Scientists Stunned By 'City-Killer' Asteroid That Just Missed Earth On July 25 (msn.com) 252
A "city killer" asteroid whizzed past earth Thursday that "would have hit with over 30 times the energy of the atomic blast at Hiroshima," according to one astronomer professor.
Long-time Slashdot reader SonicSpike shared a Washington Post story that begins with a reaction from Alan Duffy, lead scientist at the Royal Institution of Australia: "I was stunned," he said. "This was a true shock."
This asteroid wasn't one that scientists had been tracking, and it had seemingly appeared from "out of nowhere," Michael Brown, a Melbourne-based observational astronomer, told The Washington Post. According to data from NASA, the craggy rock was large, an estimated 57 to 130 metres wide (187 to 427 feet), and moving fast along a path that brought it within about 73,000 kilometres (45,000 miles) of Earth. That's less than one-fifth of the distance to the moon and what Duffy considers "uncomfortably close...."
The asteroid's presence was discovered only earlier this week by separate astronomy teams in Brazil and the United States. Information about its size and path was announced just hours before it shot past Earth, Brown said. "It shook me out my morning complacency," he said. "It's probably the largest asteroid to pass this close to Earth in quite a number of years."
So how did the event almost go unnoticed?
Scientists have spotted 90% of asteroids that more than half a mile wide -- but this asteroid was smaller, faster, and had an unusual orbit.
"It should worry us all, quite frankly," one scientist told the Post. "It's not a Hollywood movie. It is a clear and present danger."
Long-time Slashdot reader SonicSpike shared a Washington Post story that begins with a reaction from Alan Duffy, lead scientist at the Royal Institution of Australia: "I was stunned," he said. "This was a true shock."
This asteroid wasn't one that scientists had been tracking, and it had seemingly appeared from "out of nowhere," Michael Brown, a Melbourne-based observational astronomer, told The Washington Post. According to data from NASA, the craggy rock was large, an estimated 57 to 130 metres wide (187 to 427 feet), and moving fast along a path that brought it within about 73,000 kilometres (45,000 miles) of Earth. That's less than one-fifth of the distance to the moon and what Duffy considers "uncomfortably close...."
The asteroid's presence was discovered only earlier this week by separate astronomy teams in Brazil and the United States. Information about its size and path was announced just hours before it shot past Earth, Brown said. "It shook me out my morning complacency," he said. "It's probably the largest asteroid to pass this close to Earth in quite a number of years."
So how did the event almost go unnoticed?
Scientists have spotted 90% of asteroids that more than half a mile wide -- but this asteroid was smaller, faster, and had an unusual orbit.
"It should worry us all, quite frankly," one scientist told the Post. "It's not a Hollywood movie. It is a clear and present danger."
Ya know, finding asteroids is cool and all (Score:5, Insightful)
But why should people be worried? It's something that we can't stop, so why worry? Walking around scared of everything is good for getting clicks on a web page I guess, but not a great way to live life...
Re:Ya know, finding asteroids is cool and all (Score:5, Insightful)
But why should people be worried? It's something that we can't stop, so why worry? Walking around scared of everything is good for getting clicks on a web page I guess, but not a great way to live life...
If it's a "city killer" and you're warned early enough can you not choose to be somewhere else when it lands?
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Re:Ya know, finding asteroids is cool and all (Score:5, Informative)
You likely already are somewhere else when it lands. Everyone likely is. Something like 99.6% of the earth's surface is not city. A good 75% is water and Antarctica and Greenland. Of the remaining 25%, massive amounts are pretty much empty. Northern Africa, Canada, Russia, Brazil, Australia. It's mostly the coasts that have people. The interiors of continents are mostly empty. Exceptions are Europe, India, and China.
Seriously - the earth is rather empty: http://luminocity3d.org/WorldP... [luminocity3d.org]
A "city killer" faces long odds in actually being able to live up to its name. Best odds are that it lands where nobody really notices.
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Re:Ya know, finding asteroids is cool and all (Score:5, Interesting)
still a city killer, only it's vector is now a tsunami
Energy of 2011 Fukushima quake and tsunami: 4e22 joules
Energy of Hiroshima bomb (15 kT TNT): 6.3e13 joules
Energy if this asteroid impacted (30 Hiroshimas): 2e15 joules
So a very very very small tsunami.
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Small? In relation to what?
With the right distance to the coast it would be devastating.
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Yeah, just like all of the nukes we set off in the Pacific wiped out Japan and the west coast of the US.....
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Aaaaand, if you make a bomb that big, you will also create Godzilla to clean up whatever's left. Brilliant!
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Yes, it was. It was the only nuclear bomb ever made that used U235 as the fissionable. There was about 10x as much fissionables in that bomb as there was in the Nagasaki bomb, much less in well-designed bombs later....
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That's not true, there were numerous warheads tested by multiple nations that used U-235, U-235/Pu-239 mixtures, and even U-233. Little Boy was the only *gun-type* U-235 bomb ever built by the U.S., but implosion types using Uranium fissionables were built and tested by the U.S., the UK, and (probably) the Soviet Union. They just didn't bother with the gun-type because despite being easy to build, all these countries had already successfully designed or stolen working implosion designs which resulted in far
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Also I just post this and remember that I'm wrong here too. The US built, tested, and deployed a number of U-235 gun-type warheads after Little Boy, including that very famous Upshot-Knothole test of a nuclear artillery shell.
https://en.wikipedia.org/wiki/... [wikipedia.org]
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Greenland? Sounds like you've been suckered in by a Mercator-style projection of our fair globe. In actuality, Greenland fits inside Australia nearly three times. [thetruesize.com]
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This is a super click-bait article. less than 200 feet across, and more than 40k miles away? That's not a close call. Hell, you could fit all but two of the planet in our solar system in that space.
Re: Ya know, finding asteroids is cool and all (Score:2)
Depending on the asteroid and the detection, we could evacuate a populated area likely to be wiped out. It's probably not worth it, but sometimes we go above and beyond to save people's lives.
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So what? If you couldn't take your shit with you when you evacuated it was going to get destroyed in the blast anyway, and the idiot looters will probably get destroyed along with all their loot.
Before or after the blast? Just kidding, also so what?
Depends on how much time there is to evacuate. Given enough time I think a reasonably orderly evacuation could be achieved.
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There will be looting. There will be fires. It will be mayhem.
Yeah, and that's before the asteroid.
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Solar flare, gust of solar wind, and suddenly you find out it's landing on Boston instead of NY with 3 hours to spare.
At one AU, a burst of particles from a flare could barely move a grain of sand. It will have no effect whatsoever on the path of an asteroid with a mass of several million tonnes.
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Only in Texas.
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Re:Ya know, finding asteroids is cool and all (Score:5, Insightful)
Well, an economist will tell you it's a matter of marginal benefits. A hundred years ago the marginal benefit of looking for civilization-destroying asteroids would have been zero, because there is literally nothing anyone could do about it. A hundred years from now, the marginal benefit would be greater because for many objects we'll be able to nudge them away.
But what about right now? Well, we probably can't alter the course of a civilization-destroying asteroid, but we live in a world which produces a two- to three-fold surplus of food. The reason that people starve isn't that there's not enough food; people starve but because we can't be bothered to get the surplus food to them before it rots.
Given a few years' warning, it is quite feasible to get most of the world's population through a year of greatly reduced food production. Even given a few weeks of warning could allow greater numbers of people to survive than being completely blindsided.
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Well, we probably can't alter the course of a civilization-destroying asteroid
WIth a few years' notice - depending on the mass and trajectory - and Elon's reusable rockets, we most certainly can.
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Either that or n old-fashioned nuclear war - but the meteor strike won't leave us dealing with as much radiation
Maybe it's made out of uranite :)
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Exactly my first thought. It will be many decades and perhaps centuries before we can do anything about such a threat. "Worry" just makes the problem worse without adding anything on the plus-side. Maybe worry about global warming instead, were something can actually be done and which is pretty much a threat several orders or magnitude larger?
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I second that. Not much can be done to deflect a killer asteroid, it is still a struggle to put a couple tons of mass into LEO. A battlestar spacecraft much more difficult if not impossible (i.e. been decades of attempting to put a man on the moon since 1972).
"I've seen this movie before, it hits Paris."
Re: Ya know, finding asteroids is cool and all (Score:5, Insightful)
Re: Ya know, finding asteroids is cool and all (Score:4, Insightful)
Re: Ya know, finding asteroids is cool and all (Score:5, Insightful)
I find the idiots who reply to the ACs making them more visible to be worse. I almost never see an AC comment unless someone logged in replies to them.
In the old days a lot more people understood not to feed the trolls. Those were the days.
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Some percentage of that activity is no doubt paid advertisement. But some of it is just trolling. Trolls gonna troll.
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Regardless, the satire is accurate. I heard one preacher claim humans couldn't affect G-d creation because it was so big and wonderful so we needn't do anything about pollution, global warming....whatever he felt conflicted with his lifestyle.
Re:Ya know, finding asteroids is cool and all (Score:5, Insightful)
Because, unlike the dinosaurs, we have technology. Given enough warning, we certainly can stop an asteroid of this size.
A 110 kg W80 [wikipedia.org] has the power of 10 Hiroshimas. Detonate one just above the surface and an asteroid of this size would be reduced to dust and rubble. Do it even a week ahead of time, and 99% of the debris would miss the earth.
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Even better, just below the surface.
That would be far more difficult.
The asteroid and warhead would have a relative delta-V of about 10 km per second.
An impact would vaporize the warhead, so you would need lots of heavy and expensive retro-rockets, and a mechanism to burrow into the asteroid.
It would be way more cost effective to just use a bigger warhead instead. Or even better, send multiple warheads so if one malfunctions, the other will get the job done.
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If you don't want to deal with velocity matching and a "soft" impact, the obvious solution is the use of a "train" of kinetic impactors spaced out ahead of the warhead to create a hole for the warhead just before the detonation.
Perhaps, but the impactors would spray debris into the path of the warhead. If the warhead hits a rock a 10 km/sec, it is not going to detonate (well, the RDX will detonate, but the plutonium trigger will not).
If you do the math, I think you will find that if the mass of the kinetic impactors is put into a bigger warhead instead, it will have orders of magnitude more "impact".
Each kg subtracted from the impactor and replaced with a kg of lithium deuteride in the warhead will add 10,000,000 kg of TNT equiva
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Even better, just below the surface.
That would be far more difficult.
Shouldn't be really. All you need to do is send over a team of Texas wildcatters - they're sure to drill to the exact point where the explosion will have the maximum effect and detonate the bomb at the precise last second.
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Even better, just below the surface.
That would be far more difficult.
The asteroid and warhead would have a relative delta-V of about 10 km per second.
An impact would vaporize the warhead, so you would need lots of heavy and expensive retro-rockets, and a mechanism to burrow into the asteroid.
It would be way more cost effective to just use a bigger warhead instead. Or even better, send multiple warheads so if one malfunctions, the other will get the job done.
Don't you just gather up a bunch of oil rig guys to send while someone writes a snazzy rock'n'roll soundtrack?
Re:Ya know, finding asteroids is cool and all (Score:5, Interesting)
Nuking the asteroid is unlikely to work, even if you send a team of undersea drilling experts to place the bomb inside the asteroid first. Diverting the asteroid is a much better plan.
However, that's quite hard, as we have to detect the collision years in advance, and we largely don't have asteroid orbits modeled that accurately. We'd also need a way to shove the asteroid - a solar sail would get the job done, given enough time, but we don't have a proven solution.
Picking a convenient asteroid and practicing seems like a worthwhile mission.
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Nuking the asteroid is unlikely to work
Are you serious? A 300 kiloton warhead detonated next to a 100 meter rock?
My backyard is more than 100 meters across, 300 kT is 20 times the Hiroshima bomb.
Much of the rock would be vaporized, and the rest reduced to rubble.
To miss the earth, a blast a week before impact would need to change the course by less than a tenth of degree.
Giving a piece of debris a perpendicular delta-V of 10 m/s would be enough.
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Depends on the distance. It would have to be very close, but if you did send Bruce Willis &co to place it on or under the surface, then sure. For an asteroid that small.
Perhaps it's easier just to paint the rock white though?
One experiment was recently done will a small explosive, and it had basically no effect at all. Bombs make very bad rocket engines, so you'd have to blow it up: impart enough total energy to overcome the escape velocity of the asteroid for the mass of the asteroid. Perhaps pract
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Adjusting it's mass will have no effect - it's falling through space on a path determined by the gravitational gradients of the sun and planets that it's traveling across - doesn't matter if it's a mountain or a ball bearing, the path will be pretty much the same.
Well... except for the minor detail that your spring-loaded catapult or similar is in fact an incredibly inefficient rocket engine - rather like throwing a basketball while sitting on an rolling chair. Get it going soon enough, and coordinate its
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Assuming it can survive impact with precision timing
You don't impact. You detonate a millisecond before impact. At a delta-V of 10 km/sec, that is 10 meters above the surface.
A W80 is easily capable of a precise detonation on the millisecond scale, and proximity fuses are mature tech.
send a massive heavy rocket to harpoon the asteroid, then fire the main engines again to push it off course.
The energy density of a nuke is about 10 million times higher than the fuel of a chemical rocket.
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At a delta-V of 10 km/sec, that is 10 meters above the surface.
These asteroids are moving quite fast relative to us. It's vastly more difficult to match velocity with the asteroid than to simply fly into it at a few thousand m/s. It's technically doable, as we've done it, but there's a reason asteroid missions are new.
The energy density of a nuke is about 10 million times higher than the fuel of a chemical rocket.
Sure, but almost all the energy is in gamma and x-ray radiation. That could work to vaporize a small target, but if no the only meaningful thrust you'll get from that is from the surface of one side vaporizing off, across a hemisphere. That's not noth
Re: Ya know, finding asteroids is cool and all (Score:4, Insightful)
The earth has a radius of 6370 km. If you have a week, that is 168 * 3600 seconds.
So you will miss if you can change the velocity by 10 m/s.
The mass of the asteroid is 5 million tonnes = 5e9 kg. Changing the velocity by 10 m/s requires 5e10 joules.
A 150 kT W80 warhead delivers 6.4e14 joules.
So it would need to be 0.01% efficient at converting blast to kinetic energy.
Re: Ya know, finding asteroids is cool and all (Score:4, Interesting)
The earth has a radius of 6370 km. If you have a week, that is 168 * 3600 seconds.
So you will miss if you can change the velocity by 10 m/s.
That's so not how orbits work, but anyway.
It might work for a rock this small, though I suspect it will vaporize anything small enough to be effectively moved off course. It's not so much a question of energy as achieving a net thrust in some direction. Because the energy transfer is very fast, the surface of the asteroid will become a high-pressure gas, rather than being blown off one layer at a time. That means it will mostly expand in all directions, though clearly there will be some thrust. As you say, not much efficiency is needed though.
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You don't impact. You detonate a millisecond before impact. At a delta-V of 10 km/sec, that is 10 meters above the surface.
I think the W80 is the wrong tool for this job. I think you WANT to bury that weapon 100 or so feet under the surface to create a 'nozzle for the energy.
Let's use a B61 nuclear bunker buster instead. It is designed to be fitted with a hardened penetrator. 100 ft is doable. Granted, the closing velocity is higher (4km/s vs 10km/s) but perhaps they can make it work.
Re:Ya know, finding asteroids is cool and all (Score:5, Funny)
Because, unlike the dinosaurs, we have technology.
But unfortunately . . . whenever I read the Google News . . . I get the feeling that humanity these days has the intelligence of dinosaurs.
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. . . I get the feeling that humanity these days has the intelligence of dinosaurs.
Large groups of humans are ineffective at dealing with long-term problems.
But individual humans can be very ingenious, and even large groups can act intelligently when dealing with an immediate crisis.
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Re:Ya know, finding asteroids is cool and all (Score:5, Insightful)
So instead of 1 impact site you have thousands and thousands.
Thousands of particles of sand and gravel that will burn up in the atmosphere. This asteroid has a mass of about 5 million tonnes. If 1% of the debris hits the atmosphere, that is 50,000 tonnes. That would be equivalent to a very, very small volcanic eruption. Pinatubo ejected 10 billion tonnes in 1991.
an ocean strike can be a lot worse.
Energy of 2011 Fukushima quake and tsunami: 4e22 joules
Energy if this asteroid impacted intact (30 Hiroshimas): 2e15 joules
If 1% impacted, it would be 2 billion times weaker than Fukushima.
Re:"Shanghai" Bill is a known liar many times over (Score:5, Informative)
That said, it would have been great if Bill had provided some links to back up those numbers.
This Wikipedia page [wikipedia.org] lists the energy of the quake at 3.9e22 joules according to USGS. I rounded off to 4e22.
To get the other number I typed "kT of TNT to joules" into Google, and multiplied the result by 15 to get one Hiroshima, and multiplied that by 30 to get the energy of this impact.
Total time spent on research: About 30 seconds.
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So instead of 1 impact site you have thousands and thousands. That's like the people who say that there's a 70% chance it won't hit land so we're probably safe - not realizing that an ocean strike can be a lot worse.
Layman here, but as I understand it, you have at least two problems with an energetic kinetic impact:
1) The concentrated damage in a small area from a single, large impact. A sea strike can be devastating and destroy many coastal areas from the resulting tsunamis, while a land strike would statistically be very likely to occur in a sparsely populated area. Still sucks for those finding themselves at that spot, though.
2) The dissipation of energy and matter in the atmosphere, which can have catastrophic effe
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A thousand bus-sized lumps would burn up in the atmosphere (and they'd spread out so some would miss anyway) . Leave them as one mall-sized lump and it hits the ground with a bit more than soft thud.
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We currently have no means of preventing a strike on Earth. None what so ever. Comforting isn't it?
We also have no means to prevent an earthquake or a volcano going off either. What's your point?
Re: Ya know, finding asteroids is cool and all (Score:4, Insightful)
I was thinking San Francisco myself, but to each his own.
Re: Ya know, finding asteroids is cool and all (Score:2, Insightful)
Meh better that republicans who steal it for the rich. These people are willing to work for a living.
Re: Ya know, finding asteroids is cool and all (Score:3)
by left leaning illegal immigrants
Don't oversimplify. Sure, they'll vote Democrat but most of 'em are also extremely socially conservative... and ignorant: lots of low-IQ fundies; they come in many colors and faiths."
Worst of both fucking worlds.
Clear and Present Danger (Score:5, Funny)
"It's not a Hollywood movie. It is a clear and present danger."
He does realise that "clear and present danger" is a hollywood movie, right?
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This has become a new pet peeve of mine. Space is big, there is not, relatively speaking, a lot of stuff in it. A collision could happen, but it would be like setting two brownian motion cars out on opposite sides of the Gobi Desert and expected them to collide in your lifetime. Yes collisions do happen, and when several factors, size, distanc
Observational fail or science success... (Score:2)
Improbable, but according to QM, only improbable.
Interesting Revelation 8 class stuff, though.
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Don't worry (Score:2)
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You mean like voting for representatives who will adequately fund asteroid detection and deflection as opposed to, I don't know, representatives honking on about going to Mars because the Moon was sooooo yesterday?
Fucking bugs... (Score:2, Funny)
Klandathu must pay.
I'm from Buenos Aires (Score:2)
Scientists stunned (Score:2)
by their own lack of statistical education.
Yes, there are asteroids out there. Some dangerous ones will go undetected.
If our current methods are inadequate for the level of risk we consider acceptable, then maybe we're doing something wrong and something should change. Maybe it's very serious and human civilization needs to have some dialogue about doing better managing that risk. But random things happening at random isn't news.
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Maybe it's very serious and human civilization needs to have some dialogue about doing better managing that risk.
There is literally nothing we can do about this.
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Maybe if the scientists would point out (Score:3)
the climate change an asteroid strike would cause, governments could do any/all of the following:
1) Dig a hole in the ground and bury their heads.
2) Create plans for sequestering asteroids with asteroid tax money.
3) Figure out how to pass on lucrative asteroid contracts to friends and family.
4) Pass laws to ignore asteroids.
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You forgot asking Jesus to stop pissing around and get here already. He's only 2000 years late from when he said he'd return. Surely the Prosperity Preachers could spend a Preaching Hour asking for Holy Intervention instead of asking for money for G-d's Altar...which sounds suspiciously like their house.
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You forgot asking Jesus to stop pissing around and get here already. He's only 2000 years late from when he said he'd return. Surely the Prosperity Preachers could spend a Preaching Hour asking for Holy Intervention instead of asking for money for G-d's Altar...which sounds suspiciously like their house.
I thought only a couple hundred thousand people would be "saved" in case of an impending End of the World scenario. At least only the most faithful.
The alter is typically used as a source of funding to pay off incidental expenses like blackmail from male and female "professionals" and court "settlements" with no conviction for wrongdoing. Oh and maybe a nice new private jet.
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Just pass a law to make asteroid impacts illegal. That'll stop them.
TL;DR summarization (Score:2)
“We asteroid-hunting scientists obviously need increased levels of funding!”
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Overheard at a Brazilian observatory (Score:2)
It's coming right for us!!
Be quiet! Don't you have other English sentences to practice with??
How do they know? (Score:5, Funny)
Scientists have spotted 90% of asteroids that more than half a mile wide...
They know 90% of the known asteroids? Okay.
Re:How do they know? (Score:5, Informative)
They know 100% of the known asteroids. Knowing how your detection systems work in detail, and using statistics (which can also be used independently of modeling the detection process physically) allows you to calculate how many you have missed.
Statistics is not magic, witchcraft or guessing.
Thank Dog (Score:2)
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MY DOG! IT'S FULL OF RATS!
About the same size as Tunguska meteor (Score:3)
That would make it
Given the frequency with which the ~Tunguska sized events occur (about one every few hundred years), it's pretty safe to say there are many of these out there, and probably several which have had near-misses in the last decade which we never even detected. (The moon's orbit is about 385,000 km. The Earth's radius is about 3960 km. So a "near miss" inside the moon's orbit represents a target circle roughly 10,000 times larger in cross-sectional area than the Earth.)
As for the odds of a "city-killer" asteroid actually hitting the city, cities cover less than 2% of the Earth's land area [aaas.org]. or roughly 0.5% of the Earth's total surface area. So about a 1 in 200 chance that a "city-killer" asteroid would actually hit a city if it did make landfall. If you expect one of these to hit the Earth every 200 years, then it'll be an average of 40,000 years between cities being wiped out by a meteor. Factor in the odds of me actually being in that one ill-fated city the day of the impact, and I have a hard time getting worried over something like this.
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Hell yes we should be scared! (Score:2)
More people have been killed by rogue meteorites and asteroids than by the recreational use of multirotor drones -- a little acknowledged fact.
Yet every day, the media publishes hyped up predictions of death and destruction that will be caused when drones bring down airliners.
Yet the death toll remains steadfastly at a big fat ZERO.
So why aren't we equally as concerned and scared of the much bigger (and proven) risk from asteriods and meteorites?
Makes no sense, does it?
Guess where 2019 OK was first detected? (Score:2)
Two special-purpose observatories in Hawaii play a vital role in detecting Earth-approaching objects: https://en.wikipedia.org/wiki/... [wikipedia.org]
One of the ATLAS instruments has been blocked off to observers for the last two weeks because it is located on the mountain where protesters are trying to prevent construction of the newest observatory to be permitted on the astronomy reservation site. The protesters are preventing use of the existing observatories as a bargaining chip to get their way on the new project.
Tim
How can they be sure? (Score:2)
Obviously these "smaller, faster" asteroids pose a serious threat, as they are much harder to detect and would be more troublesome to react to if only spotted very late on approach. We'll clearly want to continue to improve our detection capabilities and catalog as many objects as possible, though we ne
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I saw it! (Score:2)
That's what I saw on Thursday night with my friends. We were outside having a break from a jam and looking at the stars on the blackness when the thing cut through the sky, it was really bright and big too.
Our other friends were turned the other way and we both went "whoooooooaaaaa" when we saw the thing. It took about 2 seconds to pass and it was much lower than a normal "shooting star".
How Do They Know? (Score:2)
"Scientists have spotted 90% of asteroids that more than half a mile wide "
If they haven't spotted 10%, how do they know? If you haven't spotted something, how can you generate a percentage of an unknown total???