Searchin', searchin', gotta find a place to hide
As the threat of asteroid impact remains, the sad fact is that asteroids are hard to see. They reflect little light, and since they are always on the move, you must scan the same patch of sky over and over, looking for changing objects against the static background of stars. Some researchers are looking for light in the visible or infra-
The LINEAR asteroid search observed this portion of sky last March. These are plots of the areas of the sky in which LINEAR performed asteroid search and follow-up observing during the indicated monthly lunar dark period. In each plot, each box represents a field that was searched for asteroids. Each field is revisited several times during the course of a night with a single image frame collected on each revisit. At the end of the night, the resulting frame set is processed to detect moving asteroids. Courtesy of the LINEAR project, MIT Lincoln Labs.
We won't get into the dispute about which approach is best, since each has advantages. But we will note that, according to the numbers, the most fruitful effort is run by the Lincoln Laboratory at the Massachusetts Institute for Technology.
Using a 1-meter, satellite-tracking telescope that feeds data to a 1960 x 2560 pixel video detector, the Lincoln Near Earth Asteroid Research (LINEAR) can image a chunk of sky equal to almost 8 percent of the entire heavens.
Looking away from the sun, on moonless nights, in March 1998, LINEAR saw 151,035 objects, including 13 new near-
That's a gusher of data by any standard. But although the data on sky coverage indicate that LINEAR could view the entire sky in 12 nights, more asteroids and comets are constantly coming into view, and the telescope still cannot see faint but potentially destructive asteroids.
Thus if LINEAR and the other search projects are to reach the agreed goal of finding 90 percent of all significant potentially hazardous objects within 10 years, about 10 times as much effort is needed.
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Don't wanna live there, but a great place to visit!
Not content to observe asteroids with ever-
All told, seven planned or operating missions expect to visit -- and in some cases return samples from -- 26 asteroids over the next 13 years.
A little knowledge: Dangerous?
Is it just gloom-
Let's repeat that no known asteroid threatens Earth. But if an assassinating asteroid were found, what could we do about it? At least one simulation found that an impact with a house-sized piece of basalt would do little to change the course of a 1.7 kilometer asteroid. Given that nobody knows how to accelerate such a hunk of rock to asteroid-blasting speed anyway, we need alternatives. Some scientists suggest nudging another asteroid into an orbit that would deflect the attacker.
