No Need To Get Bent Out Of Shape Over Asteroid 2011 AG5

Near-Earth asteroid 2011 AG5's orbit takes it out beyond Mars and as close as halfway between the Earth and Venus. It may have a close brush with Earth on February 5, 2040. Credit: NASA/JPL/my own additions

A recently discovered asteroid may approach Earth closely in 2040, but it’s extremely unlikely that it will crash and wreak havoc.

Asteroid 2011 AG5 was discovered on January 8, 2011 by the Mt. Lemmon Survey using at the University of Arizona’s Steward Observatory in the Catalina Mountains north of Tucson. Mt. Lemmon is one of three surveys that participate in the Catalina Sky Survey, charged by Congress to inventory 90 percent or better of all near-Earth objects (NEOs) 459 feet wide (140 meters) or larger. These are the ones that could cause potential destruction should one come crashing down.

At around 460 feet across, 2011 AG5 just makes the cut as a potentially hazardous object. As of February 21, 2012, 8751 Near-Earth asteroids have been discovered. Some 839 of these NEOs have a diameter of approximately 0.6 miles (1 km) or larger. 1290 of the NEOs have been classified as Potentially Hazardous Asteroids. These are the ones whose orbits intersect Earth’s at distances of 4.65 million miles or less and measure 360 feet (110 meters) or larger across.

This radar image of asteroid 2005 YU55 was obtained on Nov. 7, 2011, when the space rock was at 3.6 lunar distances or about 860,000 miles from Earth. Click image to learn more about NEOs. Credit: NASA/JPL-CalTech

It takes many observations to derive a highly accurate orbit for a newly-discovered asteroid or comet. Since nobody can see 2011 AG5 right now because it’s in the daytime sky, we’ll have to wait until it’s better placed in September 2013.

Then astronomers can make more observations to refine the object’s orbit, so we’ll have a better idea of its future travels.

Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif., says that it’s extremely rare for a near-Earth asteroid to impact Earth. 2011 AG5’s next near pass happens in February 2023 (1.2 million miles) and again in 2028 at 12.8 million miles. Earth’s gravitational attraction on the asteroid during these upcoming passes could potentially send it on a collision course with our planet on February 5, 2040, but the odds are quite small this will happen: only a 1-in-625 chance. That works out to piddling 0.16 percent. Yeomans fully expects the odds to drop even more once the orbit is refined.

Pictures of all the asteroids and comets (lower right) we've visited and photographed with spacecraft through June 2010. Click for a large version. Credit: See below

On the Torino Impact Hazard Scale, 2011 AG5 rates only a “1”, defined as:

“A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0.”

With that, I’d say there’s no reason to sell your house or blow all your money. Sounds like we’ll all be around for a while longer.

(Credits for asteroid/comet montage: Montage by Emily Lakdawalla. Ida, Dactyl, Braille, Annefrank, Gaspra, Borrelly: NASA / JPL / Ted Stryk. Steins: ESA / OSIRIS team. Eros: NASA / JHUAPL. Itokawa: ISAS / JAXA / Emily Lakdawalla. Mathilde: NASA / JHUAPL / Ted Stryk. Lutetia: ESA / OSIRIS team / Emily Lakdawalla. Halley:: Russian Academy of Sciences / Ted Stryk. Tempel 1: NASA / JPL / UMD. Wild 2: NASA / JPL)

10 Responses

    1. astrobob

      Thanks for your question. No, the object I wrote about was 2011 AG5, a different asteroid. The blog in the link you provided is totally overblown. This object has zero chance of hitting Earth. It rates a “O” on the Torino scale (no impact possible) and a -4 on the Palermo scale (no consequences).Please check out this more responsible link if you’d like more information:

      1. jessie leigh

        thank you! so this article was basically garbage? I didn’t understand when it was talking about painting the comet.

        1. astrobob

          Hi again Jessie,
          Well, the part about it likely hitting Earth is. It will come close though – 17,000 miles I hear. That’s not quite as close as last June’s 2011 MD but still a close shave. I don’t know how you’d paint an asteroid exactly, but changing its color, say to black, would alter how it absorbs sunlight and therefore its spin.

  1. Kevin

    Hi Bob,

    Great blog, thanks for keeping all of us laymen educated.
    I have a question about 2012 DA14. I understand that this asteroids orbit is similar to earths only inclined somewhat and it comes relatively close to us twice a year or crosses our path. Why is it that the discovery of next years close approach only made in February of this year? Did this rock just recently enter this specific orbit or has it been there for millenia and different unknown factors such as gravity and random deflections make any long term estimates impossible.

    Thank You

    1. astrobob

      Great question Kevin. 2012DA14 was only discovered in Feb. this year. For all we know, it made close approaches in the more distant past. Astronomers are still working out a more accurate orbit, but no doubt it’s been looping around the neighborhood for a long,long time. It was not discovered sooner because it’s so small and faint. No doubt there are others out there right now like this one waiting to be found.

      1. Kevin

        Thanks Bob, I find it fascinating and at the same time daunting that we even exist in this cosmic pinball machine. It’s amazing we’ve made it this far. It seems like our technology is just about on the threshold of being able to eradicate a threat like this, if our luck holds out for another hundred years or so.

        1. astrobob

          Well said, Kevin. I’m amazed, too. Thankfully the solar system has cleaned up its act since the early days. Can you imagine how it must have been a few billion years back when there was so much more material careening around?

          1. Kevin

            I read somewhere that if you could erase the effects of erosion over time impact craters would be everywhere. You can’t help but wonder that the very thing that could wipe us out now, a large asteroid hit, may have played an integral role in where we are today.

          2. astrobob

            Yes, thanks to erosion and plate tectonics, we’ve only identified about 175 craters to date on Earth. And given the best bet scenario of an asteroid hit either accelerating or causing the extinction of the dinosaurs – while our mammal ancestors made it through – asteroids have had and will continue to have significant “impacts” on Earth’s history and its life.

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