As expected, the data acquired by NASA enabled the agency to more closely estimate future visits by Apophis, which at 1,066 feet wide, could deliver a punch of over 500 megatons of TNT if it were to impact the Earth, which compares to the largest thermonuclear bomb ever developed, the Soviet Union's Tsar Bomba, which released 57 megatons of energy.
We already knew 2029 was no issue, and with the new data, NASA said that the 2036 flyby, which had been estimated to have a 1-out-of-250,000 chance of an impact, was no longer an issue.
Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory (JPL) said:
We have effectively ruled out the possibility of an Earth impact by Apophis in 2036. The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future.
That is the good news. It's that foreseeable future mention that is the bad news.
Apollo 9 astronaut Rusty Schweickart, a leader in raising awareness about the threats and opportunities presented by near-Earth objects, said the following in an interview with NBC News:
I’m hoping that we don’t follow the bad precedent of stating that the risk from Apophis has been eliminated. Please look on the JPL risk page and especially the more detailed info and note that 1) The 2036 impact possibility is, while significantly reduced, still possible, and 2) that the 2068 impact possibility is now elevated ... to a level that exceeds what the 2036 impact was prior to this apparition.
Until JPL and the other guys get more data, enough to really define the Yarkovsky effect, we really won’t be able to get definitive data for longer time scales that we can rely on.
The Yarkovsky effect refers to how solar radiation might affect the orbital path of an object. it's somewhat ironic that the Yarkovsky effect might lead to our doom. Earlier, it was posited that paintballs could save the world from an asteroid impact, by using increased solar radiation pressure, yet this new report indicates scientists don't understand the effect all that well.
Asteroid Apophis earned the term "doomsday asteroid" after a 2004 study that predicted there was a 2.7 percent chance of it hitting Earth when it passes within 22,364 miles of our home planet in April of 2029. Later -- and more precise -- measurements, though, proved that Apophis poses no threat during that flyby, either.
However, Apophis will continue to visit Earth on a fairly frequent basis. In addition, while we can track it, as we are aware of it, there isn't a way to stop it if we were to discover it were on a collision course.
In addition, as Dan (Billy Bob Thornton) said in "Armageddon,"
Well, our object collison budget's a million dollars [it is unclear what NASA's actual and current budget for this is]. That allows us to track about 3 percent of the sky, and beggin' your pardon sir, but it's a big-ass sky.