This week, scientists from NASA, the European Space Agency and other institutions will gather at a conference in Italy, where they’ll be looking at a bold proposal to use two spacecraft to deflect an asteroid.
That planetary defense plan is one of many worldwide efforts to ensure that Earth remains safe from collisions. While ground-based observatories have done great work in detecting asteroids, Adler Planetarium astronomer Mark Hammergren says they’re stymied by the bright light of the sun and that an infrared satellite orbiting Earth would be a more valuable sentry.
“Out in space there’s no atmosphere, so you can look closer to the sun,” Hammergren said. “You can find what we think is an almost entirely unknown population of hazardous asteroids orbiting closer to the sun than us and every once in a while crossing our path.”
Why infrared? Hammergren says it’s because darker asteroids are harder to detect visually. “If you have … a dark car sitting in the summer sun, it gets hotter than the white car next to you. The darker car – or darker asteroid – will emit more infrared light, so they appear brighter.”
While Hammergren thinks a satellite to detect asteroids is valuable, he also advises people not to worry too much about Armageddon scenarios. “We have found virtually all of the large asteroids that could cause mass extinctions on Earth and not a single one of them is going to hit the Earth for at least a thousand years in the future,” Hammergren said. “It’s probably one of the greatest unsung victories that NASA and maybe even civilization has accomplished.”