Access

Published online 25 March 2009 | Nature | doi:10.1038/458401a

Astronomy: The rock that fell to Earth

When an asteroid was spotted heading towards our planet last October, researchers rushed to document a cosmic impact from start to finish for the first time. Roberta Kwok tells the tale.

Comments

Reader comments are usually moderated after posting. If you find something offensive or inappropriate, you can speed this process by clicking 'Report this comment' (or, if that doesn't work for you, email webadmin@nature.com). For more controversial topics, we reserve the right to moderate before comments are published.

  • The parent body aged under mild conditions. Considerable mass was recovered. There is substantial carbon content. A sample should be crushed, extracted, and HPLC assayed for trace alpha-amino acids. If detected, is there consistent chiral enrichment as opposed to racemate? http://www.pnas.org/content/105/10/3700.abstract

    • 26 Mar, 2009
    • Posted by: "Uncle Al" Schwartz
  • Thank you very much for this story, it was very interesting. Is there anyways I as a retired electrical engineered, very interested in Astronomy, be of any assistance to Nature in this field at all? Yours Truly, Boyd Corcoran

    • 27 Mar, 2009
    • Posted by: Boyd Corcoran
  • Great story both for the science itself and for the picture it gives of the trans-national nature of science. A question. The story states: "Around midnight on 6 October 2008, a white dot flitted across the screen..." "The brightness of 2008 TC3 suggested it was only a few metres across..." "These asteroids reflect very little light..." So was TC3 likely much larger than originally estimated?

    • 31 Mar, 2009
    • Posted by: Douglas H. Borsom
  • This part... "The only thing that had puzzled Kowalski about the midnight blip was the Minor Planet Center's response to his report. Its website posted the discovery right away but when he tried to add more data, the system stayed silent. Tim Spahr, the Minor Planet Center's director, found out why the following morning. The centre's software computes orbits automatically, but this asteroid was unusually close to Earth. "The computer ran to me for help," says Spahr. He did some quick calculations on Kowalski's data to figure out the path of the asteroid, which was now named 2008 TC3. "As soon as I looked at it and did an orbit manually, it was clear it was going to hit Earth," and this part... "Spahr also called astronomer Steve Chesley of the Jet Propulsion Laboratory (JPL) in Pasadena, California, who at the time was hustling his kids out of the door for school. Chesley hurried into the office, ran a program to calculate the asteroid's orbit and "was astounded to see 100% impact probability", he says. "I'd never seen that before in my life." Chesley calculated that the asteroid would hit Earth's atmosphere less than 13 hours later, at 2:46 UT the next day; " Made me wonder... "What, if it was 200 metres wide?"

    • 01 Apr, 2009
    • Posted by: Mike Venios
  • An asteroid "fragment" a few meters across with the explosive power of 10% of Hiroshima Bomb !! What would happen if Apophis had mood fluctuations and decided to give us a visit...given that its about 270 Meters across ?

    • 07 Apr, 2009
    • Posted by: Sougata Pahari