The mission of protecting the earth from threatening asteroids is increasing, as "an absolute flood of new observations" comes from a new telescope designed to scan the sky, says Ed Lu, founder of the B612 Foundation, a non-profit organization devoted to planetary defenses.
The large Synoptic Survey Telescope (LSST) in Chile is expected to have "first light" in 2020, which means that the telescope's mirrors will be exposed to the sky for the first time. Then, the entire operation for its decade of the southern sky will begin in 2022, if all goes to plan. Lu said the telescope will detect tens of thousands of new asteroids in its first year alone, with many more coming.
Lu and others shared the latest developments in the planetary defense just in time for Asteroid Day, an annual celebration on June 30 to discuss the science of asteroids and the possible threat they pose to the earth. While we know of no asteroids that will suddenly cause damage to our planet, there is always the possibility, the participants said in a telephone conference on Asteroid Day on Thursday, June 27.
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Between LSST and other already operative telescopes, Lu added, researchers predict that they will quickly catalog "70% or more" of the asteroids – or space stones – that are greater than 460 feet (140 meters). The statistics are relevant to the congress, which in 2005 asked NASA to catalog at least 90% of the asteroids of these sizes by 2020, according to the agency. Lu admitted that scientists will not meet the deadline, but he said they could generate that directory with enough time and funding.
Lu said scientists should start thinking now about how to frame new discoveries for the public. When LSST first spits these objects, observations of them will be so sparse that it becomes difficult to limit the asteroids paths. At the time before the researchers are convinced of the paths of these objects, several of them can be seen as a threat to the earth, simply because researchers cannot read where they are moving in space.
Air Burst Danger
But smaller asteroids also pose a threat, on a more local scale, said Mark Boslough – who was the first American scientist to visit Chelyabinsk after a six-city object exploded over the Russian city in 2013. Also 130-foot-40-meter-sized objects can be a hot against cities, he said.
Boslough cited Tunguska Event, a 1908 incident in which an asteroid was split into the Earth's atmosphere and flattened 830 square kilometers (2150 square kilometers) of Siberian forest. This and other "air bursts" are quite capable of causing much material damage, so minor size asteroids should also be included in emergency planning, he said.
"I always thought we should be more concerned about them than we are [now], mainly because they are just so much richer. There are something like 10 million of those things, he says.
Boslough – a physicist at Los Alamos National Laboratory – said these smaller items might not be cataloged, as there are so many of them. Instead, he recommends drawing up surveys that would note something that is damaging to the earth in a close way. Then, disaster planners can evacuate cities that may be threatened by the object, just as we do today for incoming hurricanes.
There are also other possibilities to look for these items. This summer, the Beta Taurid meteor stream from Comet Encke will pass a little closer to Earth than usual. This swarm of objects lies in a 7-to-2 resonance with the planet Jupiter, which means that they orbit the sun seven times each time Jupiter orbits twice. The orbit of these objects cuts with the earth's, though they do not pass near our planet every year.
Telescope will monitor the swarm for Tunguska-size objects over the next few weeks, as the swarm will pass through our circulation at the end of June and continue through August, he said. He added that developing Tunguska is not a coincidence, because this object "was more than likely a Beta Taurid" based on the time of the one who struck the earth on June 30, 1908.
Asteroid mission ongoing
Another aspect of the planetary defense is studying near the Earth's asteroids closely. NASA's OSIRIS-REX (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission is in orbit on asteroid Bennu, and Japan's Hayabusa2 circles asteroid Ryugu. In the next few years, both spacecraft are expected to deliver samples to the earth.
And there's more to come. Patrick Michel, co-researcher of upcoming asteroid missions Hera, talked about the progress of the European asteroid mission. Hera is expected to start in 2024 for double-asteroid Didymos. What makes Hera unique from previous assignments is that it will work in tandem with a NASA spacecraft, called DART (Double Asteroid Redirection Test). DART will try to change the orbit of the moon Didymos, and Hera will investigate which crater DART leaves behind.
Hera is still in the planning stage and will go through another major approval milestone in November, Michel said. He added that it is an important milestone for the European Space Agency, as it could be "the only asteroid mission possibly made by Europe in the next decade."
But asteroids are not only dangerous – they can also be very valuable, says Marc Serres, CEO of Luxembourg Space Workshop. Because they contain water and minerals – resources that can be used for space missions – he said the time to create a catalog is now before we start exploring the solar system. When people start moving to the moon and other destinations, he said, it will be important to me as much as we can on the road.
"Using the resources we can find in space will completely revolutionize how we act in space because we don't have to take everything with us," he said.