Asteroid flyby

by Tanya
Publish date
7 November 2011
Comments (3)

On Wednesday 9 November an asteroid is going to fly past Earth.

Vesta from Dawn spacecraft NASA's Dawn spacecraft was sent to the Asteroid Belt to obtain close-up images of Vesta.
Source: NASA

But not this one! This is a picture of Vesta, the third largest asteroid in the Asteroid Belt, located about 200 million kilometres away. This lovely picture was taken by the Dawn spacecraft, which is currently in orbit around Vesta. It shows what a large asteroid looks like from a distance of just 5,200km.


asteroid 2005 YU55
Radar image of the near-Earth asteroid 2005 YU55 when it was 2.4 million km away.
Source: NASA/Cornell/Arecibo

The asteroid that is going to fly past Earth is known as 2005 YU55. This radar image of the asteroid was made last year using the Arecibo Radar Telescope in Puerto Rico. At 400m across this near-Earth asteroid is over 1,000 times smaller than Vesta. Rather than having to send a spacecraft out to it, this asteroid is coming to us.

But there’s no need to go crazy - the closest the asteroid will get is 325,000 km from Earth. That’s just a little closer than the Moon which on average is 380,000 km away. It won’t pose any threat to Earth or have any noticeable gravitational effect. But we should get a great look at it.

NASA scientists will be using antennae from the Deep Space Network to bounce radio waves off the space rock. The data is then used to create a three-dimensional model of the asteroid and with the asteroid being so close it should provide us with a really detailed image so we can learn more about it.

Hundreds of asteroids have been observed using radar astronomy and the interesting thing is that asteroids can be so different. They come in all sorts of shapes and sizes, with some having very smooth surfaces and others being rough and textured. Radar astronomy can also be used to determine the composition of an asteroid and it's even discovered some asteroid moons.

Most importantly of all, radar astronomy gives us the best insight into an asteroid’s trajectory. That’s how we can work out that this near-Earth asteroid won’t harm us and provides the lead time to prepare for great science observations like this one.

I look forward to the day when astronauts will once again take the leap beyond Earth orbit. Many say that after the Moon, the next step for astronauts should be a near-Earth asteroid. The information that’s gathered now could one day be used to choose just which asteroid we'll be visiting.


JPL’s Asteroid Watch Page

NASA’s Near Earth Object Program

Comments (3)

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Lucy 8 November, 2011 09:14
Fascinating! So will we be able to see it from our backyards?
Kate C 8 November, 2011 13:34

Hi Lucy, someone asked a similar question on Twitter yesterday. According to Martin in the Planetarium:

Closest approach will be at 10:23 AEDT so it will be daytime for us. Even if it were night the visual magnitude is not expected to get much brighter than 12 at closest approach so you would need a reasonable telescope – probably around 30cm - to see it.

Tanya 9 November, 2011 12:30

NASA has released the first video of asteroid 2005 YU55 which you can view on NASA's website. The images were obtained between 6:30am and 8:30am (AEDT) on Monday 7th Nov, when the asteroid was still 1.38 million kilometres away.

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