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Impact ~ NEO; Near Earth Objects

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  • G David Bock
    replied
    Dinosaur-killing space rock 'was a comet'

    The space rock that hit Earth 65m years ago and is widely implicated in the end of the dinosaurs was probably a speeding comet, US scientists say.
    http://www.bbc.co.uk/news/science-environment-21709229

    Leave a comment:


  • GCoyote
    replied
    Originally posted by G David Bock View Post
    Not that "science" or NASA is endorsing religion etc.;
    Nasa's advice on asteroid hitting Earth: pray

    http://www.telegraph.co.uk/science/s...arth-pray.html
    Well that's not any worse than my advice:

    Leave a comment:


  • G David Bock
    replied
    Not that "science" or NASA is endorsing religion etc.;
    Nasa's advice on asteroid hitting Earth: pray

    http://www.telegraph.co.uk/science/s...arth-pray.html

    Leave a comment:


  • GCoyote
    replied
    Originally posted by Pirate-Drakk View Post
    Here's a new NASA web site for NEOs.
    http://neo.jpl.nasa.gov/

    Lot's of good info...
    Nice link PD and it included this one. http://neo.jpl.nasa.gov/fireballs/

    Now that everyone and his brother has a video camera, this table should start to populate on a pretty regular basis.

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  • Pirate-Drakk
    replied
    Here's a new NASA web site for NEOs.
    http://neo.jpl.nasa.gov/

    Lot's of good info...

    Leave a comment:


  • G David Bock
    replied
    Four Asteroids Buzz Earth in Single Week

    http://www.space.com/20149-asteroids...arth-week.html

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  • Pirate-Drakk
    replied
    Not a lot of useful info coming out of Russian on the latest "event". However, this is interesting and it "explains" the dual contrails. One from the "object" and one from the "interceptor". It also explains why one smoke trail ends abruptly.

    http://www.dailymail.co.uk/news/arti...e-emerges.html

    Why is this sentence included in the article?

    "Nuclear installations in the Urals remained undamaged by the fallout."

    Any nuclear blast that does not eject surface materials into the air (e.g. air burst) will not create "fallout".

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  • G David Bock
    replied
    Latest on the Russian meteor blast -
    Meteor lurked for thousands of years before blasting Russia, experts say

    EXCERPT:
    Based on the readings from infrasound sensors stationed all over the world to monitor nuclear-weapons tests, NASA said the energy release was equivalent to 500 kilotons of TNT, or roughly 30 times the energy released by the atomic bomb dropped on Hiroshima at the end of World War II. That translated into an object about 17 meters (55 feet wide), weighing 10,000 tons. The space agency said it was the biggest cosmic impact recognized since the 1908 Tunguska asteroid blast that leveled millions of trees in Siberia.
    Less than a week after the blast, Colombian astronomers worked out a rough orbital path for the Chelyabinsk asteroid, based on an analysis of the videos captured by dashboard cameras and traffic cams in the area. On Friday, NASA produced a more definitive orbital track, based not only on the videos but also on the readings from the federal government's space sensors. The report took advantage of a recently signed agreement with the Air Force Space Command for the public release of previously hush-hush data.
    http://cosmiclog.nbcnews.com/_news/2...id=msnhp&pos=2

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  • G David Bock
    replied
    Here's a short vid clip of a couple of 'small' comets currently being seen in southern hemisphere skies;
    http://msnvideo.msn.com/?channelinde...e-c7ead13d69c4

    Leave a comment:


  • GCoyote
    replied
    Russian fireball largest ever detected by nuke monitoring organization

    Published 25 February 2013

    Infrasound has been used as part of the Comprehensive Nuclear Test Ban Treaty Organization’s (CTBTO) monitoring tools to detect atomic blasts since April 2001 when the first station came online in Germany. Infrasonic waves from the meteor that broke up over Russia’s Ural Mountains last week were the largest ever recorded by the CTBTO’s International Monitoring System.
    More - http://www.homelandsecuritynewswire....g-organization

    The CTBTO’s site is here - http://www.ctbto.org/press-centre/pr...sound-sensors/

    Leave a comment:


  • GCoyote
    replied
    I'd really like to see map of the distribution of damage on the ground. That would give us means of estimating the area of damage which tells us the extent of the over-pressure. That would help discriminate between a large object at ~25 km altitude and a much smaller one which would have to be much closer to the ground.

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  • The Doctor
    replied
    Originally posted by Pirate-Drakk View Post
    While this may be correct, the "asteroid" was estimated to be 20,000,000 lb. = 10,000 tons.

    You and TigerSqdn are off by three orders of magnitude in mass, which is a significant error. I am referring to an object supposedly 500 times more massive than what you are talking about.
    http://www.nasa.gov/mission_pages/as...d20130215.html
    The Barringer asteroid is estimated to have had a mass of 100,000 to 270,000 tons and it is likely that less than 1% of that mass has been recovered as meteorite fragments.
    The current estimate of the recovered meteoritic iron mass is 30 tons (Nininger, 1949; Grady, 2000), although this is a highly uncertain number.

    Asteroids smaller than Barringer tend not make big craters...

    With regard to Barringer Crater and the projectile that produced it, there are two other observations worth noting. First, with a diameter of ~1 km, the crater approaches the lower limit of hypervelocity craters on Earth (Table 8.3). The atmosphere screens most objects that make smaller craters. That is, the atmosphere shields the surface from objects that are smaller or weaker.

    Kring (2007)



    The Chelyabinsk meteoroid had less than 10% of the mass of the Barringer asteroid. That coupled with the fact that it followed a very shallow trajectory is a pretty good indication that it should have mostly vaporized prior to impact, leaving little if any crater.

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  • Pirate-Drakk
    replied
    Originally posted by The Doctor View Post
    ...
    A 10,000 kg (10 mt) meteoroid would have almost entirely vaporized prior to impact.
    While this may be correct, the "asteroid" was estimated to be 20,000,000 lb. = 10,000 tons.

    You and TigerSqdn are off by three orders of magnitude in mass, which is a significant error. I am referring to an object supposedly 500 times more massive than what you are talking about.
    http://www.nasa.gov/mission_pages/as...d20130215.html
    Last edited by Pirate-Drakk; 21 Feb 13, 12:27.

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  • G David Bock
    replied
    Small and likely expended comet looks appealing. Consider they are presented as "dirty snowballs" though the "ice" can be other compounds besides H2O, like methane or similar frozen gases/liquids. After several passages around the Sun effervescing some of it's mass each time, eventually that comet is just a loosely packed pile of gravel, i.e. an asteroid.

    This object was rather small and coming at Earth 'out of the Sun' which if combined with being a comet with little left to make a 'tail' would have been hard to observe in the first place. Compacted 'gravel' with some 'ice' inside as a core would explain why it began to leave a 'smokey trail' (steam and/or some other compounds burning), plus it started to break-up, then the compression forces and heat caused it to explode.

    It's sounding very similar to the object involved in the Tunguska Blast of 1908, where the object supposedly left a 'smokey trail' in the sky, produced no crater, exploded in the air and left few findable 'meteorite' fragments.

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  • Bwaha
    replied
    I'm still waiting for the forensic evidence.

    But due to the lack of emp, its not a nuke...

    Otherwise we'd not see the videos....

    Any Russian care to mention the gold rush going on?

    Good for those Capitalists...

    That's the way to do it...
    Last edited by Bwaha; 20 Feb 13, 19:17.

    Leave a comment:

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