Observations

Asteroid 2005 YU55 to shoot by the Earth closer than the Moon on Wednesday 9 November 2011. Where and when can it be seen from Australia?

Track of YU55 on night of 9 November 2011

The position of asteroid 2005 YU55 at 9 pm AEST on 9 November 2011 as seen from Sydney with an indication of its track with respect to the stars and the Moon until dawn the next morning. Image and copyright Nick Lomb ©, all rights reserved

On the morning of Wednesday 9 November 2011 a 400-metre wide piece of space rock designated as 2005 YU55 will hurtle past the Earth at a distance that is 85 per cent of the distance of the Moon. Of course, that distance provides a sufficiently wide margin of safety that we do not need to have any concerns about our safety. Still it is of considerable interest as the only other pass we know about by an asteroid at a similar or closer distance will not occur until 2028.

As can be deduced from the designation of the asteroid, it was discovered in 2005. The discovery was made through the Spacewatch program near Tuscon, Arizona. The size of the object is known as it has been observed with radar with the Aricebo radio telescope on a previous approach. The radar showed that the asteroid was nearly spherical and spinning around its axis roughly every 20 hours. From its distance, brightness and size, scientists have found that 2005 YU55 is a very dark object that reflects only a small fraction of the sunlight falling on it.

2005 YU55 approach movie frame 0017 as first seen from Australia

The position of asteroid 2005 YU55 with respect to the Earth and the Moon at approximately the time when it first becomes viewable from Australia. Movie frame 17 from a JPL/NASA animation of the close approach on 9 November 2011

Closest approach is at 10:28 am AEDT on 9 November 2011 when the distance of the asteroid is 85 per cent of the distance from the Earth to the Moon. Obviously, at that time it is daylight in Australia and it is not possible to see the object by visual means. In the vicinity of Sydney it becomes dark from about 8:30 pm AEST onwards and that is when it becomes possible to view the object.

Unfortunately, it will not be easy to find it in the sky. As it is such a dark body, its brightness is expected to be less than 11th magnitude or more than 100 times too faint to be seen with the unaided eye from a dark spot in the country. A reasonably large telescope and a good knowledge of the sky, including the RA and declination coordinate system, will be needed to find it. What makes seeing it even more difficult is that its path is near the gibbous Moon that will be brightening the sky that night.

Interesting radar observations can be expected from the near Earth passage of the asteroid. Seeing it through a telescope from Australia though will be challenging even for experienced amateur astonomers at good locations.

85 responses to “Asteroid 2005 YU55 to shoot by the Earth closer than the Moon on Wednesday 9 November 2011. Where and when can it be seen from Australia?

  • What about all the junk we have floating around up there,is there anything that could crash into it and knock it on to a collision course with the earth or moon???

    • 25000 tons doing warp speed colloiding with a few kilos of space junk? I think it may take more than that to change it’s trajectory. Maybe something the size of Starship Enterprise would do it.

  • also loved when they asked the scientist….who he has to call, if it decides to head for us????…..GHOSTBUSTERS!!!

  • No you won’t be able to see 2005YU55 without the right equipment. Yes it is 400m. No it is not on the eliptic, thus presenting negligible threat to Earth. 2004 MN4 “Apophis” is returning in 2029 and is 270m. Apophis may by deviated by Earth’s gravitaional pull which could cause issues on it’s further return in 2036. Good Night and Good Luck.

  • get the Yahhoo, sky and star Map for Android ,it should give you an indication of where to Look once you activate GPS

  • Faint warning for us humans that the big one is out there heading for earth. That will be the reset button for mother earth. But for many of us it won’t be this life time…….

  • Well, I gotta say…I love this stuff…but am really disappointed to learn that we won’t be able to see it as clearly as Channel 7 incorrectly reported (idiots).  As Dans says, how about giving used the coordinates so we might have a chance and at least face the right direction.

  • So you say this ” A reasonably large telescope and a good knowledge of the sky, including
    the RA and declination coordinate system, will be needed to find it.” Well how the hell do we get these coordinates if you dont tell us where it will be in the sky at what time etc. Pathetic report for the Sydney Observatory. It almost smacks of talking down to us who could hope to see it if we knew where/when.

    • Hello Dans. The diagram above gives the general direction indicating where to look. For your information the coordinates at two times are

      At 9:00 pm AEDT
      RA 0h 24m 44s Dec +20° 0′ 43″
      Azimuth (east of north) 19.0° elevation 33.8°
      Predicted magnitude 11.4

      At 10:00 pm AEDT
      RA 0h 34m 01s Dec +19° 57′ 50″
      Azimuth (east of north) 4.7° elevation 36.0°
      Predicted magnitude 11.5
       

      • Mate thanks for that. I saw the diagram at the top however no real reference to scale. Also it seemed a bit too simplified. Maybe I was looking too deep. But again thank you

  • “What makes seeing it even more difficult is that its path is near the gibbous Moon that will be brighting the sky that night.”    Ha! Who wrote that? A schoolkid? Here’s the correction for ‘brighting’… BRIGHTENING! Standards are pretty low in journalism when made up words are used instead of correct English. LOL!

  • So we can’t see it with our own shitty telescopes, it’ll be daytime when it passes, hmm, anyone know how to hack the Hubble telescope? NASA isnt using it much these days.

  • space rocks pass us evryday its the one that slams into earth and ends what we call life so until that happens we just live our shitty life as usual

  • Well,if nothing else it is food for thought.Sooner or later it will be  the last dawning of our earth.Nothing lasts forever.Maybe we as a planet need to understand we are all connected,regardless of race,creed or color.

  • I don’t know why a lot of people start worrying about something like this, it’s been happening for millions of years. There are thousands of “near Earth” astoroids out there. This will be similar to a bus been driven through Newcastle, between Brisbane and Sydney.

    • Hello Bigoldjase. Spaceweather.com like every reputable source reports the asteroid as 400-metre wide. We know its diameter from radar observations at its previous pass.

  • after making several calculations (please don’t ask how i came to know this) i can tell you that the astroid is made up of more than what has been revealed. Think about this for a moment, If you grab two apposing magnetic fields more powerful than any man made capabilities, you create an invisible & and unpredictable ever shifting gravity effect i.e- the Moon’s effect on our oceans…
    The Astroid in question holds a magnetic field so powerful (due to the velocity of its traveling speed) that ‘will’ react as it passes between the two magnetic fields that we know as “Earth & Moon”
    Depending on the tra- jectory and velocity of its travel it “could” react to the Moon’s magnetic field and slightly swing into a course even closer to the Earth, causing simultaneous Global effects, including swinging into a direct collision.
    The “Matter” in which the Astroid is fully composed of is the only way to know whether this Wednesday or any day in the future, the Astroid will threaten Earth.

  • steve s sucked in i made my scope 34years ago  10 inch   im going to see it haha   if sky is clear   at ourimbah  n.s.w

  • NASA is a pack of str8 up wankers,

    How is there “no boss” when it comes to this sorta stuff.

    As if the world wouldn’t work together on this.. (if it was a threat)

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