nearly 1,500 people to seek medical treatment and damaged over 7,200 buildings.
“We could be struck tomorrow by an object that wipes out a city and we have no knowledge,” NASA astronauts and planetary scientist Tom Jones told Digital Trends. “We have very little knowledge of what could happen to us tomorrow or a thousand years from now, just because we haven’t used our space tools to evaluate the hazard thoroughly.”
To be sure, there’s slim chance we’ll be hit by a large asteroid like the one that lead to the dinosaurs’ extinction. We’ve identified most of them and they’re travelling at a safe distance from Earth.
“We do not have to be concerned about a significant asteroid impacting Earth on the short-middle term, if significant means a body that is capable of global effects,” planetary scientist Patrick Michel told Digital Trends in November.
“We’ve found about 1.5 percent of the million or so objects that could be a city-buster-type asteroid.”
The more realistic concerns come from smaller objects like the one that exploded above Chelyabinsk, which are small enough to sneak by undetected but big enough to cause local damage. However, at 65 meters wide, the Chelyabinsk meteor was small compared to objects around 450 feet in diameter, which can cause regional destruction. But even these city-busters are difficult to spot.
“About 95 percent of the large ones that could do-in civilization have been found,” Jones said. “But we know about 1.5 percent of the million or so objects that could be a city-buster-type asteroid.”
Avoiding Armageddon
Mitigating the risk of an impact is a two-pronged approach. First we have to discover and track asteroids. Then we demonstrate ways to deflect them.
Scientists around the world are working to identify, track, and protect against asteroids and other near-Earth objects (NEOs). Since 1998 NASA has had a congressional mandate to catalogue NEOs, particularly those over a half-mile wide, which could cause destruction on a global scale.
ESA and NASA’s proposed Asteroid Impact and Deflection Mission (AIDA) would send a spacecraft to an asteroid to test technologies that may someday save us from an impact.
AIDA would consist of two spacecraft — ESA’s Asteroid Impact Monitoring Mission (AIM) and NASA’s Double Asteroid Redirection Test (DART). The joint missions would head to a double asteroid system called Didymos, which pass about ten million miles by Earth in 2022.
After AIM performs scientific surveys of the asteroid system, the DART spacecraft will crash directly into the smaller of the asteroids. The idea is that an impact may be sufficient to deflect an asteroid that’s on a collision course with Earth. Although ESA denied AIM funding in favor of its ExoMars mission, NASA still intends to pursue AIDA.
Meanwhile, another NASA project, the Asteroid Redirect Mission (ARM) seeks to tug an asteroid off its trajectory by using a spacecraft’s gravitational attraction. The agency asked for proposals from private partners to help with experimentation and payload delivery.
The private sector has an important role to play in our study of asteroids. The nonprofit B612 foundation’s sole goal is to protect Earth from asteroids and its current Sentinel Mission aims to develop an infrared telescope specifically designed to spot NEOs.
But asteroids aren’t all bad. As the leftovers from our solar system’s early days, they hold clues to how the solar system formed and offer a perspective on our place in it. NASA’s OSIRIX-REx spacecraft is on its way to study the asteroid Bennu before taking samples and returning to Earth. Asteroids also contain metals like iron, nickel, and cobalt, which make them of interest for Luxembourg and mining companies like Planetary Resources.
“We will be struck again — it’s just a matter of when.”
It’s clear that asteroids are a topic of increasing interest for public and private institutions, but Jones and those behind Asteroid Day are concerned that we aren’t doing enough. “We will be struck again,” he said. “It’s just a matter of when.”
He added that we have the potential to stop a catastrophe “on a scale that’s unimaginable in human experience” within the next century by putting even just a fraction of our effort and funding into programs like AIDA. “Postponing activity at Mars for a couple years is a good trade for…this unique opportunity to hit and deflect the small asteroid Didymos. If we miss this we’ll have to find another nice target down the road.”
“It’s pretty cheap insurance,” he quipped.
An asteroid impact of global scale is unlikely, but the fact remains that we’re unprepared. On the other hand, we know about just a fraction of the asteroids that could cause regional damage, and will need to increase our efforts to identify them. Hopefully Asteroid Day can raise awareness of the issue and inspire future generations of scientists to take up the task.
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