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Big Asteroid (With Its Own Moon) To Have Closest Approach With Earth Today

An anonymous reader writes "Asteroid 1998 QE2 has an estimated diameter of 2.7 km. This asteroid will have a close approach with Earth at about 15.2 LD (Lunar Distances = ~384,000 kilometers) or 0.0392 AU (1 AU = ~150 million kilometers) at 2059 UT on 2013 May 31 and it will reach the peak magnitude ~10.8 on May 31 around 2300 UT." Radar images of the asteroid taken Wednesday show that 1998 QE2 has its own tiny moon, about 600 meters wide. Phil Plait explained how the images were taken, and what further information we gleaned from them. 'The very presence of the moon is a good thing. By measuring how long it takes to go around the primary, the mass of the primary can be found using math known for centuries (the more massive the big asteroid, the faster the moon will go around it at a given distance). We also know the size of the primary, so that means we can find its density, and therefore what it’s made of (probably mostly rock).'

41 of 87 comments (clear)

  1. Thats no moon... by Anonymous Coward · · Score: 4, Funny

    It's a space station!

    1. Re:Thats no moon... by fishbonz · · Score: 1

      Thats no moon

    2. Re:Thats no moon... by Striikerr · · Score: 2

      I sense something.. a joke I have not heard since... a few days ago...

    3. Re:Thats no moon... by Anonymous Coward · · Score: 2, Funny

      It's all fun and games until this thing slams into Uranus next year.

    4. Re:Thats no moon... by Tablizer · · Score: 2

      with its baby space-station. How cute!

    5. Re:Thats no moon... by MrKaos · · Score: 1

      I sense something.. a joke I have not heard since... a few days ago...

      Like millions nerds all went "uuuurrrrrrhhhhhh", and were suddenly silenced.

      --
      My ism, it's full of beliefs.
  2. Yo dawg I heard you like asteroids by GameboyRMH · · Score: 4, Funny

    So I put an asteroid on your asteroid, so you can watch a flyby while you're watchin' a flyby!

    --
    "When information is power, privacy is freedom" - Jah-Wren Ryel
  3. Well by Antipater · · Score: 4, Funny

    (probably mostly rock).

    At least it's not some kind of smooth alternative. But I was hoping for something heavier, maybe with metal influences.

    --
    Everything is better with chainsaws.
    1. Re:Well by aliquis · · Score: 1

      Read with stereotypical (?) japanese advertising voice:
      "Happy hardcore asteroida!"

      Jazz/whatevermusicstylecannabissmokersenjoy asteroid.

      "The asteroid appear to be chipping ..."! ;D

      Start worry at imperial march.

  4. Any luck... by Arkh89 · · Score: 1

    ... that the tidal gravitational wave of Earth/Moon will disrupt the small couple?

    1. Re:Any luck... by jeffmeden · · Score: 2

      ... that the tidal gravitational wave of Earth/Moon will disrupt the small couple?

      Shut it... You just gave Michael Bay a terrible idea for a disaster movie.

    2. Re:Any luck... by cusco · · Score: 3, Insightful

      No, not much chance of that. Gravity, like other forms of energy, falls off according to the inverse square rule. If object B is twice as far away as object A it is only attracted at 1/4 (1/2^2) the force. Object C is five times further away as Object A, only gets attracted 1/25th as much (1/5^2). These are far enough away that their mutual gravity is a much stronger force than that of the Earth/Moon system, so our gravity applies effectively equal force on both objects. Clear as mud?

      --
      "Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin
    3. Re:Any luck... by Arkh89 · · Score: 1

      Nope that's clear. Although, I wouldn't expect it to crash on my house but rather I should re-phrase : is it possible to see a change in the elliptic trajectory while it is passing next to us?

    4. Re:Any luck... by CrimsonAvenger · · Score: 1

      Well, you really need to replace "force" with "acceleration" in your explanation. Because if "our gravity applies effectively equal force on both objects", then the smaller object is going to accelerate away from the larger object quite nicely...

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
  5. Your asteroid is so fat... by GodfatherofSoul · · Score: 1

    It's got another asteroid orbiting it

    --
    I swear to God...I swear to God! That is NOT how you treat your human!
  6. Intellible units... by taiwanjohn · · Score: 3, Informative

    15.2 LD (Lunar Distances = ~384,000 kilometers) or 0.0392 AU (1 AU = ~150 million kilometers)

    Or maybe we could just say "around four million miles" and be done with it. Add in the metric conversion if you want, but really, do we need an explication of "AU" and "LD" for this story? Just convert it to human readable format. It's one of those things that "journalists" do...

    --
    XML is like violence. If it doesn't solve your problem, you're not using enough of it. --AC
    1. Re:Intellible units... by nielsm · · Score: 1

      On the other hand, the comparison to the Moon's distance is useful. "It's more than 15 times further away than the moon" gives a good point of comparison. It certainly makes it clearer to me that there's no risk it will hit anything we should care about.

    2. Re:Intellible units... by camperdave · · Score: 1

      How many Rhode Islands is that?

      It depends on how big they are, but offhand, I'd say a lot.

      --
      When our name is on the back of your car, we're behind you all the way!
    3. Re:Intellible units... by gmuslera · · Score: 3, Insightful

      Scientific units are basically metric, those are the intellible units, not the arbitrary cultural ones that are used just for 3 or 4 countries in all the world. And putting the distance in lunar distances (or, maybe, Earth diameters that are around 12000km) puts in the right perspective how far they will be and how little we should worry about them, at least this pass (should you worry about a collision if a grain of sand passes 1km away from you at the closest point?)

    4. Re:Intellible units... by gv250 · · Score: 1

      A Rhode Island is a unit of area. You're looking for football fields.

    5. Re:Intellible units... by invid · · Score: 1

      AU is fairly common when discussing distances within a solar system. If you play Eve Online it is a unit of measure you are familiar with. If the asteroid was tree shaped it would be really familiar to an Eve player.

      --
      The Moore-Murphy Law: The number of things that will go wrong will double every 2 years.
    6. Re:Intellible units... by taiwanjohn · · Score: 1

      I agree, but I would have said "Around four million miles (roughly 15 times as far as the moon)".

      I'm "geeky" enough to know that one "LD" is about a quarter-million miles, but most people don't know that. And even I don't want to get the info in those units. It's just awkward.

      PS: BTW, I seem to be missing a "gi" in my subject line... I meant to say "intelligible", not intellible. ;-)

      --
      XML is like violence. If it doesn't solve your problem, you're not using enough of it. --AC
    7. Re:Intellible units... by taiwanjohn · · Score: 1

      I'm quite familiar with the "AU" unit. But it's not a very useful measure to most folks when the value is 0.0392. Might as well measure it in rods or furlongs or cubits...

      --
      XML is like violence. If it doesn't solve your problem, you're not using enough of it. --AC
    8. Re:Intellible units... by Coren22 · · Score: 1

      I was expecting to find that the item orbiting the asteroid would be tree shaped perhaps. That would be a great find :)

      I want my Archon :)

      --
      APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
    9. Re:Intellible units... by gmuslera · · Score: 2

      The "base" unit, i.e. the meter, is arbitrary. What is not arbitrary are the proportions between different escales on the same dimension. Just power of ten converts between different ways to measure lenght, as opposed as the extra arbitrary requirements that are conversion between inches, feets, miles, yards, and so on. And it scales to other dimensions too, like volume (1 lt=a cube of 10 cubic cm), weight (1kg=the weight 1 lt of water at 0C, etc), and more, not extra arbitraty measures like gallon, pint, acres, ounces or pounds. Take 1 arbitraty unit, and some very universal element (water) and you have enough to know how much is a lot of units. But for imperials most of those are arbitrary (and by now, the "right" definition of most of them is be done relative to metric).

    10. Re:Intellible units... by __aaltlg1547 · · Score: 1

      For people who don't already know those things off the top of their heads, it gives them a sense of scale.

  7. Re:Well, the "moon" is reflective by NReitzel · · Score: 2

    Gee, that moon sure is reflective of radar. Almost like it was specular and made of metal.

    --

    Don't take life too seriously; it isn't permanent.

  8. And are we dropping another rock on Russia? by tekrat · · Score: 1

    During the last asteroid flyby there was a coincidental meteor explosion in the former Soviet Union, caught by hundreds of in-car dash cameras... SAME DAY...

    So, I would assume that this flyby should also have an associated and completely unexpected rock from space approaching from the opposite direction and oh, I dunno, wipe out Paris?

    I mean, destruction of a major city from space would be horrific and all, but I can't imagine anything joining the world together in unity to create a real space defense (and get us out there and off this rock) than a few million people getting killed at once.

    --
    If telephones are outlawed, then only outlaws will have telephones.
    1. Re:And are we dropping another rock on Russia? by VortexCortex · · Score: 2

      I can't imagine anything joining the world together in unity to create a real space defense (and get us out there and off this rock) than a few million people getting killed at once.

      You missed the memo. It was in the We The Geeks NASA G+ hangout today. Some folks actually care about the issue enough to put their money and time where their mouth is and thus are actually doing what you propose.

    2. Re:And are we dropping another rock on Russia? by jalet · · Score: 1

      How much is this in kilograms ?

      --
      Votez ecolo : Chiez dans l'urne !
    3. Re:And are we dropping another rock on Russia? by stjobe · · Score: 1

      You missed the memo. It was in the We The Geeks NASA G+ hangout today. Some folks actually care about the issue enough to put their money and time where their mouth is and thus are actually doing what you propose.

      Thank you for that link!

      That Hangout was surprisingly informative, and the panel was excellent; not a dud in there:
      Lori Garver, Deputy Administrator, NASA
      Bill Nye, Executive Director, Planetary Society
      Ed Lu, former astronaut and CEO, B612 Foundation
      Peter Diamandis, Co-Founder and Co-Chairman, Planetary Resources
      Jose Luis Galache, Astronomer at the International Astronomical Union’s Minor Planet Center

      --
      "Total destruction the only solution" - Bob Marley
  9. Ouch by quax · · Score: 1

    That's one mofo of a planet killer sized asteroid.

    1. Re:Ouch by iggymanz · · Score: 1

      not really, it would "kill the humans" but not all life. Earth took a 10km asteroid back in the day 65 million years ago and it caused mass extinctions, but still not complete obliteration of the biosphere.

    2. Re:Ouch by quax · · Score: 1

      Yeah, I am just anthropocentric like that.

    3. Re:Ouch by iggymanz · · Score: 1

      good news for you then, some humans are predicted to survive an impact even of asteroids twice the diameter of this article's one though most would die. Taking a philosophical view, something would "evolute" to take man's place even if all humans wiped out, so why not just care as much about the next kind of people as human ones? I don't see any reason to care more about future humans I''ll never meet as some other kind of people-creature.

    4. Re:Ouch by quax · · Score: 1

      You must not have kids.

    5. Re:Ouch by iggymanz · · Score: 1

      yes I do

      so your telling me you deeply care about your great-great-(twenty times) grandchildren? bullshit. you'll never know them, they're total strangers.

    6. Re:Ouch by quax · · Score: 1

      You only care about people you know personally?

    7. Re:Ouch by booch · · Score: 1

      so your telling me you deeply care about your great-great-(twenty times) grandchildren?

      Of course I care about them. Why else would I need my copyright to last so long?

      --
      Software sucks. Open Source sucks less.
  10. Oh my God, I want one by __aaltlg1547 · · Score: 2

    How cool is this. 1.7 miles of orbiting rock. Let's capture that sucker and bring it where we can use it.

  11. Asteroid "QE2" by markdowling · · Score: 1

    I'm guessing the "moon" is called Philip?