It'd be such a shame to lose this fragile, watery planet to an asteroid strike. NASA's newly-formalized Planetary Defence Coordination Office will do its best to save us -- money and physics permitting. The Planetary Defence Coordination Office sounds like a science fiction agency charged with protecting us from invading aliens, but it's real and serves the much more practical purpose of coordinating all NASA-funded projects involving potential impacts from above. That includes discovery and tracking of any asteroids or comets that pass near our orbit.
It's taken us a long time to warm up to the idea that maybe we should fund all-sky surveys to look for near-Earth objects threatening our home planet. But we're finally getting there -- more than 95 per cent of 13,500 catalogued near-Earth objects were discovered since 1998. Astronomers are finding another 1500 objects each year, giving us plenty of fodder for nightmares about potential Earth-killing impacts.
Despite frequent media hype to the contrary, however, we haven't discovered anything that will kill us yet. In a press release, associate administrator for NASA's Science Mission Directorate John Grunsfeld explained:
While there are no known impact threats at this time, the 2013 Chelyabinsk super-fireball and the recent "Halloween Asteroid" close approach remind us of why we need to remain vigilant and keep our eyes to the sky.
Most near-Earth objects are found using either ground-based telescopes (like Pan-STARRS), or the space-based instruments (like the NEOWISE infrared telescope). All tracking data is submitted to the Minor Planet Center to coordinate observations and refine models to predict the objects' future positions. Once found, additional infrared and radar telescopes are tasked with determining an object's size, shape, composition, and any orbital oddities.
NASA is fairly certain it's found at least 90 per cent of all near-Earth objects that are at least 1 kilometre in diameter, so scientists have turned their focus to smaller targets. The current objective is to find all the objects that could neatly cover a football field -- those 140 meters or larger. Since starting the search in 2005, NASA has found an estimated 25 per cent of this mid-sized population, and the agency hopes to pinpoint at least 90 per cent by the end of 2020.
The Planetary Defence Coordination Office is also stepping up interagency and international cooperation on what we'd do in the face of imminent danger. Instead of NASA whistling in the dark about near-Earth objects, it's now working with the Federal Emergency Management Agency (FEMA) to figure out plans for potential catastrophes.
Part of that plan is to develop new technology to defend our planet by deflecting or redirecting objects on target for impact. Although we don't have anything functional yet, the office is keeping a close eye on both NASA's Asteroid Redirect Mission, a concept using gravity tractors, as well as on the NASA-European Space Agency joint Asteroid Impact and Deflection Assessment mission concept.
If sending an asteroid or comet on its merry way without smacking the Earth fails, the next step is to predict impact timing, location and effects. The NASA scientists would hand this data to FEMA so the emergency response agency can plan on how to best prepare our population to survive. Depending on the scale of the catastrophe, that can be an intimidating challenge.
The new attention has come with a bigger budget. Previously working with just $US4 million per year, the 2012 budget expanded near-Earth observations to $US20.4 million. Funding doubled in 2014. The most recent budget is higher still, with $US50 million dedicated to observations and planetary defence.
With all this money and effort finally focused on the skies, it's looking good we might be able to stave off our own extinction. It's nice to be doing this before a big hunk of rock and ice is looming.
Top image: Maui's Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) telescope is a vital part of discovering new near-Earth objects. Credit: University of Hawaii/Rob Ratkowski