

Asteroid set to come closer to the Earth than the moon Nov. 8 - mccooscoos
http://www.nasa.gov/mission_pages/asteroids/news/yu55-20111025.html

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Cushman
The Moon is much larger and much farther away from the Earth than you are
probably imagining when you hear this.

Still cool, though.

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127001brewer
Here's an image of the Earth (on the left) and the Moon (on the right) to get
a better sense of the distance between the two:

[http://eoimages.gsfc.nasa.gov/images/imagerecords/51000/5196...](http://eoimages.gsfc.nasa.gov/images/imagerecords/51000/51969/EarthMoon_juno_2011238_lrg.jpg)

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losvedir
Wow, I'm not sure I fully grasped the distance until I saw that picture. The
fact that people actually went allllll the way out there and back just
astounds me.

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cwilson
Am I the only one who read the article hoping for a "If it DID hit the earth,
X would happen..."?

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bh42222
A couple of nights ago a had strange dream about asteroids hitting earth.
Didn't think much of it... still don't think much it.... but I would like to
know _where_ this would hit if it were to hit.

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orblivion
That's kindof like not having a sweater, and asking what color it would be if
you had one. If you alter reality such that it would hit, I think you sortof
have your arbitrary choice of where.

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hugh3
Hmm, I wonder if the poles would get hit less often than the tropics due to
the distribution of asteroids being more or less in the ecliptic, or whether
that's not sufficiently significant. Probably not -- I don't know of any
latitude-dependent distribution of lunar craters.

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Achshar
Brace yourselves: the doomsday articles/memes/stories are coming..

PS will it be visible to naked eye? if yes then when and where and for how
long and where in the sky? can there be a real time Google earth 3d simulation
like NASA did for space shuttle launch?

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brlewis
_The asteroid's surface is darker than charcoal at optical wavelengths.
Amateur astronomers who want to get a glimpse at YU55 will need a telescope
with an aperture of 6 inches (15 centimeters) or larger._

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lutorm
Yeah, it's the low albedo that kills you. Something that large made of ice
would probably be quite bright.

Quick OOM calc: This thing has an area proportional to the moon of
(200m/1700km)^2. The moon has an albedo of ~0.12. An object with albedo 1
would thus have a brightness of ~1e-7 of the Moon's. The full Moon has a
magnitude of -12.7, so such an object would have a magnitude of
-12.7-2.5log10(1e-7), or about 4.8. That's clearly visible to the naked eye at
a dark site, but not very impressive.

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meric
Hmm, the Mayans did quite a good job. They only guessed wrong by 324,600
kilometers and 53 days.

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macrael
Anyone know how fast it is going relative to the earth? And I'd love to get an
answer to wether it will be visible.

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arien
13.72km/s - 49392km/h

Source: <http://hisz.rsoe.hu/alertmap/index2.php> (scroll to the bottom for
Earth approaching objects)

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suprgeek
Would be interesting if during the flyby our analysis revealed that it was
made up of a Gold core or something :). Suddenly NASA might get a bunch of
funding to prepare for the next flyby

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blhack
I hear stuff like this a lot (mining asteroids for precious metals)...

Wouldn't flooding the market with that much gold...crash it? Are we really
talking about that many billions and billions of dollars worth of potential
revenue from mining an asteroid?

This all just seems like fun sci-fantasy.

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CWuestefeld
_Wouldn't flooding the market with that much gold...crash it?_

Well, presumably only a single party is going to recover that gold. If they
dumped the whole load onto the market, it would crash. But if they release it
slowly, then a greater supply from each batch would cause "inflation", so that
the price they could get from the next batch would be lower. But they could
still derive significant wealth before trailed off.

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darnton
Seville in the 16th century is the best example of what might happen. Spain
got hold of the equivalent of a gold-filled asteroid - South America. All the
gold and silver came in through the port at Seville, which became very rich,
and inflation slowly radiated out from there to the rest of Europe.

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whyme
Anyone have a recommendation for a kick ass telescope that could see this
thing? Best bang for the buck kinda deal.

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bradleyland
It's actually much easier to locate and track large, distant objects than it
is to track small, (relatively) close objects. Ever try to track a jet with a
pair of binoculars? Not easy.

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shasta
I'd guess that roughly 50% of asteroids passing by end up closer to the earth
than the moon.

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jerfelix
Isn't about half the universe closer to the Earth than to the moon (at a
particular time)?

Meaning: stand on a point of the Earth such that the moon is situated exactly
above the opposite side of the Earth. Then look up. All that stuff you see is
closer to the Earth than the moon.

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duggan
This is the logical extension of the peek-a-boo fallacy.

The moon doesn't stop being closer to the earth simply because you can't see
it from a particular point on the Earth.

About the only thing you can say is that if you were to proceed outward on a
linear path from the opposite side of the Earth from that which the moon is
currently positioned, then you would reach something other than the moon
sooner than you would reach the moon.

But that would be saying nothing, really.

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adyus
Let's hope it has enough velocity to escape Earth's field and carry on. I'm
sure it does, but I'll keep my fingers crossed, just in case.

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Cushman
Give science a little more credit :) The n-body problem is hard, but it's more
like "we don't know if this same asteroid will hit the Earth 20 years from
now" hard than "this asteroid could shift course at any moment!" hard.

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hugh3
The _n_ -body problem is hard to solve analytically, but trivially easy to
solve to arbitrarily high precision numerically.

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maaku
I work at NASA, supporting the person who wrote the codes that is now used for
planetary dynamics simulation, like this. It is an extraordinarily complex
problem, and a specialized academic discipline in its own right.

n-body dynamics is a complicated, chaotic system. Getting any precision at all
over any reasonable period of time is a feat of itself.

