This summer, NASA’s new planetary defense mission DART (Double Asteroid Redirection Test) will start its journey to the asteroid Didymos. The plan is for it to alter the trajectory of the asteroid’s moon enough to make sure that a collision course with Earth is not in its future.
"The notion is that we’re going to take this little space craft, we're gonna crash it into the moonlet ... and by doing that hope to change its orbit around the primary asteroid," explains astronomy contributor Jean Creighton.
Creighton notes that most asteroids are between Mars and Jupiter, but some do get closer to the sun. Depending on their size and orbit, many are monitored to keep track of what could be a threat to Earth.
"Anything that is smaller than 1.3 astronomical units is considered a near-Earth object at its closest," she says. "Now that doesn't necessarily mean it's dangerous. Hazardous is considered if its shown that its trajectory will intersect with the orbit of the Earth, and if it's 140 meters across. And, 140 meters is something like a football field."
The capacity and technology to monitor asteroids and other near-Earth object's trajectories has improved, especially since the '80s when we came to realize there's more of these objects than we thought, according to Creighton.
"Whether we should do something about this emerged in sort of all heat again after the Cold War subsided, and then took a backseat after 9/11, and then reemerged just before an asteroid exploded over Siberia in 2013," she notes.
Technology and methods of stopping a near-Earth object causing damage to Earth is still changing, and Creighton says there's not one universal approach to rely on.
"Every situation is different. I mean, we like to think of asteroids as one big, happy family but in fact they're very different," she says.
Outside of systems like DART being deployed, Creighton says that everyone can help monitor asteroids through efforts like Unistellar and the International Astronomical Search Collaboration (IASC) to collect and analyze data.
"A human eye does very good work in terms of identifying changes in a field of view, so that's something to consider," she says.
You can find out more about Earth's history with asteroids and the future of planetary defense against possible threats through the UW-Milwaukee Manfred Olson Planetarium show, “Dodging Doom - Protecting the Planet from Perilous Asteroids.” It will take place on July 16 at 7 p.m. over YouTube.
