Asteroid to scrape past Earth next week but it’s no Tunguska

An asteroid expected to hurtle past Earth next week will fly within range of communication satellites but will not hit the planet, experts said today. Known as 2012 DA14, the asteroid is around 45m in diameter and is on track to whiz within 27,700km above Earth’s surface next Friday at around 9.24am…

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Relax. The asteroid won’t hit Earth, NASA said. NASA

An asteroid expected to hurtle past Earth next week will fly within range of communication satellites but will not hit the planet, experts said today.

Known as 2012 DA14, the asteroid is around 45m in diameter and is on track to whiz within 27,700km above Earth’s surface next Friday at around 9.24am AEDT, a record close call for an asteroid of this size.

The US space agency NASA said “there is no chance that the asteroid might be on a collision course with Earth. Nevertheless, the flyby will provide a unique opportunity for researchers to study a near-Earth object up close.”

Professor Phil Bland, an asteroid expert and ARC Laureate Fellow at Curtin University said such a close visit would help scientists better prepare for an asteroid that was actually on track to hit Earth.

“One of the things we are interested in is if we saw something coming that we thought might be a problem, would we be able to track it accurately enough to know whether we should try to deflect it or do something about it?” he said, adding that even at 45m across, 2012 DA14 was still considered a smallish asteroid.

“In terms of its effect on Earth, if it hit us it would still make a reasonable mess. That’s a bit bigger than the one that blew up over part of Siberia in the beginning of the 20th century, called Tunguska,” he said.

“No one saw that one coming. It was a huge fireball that came in and blew up around 10km in altitude over part of Siberia and really devastated a huge area. It’s the same sort of energy as a big nuclear blast.”

That blast created shock waves powerful enough to flatten trees and houses, he said.

“If this one next week did hit us, it’d do something like that, it would be more likely to blow up in the atmosphere than on the ground. But we are safe and sound, they know where it’s going to be. This one is not going to hit us, we will not have any trouble at all.”

Professor Trevor Ireland from the Australian National University’s Research School of Earth Sciences said between two and 40 tonnes of extraterrestrial material entered Earth’s atmosphere a day.

“Most of the meteorites or shooting stars you see are the size of grains of sand or a match head but they come into the Earth’s atmosphere fast, at about 16km per second,” he said.

“The solar system is rather active. Even though we look up in the night sky and see not much happening, there’s certainly a lot of activity in the asteroid belt.”

Next week’s asteroid follows the release of a new scientific paper, published in the journal Science, that presented new evidence linking a giant asteroid impact in Mexico with the disappearance of the dinosaurs.

“These researchers have been able to find something dating the end of the dinosaurs as well as the impact and it’s getting close. It’s removing any doubt that dinosaurs were wiped out following that incident,” Professor Ireland said, adding that the impact, which caused the Chicxulub crater, may have coincided with a period of high volcanic activity.

“[The asteroid] was potentially ejecting sulfates and carbonates which put nasty chemicals into the air and block out the sunlight. You put that on top of the volcanoes at the time and you have something that could be quite toxic to the lungs of larger animals.”

Professor Ireland said the new evidence showed that “something really nasty happened there for the dinosaurs.”

“The good news is their departure allowed for the rise of mammals like us. So it’s swings and roundabouts.”

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7 Comments sorted by

    1. Sunanda Creagh

      Editor at The Conversation

      In reply to Michael Shand

      Thanks Michael! Let us know if there are any other space stories you'd like to see covered.

      report
  1. John Harland

    bicycle technician

    My understanding is that the Chicxulub impact had been accurately dated to around 32,000 years before the extinction of dinosaurs (excepting birds).

    I am puzzled how this "confirms" that it was the primary cause. That span of time may seem foreshortened to almost nothing to a geologist looking back. To anything living at the time, that was span-enough for a significant amount of evolution.

    Rather than killing the dinosaurs by anything as dramatic as toxic air or famine, it seems more likely…

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  2. Caroline Copley

    student

    Aha it IS all an Act of God. The volcanoes are largely irrelevant, and so are competing theories about Tunguska?? I must say that my skepticism about a meteor being the cause of Tunguska was shaken by the recent meteor in Russia, which landed in a lake just like the Tunguska one is supposed to have (so I feel humbled completely) but where are the flattened trees??? Plenty of broken windows, but flat trees??
    My knowledge of this subject is a bit scarce, but the reports are this one was 17m across…

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    1. John Harland

      bicycle technician

      In reply to Caroline Copley

      The Tunguska effect might not be size of a meteor alone.

      Meteors commonly break up in the atmosphere. Presumably from the enormous heat buildup and very strong thermal gradients that sudden heating causes, as well as vaporisation of any volatile constituents.

      Such breakup would release a lot of energy, hence a shockwave. It may be that such breakup happened much closer to the ground at Tunguska than is usually the case.

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    2. Caroline Copley

      student

      In reply to John Harland

      John, Yep but one of the other articles (Forensic astronomy: the Russian meteor and 2012 DA14 by Simon O'Toole) on the Conversation discussed the meteor as follows:
      "They estimated that the amount of energy released when the meteor exploded was around 30 times that of the nuclear bomb dropped on Hiroshima."
      Yep ok Tunguska which was thought to be at least twice the size of this one, which is estimated at about 17m, happened closer to the ground-
      and all that happened from about 60X Hiroshima was…

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