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Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region Forums'Doomsday' asteroid Apophis more massive than first thought
Watch its Earth flyby live tonight at 0100 UTC
By Iain Thomson in San Francisco Get more from this author
Posted in Science, 9th January 2013 22:19 GMT
Astronomers following the so-called doomsday asteroid Apophis, which will be whizzing past Earth on Thursday morning, have found the rock is much larger than had previously been assumed. Since the asteroid could hit Earth in 2036, that's a problem.
The asteroid, named after an Egyptian god of death, had been thought to be around 885 feet (270 meters) wide, plus or minus a couple of hundred feet (60 meters). But as Apophis approached last weekend, astronomers at the Herschel Space Observatory took new observations and have concluded that astronomers have seriously underestimated both its size and its mass.
"The 20 per cent increase in diameter, from 270 to 325m, translates into a 75 per cent increase in our estimates of the asteroid's volume or mass," said Thomas Müller of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany.
"These numbers are first estimates based on the Herschel measurements alone, and other ongoing ground-based campaigns might produce additional pieces of information which will allow us to improve our results." ...
http://www.theregister.co.uk/2013/01/09/apophis_size_mistake/
still_one
(91,937 posts)greytdemocrat
(3,299 posts)struggle4progress
(118,032 posts)... While trajectory knowledge was substantially corrected by the Arecibo data, a small estimated chance of impact (less than 1 in 45,000 using standard dynamical models) remained for April 13, 2036. With Apophis probably too close to the Sun to be measured by optical telescopes until 2011, and too distant for useful radar measurement until 2013, the underlying physics of Apophis' motion were considered to better understand the hazard ...
It was found that small uncertainties in the masses and positions of the planets and Sun can cause up to 23 Earth radii of prediction error for Apophis by 2036 ...
The future for Apophis on Friday, April 13 of 2029 includes an approach to Earth no closer than 29,470 km (18,300 miles, or 5.6 Earth radii from the center, or 4.6 Earth-radii from the surface) over the mid-Atlantic, appearing to the naked eye as a moderately bright point of light moving rapidly across the sky. Depending on its mechanical nature, it could experience shape or spin-state alteration due to tidal forces caused by Earth's gravity field.
This is within the distance of Earth's geosynchronous satellites. However, because Apophis will pass interior to the positions of these satellites at closest approach, in a plane inclined at 40 degrees to the Earth's equator and passing outside the equatorial geosynchronous zone when crossing the equatorial plane, it does not threaten the satellites in that heavily populated region ...
neo.jpl.nasa.gov/apophis/
cthulu2016
(10,960 posts)Buns_of_Fire
(17,119 posts)Oh, wait. No, I don't.
ThoughtCriminal
(14,009 posts)I hate that about radar.
lumberjack_jeff
(33,224 posts)This orbital inclination makes my equator look big.
struggle4progress
(118,032 posts)uponit7771
(90,225 posts)leveymg
(36,418 posts)DogPawsBiscuitsNGrav
(408 posts)randome
(34,845 posts)Blue_In_AK
(46,436 posts)The psychics have told me I'm going to live to 93, which doesn't happen until 2039. You can all relax now.
Heywood J
(2,515 posts)Are there ring-like objects descending from it?
Tyrs WolfDaemon
(2,289 posts)This is just great. The last thing we need is for symbiotes to infiltrate our govt. The Teabaggers are enough of a pain as is.
hobbit709
(41,694 posts)muriel_volestrangler
(101,146 posts)Right now Apophis is in the midst of a rather distant yet much-awaited pass in Earth's vicinity, coming within 9 million miles (14½ million km) earlier today. It's been tracked for about a week by NASA's 230-foot (70-m) Goldstone radio/radar dish in California, and those observations have given astronomers the confidence to issue an "all clear" for the foreseeable future.
"Goldstone single-pixel observations of Apophis have ruled out the potential 2036 Earth impact," says Jon Giorgini, a dynamicist at NASA's Jet Propulsion Laboratory. Based on revised orbit calculations, he says Apophis will then come no closer than about 14 million miles and more likely miss us by something closer to 35 million miles. Moreover, the radar data have improved the asteroid's positional uncertainty so much that dynamicists can now accurately predict its trajectory decades into the future.
"We're observing it at 75-meter resolution, which is better than we expected," notes Lance Benner (Jet Propulsion Laboratory), who's leading the radar effort. "The signal-to-noise ratios are a bit stronger than we thought they'd be, so the radar astrometry is more precise than we expected."
http://www.skyandtelescope.com/news/Asteroid-Apophis-Takes-a-Pass-in-2036-186245171.html
ChisolmTrailDem
(9,463 posts)on a live broadcast on Slooh.com. I was under the impression it would be within the orbit of our geosynchronous satellites in '29 or '36. Now this guy is saying 35 million miles?
muriel_volestrangler
(101,146 posts)to become a collision - but now they know it won't:
The problem was we didnt know the trajectory of the asteroid well enough to say if there would be an impact or not. There simple werent enough accurate observations, so trying to predict where it would be more than two decades in the future introduced a fuzziness to its position. There was a small but significant chance it would pass through the keyhole in 2029, leading to a later impact.
Observations taken a couple of years ago nailed down the orbit better, and the odds dropped to about one in a million. Yay! But still, a better number would be zero.
And thats where we are now. Apophis is currently making a pass of Earth (at a distance of 14 million kilometers, or 9 million miles), which is favorable for observing it. Astronomers used NASAs Goldstone radar facility to send pulses of radar to the asteroid and back, which yield highly accurate positions for the rock. When the new data were added to what was already known about its orbit, it was found the asteroid will definitely miss the keyhole in 2029, and thus miss us in 2036. By a large margin, actually: more than 20 million kilometers (14 million miles), or 50 times the distance to the Moon. And thats a minimum distance, so it looks like were safe from this rock.
http://www.slate.com/blogs/bad_astronomy/2013/01/10/apophis_impact_new_observation_show_it_to_be_bigger_but_no_longer_a_threat.html
sadbear
(4,340 posts)Nobody else is even talking about it.
Tyrs WolfDaemon
(2,289 posts)It would be cool to make it land/crash on the moon so we could study it. Who knows what kind of things we might glean from an in depth examination.
theKed
(1,235 posts)to stop an asteroid like that would be absolutely ridiculous. The sheer amount of delta-v to brake it enough to land or brake would be huge. I don't recall seeing a velocity anywhere but, we'd have had to start a deceleration burn quite some time ago - which means heaving a whole bunch of dead weight into space (fuel) just to even start...we're really not set up for that kind of op
Tyrs WolfDaemon
(2,289 posts)I really hadn't given it that much thought.
We ought to prove it though by launching GOPers at it. They are so into stopping things these days, perhaps they might be able to slow it down, even if only by a millimeter/sec or so. Finally, a scientific use for Repubs.
We might even get them to launch themselves at it if we told them it had oil or tons of gold.
theKed
(1,235 posts)it would be fantastic if we could do such a thing. unfortunately, we seem content to keep to our ball of rock for the time being. an orbital fueling station would be an excellent start for such a thing, or manned planetary trips. some of the non-rocketry ascent prospects on the horizon are very promising - ie. space elevators - and make hauling fuel out of the deepest part of earth's gravity well much more feasible. that eliminates a huge hurdle.
much like last time, the next wave of colonization will probably be fueled by resources and population pressures - and accomplished with a lot of commercial backing.
NickB79
(19,110 posts)And there is NO FUCKING WAY I'd be comfortable with that.
theKed
(1,235 posts)Yeah. No goddamn way anyone would willingly aerobrake a massive asteroid in our own atmosphere. Not without a damn good reason.
Whovian
(2,866 posts)leveymg
(36,418 posts)Out with a bang, a whimper, and then a great BIG BANG.
bluestateguy
(44,173 posts)Just do a hell of a lot of damage, to be sure.
And I think that is small enough of a rock that we could shoot it down with a missile.
RC
(25,592 posts)ThoughtCriminal
(14,009 posts)Impact Threat from Near-Earth Asteroid Apophis in 2036 Now Ruled Out
http://www.slate.com/blogs/bad_astronomy/2013/01/10/apophis_impact_new_observation_show_it_to_be_bigger_but_no_longer_a_threat.html