Asteroid Apophis has one in 100,000 chance of hitting Earth, expert estimates

August 14, 2017 by Tomasz Nowakowski, Astrowatch.net

The huge, nearly 400-meter-wide asteroid Apophis is still on a list of hazardous near-Earth objects (NEOs), regarded as a potential threat to the planet. However, new calculations made by NASA's Jet Propulsion Laboratory (JPL) show that Apophis' odds of Earth impact are lower than previously estimated.

"We cannot yet exclude the possibility that it could impact our planet, but we can calculate that the chance of Earth impact is only one-in-100,000 over the next century, which, of course, is extremely small," Paul Chodas, manager of JPL's Center for Near Earth Object Studies told Astrowatch.net.

Discovered in 2004, asteroid Apophis is slated to fly by Earth on April 13, 2029. Initial observations of this indicated that it has one in 36 chance of hitting the Earth on that day, but additional monitoring of Apophis completely ruled out this possibility.

However, Alberto Cellino of the Observatory of Turin in Italy told Astrowatch.net in June that although the potential impact in 2029 was excluded, we cannot rule out such an event in the more distant future. Given the fact that NEO orbits are chaotic, what is not dangerous today can become a candidate impactor in the future.

That is why astronomers, including Chodas, emphasize the importance of detailed observations of Apophis and its constant monitoring, which could confirm that this asteroid poses no danger to us.

"Apophis is certainly a hazardous asteroid, and for that reason, it has been tracked extensively. And so we know its orbit very accurately. In all likelihood, further tracking measurements will eliminate even that possibility (one in 100,000)," Chodas noted.

Astronomers estimate that on April 13, 2029, Apophis will pass by the Earth at a distance of no closer than 18,300 miles (29,470 kilometers). The next close approach of this asteroid is expected in April 2036, when it will miss Earth at a much larger distance of approximately 30.5 million miles (49 million kilometers).

Currently, there are 1,803 (PHAs) detected to date. PHAs are space rocks larger than approximately 100 meters that can come closer to Earth than 4.65 million miles (7.5 million kilometers). However, none of the known PHAs is on a collision course with Earth.

Explore further: Impact threat from asteroid Apophis cannot be ruled out

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eachus
not rated yet Aug 16, 2017
The possibility that Apophis will hit the Earth in the next century is non-zero, but extremely low. The probability that Apophis will hit the Earth sometime in the future is quite high. There are three interesting ways humans can modify that probability. 1) Putting a sufficiently large mass in Apophis's path in 2029 could target the moon. It might not get there for a century or two, which is good, because it would allow a better choice. 2) Do the same, but instead put it in orbit around the Earth. In this case it would probably be intended as a carbon source for making a space elevator, and eventually the far anchor point. 3) Land an engine with a human or robot crew, and use it for trips between Earth and Mars. The engine needed is not that big, the goal is to have Apophis pass near Earth and then Mars on a regular basis. Any passengers would need to accelerate to catch it, then decelerate at the end of the trip. Why? To provide lots of radiation shielding during the trip.
Sonhouse
not rated yet Aug 17, 2017
Ah, you mean to safely store the antimatter needed for propulsion. Got it.
antialias_physorg
not rated yet Aug 17, 2017
1) Putting a sufficiently large mass in Apophis's path in 2029 could target the moon

Erm...no.
2) Do the same, but instead put it in orbit around the Earth

Erm...no. Please no.
3) Land an engine with a human or robot crew, and use it for trips between Earth and Mars.

Erm. Nope, no and not a chance.

Check out the size (and specifically the mass) of Apophis. Then do some rough back-of-the-envelope calcs about the stuff you're suggesting.

(Hint: Apophis is estimated to have roughly 10000 times the mass of a modern day aircraft carrier...Neeeeo. We're not gonna move this to Mars, to the Moon, or anywhere else with an 'engine not that big'. We're not gonna impress this sucker - even with a nuke. Or 10. Or 100.)
StudentofSpiritualTeaching
not rated yet Aug 19, 2017
The calculations for 2029 and 2036 are false. They will be corrected in the coming years. Get ready for the panic when that happens, as it will predict an impact in Europe. And on the means for interfering: an atomic explosion close enough for changing the trajectory but not to break the object apart.
eachus
not rated yet Aug 24, 2017
(Hint: Apophis is estimated to have roughly 10000 times the mass of a modern day aircraft carrier...Neeeeo. We're not gonna move this to Mars, to the Moon, or anywhere else with an 'engine not that big'. We're not gonna impress this sucker - even with a nuke. Or 10. Or 100.)


Hint: Changing the orbit of Apophis slightly when it is deep in the Earth's gravitational field amplifies the effect. Changing Apophis' momentum/velocity vector slightly can send it deep into the Earth's gravitational field in the future. There are a few hundred tons of otherwise dead or obsolete satellites in geosynch orbit that can be easily (in terms of delta-v) placed where they will be struck by Apophis. You get much more delta-v than from flying an engine to Apophis. Do the math.

As for making Apophis a joint satellite of Earth and Mars, you again get to play with gravitational fields doing most of the work. (I call these dynamic orbits.) Well, computers do a lot of the work as well.
rrwillsj
1 / 5 (1) Oct 10, 2017
Oh yeah! Let the monkeys nero-ically fiddle with the orbits of mega-tonnage of unstable amalgamations of rocks and ices.

Utilizing Coyote's Mail-Ordered, patented Acme Miracle Rocketry.

After all, that worked out so well for the dinosaurs!! Huh, huh, Am I right or am I right?

"Is there any disaster so stupid as a self-inflicted catastrophe?"

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