Asteroid Close Calls

November 21, 2021 7:12 AM

Under the right circumstances, asteroids just 20 meters wide can destroy a city. So far, humans have discovered 266 asteroids with possible diameters of this size that have passed or will pass closer to Earth than the Moon. This chart shows each flyby at its relative distance from Earth.
posted by curious nu (51 comments total)

Promises, promises.
posted by Kitteh at 7:21 AM on November 21, 2021 [18 favorites]

Neat visualization! Asteroids are sublime.
posted by Don.Kinsayder at 7:26 AM on November 21, 2021

And with DART we'll learn how to pick which city. Launched by everyone's favorite super villain.
posted by sammyo at 7:37 AM on November 21, 2021 [1 favorite]

And with DART we'll learn how to pick which city.

Specifically, None Of The Above.
posted by zamboni at 8:10 AM on November 21, 2021 [3 favorites]

Perfect timing for the release of this new film. If the end of civilization comes in the form of a space rock, we'll monetize every moment of it. :-p
posted by johnxlibris at 8:10 AM on November 21, 2021 [5 favorites]

Okay, but I will be seeing that movie.
posted by Don.Kinsayder at 8:27 AM on November 21, 2021 [1 favorite]

This is the list that tabloids use to print their "ASTEROID THREATENS EARTH" headlines, I think they've got them automated at this point
posted by BungaDunga at 8:28 AM on November 21, 2021

Is there a way to train one on Mar-a-lago?
Asking for all humanity.
posted by BostonTerrier at 8:35 AM on November 21, 2021 [12 favorites]

One should bear in mind that every planet in the solar system could fit in between the Earth and the Moon, if they were lined up together.

It’s a long way to the Moon.
posted by vitout at 8:37 AM on November 21, 2021 [13 favorites]

One should bear in mind that every planet in the solar system could fit in between the Earth and the Moon, if they were lined up together.

Maybe even a bit more, if the earth was really relaxed...
posted by Insert Clever Name Here at 8:48 AM on November 21, 2021 [13 favorites]

> One should bear in mind that every planet in the solar system could fit in between the Earth and the Moon, if they were lined up together.

Another Interesting Fact: This would destroy the Earth (and Moon).
posted by Godspeed.You!Black.Emperor.Penguin at 8:51 AM on November 21, 2021 [9 favorites]

Destroy a city? Child's play. We've got ambitious people working on destroying the entire planet.
posted by chasing at 9:08 AM on November 21, 2021 [5 favorites]

On the other hand imagine cruising along in your 747 and having a 340m rock pass by underneath you.
posted by Mitheral at 9:13 AM on November 21, 2021 [7 favorites]

I’m really enjoying the amazing science facts and the bleak/bawdy jokes. If we can keep both going, this will be my favorite thread ever.
posted by Don.Kinsayder at 9:22 AM on November 21, 2021 [1 favorite]

I can’t help but notice that a 300+ meter asteroid, ominously named Apophis, will be passing within 50,000 km of Earth in 2009.

On a cosmological scale, that’s really, really close. I wonder just how much of a gravitational perturbation it would require now to deviate it’s flight path by 50,000km seven years from now. Which then led me to this:

Possible Apophis Impact in 2068?

In April 2029, the asteroid 99942 Apophis will make a near-flyby of just 19,820 miles above the Earth's surface---slightly farther away than asteroid DA14 did in February 2013. The Earth's gravity will deflect Apophis' path by a such large amount that there was initially a possibility the asteroid could impact the Earth in 2036 because of the uncertainties in the measurements of Apophis' position and motions. Recent very careful observations with telescopes and radar have greatly fine-tuned our knowledge of Apophis' orbit and its rotational motion, so that there is essentially NO chance of a 2036 impact. A possible impact a few decades later in 2068 is the most likely now but that chance is just 2.3 in a million---still a very small chance. At 1070 feet in size, Apophis is about seven times bigger than DA14, so if it is made out of the same stuff as DA14 (primarily stone), Apophis would hit with about 360 times bigger punch than DA14 or about 860 megatons of TNT, assuming the speeds are the same. To see the effects of such a hit, go to the Killer Asteroids website and find out the effects from its impact calculator.

I just used that site to model an Apophis impact on Phoenix, AZ (asteroid, medium size), and the results were…not pretty. Steel buildings knocked down from one side of our metropolis to another (about 40 miles wide), with a heat blast igniting clothing further out to surrounding towns. But, mercifully, not an Extinction Level Event. (Unless you happen to be in Phoenix at the time.)
posted by darkstar at 9:47 AM on November 21, 2021 [2 favorites]

darkstar: "I can’t help but notice that a 300+ meter asteroid, ominously named Apophis, will be passing within 50,000 km of Earth in 2009."

Gotta say, I'm not really worried about this one.

[Also, eponysterical.]
posted by chavenet at 9:54 AM on November 21, 2021 [10 favorites]

On the other hand imagine cruising along in your 747 and having a 340m rock pass by underneath you.

I suppose my reaction would depend on whether I just departed the soon-to-be-vaporized city or on final approach.
posted by Thorzdad at 9:55 AM on November 21, 2021 [1 favorite]

Thorzdad: "On the other hand imagine cruising along in your 747 and having a 340m rock pass by underneath you.

I suppose my reaction would depend on whether I just departed the soon-to-be-vaporized city or on final approach."

I would probably still be wondering just how it happened that I bought a 747
posted by chavenet at 9:56 AM on November 21, 2021 [16 favorites]

LOL! Yes, that should be 2029. :)

More here on Apophis from NASA.
posted by darkstar at 9:56 AM on November 21, 2021 [2 favorites]

In case anyone hasn’t seen Scot Manley's Asteroid Discovery series this one, with the original explanatory dialogue is my favourite. Wonderfully chilling and best viewed full screen in the highest resolution you can manage. (There's a later 8k version as well but it lacks the narration)
posted by brachiopod at 9:57 AM on November 21, 2021

Under the right circumstances, asteroids just 20 meters wide can destroy a city.

If used properly, nuclear weapons can destroy life on earth.
posted by ricochet biscuit at 9:58 AM on November 21, 2021 [4 favorites]

Despite teh lolz, once again, a criminal indictment of our culture's priorities. Mature sentient cultures would have insurance for rare, devastating, but almost inevitable large events if it was cheap . We could make such insurance cheap but we choose not to.

Some of the only people working on it are the B612 foundation
posted by lalochezia at 10:15 AM on November 21, 2021

Really, really, want a giant hi-res poster of all these death rocks.
posted by sammyo at 10:21 AM on November 21, 2021 [4 favorites]

But if the chart in the previous comment looks really dense, remember just pick two asteroids right next to each other and the time from one to the next with the fastest spaceship we could possibly build would be many months. That chart really needs a "not to scale" disclaimer. ;-)
posted by sammyo at 10:27 AM on November 21, 2021

Despite teh lolz, once again, a criminal indictment of our culture's priorities. Mature sentient cultures would have insurance for rare, devastating, but almost inevitable large events if it was cheap.

You assume the human race is mature. Please cite.
posted by Thorzdad at 10:28 AM on November 21, 2021 [3 favorites]

It’s a long way to the Moon.

That was my initial response. I was a little bit surprised to realize that, as rendered on my browser at least, the scale of the diameter of the Earth and Moon are only exaggerated by a factor of 2.5 and 3, respectively, compared to the labeled axis. That is still an odd choice, but a lot closer than I was expecting. Finding the nearest ones a bit unsettling doesn't seem unreasonable. It's only 60 Earth radii to the moon. (Which is human-scale in a way that is pretty neat.)
posted by eotvos at 11:05 AM on November 21, 2021 [1 favorite]

Just to say, I worked on the avionics for DART. I'm very excited to see it so its thing!

DART's first launch attempt comes this Wednesday (the day before Thanksgiving 2021.) I'll stop back here and post more info on how to view it live, when I find out.

This is one of my favorite videos about DART:
https://www.freethink.com/shows/guardians-of-the-apocalypse/asteroid-headed-for-earth
posted by newdaddy at 11:16 AM on November 21, 2021 [26 favorites]

Neil deGrasse Tyson: "Asteroids are nature's way of asking: 'How's that space program coming along?'"
posted by doctornemo at 12:32 PM on November 21, 2021 [9 favorites]

newdaddy, thank you on behalf of the human race!
posted by doctornemo at 12:32 PM on November 21, 2021 [1 favorite]

I would probably still be wondering just how it happened that I bought a 747

And you may find yourself in another part of the world
And you may find yourself behind the wheel of a large aeroplane
And you may find yourself in a beautiful house, with a beautiful wife
And you may ask yourself, "Well, how did I get here?"
posted by thecincinnatikid at 12:35 PM on November 21, 2021 [10 favorites]

So cool that we have an actual rocket scientist here!

So to watch the DART launch, one option, the spacex stream usually starts 10-15 minutes prior to the final countdown so 10:10PM PST this wednesday at spacex.com.

newdaddy: any personal observations about DART or spaceflight in general would be welcomed by many of us.
posted by sammyo at 12:44 PM on November 21, 2021 [2 favorites]

In April 2029, the asteroid 99942 Apophis will make a near-flyby of just 19,820 miles above the Earth's surface...

Wasn't Apophis taken care of by SG*1 back in 2001?
posted by Insert Clever Name Here at 1:42 PM on November 21, 2021 [6 favorites]

God does not play dice. But she loves bowling.
posted by credulous at 2:41 PM on November 21, 2021 [7 favorites]

"Pounded by hard projectiles" is very much the venn diagram intersection of asteroid strikes and Chuck Tingle literature.
posted by Wordshore at 2:42 PM on November 21, 2021 [16 favorites]

Obligatory.
posted by The Ardship of Cambry at 2:42 PM on November 21, 2021

A steroid threatens earth: testosterone.
posted by dances_with_sneetches at 3:01 PM on November 21, 2021 [6 favorites]

I'm banking on it coming before / my end of year exams
posted by Fiasco da Gama at 4:05 PM on November 21, 2021 [3 favorites]

It’s a long way to the Moon.

Yet the entire orbit of the moon fits easily inside the sun.
posted by sjswitzer at 6:18 PM on November 21, 2021 [2 favorites]

every planet in the solar system could fit in between the Earth and the Moon

As an orbits guy, I've got to correct this with a little technicality that only makes it half true/sometimes true. Welcome to Stampytown.

The diameters of the planets (miles):
Jupiter - 86881
Saturn - 72367
Uranus - 31518
Neptune - 30599
Venus - 7520
Mars - 4512
Mercury - 3031
TOTAL: 236,530mi

Earth radius: 3958mi
Moon radius: 1079mi
TOTAL SPACE NEEDED: 241,567mi

Distance between Earth center and moon center: 239,000mi (mean)

So you could stick the planets between the mass centers of the two, but not between the two "on average" (geometrically).

BUT! At their farthest separation, you could do it! Then you get something like 251,000mi to work with, which is plenty of space and you could even shove in a Galilean moon or two. Instantly collapsing the entire system in the process, but, you know, you still could.

For the completists out there: the true anomaly where you run out of space for the planets is about 95 deg on either side of perigee, which - by my quick calculation that might be full of small errors - puts the time of being in this region at just over half the orbit period, though geometrically it's less than half the ellipse. (Orbital motion is weird.)

In conclusion, sometimes - or maybe even most of the time - every planet in the Solar System could fit between the earth and the moon.

Space is still big. Really big.

Thank you for attending my conference presentation on how to ruin a planetary system.
posted by ptfe at 7:26 PM on November 21, 2021 [28 favorites]

It's interesting that there are thirteen asteroids from 30,745 to twice that, but none below 30,745. I suppose it's mostly just a matter of the increase in volume of spheres, but if my math was right I'd still expect to see a couple.
posted by tavella at 8:18 PM on November 21, 2021

It's interesting that there are thirteen asteroids from 30,745 to twice that, but none below 30,745.

Maybe it's because smaller ones aren't included in this list.
Just two months ago there was a small one (3.5m) which travelled 15,340 km from the surface of Earth. It probably would have burned up if it hit the atmosphere. Still that's less then half of the altitude of geosynchronous satellites.
posted by eye of newt at 1:28 AM on November 22, 2021

I would prefer if this visualization showed the meteorite that exploded over Chelyabinsk in 2013 as a line grazing Earth’s surface. (Or was that one too small for this data set?)
posted by fantabulous timewaster at 7:25 AM on November 22, 2021

Out of date, but with a minor correction...
posted by Halloween Jack at 8:33 AM on November 22, 2021

It's a long way to the Moon.

God does not play dice. But she loves bowling.

It's a Long Way to the Moon (If You Wanna Rock 'n' Roll)
posted by indexy at 8:47 AM on November 22, 2021 [1 favorite]

Check this back of the envelope cross section analysis!

So it is about 60 earth radii to the moon as mentioned above, or 60 earth diameters across the orbit of the moon. 266 asteroids in the chart look uniformly distributed across that distance, and lets assume that's a uniform distribution across the whole cross section of the moon's orbit. That means if you drop the earth randomly on the big disk marked out by the moons orbit you cover about 1/3600 of the disk, and that would cover about 0.07 asteroids, in the time span shown of 240 years or so.

Looks like we need about 14*240 = 3360 years to see our expectation of a hit approach 1.
posted by TreeRooster at 11:56 AM on November 22, 2021 [3 favorites]

Everyone And Everything Is Doomed, Part 19: Death From Space
posted by JHarris at 4:17 PM on November 22, 2021

Looks like we need about 14*240 = 3360 years to see our expectation of a hit approach 1.

With the caveat that the 270 objects on the chart aren't anywhere near an exhaustive listing just the ones we know about.
posted by Mitheral at 5:48 PM on November 22, 2021

Carter: I was right.
Jackson: This could be a problem.
Teal'c: Indeed.
O'Neill: (touches his face and waves his right hand in the air slightly) I don't wanna hear it.
Carter: Sir, the asteroid's core is composed almost entirely of naquadah.
O'Neill: Of course it is.
posted by clavdivs at 6:54 PM on November 22, 2021

If used properly, nuclear weapons can destroy life on earth.

I believe that I've quoted this line on Metafilter several times.
posted by neuron at 9:56 PM on November 22, 2021

One should bear in mind that every planet in the solar system could fit in between the Earth and the Moon, if they were lined up together.

Maybe even a bit more, if the earth was really relaxed...

Wait, are we doing Uranus jokes?
posted by nickmark at 8:39 AM on November 23, 2021 [1 favorite]

Death from above: 7 unlucky tales of people killed by meteorites — Thousands of years of historical records show people are likely struck by meteorites surprisingly often., Eric Betz, Astronomy, May 28, 2020:

...Our planet is vast, so meteorites typically don’t concern us. But every once in a while, these objects actually strike humans and our property. Based purely on statistics, researchers estimate that a space rock should strike a human roughly once every nine years. And with those odds, you’d expect people to get killed by meteorites fairly often.

“I do strongly suspect that stats on ‘death by asteroid’ have been severely undercounted through human history,” NASA Planetary Defense Officer Lindley Johnson told Astronomy via email. “It’s only been in the last half century or so that we’ve even realized that such a thing could happen.”...

On November 30, 1954, Ann Hodges learned all about the astronomical odds.
posted by cenoxo at 6:56 PM on November 23, 2021