The massive coal black asteroid 2005 YU55 zoomed by Earth this week in harmless fashion, but interest groups say the relatively close encounter is a reminder the world is "a sitting duck in a cosmic shooting gallery," with no international plan in case of a disaster.
Ray Williamson is executive director of the Secure World Foundation (SWF), one of many groups that have submitted papers to a UN working committee looking to develop guidelines for member states on how to respond to near-Earth objects.
In a phone interview on Wednesday from the Denver, Colo., area, Williamson said there's an important need now for an international defence strategy that includes finding potentially hazardous objects such as asteroids, predicting their locations, and giving adequate warnings to citizens about when and how they will hit the Earth — even though such a disaster may be decades away. Among the foundation's recommendations is the establishment of a global Information, Analysis, and Warning Network.
"If it's not an international plan, there could be difficulties because there is so much uncertainty about where an asteroid would strike if it struck, and uncertainty further about trying to move an asteroid in orbit," he told CBC News after an SWF release said failing to put together a "planetary defence strategy" makes the Earth "a sitting duck in a cosmic shooting gallery."
Space programs have emphasized locating, tracking and analyzing asteroids such as 2005 YU55, which was 400 metres wide. The asteroid was no closer than 324,600 kilometres as measured from the centre of Earth, around 6:30 p.m. ET on Tuesday.
An asteroid is a large piece of rock, generally between 100 metres and several hundred kilometres across, and is also known as a minor planet. Most asteroids are located between the orbits of Mars and Jupiter.
Before 2005 YU55, the last time an asteroid came close to Earth was in 1976, and experts have said that won't happen again until 2028.
Dinosaurs' extinction blamed on asteroid
But Williamson and officials with the non-profit B612 Foundation, founded by a group of astronauts and scientists with the goal of predicting and preventing catastrophic asteroid impacts, said it's never too early for disaster management planning.
Williamson recalls that the last time an asteroid hit the Earth was 1908, when one 50 metres in diameter exploded above Tunguska, Siberia, flattening and burning trees, and killing reindeer across 2,000 square kilometres of remote land. It wasn't until 2001 that Italian scientists finally determined the devastation was caused by an asteroid. There were no known human deaths.
In the 1980s, scientists also uncovered that the chain of events that led to the demise of dinosaurs was triggered by an asteroid that plummeted to the Earth about 65 million years ago.
"Unlike the dinosaurs, we have the means to prevent catastrophic impacts," says the B612 Foundation, which also advocates finding and tracking asteroids to learn about potential threats to the Earth decades in advance, and testing technology to deflect asteroids.
NASA's Near-Earth Object Program Office, which co-ordinates efforts to detect, track and characterize potentially hazardous asteroids and comets that could approach the Earth, says although Hollywood has created colourful methods for stopping an object on a collision path with Earth, "no government agency, national or international, has been tasked or accepted the responsibility to stop such an asteroid, should one be discovered."
Providing appropriate responses to a possible asteroid disaster is extremely challenging "because of the wide range of possible sizes, trajectories and warning times for Earth-threatening asteroids," NASA notes. "Unless there are a few decades of warning time, hazardous asteroids larger than a few hundred metres in diameter will require enormous energies to deflect or fragment."
There's only very preliminary research in the area of how best to shove away an asteroid if it's in the rare position of heading in the Earth's direction. Nuclear explosions in space, for instance, could push the asteroid out of Earth's harm or fragment it. With early warning of a few years to several decades, asteroids "smaller than a few hundred metres in diameter" could involve sending a weighted robotic spacecraft that would collide with the asteroid and nudge it to the point that it would no longer be heading to Earth.
Canadian satellite detects space objects
Denis Laurin, program scientist, space exploration, with the Canadian Space Agency (CSA), said Wednesday that any discussions about how to plan if an asteroid is predicted to reach the Earth are just "concepts." But telescopes are getting more sophisticated at showing where asteroids are located, and predicting their path well into the future.
Canada, for instance, is currently building a Near-Earth Object Surveillance Satellite (NEOSSat) in what the CSA is calling "the world's first space telescope dedicated to detecting and tracking asteroids and satellites." Slated for launch in spring of 2012, the satellite —which Laurin says is about the size of a large suitcase — will contribute to international efforts to catalogue asteroids. The satellite will circle the globe every 100 minutes, scan space near the sun to pinpoint asteroids that may someday pass near the Earth, and will also sweep the skies in search of satellites and space debris.
The hundreds of images that NEOSSat will generate daily will be downloaded and analyzed by the University of Calgary's NEOSSat science operations centre.
"Essentially we want to look for [asteroids] and try to find as many as possible," said Laurin, who is based in Montreal. "It's scientifically important to understand the population and distribution of these types of asteroids, and where they will eventually end up ... [and] if there could be anything threatening to us."
'We would have little time'
CBC News made phone calls on Wednesday to the UN's Office for Outer Space Affairs but was greeted with busy signals.
However, when asked earlier this year if there would be time to mitigate the effects of an asteroid crash on Earth, Mazlan Othman, who heads the Office for Outer Space Affairs, said, "If an asteroid were small enough and coming from behind the sun, we would have little time."
"But we now have a network of observatories that continuously monitor asteroids," she added. "This is the reason why we have the scientific discussions at the UN because it is through the UN that together we can co-ordinate on what each observatory can do and compile the information."
Othman said a committee proposal "appears to be making traction" on how to deal with potentially threatening asteroids and other near-Earth objects that could come before the Security Council.
Williams said he believes the UN committee is expected to complete its work by 2013.
In the meantime, the SWF continues to hold workshops on how to plan if asteroids and other space objects threaten the Earth.
"One of the questions we're dealing with right now is, 'How do you inform the public and try not to cause panic — what kind of information do you give them and how do you do it?'" said Williamson.
"The other aspect is, once you say, 'OK, we think this asteroid will fall in, say, Quebec,' you need to mobilize your disaster response people. That's where you bring your disaster preparedness people in, and right now, there is no plan for that.
"We want disaster modelling authorities to know that they should pay attention to these things."