In fact, recent research by JPL scientists D. Farnocchia and S.R. Chesley have taken into consideration the Yarkovsky effect on 1950 DA based on known values from previous observations, as well as new research suggesting that the asteroid has a retrograde rotation. While their latest assessment does put the risk of an impact in 2880 within the lower end of the probability spectrum (4×10^-4, or -0.58 on the Palermo Scale) it is still far from zero, and in fact remains higher than any other known potential impacts.
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So what would happen if the half-mile-wide 1950 DA were to hit Earth? While that depends on a lot of things, such as its composition, speed, angle of impact, where it impacts, etc., needless to say it would cause a lot of damage across a large area. I'm talking an energy release upwards of half a million megatons, which, were it to strike say, New York City, everything within at least a 100-mile radius would be flattened by the force of the impact alone - that's halfway to Boston and Washington, DC (source). And that's not even taking into consideration the air blast, atmospheric dust cloud, secondary impacts from debris, or damage from any resulting tsunami (if the impact were in the ocean)... the destruction would easily extend out many more hundreds of miles, and the repercussions - physical, financial, economic, and emotional - would extend around the globe.
Put it this way: if a 40-meter object could do this, imagine what a 1-kilometer one would do.
But again, precisely where 1950 DA will be in another 866 1/2 years (and whether or not it will occupy the same point in space as our planet) relies on many factors that aren't well known - even though its orbit is pretty well understood. More in-depth observations will need to be made, and that is why asteroids like this must be carefully - and continually - watched.
Luckily, 35 generations offers plenty of time to improve our knowledge. According to JPL's Near-Earth Object program, "If it is eventually decided 1950 DA needs to be diverted, the hundreds of years of warning could allow a method as simple as dusting the surface of the asteroid with chalk or charcoal, or perhaps white glass beads, or sending a solar sail spacecraft that ends by collapsing its reflective sail around the asteroid. These things would change the asteroids reflectivity and allow sunlight to do the work of pushing the asteroid out of the way."
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Still, whether because of ongoing research, faith in future generations of scientists, or just sheer probability, JPL remains confident that 1950 DA should cause little concern. "The most likely result will be that St. Patrick's Day parades in 2880 will be a little more festive than usual as 1950 DA recedes into the distance, having passed Earth by."
Let's just hope the luck of the Irish is with our planet big time that year...
Source: JPL's Near-Earth Object site. From an article originally posted on LightsInTheDark.com.
Learn more about ongoing NEO research on the JPL site here, and find out about asteroid-hunting programs like NASA's repurposed WISE spacecraft and the proposed Sentinel spacecraft from the B612 Foundation. Because in order to learn more about NEOs, we first need to find them (and there are a lot more out there where 1950 DA came from!)