Asteroid to pass Earth harmlessly Wednesday

By Phil Plait | January 12, 2010 11:37 pm

A small (10 meter wide) asteroid will pass by the Earth Wednesday, at 12:47 UT. This tiny rock, called 2010 AL30, will pass us at a safe distance of 130,000 km (80,000 miles). As cosmic encounters go, this is a hair’s breadth, but in human terms it’s a long way off; as this graphic makes clear. It’s about a third of the way to the Moon.

2010 AL30 was only discovered on Monday. It’s escaped our previous notice because it’s dinky. Even when it passes you’ll need a telescope to see it. There has been some speculation that this was a man-made object like a rocket booster, since it’s about the right size, and sometimes near-Earth objects turn out to be space junk. But in this case the orbit doesn’t really match any rocket trajectory, so it’s probably a natural rock.

And since I know someone would ask, if this were aimed at us, it would probably explode high up in the atmosphere and not hit the ground. It would be quite a show, but most likely wouldn’t do any damage on the ground (even if it were iron, at that size it’s unlikely it would make it to the ground, and instead would tear itself to pieces on the way in).

And one last thing: note what I titled this post. Now look around the web to see how other articles are titled. Just sayin’.

Tip o’ the Whipple Shield to Mike Murray for putting that graphic together and letting me know about it.

CATEGORIZED UNDER: Astronomy, DeathfromtheSkies!

Comments (51)

  1. Eh, this time around the news media seems pretty sedate, at least as far as headlines go. The only one I see on a quick Google News search that’s particularly “OMGOMGOMG”ish is Wired, with “Earth to Get Close Shave Wednesday From Newly Discovered Asteroid” – most of the headlines are along the lines of “say hi to the visitor that’s just passing by,” or at least that’s how they come across to me.

  2. Is that really how far out satellites are? It seems to be a lot further than I’ve been led to believe before now.

  3. I love those kinds of size comparisons. You always learn something interesting, like for example, how far our satellites are.

  4. Adrian

    Awsome graph….just one thing, why does it say Wednesday, January 12, 2010?
    Is my calendar wrong?

  5. Pretty cool graph. I hadn’t realized our satellites were that far out, and I also didn’t realize how “close” Apophis was going to come.

  6. That’s Apophis’s first pass, right? It comes closer and may even hit us the second time around, which is in 2036. I guess the graphic artist didn’t want to put that on the graph.

  7. Near Misses From The Skies

    Naw, just don’t make it as a book title…….



  8. Dan

    Speaking of Apophis, and looking at the cool image, I know that it is not going to hit us on this pass but what about those satellites it will be passing under? How close it is going to get to those guys?

  9. @ GuanoLad and Unikraken: Yes, but just geosynchronous satellites, like communications and TV satellites, which are approx. 36,000 km above the surface. Many other satellites are in lower orbits, especially in Low Earth Orbit (LEO), between 160 and 2,000 km above the surface. ISS and Space Shuttle missions, for example, are always in LEO. GPS satellites, on the other hand, are somewhat higher, in Medium Earth Orbits (MEO), around 20,000 km.

  10. Hedgie

    Awesome graphic 😀

    I too wonder about the poor satellites in the green band, and the ones muddled up in that area between us and said green band.

  11. I hope I will remember this and will be able to see it (no many damn trees).

  12. Tim

    How might Earth/Moon gravity affect this asteroids trajectory and when will it pass us again? In other words, will it hit us next time around?

  13. Plutonium being from Pluto

    @2. GuanoLad Says:

    Is that really how far out satellites are? It seems to be a lot further than I’ve been led to believe before now.

    Well our Moon is a satellite too … a natural rather than an artificial one but nonetheless. 😉

    I second (12) Tim’s question – how will Earth’s gravity affects its orbit & wish to add two of my own :

    Is the Earth to scale in that graphic ?


    Where are the Earth’s quasi-moons eg. Cruithne on that scale / graphic?

    (See : )

    Thanks BA – interesting hadn’t heard of that. :-)

  14. SionH

    “Dinky”? Phil, don’t blind us with your astrojargon!

  15. Astronomers are unable to explain how the asteroid can have two active volcanoes, nor are they able to contact the young man in royal finery who appears to inhabit it.

  16. I’ve seen several of these charts recently that show GPS satellites at a lower orbit than a geostationary orbit. I sort of assumed GPS satellites were geostationary… don’t they have to be?

  17. Dukie1993

    AP: Mystery object to whizz by Earth Wednesday

    Six sentence article “It won’t hit our planet, but scientists are stumped by what exactly it is.”

    I came here after finding nothing at to get the real scoop.

    I concur with the praise of the graphic. Mike should send it to

  18. SionH

    Nope, GPS satellites rise and fall in the sky like anything else. It’s a real pain for us surveyors who rely on them. I frequently have to revisit an area later in the day that I couldn’t survey in the morning due to the number of satellites ‘visible’ and in a good position changing throughout the day. Winter is worst of all, here in the UK, as the Americans fight their wars in hot countries. This means the GPS constellation is clustered at lower latitudes. In midwinter you’re lucky to have them rising high enough in the sky to clear trees and buildings. Damn you America, why can’t you declare war on Finland!

  19. Brett

    Nope. As long as their software can keep track of where they are relative to the Earth, gps sats can move around. There are a ton of them up there that moving gps sats will simply shift which sats your gps is using at any one time.

  20. CW

    @ Kathy

    “That’s Apophis’s first pass, right? It comes closer and may even hit us the second time around, which is in 2036. I guess the graphic artist didn’t want to put that on the graph.”

    Not necessarily. Check this out: (and also, Phil talks about this in detail in his book).

    In order for it to hit us on the second pass, the asteroid will have to pass through what is known as the keyhole (a very narrow window, where the gravity of Earth will tug on it to put it in a trajectory that will increase the odds of a collision the second time around).

  21. Tsar Bomba


    Odd. Looks like an old-style London police box.

  22. if this were aimed at us, it would probably explode high up in the atmosphere and not hit the ground.

    True. But, what if it were aimed at the Moon? That could make a nice show.

  23. Mooney

    Had to put the Apophis drift-by on there, didn’t they? Just enough to remind me of that nagging “hey look, if we started pushing it around a few years before that, we could potentially pop it into a very useful orbit…” thought I keep having.

  24. And one last thing: note what I titled this post.

    Kind of boring, considering it could have been worded “Killer Asteroid To Miss The Earth By Mere Minutes!“. (The Earth travels 80,000 miles in just under 71 minutes. Of course, “Kill Asteroid” is a bit of a stretch.)

  25. Tom

    Sorry Phil you are completely wrong, the asteroid has already hit and we are already dead. There is nothing worse than people in denial.

  26. Trebuchet

    Nuts, I can’t see the graph here at work: “Access Denied. The external website you have requested is blocked due to inappropriate or restricted content.”

    Perhaps, Phil, you could find some way to post this other than ImageShack for us in the corporate world.

    Off Topic: On the radio on the way to work this morning, the DJ said, “Today is international skeptics day. Ehh, I don’t believe it….”

  27. @GuanoLad

    The orbits around the Earth are divided into 3 parts, inner, medium and high orbits. The inner orbit is about 190miles from the surface and that’s where the space stations and the Hubble reside along with some other satellites. The mid orbit is used for a lot of GPS satellites and the high orbit is used for satellites that require elliptical orbits around the Earth. This article most likely refers to the high orbit.

  28. Daniel J. Andrews

    Damn you America, why can’t you declare war on Finland!

    Because last time they invaded a cold northern country, they got their rears chased back south and had the White House burned down around their ears….twice. They learned their lesson and now only invade southern hot countries. :)

  29. Chris

    Let’s look at it logarithmically, then it seems close!

  30. NASA:

    Because its orbital period is nearly identical to the Earth’s one year period, some have suggested it may be a manmade rocket stage in orbit about the sun. However, this object’s orbit reaches the orbit of Venus at its closest point to the sun and nearly out to the orbit of Mars at its furthest point, crossing the Earth’s orbit at a very steep angle. This makes it very unlikely that 2010 AL30 is a rocket stage.

    Hmm… Out to Mars, back to Venus. Why couldn’t it be from a rocket used to get a probe to one of those planets?

    Anyone get some good images as it went by? I expect it to be “just a rock”, but wouldn’t it be interesting to find out otherwise?

  31. costas

    It’s a probe the Nefelim are sending before their planet enters our solar system in 2012 :p

  32. Petrolonfire

    note what I titled this post… Asteroid to pass the Earth harmlessly Wednesday

    Wait … an asteroid swallowed the Earth & now has to *pass* our planet! 😉

    How is that possible!?

    And being put through an asteroids alimentary canal is “harmless” eh? 😉

  33. Menyambal

    I caught this first on the news article linked to, and it didn’t seem very hysterical.

    But, speaking of strong words, can we come up with term instead of “explode” for those objects that dissipate all their energy of motion by fragmenting in the upper atmosphere? I have seen bad animations (the History Channel is worst), that make it look like a rock comes smoking quietly into the atmo, then goes off like a frakking nuke in the blink of an eye.

    A speeding object scattering into the air and bitch-slapping the planet without even touching the ground is just about the most amazing example of the sheer force of astronomy and physics. The word “explode” is quite lame by comparison, and quite misleading.

    I’m not faulting this articale or the assurance that if this object did hit Earth it wouldn’t hit the ground. I’m just hoping that the great Phill can come up with a more earth-shaking term for that flavor of possible death from the sky.

    “Atmo-slap”, maybe?

  34. Dan I.

    @ 17 SionH.

    “Damn you America, why can’t you declare war on Finland!”

    We’re getting there, we’re getting there, give us some time…the Army is only so big you know.

  35. ND

    Does Finland have oil?

  36. Lyr

    I was just about to say they have no oil, so they’re safe.

  37. @15

    The astronomers could say, however, that the asteroid appears to be devoid of baobab trees.

  38. Oh my god we’re all going to die aiiiieeeee!!!

  39. !AstralProjectile

    16: GNSS (GPS,GLONASS,Gallileo) sats can’t be in GSO, or you couldn’t trilateralize on them effectivly.

    I thought all survey grade receivers also got GLONASS. (The Russians have their sats orbit into higher latitudes, for obvious reasons.)

  40. Can’t all celestial objects just get along?!

  41. Arthur Maruyama

    Speculation here:
    that 2010 AL30 may be the “the Fregat upper stage from the Soyuz launcher used for Venus Express” launched in November 2005.

  42. mike burkhart

    Well good it wount hit the Earth but I woun’t be able to see it

  43. Ubermoogle

    Hey Phil, I’m kinda wondering why this little teeny tiny asteroids gets an article and this behemoth doesn’t even get a slight nod from @lowflyingrocks on Twitter: 169P/NEAT, ~2700000m-5900000m in diameter, just passed the Earth at 19km/s, missing by ~twenty-nine million, one hundred thousand km.

    Is that accurate? You’d think an asteroid that big would at LEAST have a Wikipedia entry. 😉

  44. Marc

    its probably an Alien wanting to take a bathroom break but his scanners see no intelligent Life on earth so he is moving on

  45. Davros

    Are we not dead yet ?

  46. StevoR

    22. Ken B Says:

    if this were aimed at us, it would probably explode high up in the atmosphere and not hit the ground. True. But, what if it were aimed at the Moon? That could make a nice show.

    I don’t think so. Sorry. :-(

    Why? Well its a very small asteroid – perhaps ‘meteroid’ would be a better word for it – and so it likely wouldn’t make a very big bang or kick up much of an impact plume. There’d probably just be a very brief flash and a very small crater over in less than an eyeblink. No atmosphere (not much anyhow) so no “shooting star” trail either.

    Remember the lack of sensation & bright plume with the LCROSS impact earlier this year? How big was the LCROSS impactor again – bigger than this? About the same? I reckon it’d just be like that if it was a lunar impact for 2010 AL30.

    @ 48. Davros Says:

    Are we not dead yet?

    Can you not tell the difference there for yourself, Davros?

    If we were dead would we know it? 😉

    Besides this flyby is due on Weds. at 12:47 UT. (Universal Time) – not exactly sure where that puts it in either US or Aussie time – & today is Thurs.14th Jan. 4.12 pm where I am (Adelaide, South Oz.) So I’m thinking it has probably been and gone already. Anyone get any images or latest news on it?

  47. Messier Tidy Upper

    Now we’re definitely NOT dead and it has indeed flown by harmlessly. :-)

    Looks like it could be the booster for the Venus Express spaceprobe.

    For the latest news on this via the BA blog see :

  48. Messier Tidy Upper

    Apparently its NOT the Venus Express booster after all. The Minor Planet centre folks seem to be pretty sure its just a small meteoroid & they’re the experts on this.

    See the thread linked above (50) – & thanks awesomekip. :-)


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