Join 3,561 readers in helping fund MetaFilter (Hide)


Strike One for Comet Apophis
January 10, 2013 11:22 PM   Subscribe

Comet Apophis flew to within 9 million miles of the Earth yesterday. In 2029 it will come around again and get within 20,000 miles (closer than geosynchronous satellites). Then in 2036 it will approach again. At one time it was thought that it had a 3.5% chance flying through a specific keyhole of space in 2029, which would indicate that it would hit the Earth in 2036. But now the odds are calculated to be infinitesimal. Let's hope the astronomer assumptions are correct about that pesky Yarkovsky Effect.

The Russians want to put a beacon on the comet.

Next month a smaller comet comes within 21,000 miles. And in late 2013, astronomers are promising a visible comet, ISON, possibly brighter than the moon.
posted by eye of newt (32 comments total) 11 users marked this as a favorite

 
Apophis and 2012 DA14 are asteroids, not comets. It's a shame, really, because the light show would have been spectacular.
posted by Joe in Australia at 11:41 PM on January 10, 2013 [1 favorite]


i saw this film

first we'll try to blow it up in space with some nuclear bombs

and then a part of it will fracture off and hit earth anyways but some people running up a hill will survive the mega-tsunami that turns NYC into Waterworld (again)

that really really wasn't a good movie
posted by ninjew at 11:55 PM on January 10, 2013 [4 favorites]


"first we'll try to blow it up in space with some nuclear bombs"

If this comet were indeed a problem, this would be a pretty spectacular but pretty stupid idea if only because of exactly what happened next as well as all of the people who saw the explosion and then looked at it. If this were something we actually had to address, the smart move would be to put something about the size of an especially heavy washing machine in orbit next to the comet to use gravity to slowly pull it out of the orbit that we don't want in a controlled way.
posted by Blasdelb at 12:13 AM on January 11, 2013 [1 favorite]


The NASA FAQ about Near Earth Objects is very clear. And very depressing:

How much warning will we have?

With so many of even the larger NEOs remaining undiscovered, the most likely warning today would be zero -- the first indication of a collision would be the flash of light and the shaking of the ground as it hit.


Really. The world could easily end tomorrow according to NASA. It's scientific. Think about it.
posted by twoleftfeet at 12:24 AM on January 11, 2013 [1 favorite]


Say our little planet takes a direct hit. Okey dokey. How big does an asteroid need to be to do some catastrophic damage? This asteroid has about an 1100ft (325m) diameter...before encountering atmosphere. Would that create a nuclear bomb-like incident?
We know meteoroids hit Earth regularly, but those are just dinks.
posted by artdrectr at 12:33 AM on January 11, 2013


Really. The world could easily end tomorrow according to NASA. It's scientific. Think about it.


I guess I shouldn't tell you about the possibility of a local gamma ray burst.
posted by mr_roboto at 12:34 AM on January 11, 2013 [11 favorites]


Which we also have no way of predicting. Yay.
posted by sunnichka at 12:37 AM on January 11, 2013


How big does an asteroid need to be to do some catastrophic damage?

The NASA FAQ is pretty clear about this: Above an energy of a million megatons (diameter about 2 km), an impact will produce severe environmental damage on a global scale.

NASA goes on to say there are many more smaller undiscovered NEAs, and we are likely to be hit somewhere on Earth by one of these, with an energy equivalent to a large nuclear bomb, sometime in the next couple of centuries. The last such impact was in 1908 in Tunguska ( Siberia ) with an estimated explosive energy of 15 megatons.

So it kind of depends on your definition of "catastrophic damage". It's likely that some part of the Earth will be destroyed by a huge asteroid within the next few generations. The social impact will depend on whether the hit is in a remote area like Tunguska or whether the hit is in a major metropolitan area. We can't predict where. But we can predict that within the next few millions of years here it's likely that a similar event kills complex life on this planet. That's roughtly how much time we have to grow up.
posted by twoleftfeet at 12:58 AM on January 11, 2013 [2 favorites]


Say our little planet takes a direct hit. Okey dokey. How big does an asteroid need to be to do some catastrophic damage? This asteroid has about an 1100ft (325m) diameter...before encountering atmosphere. Would that create a nuclear bomb-like incident?

Article says that at the previous size estimate of 275m it would correspond to a 500 megaton explosion; for comparison, the largest nuclear weapon ever detonated is only 57 megatons, and the bomb dropped on Hiroshima only had a yield of 16 kilotons. So it would be very bad.
posted by Pyry at 12:59 AM on January 11, 2013


The more I know about rocks flying about in the Universe, the more I realize that the Fermi Paradox isn't really a paradox.

"How come there isn't more intelligent life in the Universe?"

It's because of these bigass rocks flying around. Every so often a planet gets lucky. Hundreds of thousands of years go by. Prokaryotes become eukaryotes. Language binds animals together, and collective learning has a holiday. It's a happy moment, lasting a million years!

And then a big rock smashes up the party. Because big rocks, slow and stupid as they are, don't care how smart you are. It takes millions of years for a planet just to recognize that.
posted by twoleftfeet at 1:17 AM on January 11, 2013 [8 favorites]


And then a big rock smashes up the party.

Once upon a time, math. Will we have humanity elswhere, or will we scramble like ants?
posted by Mblue at 2:43 AM on January 11, 2013


You really can't stop the rock.
posted by colie at 3:23 AM on January 11, 2013 [5 favorites]


A quote that I've seen attributed to Neil Degrasse Tyson:

"Asteroids are nature's way of asking 'How's that space programme coming along?'"
posted by metaBugs at 4:02 AM on January 11, 2013 [23 favorites]


I guess I shouldn't tell you about the possibility of a local gamma ray burst.

On the plus side, HULK SMASH PUNY ASTEROID.
posted by Pallas Athena at 4:05 AM on January 11, 2013 [1 favorite]


And Gamma Ray Bursts are nature's way of saying "don't bother."
posted by absalom at 4:33 AM on January 11, 2013 [3 favorites]


I'm so glad they gave this thing a happy, cheery nam...oh wait, the deification of darkness and chaos?!
posted by jetlagaddict at 4:45 AM on January 11, 2013 [1 favorite]


that really really wasn't a good movie

Any movie with Keith David, Peter Stomare, Owen Wilson, Billy Bob Thornton, Ken Hudson Campbell, William Fitchner, Steve Buscemi and Michael Clark Duncan is by definition good, regardless of its content.

What would be even better is if there was a movie where they all reprised their best characters - "Unpimp Ze Auto" scientist hanging out with Mr. Pink, Louis, Animal and Slingblade... who wouldn't pay cash money to see that?
posted by Slap*Happy at 5:18 AM on January 11, 2013 [2 favorites]


Oh good, I was looking for something to add to my list of neuroses.
posted by Kitteh at 5:34 AM on January 11, 2013


Would that create a nuclear bomb-like incident?

Neil deGrasse Tyson did a talk on this that I can't find back when there was still a fair chance it'd hit the keyhole. He said he estimated that if it hit the keyhole dead center, it would plunge into the Pacific not far off tha coast of California, causing a chain of tsunamis that would basically destroy everything on the west coast of North America.
posted by middleclasstool at 6:05 AM on January 11, 2013


Every time I hear about asteroids destroying all life on Earth, my first reaction is, "At least I wouldn't have to pay my student loans anymore."
posted by lineofsight at 6:08 AM on January 11, 2013 [7 favorites]


that really really wasn't a good movie

Any movie with Keith David, Peter Stomare, Owen Wilson, Billy Bob Thornton, Ken Hudson Campbell, William Fitchner, Steve Buscemi and Michael Clark Duncan is by definition good, regardless of its content.


Ooh, no, I'm sorry. We were looking for the movie Deep Impact. Deep. Impact.
[/trebek]
posted by Etrigan at 6:18 AM on January 11, 2013 [1 favorite]


How big does an asteroid need to be to do some catastrophic damage?

A while back, posted to the blue, there was a simulation program from some university (Iowa?) where the user could input variables regarding a foreign body smashing into Earth and it would compute the damage. I thought I favorited it but I guess I didn't. Sorry.

Correction: I found it:
posted by Renoroc at 6:34 AM on January 11, 2013


http://simulator.down2earth.eu/
posted by Renoroc at 6:36 AM on January 11, 2013 [2 favorites]


I always thought Deep Impact would have been a much better movie if it started with the final scene of the speech in front of remnants of DC after the wave hit - how does a society rebuild after something that devastating?
posted by modernnomad at 6:44 AM on January 11, 2013


So nature's throwing a little chin music at the Earth. Any closer and I say we empty the dugout and rush the mound.
posted by three blind mice at 7:00 AM on January 11, 2013 [2 favorites]


I always thought Deep Impact would have been a much better movie if it started with the final scene of the speech in front of remnants of DC after the wave hit - how does a society rebuild after something that devastating?

That depends on whether there's a Democrat or Republican in office.
posted by Brandon Blatcher at 7:58 AM on January 11, 2013 [1 favorite]


Above an energy of a million megatons (diameter about 2 km), an impact will produce severe environmental damage on a global scale.

Phew, thank God that absent a 2km+ asteroid strike, we're scot-free on that whole "severe environmental damage on a global scale" thing.
posted by threeants at 9:14 AM on January 11, 2013


Do you smell what The Rock is cooking?
posted by not_on_display at 9:47 AM on January 11, 2013


jetlagaddict: I'm so glad they gave this thing a happy, cheery nam...oh wait, the deification of darkness and chaos?!
They were only indirectly referencing the Egyptian deity.
posted by ob1quixote at 9:49 AM on January 11, 2013


Odd to overlook the other potentially-impressive comet of 2013, PANSTARRS, coming in March -- though it will only approach Earth within about 1.10 AU. There aren't many years with two visible (to the naked eye) comets.

Factoid: Both ISON (C/2012 S1) and PANSTARRS (C/2011 L4) are going by these popular names in the media, but these are really the names of the discovering institutions (the International Scientific Optical Network in Russia and the Panoramic Survey Telescope and Rapid Response System, respectively). We may have reached the point where comets are all going to be discovered by Big Sky, so to speak, rather than dogged back-yard amateurs.

How big does an asteroid need to be to do some catastrophic damage? This asteroid has about an 1100ft (325m) diameter...before encountering atmosphere. Would that create a nuclear bomb-like incident?

Well, the Tunguska event is speculatively tied to an object about 100m across, and the nearby Lake Cheko -- a 50m deep lake about 700m long -- might have been formed by a fragment from that object as small as 1m across. It doesn't take much to be "catastrophic" in localized terms. Kinetic energy is a bitch. (Similarly, the International Space Station or any other spacecraft could potentially be destroyed by an impact with a piece of space junk as small as 1cm, well below what we can track.) But as noted by Tyson, an ocean impactor -- which has about a 2/3 chance of happening -- would be even worse from a civilization-affecting standpoint due to the tsunami that would be produced, and in 2004 we got a preview.
posted by dhartung at 11:42 AM on January 11, 2013 [3 favorites]


I was actually hoping that it would pass through the keyhole. The world could us an existential threat to spur reassessment of the social constructs that determine how humanity treats itself.
posted by troll at 8:42 PM on January 11, 2013


But as noted by Tyson, an ocean impactor -- which has about a 2/3 chance of happening -- would be even worse from a civilization-affecting standpoint due to the tsunami that would be produced, and in 2004 we got a preview.

For a moment I struggled to remember the Great Asteroid Impact of 2004 before I realized that you were talking about the 2004 tsunami created by an earthquake, which, of course, is a different kind of thing to worry about.

Impacts usually follow a reverse power-law distribution. For example, for meteor diameters D between 5 centimeters (2 inches) to roughly 300 meters (1,000 feet), we know that the smallest annual number N of meteor impacts on Earth obeys the power-law distribution: N = 37D-2.7. (cite) Extrapolating that model for 2000 m asteroids (NASA's "complete annihilation threshold", mentioned above), we should expect 4.5 X 10-8 life-annihilating impacts per year, or roughly one every 450,000,000 years.

This bodes well. That's a pretty long time.

But the bitch is that these reverse power laws work the other way. Sure, a really nasty life-annihilating event might only happen once every 450,000,000 years, but semi-life-annihilating events happen much more often. The number of annual impacts by 1000 m meteors should be 37*1000-2.7 = 2.9 X 10-7, or once every 29,000,000 years. And even smaller, but still dangerous, impacts should happen much more frequently. That model predicts that meteors 500 m in diameter should impact every 500,000 years or so.

People have guessed that the Tunguska event involved a meteor roughly 100 m in diameter. The same crude model predicts one such event every 10,000 years or so. And another event like that could fuck shit up if it just happens to hit the right place, like in the ocean, creating a deadly tsunami near coastal cities.

If you study these things, you get an odd mixture of terror and helplessness, combined with a probabilistic certainty that you don't need to worry about this anytime soon.

I like the way NASA's Near Earth Object thing works. Basically they admit that really bigass rocks could wipe us all out, but they're hoping this won't happen anytime soon. So they're trying to be realistic about what we can do. Maybe we can stop one of the smaller rocks from killing us all, and keep the whole show going for another one million years.
posted by twoleftfeet at 11:50 PM on January 12, 2013


« Older Space Cartoons to Space Psychedelia: How Sci-Fi Bo...  |  How to listen to the radio wit... Newer »


This thread has been archived and is closed to new comments