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.
The object that caused the 1908 Tunguska event is estimated to be either 40 or 60 meters in diameter[1], and it still managed to do an incredible amount of damage[2]. The object described here has a diameter of 400 meters. My understanding is that this wouldn't be anywhere near as devastating as the impact associated with the K-T extinction event, but it certainly wouldn't be very good for anyone.
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.
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.
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.
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?
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.
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.
Good question - an aircraft carrier nearer than the moon? I can't imagine that'd be visible to the naked eye - even ships on the horizon disappear pretty quick. Then again you can see satellites sometimes, but that's like 4 orders of magnitude closer.
well but if it comes when its night and it has a tail long enough and is also bright enough,and is close to moon from the perspective of someone on earth and hence moon light makes it more visible, then.. who knows??
Its funny how here you get down voted for not reading a part of news thoroughly, or for that matter being wrong. (Or even for acknowledging that you were wrong), i am dying laughing here guys haha..! great work keep up..
EDIT: in case you couldn't fathom, that was sarcasm.
EDIT 2: seriously, stop it! or reply as to why are you down voting? is it a crime to mistakenly post a comment and then acknowledge your mistake or are you guys just some proud 'elite' HNers?
well i don't want to get upvotes but if you disagree with me then please take some more time to write a quick comment as to why.
Well i posted asking if it will be visible to naked eye, someone quoted a part of the story (indirectly) saying that it won't be and i happened to have missed that part, and i get down voted (for missing reading a part of the story).. well then i acknowledge that i missed it and i get down voted still even then i asked the down voter why was he is down voting my comments and guess what.. i got down voted.. again. but no one has balls to write back, or maybe they are super busy with their work but anyways, and i wont edit this comment but i can say two things:
- you (or any of the downvoters) probably won't reply to this comment either.
- this comment will (almost certainly) be down voted too.
again.. i dont need karma, i am just saying that if someone disagrees with me, just comment and tell me why, so that we can discuss or i can know why am i wrong.
You get downvoted when your comments are low quality and/or don't add to the discussion. Every comment you write with "why did you downvote me???" is both low quality and doesn't add to the discussion.
so i cannot add a comment as long as i don't have anything useful and accurate to say..? hmm can you honestly say that you agree with the notion that 'write constructive and accurate comments or don't write anything at all'?
My first ever comment in this thread was a legit question only that it's answer was already hidden in the parent article. I guess that didn't "add to discussion" then.
In short newbies cannot learn about the 'ways' of HN without being looked down upon (which is always so great for the morale). interesting. I hope my comment 'adds to the discussion' of the condition of 'ways' of HN :)
Right: if you can't say something useful and accurate, please don't post. (There's still a LOT to say, so don't let that stop you from posting at all!) If you post in good faith and are inaccurate, then it's good form to either edit your post to acknowledge the error, or delete your post.
Getting downvoted is one way that newbies learn about HN; most of the time, the downvote comes with a discussion.
(One last note: sarcasm is really hard to detect in writing; we miss the tone of voice and all the nonverbal cues. It's polite to mark a sarcastic response with something that shows you're being sarcastic. Don't count on just the content of your post to show sarcasm.)
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
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?
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.
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.
Would it sound less far-fetched if we talked about mining asteroids for rare-earth metals, conductive metals like copper, industrial metals like titanium, etc?
Not yet. Give me a space elevator that gets me to geostationary orbit via electricity, and I think that statement could become untrue (assuming sufficient amount of ore and ease of extraction).
You could make the same arguement without any sci-fantasy. Why bother starting a new gold mine? If it doesn't have any gold then it's wasted effort, and if it has tons of gold then it will just depress prices. So why bother exploring for any resources anywhere?
Instead consider a big hunk of asteroid mined gold sitting in orbit. Free storage, and quick delivery to anywhere in the world. Park it up there and drop pieces of it when the prices are high enough.
The way you describe that perfrectly fots in with my idea that a 'caught' asteroid in orbit is worth more as a weapon system than as a gold mine. "Park it up there and drop pieces of it when you need some penetrating power"
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.
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.
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.
Haha, yes! They meant "closer to the earth than the moon is", not "closer to the earth than to the moon." It will never meet that second criterion, since it will only be about 20% closer to the earth than the moon is.
I suppose so but that is not really the point. The point is that the asteroid will be closer to the Earth than the moon is to Earth. Now, that is worth noting.
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.
From an earlier press release on this asteroid, from a 2010 pass:
[The radar imaging] reveals 2005 YU55 as a spherical object about 400 meters (1,300 feet) in size.
Not only can the radar provide data on an asteroid's dimensions, but also on its exact location in space. Using Arecibo's high-precision radar astrometry capability, scientists were able to reduce orbit uncertainties for YU55 by 50 percent.
"At one time we had classified 2005 YU55 as a potential threat," said Steve Chesley, a scientist at JPL's Near-Earth Object Program Office. "Prior to the Arecibo radar passes on April 19 thru 21 [2010], we had eliminated almost all upcoming Earth flybys as possibilities of impact. But there were a few that had a low remaining probability of impact. After incorporating the data from Arecibo, we were able to rule impacts out entirely for the next 100 years."
*
So, they do know this one will be well-behaved for 100 years.
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.
Not entirely trivial. Because it is chaotic, it's not terribly well behaved. People who try to integrate the solar system forward in time have to put some effort into accuracy, and ultimately accuracy is limited by our limited knowledge of the initial state of the system.
from NASA's gif, it doesn't even bend its trajectory.. and also it's gravity will not affect earth's tides and tectonic plates :)
EDIT: although from the gif it appears that it was a close call on the moon. But i close my eyes and i see a world where i get out and see a small piece of rock hit our moon with a decent explosion when the moon is full. Man if it does't affect out planet in any way, i would really like to see that happen. Gives me goosebumps every time i visualize it! amazing..
There's a thought. What would happen, hypothetically speaking, if an asteroid large enough were to hit the moon and spin it out of its orbit? What would happen to life here on Earth? Obviously tides would be affected, and I am assuming that this in itself would probably affect a lot of animals, fish, birds etc?
I'm pretty sure that said hypothetical impact can't exist. The object either has far too little energy to significantly change its orbit, or alternatively has enough energy but there is nothing moon-like left after that collision.
The moon has a mass of 7.349×10²² kg. Its mean orbital velocity is 1023m/s. So, with a perfectly-aligned impact, and perfect efficiency, to add velocity, you'd need to add energy equal to difference in kinetic energy. For 1m/s, that'd be 10²⁵J (assuming the change in mass is negligible). That's an incredible amount of energy, about 20 times greater than the Chicxulub impact (believed to have triggered the mass extinctions at the K-T boundary).
That's 1 m/s. You need far more than that. Earth escape velocity is 11200m/s. So, that would seem to need 10³⁰ J. And an impact would deliver that in well under a minute. Which would be a problem, since that's an order of magnitude greater than the gravitational binding energy of the moon.
Conclusion: impact required would fully obliterate moon.
well moon moving out of its trajectory means alot more than tides (which in itself is pretty darn serious) IMO. The nights would be absolutely dark, also earth's rotation speed (AFAIK) is also affected by moon's gravity and bulges in both earth and moon's softer crust. Plus maybe we can adapt to such changes but our culture will change and it will be alot more difficult to live through that, imagine explaining to your kids/grandchildren what moon is (or rather was) and how it looked when it was closer/farther.
PS if moon gets a major hit, its highly unlikely earth stays 'physically' unaffected. The aftermath of the collision would leave numerous chunks of huge rocks in earth's near space and it would be almost certain that some of then then hit earth. And the effect of decent sized rock hitting the planet is better known to our long lost friends, the dinosaurs :)
Thanks for that. Quite a thought. Hopefully this will never happen - am assuming that the Earth has more chance of being hit than the moon (the moon being smaller and faster)?
But would the nights be totally dark? I've experienced a lot of nights out on a boat on a moonless night and the stars provide a (relatively) large amount of light on their own.
The Moon isn't faster. The velocities you care about for Solar System impacts are sun-relative. The Earth and Moon have essentially the same velocity relative to the sun, since they orbit it together. The Moon moves a bit slower at new phase and faster at full phase because its Earth-relative velocity subtracts from or adds to its Sun-relative velocity, but the former is 1 km/sec and the latter is 30 km/sec, small potatoes.
As for who gets hit; Earth's mass is 81 times that of the Moon so it attracts objects 81 times as strongly. Really, the Moon would only get hit if Earth already pulled an object into a collision course or near-miss and the Moon just happened to get in the way at the right time. Earth has 4x the diameter so presents 16x the cross-sectional target that the Moon does.
Don't forget that's a two-dimensional picture of 3D space, so it's probably not nearly as close to the moon as it appears. While most of the objects in the solar system are in kinda-sorta the same plane, they're not quite.
If all the objects in the solar system were in exactly the same plane we'd have a solar eclipse every month. The moon's orbit, for instance, is inclined at five degrees to the ecliptic.
Still cool, though.