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?

  • Thank you channel 7, for telling me to go to your website for details on how to see the asteroid. The link that brought me here didn’t work for the first half hour as every man and his dog was clicking it frantically at the same time. When I finally get here it turns out it’s only 100 times too dim to be seen with the naked eye anyway. Great. Unless of course you happen to own a $5000 telescope, have a degree in astronomy and some magical way to blot out the moon. Thanks for that.

    • Yeah, I think you’ll need the iPhone 4 or above to get that close. If you get an iPhone 4S before Wednesday, maybe you could ask Siri to show you exactly where 2005 YU55 is???

  • Wow!!!  I am in far North QLD – Cardwell, Will we be able to see it as there is NO artificial light here to distort the show 

  • thank goodness for this news we carn’t run and hide or leave this planet so we can stress, spend our money,and enjoy life till the end

  • and how likely is it that this may even affect the moon . and did they park the space station to the left that day. telephones , weather and other satellites?  seems like we wont see much of it cause its too dark 
    what a shame 

  • hi guys is there any debris field traveling with this thing . how big and how fast?  west   east the make up of this rock is ?

    keith tassie 

    • Fran, I too live here in bundaberg and from my understanding theres not a hope in hell that we gonna see anything. Go to the local observatory on goodwood road, they will likely have good telescopes and may possibly be doing a public opening for a fee. Cheers, Lee

      • Hi Ssidunno & Fran I live in Elliott Heads where on Goodwood Rd is the observatory and is it my understanding that if and only if it hits earth it will be in 2028 if I am right I have no reason too orry cos on my calculations I probably will not be here anyway LOL not funny really but at least I think I know where I will be going and also if it hits earth do they know where in the world it will hit

        • hello guys,,,I am the director of Alloway Observatory on Goodwood Road…The observatory will not be open to the public..sorry to burst anyones bubble but i think it will be a no show….The average person is looking for a WOW…chances are it will be a GEE ! i THINK THAT MIGHT BE IT….regards Mac Jonsen

  • Please, present your own calculations as to yu55’s deviation due to Earth’s gravity. I’m sure your capable. All NASA seams to shows are solar center of mass based calculations. 

  • Ellie, In refernce to FEMA? What do ypu mean? Please elaborate? Seams it’s a little difficult to get specifics for some reason as to the 3 min. you refer to?
    Thank you.


  • Do you know if the asteroid’s path will be affected by earth and will this move it closer to the moon?

    • Hello Mg-tiger. Yes, the Earth will slightly deflect the path of the asteroid, but that deflection has been included in the calculations of its present and future path.

    • my thought exactly – the trajectory predictions I have found show no deviation of course due to earth’s gravitational field. Like something calculated by a primary school student.
      A 2-3 degree deviation would at least be expected, and a deviation in the vicinity of 20 degrees would put it on a possible colision course with the moon.
      If it’s course is altered, where does it go from here?

  • I have a 150mm reflector telescope and live in Bundaberg Queensland  would i be able to see yu55 if so could you send me information on were to look to bear59@mail.com  

    • Hello Greg. You will need to use the setting circles on your telescope to try to find the object. Ensure that the setting circles on your telescope are carefully aligned first though. Use the Horizons website http://ssd.jpl.nasa.gov/horizons.cgi to work out the coordinates for your location in advance. And as I note in the post it will be a challenging observation due to the vicinity of the gibbous Moon. Good luck.

Leave a Reply

Your email address will not be published.