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An artist's conception shows a cosmic impact on Earth. Comet impacts are harder to predict and more energetic, but asteroid impacts are much more common.
NASA's top expert on near-Earth objects says that new telescope systems, including a "last alert" system that's just now being set up, are gradually getting a handle on potentially threatening asteroids. But comets? That's a completely different story.
"We can do something about asteroids. Comets are a problem," said Donald Yeomans, the head of the Near-Earth Object Program at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
Yeomans is the author of "Near-Earth Objects: Finding Them Before They Find Us," a new book sizing up the cosmic perils posed by asteroids and comets — and looking ahead to the potential they offer for scientific discovery and economic exploitation.
For an example of the perils, you need look no further than the dinosaurs — or, more accurately, the lack thereof. Scientists believe an asteroid impact along the coast of Mexico's Yucatan Peninsula set off a chain of events that killed off the dinosaurs and many other species 65 million years ago. A much smaller impact in 1908 blew down half a million acres' worth of trees in Siberia, and could have leveled a city nearly the size of Tokyo if its trajectory were different.
NASA / JPL-Caltech
Donald Yeomans is manager of Near Earth Object Program Office.
Princeton U. Press
"Near-Earth Objects" focuses on the peril and the potential of asteroids and comets.
More recently, astronomers have sounded a series of alerts over close encounters with passing asteroids — including three cases involving the asteroids 2012 DA14, 2011 AG5 and Apophis. It turns out that none of those space rocks will hit us in the foreseeable future, but 2012 DA14 is due to come within 13,000 miles on Feb. 15. That's closer than the orbits for geosynchronous satellites. And experts agree it's only a matter of time before astronomers find a large asteroid that's actually on a collision course.
This is why Congress asked NASA in 1998 to identify 90 percent of the asteroids wider than a kilometer (0.6 miles). In 2011, NASA researchers declared that they achieved that goal. But they still have a long way to go to identify the smaller threats: The experts estimate that there are more than a million near-Earth asteroids capable of causing damage on the scale of 1908's Siberian fireball.
Several projects are in the works to catalog those smaller asteroid threats, including some projects that are funded by NASA's observation program for near-Earth objects, which is allocated more than $20 million annually. One such program — known as the Asteroid Terrestrial-impact Last Alert System, or ATLAS — started receiving NASA funding just this month. The $5 million, five-year effort calls for building telescopes in Hawaii that could provide advance warning for the kinds of asteroids that have eluded bigger detection programs.
"We think it's possible to provide a useful degree of warning for most impacts, meaning a day for a 30-kiloton 'town killer,' a week for a 5-megaton 'city killer,' three weeks for a 100-megaton 'county killer,'" the ATLAS team says on its website. (The numbers refer to the same TNT equivalents used to describe nuclear explosions.)
Yeomans acknowledged that even three weeks wouldn't be enough to divert an asteroid from its path — but it would provide enough time to plot the object's course, determine the impact zone and plan for evacuations if necessary.
What about the comets?
And then there are those pesky comets. We're not talking about comets that follow a regular route through the solar system, such as Halley's Comet. The course of those comets can be predicted decades in advance, and so far they appear to pose no threat. Yeomans and other experts are more concerned about long-period comets, which spend most of their time on the solar system's icy edge.
"Long-period comets, defined here as active comets with orbital periods greater than 200 years, are the most difficult objects to mitigate should one be found on an Earth-threatening trajectory," Yeomans says in his book. "The arrival of these objects from the outer solar system cannot be predicted, and the impact warning time would be measured in a few months, not years."
Generally speaking, long-period comets don't become discoverable until they come within the orbit of Jupiter, which would leave about nine months before they hit (or miss) Earth, Yeomans said.
If a truly monstrous comet were on a collision course, the scenario might well play out the way it did in the 1998 disaster movie "Deep Impact." There wouldn't even be enough time to mount a comet-blasting mission like the one that Robert Duvall took on in the movie. Fortunately, Earth's comet impact rate is thought to be less than 1 percent of the asteroid impact rate, Yeomans said. That's one reason why asteroids have dominated the discussion of potential cosmic threats.
From peril to profit?
All this may sound scary — and yes, it's scary enough that experts around the world have been discussing policy initiatives under the aegis of the U.N. Office for Outer Space Affairs. Yeomans is due to attend U.N.-sponsored meetings on space policy in Vienna next month, at just about the time that 2012 DA14 will be flying past. But Yeomans says there's no need to press the panic button.
"No one should be losing sleep over this issue," Yeomans told NBC News this week during his visit to Town Hall Seattle. "We've got much bigger problems, such as global warming or firearm safety. But none of those issues have the capability to bring us back to Square Zero. ... This is sort of an insurance program. You want to know what's out there, and if there's something threatening out there. Twenty years ago, maybe we should have been losing sleep, but we didn't know it."
Twenty years from now, will near-Earth asteroids still be perceived as potential killers — or will they instead be seen as opportunities to make a killing? Some boosters say asteroid mining could eventually generate a trillion dollars' worth of economic activity annually. Two sets of entrepreneurs are working on ventures aimed at laying claim to asteroids that could provide water, oxygen, construction materials and fuel for space-based operations, as well as precious metals that could be brought back to Earth. One venture, Planetary Resources, started up less than a year ago. The other, Deep Space Industries, was unveiled just this week.
Yeomans thinks it's great that investors are willing to put their money into space technologies, but he doubts they'll see a profit anytime soon.
"I don't understand their business model," he said. "What if you were to ask Colonial Americans to invest in the airline industry? Sure, the airline industry is coming, and it's great, but would you invest the Colonial equivalent of your 401(k) in it?"
In his book, Yeomans says the biggest reason to invest in the asteroid search now is to make sure we survive long enough to reap the longer-term payoffs:
"Near-Earth objects may one day be the fueling stations and watering holes for interplanetary exploration," he writes. "Ironically, the easiest ones to reach and mine are also those that are most likely to one day collide with Earth and perhaps disrupt or destroy our fragile civilization. We need to find them early and track them to ensure than none among them has our name on it. While these objects are critically important to our future, if we don't find them before they find us, we may not even have a future."
Update for 11 p.m. ET: I mused in a Twitter tweet whether it'd be better to face a killer asteroid or a killer comet. If you're musing over the same question, here's an extra bit of data from Yeomans' book: A comet streaking in from the outer solar system would typically have three times the impact velocity of a similarly sized Earth asteroid hitting Earth. When you factor in the density difference, "the comet's impact energy would be about twice that of the asteroid," Yeomans says. Considering that we're likely to have more advance warning about an asteroid, I'd probably go with the asteroid if I had to make a choice. Which would you pick?
More about asteroids:
- Reality check for asteroid miners
- Asteroid activists raise funds for space telescope
- Can paintballs save us from asteroid threats?
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.
Leave a Comment:
Sharks scare me more .
It looks like they are taking the danger from comets and asteroids pretty serious though .
At least tracking and projecting a hurricanes landfall , intensity and direction has dramatically improved .
If an asteroid threatens earth, line up all Republican men with beer bellies from side to side, and bounce it back in space. Reward them with t-shirts that says, "I saved the earth with my lard belly". And, then provide them with beer.
I'm not too worried about a comet or asteroid in the near future, but by the same token past history has shown that they do lead to global event level changes and it's not a case of if but when. We spend more on sodas, tv dinners, and political trips each year than we do on researching things that actually could destroy our planet.
ps. Thanks Rooster for your enlightened comment and being part of the problem and not the solution.
The article's title "Asteroids VS. Comets" gave me a great idea!
First we capture a large asteroid and place it in orbit around the earth, then we mine it and use the materials to build huge thrusters on it. Then if a comet or even another asteroid threatens, we maneuver our que ball asteroid onto a course to deflect it. Space Billiards!
Roosterboy's reaction may be over the top, but there is a religion based on praying before a space object, and often the after-effects on an impact can mean that people do strange things, even destroying the World Trade Center, not by the space object but by those who worship towards it.
Dan: Space Balls!
That's quite a profound statement, Donald. What is it that we can do about asteroids that makes them less dangerous??? Put up a sign in the sky to make it turn left?, away from Earth?
Three things:
1- Find them early enough to do something
2- Find them early enough to do something
3- Find them early enough to do something
Comets come screaming in from the outer Solar System, giving us months of warning - not enough time with current tech to do anything about it.
Asteroids live in the inner Solar System, and once discovered their orbits can ascertained for decades in advance of a potential impact; time enough, even with current tech, to do something to alter its course.
So, Michael, are you saying early detection is the key?
FIRE EVERYONE AND SHUT DOWN NASA----While all the over paid whiners who are doing absolutely nothing all day--while being paid hundreds of millions of dollars out of working people's taxes---are waving their save-our-jobs whine signs--The only way to save the the space program is to fire absoutely everyone at NASA
and Alan, our village idiot has chimed in! Yes, Alan, porridge is good, we all like porridge. Good boy....
(I agree with your statement Needle) Though I believe that we (Earth) should expend monies for "detection" research and ID'ing asteroid/comet threats. This research could foster further space exploration and scientific development in general. But I do not believe in the cataclysms that are purported in this article and the like:
1. If a asteroid/comet was on a collision course that was a "planet killer" and we could not "Armageddon" it from striking Earth then the point is mute.. what can we do... and if we could do something (evacuations, taking cover, disaster prep.) then.... well we'll do it.
2. Better to be safe then sorry.. again we should spend money and look But if life could survive the KT extinction event... I',m laying odds we can survive, thrive AND rebuild if it happens a gain... after all we are "smarter" now .. aren't we?
Crater National Monument is 3/4 of a mile deep and 3/4 of a mile wide hole in the ground. That was made by an asteroid only 150 feet in diameter.
"We can rebuild" is always said, but it might not mean as the civilization we think. It might not even be "us," i.e., humans. I think cockroaches might survive, or woolly caterpillars. Or, we might have enough bunkers scattered over the earth (and these had better have air supply and ability to seal, in case oceans do strange things), and enough biodiverse greenhouses (running on lightbulbs until the sky clears). The shaking alone might be enough of a shock to not survive.
If there is something that could be done, it will need public, not private funding, because what company will waste its money just destroying dangerous objects? Unless they can send the world the bill for their efforts, and what country would bother to pay it? Very often, we don't even pay the bills for international agencies.
Seems to be a lot of articles on this subject lately. What's out there???
There are links in this article to some of them, such as the ones that are nearby on Feb.12th and 15th of 2013, March 17th of 2013, and larger one in 2029, 2036, 2068. Without a space program, you won't hear much more though, even if one is on a collision course in the future.
"Without a space program, you won't hear much more though, even if one is on a collision course in the future."
You technically don't need a 'space program' (whatever that really means) to know something's coming. Not as long as the science of astronomy exists.
But you do need a meaningful spaceflight capability, to be able to do anything about one...
How did global warming and firearms safety get into this article?
@ Viewer_Ready
Umm... because Donald Yeomans said it in a quote?
I realize he's only a mere rocket scientist, and you're a... well, I'm betting on redneck... but I think you can rest easy that it wasn't an MSNBC conspiracy to rob you of your precious SUVs and assault rifles.
All of the better made firearms, such as the AR15, have very positive safeties. When the safety is on, you can drop one from a plane or hammer on it with a rock and it won't fire.
With respect to global warming, we could wish for some, it is brutally cold here today.
The "global warming" impacts include colder temperatures because of changes in the jetstream and moisture closer to the north pole. It's like "lake effect snow" around the Great Lakes.
In virtually all cases or scenarios, the answer is nuclear warheads. Even if you do not have time to slow down an asteroid or a comet in order to divert it from collision with the Earth, you can at least shatter it into many pieces, and maybe even hit any large remaining pieces with secondary strikes, or else divert many of those pieces with multiple warhead detonations in the near vicinity of those shattered remains, which in turn should dramatically lessen any impact with the Earth.
This is why I keep recommending that our international community build a standing arsenal of Deep Space Ballistic Missiles (DSBMs) as soon as possible. A couple of dozen missiles should probably do the trick, and our world can easily afford this together. - Rick Carter
(MIRV warheads might be best for slowing down a threatening asteroid or comet. Just a suggestion.) - RC
The impact with Jupiter years ago was a broken comet, and the multiple impacts allowed many parts of Jupiter to feel the pain. Breaking up is hard to do.
Actually, nuclear weapons is about the last thing you want to hit an asteroid with. With big asteroids, there would be little effect. With small asteroids the "smashing" thing would only serve to send smaller particles through the atmosphere and spread out the energy (heating) over a greater area and causing more damage to the Earth, than just letting it hit and concentrate the damage to one area.
The best thing is to "nudge" it with either a motor or paint it and let the Sun's influence move it about. The drawback to this method is we would need a lot of time to influence the orbital path enough to miss the Earth, depending on the mass involved.
If you cannot divert an asteroid, it is always (without fail) better to detonate a nuke on it if it poses any kind of danger.
Mitchell
Trying to blow these things up would be like blowing up New Hampshire and hoping it would sink into the ocean. One large enough/enough mass to avoid being diverted out of our path or sucked in elsewhere by natural gravitational forces would not be so easy to just nuke out of existence.
Doug, I understand it will be a very difficult call, and I also appreciate your concern about getting "MIRVed" by an asteroid, but please understand that generally speaking at least, by spreading out the energy over a larger area of the Earth, and correspondingly over a much longer period of time as well (especially if you shatter it into small enough pieces, most of which won't make it through the atmosphere), you will actually cause less damage to the surface of the Earth. Like I said, I know it is a very difficult call to make, but shattering an asteroid or comet with a series of big nukes would only be used on asteroids or comets over a certain size. Please keep in mind that an Extinction Level Event (E.L.E.) impact will threaten every city, and indeed all life here on Earth. Even an impact which just causes a monstrous tsunami in one of our major oceans would still threaten more cities than you would by shattering the asteroid or comet. Please remember that the Clovis comet caused a major extinction here in North America just 13,000 years ago, by igniting the entire North American continent with brilliant balls of aerial fire. If that energy could be spread out over a much larger area, and correspondingly a much longer period of time, by shattering any major comet like that far enough in advance, then this kind of devastation most likely would not happen. It would actually take an advanced computer simulation to make this kind of difficult call, since there are so many variables involved, so I also hope our world will be working on this kind of advanced computer simulation software (which will also tell them exactly where, when, and how much to hit as well) in the meanwhile. Sincere regards! - Rick Carter
(PLEASE don't wait to prepare this kind of advanced computer simulation software ahead of time, everyone, because when this kind of serious threat presents itself in the future, we will have to make this kind of refined nuclear targeting call ASAP !!!) - RC
Rick, I agreed with your point on distributed impact providing a greater likelihood of global survival, even if the immediate impact was much worse on major population centers if they were hit. However, bouncing a nuke off one of these things if it's core is primarily metal may deform it but it's unlikely to have a significant enough effect to shatter it into small enough pieces that it would matter. Now if we could land a nuke in a cavern inside of one then we might have a chance at cracking it up.
We definitely need to put together the tech to deal with such things, but we are a species that lacks global will to do little more than rush a response to a threat after it has already occurred. Then the response is often meaningless to preventing future occurrences, but it does make us feel better so we pat our backs and stick our heads back in the sand. If we were really smart we'd put science into getting off this rock, as that will determine the ultimate fate of humans.
It's very unlikely to have a solid metal core. Besides even if that was the case, we aren't talking just shattering it, we are talking about ionizing it too and that's as easy to do with metal as it is with rock.
Here's the thing. Tunguska was a rock that was only about 120ft (36m) in diameter. That's just an office building, and it leveled about 800 sq miles. That's far larger than either New York City or Los Angeles.
That means that small rocks pose a great danger. Rocks at 1000ft start affecting regions like England, Europe (continent), or New England. Effects of a 5000ft rock are global.
A one megaton nuke does serious damage, regardless of composition it'll take care anything under 200-300ft easily. If we are launching multiple warheads, perhaps up to 1000ft or more. Regardless of single or multiple, we are already talking about sizes than can be extremely destructive, sizes that you don't want left alone. Therefore that's why you would always want to detonate a nuke on it.
The best thing would be to nudge it off it's course, but if that's not an option, nuke it.
Mitchell
>Mitchell.. I would love to see the math on such and agree that if we can't nudge it then nuking it is likely our best option currently. My concern is that we get a 1000-5000m plus object and the nuke digs a big crater so we end up being hit by a 10 million ton glowing donut vs. a 15 million ton solid rock. Either way we'd be screwed. Another issue is that the object would have to be pretty close for the nuke option to work, as we lack the capacity right now to send that many nukes out to intercept it at a far distance. With a true global killer our likely best hope would be to crack it up and taking our punches.
Smaller ones nuking them would very likely be the best option, IF we see them coming in time.
At 5000m, you launch the world's arsenal that can get to it, at it. It is an extinction level meteorite.
The point I was making is that even small meteorites are very destructive and it gets worse from there. There is absolutely no middle ground where you would debate hitting it with a nuke or not as it will always be less destructive after a denotation. There's no math involved in this one.
The original claim was that nuking one was the last thing you wanted to do (doug's) and I'm just countering that, delivery mechanism was irrelevant to the original claim.
Mitchell
"In virtually all cases or scenarios, the answer is nuclear warheads. Even if you do not have time to slow down an asteroid or a comet in order to divert it from collision with the Earth, you can at least shatter it into many pieces..."
Unless it's a fairly small object, you absolutely do want true deflection, nit just pulverization. Otherwise, the same amount of kinetic energy will be delivered to Earth. Just in a different, but approximately as disastrous manner.
Having thousands of tons of 'gravel' enter the atmosphere, at once, in one area, to 'burn up' will mean not only a dangerously bright and intense (on a multiple nuclear scale) patch of sky for several minutes (you know how bright a single small rock can be as it streaks in...multiply that as much as required), but because the material doesn't just 'go away,' you've now deposited said thousands of tons of ash into the upper and perhaps lower atmosphere that is going to have severe climactic effects.
You want to make it miss. Period.
"Actually, nuclear weapons is about the last thing you want to hit an asteroid with. With big asteroids, there would be little effect."
Well, that would depend on how big, and how early.
Using nukes to push things in space is not an unknown quantity. In Project Orion (no, not the current Orion), the use of 'nuclear pulse' to propel spacecraft was well studied, and would have to have some relevance to asteroid deflection, especially if it's an object of largely metallic composition.
"At 5000m, you launch the world's arsenal that can get to it, at it. It is an extinction level meteorite."
'The world's nuclear arsenal' doesn't all consist of space-capable missiles. Those in cruise missiles, nuclear torpedoes, short-range ballistic missiles, gravity bombs, etc. Won't be of much help.
And, even with multiple warheads somehow converging on the same spot, you absolutely must somehow arrange for the perfect simultaneous detonation of all of them. Otherwise, any that delay will be destroyed by the others, and add nothing to the overall release of energy.
(No, it's not like chemical explosives where one can potentially trigger others. I don't care what you may have seen in movies, it doesn't work that way. Nuclear explosives are essentially mechanical devices where a number of things must occur just right, in a very short period of time, to work. If they don't, you get a reduced efficiency detonation, or none at all. And a nearby explosion of any kind that damages the structural integrity and triggering electronics of the device in question, is quite enough to do that. Nuclear tacticians have long understood that if they must attack a target more than once, they can't send in the second warhead until the area has had a few minutes to 'settle down' [including not approaching from a direction that comes through the previous debris cloud at tens of thousands of miles per hour], or it could be disabled/destroyed to no useful effect. That's why early anti-ballistic missile systems, with less accuracy than is possible today, were nuclear armed. It was considered preferable to detonate a 1-kiloton nuke on an intercepting missile at 40,000 feet or so, to kill an incoming warhead of 500 kilotons to 1 megaton meant to detonate at or near the surface.)
Consider this, in your asteroid attack plans...
@Frank: That's why I said that 'can' get to it, obviously not all are capable.
Also, you don't need them all grouped together, it can be staggered. On top of that you'd do it in pairs where you detonate on opposite sides to increase the internal stress in hopes breaking it apart.
But, the EMP effects are vastly smaller in space than in the atmosphere. The E3 component is virtually eliminated once you get several tens of thousands on miles away (which is the reason for 'cool down period' on multiple strikes). The E1 component is largely irrelevant since there is little ionization occurring. That leaves the E2 component which is far less effective than the other 2 and is something that can be hardened against.
The reason why nukes are so destructive here is because they are being used in the atmosphere on a planet with a magnetic field. Once you get into space, their destructive power decreases quite a bit, but they are still the most powerful thing we have.
But, as I said twice above, the best thing is to simply alter the course.
Mitchell
Sounds like most of us agree on the basic solution (we don't have that many options), just debating over the details required to implement such most effectively.
I'd still like to see the math (graphs) on # of megatons at what distance vs. size/composition/speed it would take to either nudge or crack up a comet or asteroid, but that likely won't be calculated until our hind quarters are in a sling. Our biggest issue IMO is the delivery, as we'd likely have weeks or months if something is zooming in at us previously unknown. Think about how long it would take for us to throw together the rockets to do the job, these days probably a year or more.
Our biggest issue is detection, there's so little resources devoted to it. We need time, time to develop a plan to deal with a threat, preferably with enough time to divert it.
The people doing it are doing a heck of a job with what they are given, but they are vastly understaffed and underfunded. I believe there's only about 20-30 astronomers tops working on finding potential threats working on a budget of only a few million and this is worldwide. There just needs to be a better system put into place.
Mitchell
The problem with nukes is you take one big rock and turn it into lots of smaller rocks, each one seeking out a target. This isn't Star Wars; real space objects don't blow up in pretty little orange explosions so you can fly your X-wing through them.
Our ICBM's are made to attack our fellow man here on Earth, not engage targets in space, meaning very short range flight time as compared to distance we would need to intercept the inbound asteroid. At a minimum, they would need to be reprogrammed to not fly back into Earth's atmosphere to release their payload. Second, some type of booster would be needed to extend its range sufficient to hit the target. Finally the nuke would need a significant upgrade in its targeting software as GPS is useless in space.
All that, and we STILL have the problem of turning a cannon shell (one big asteroid) into grapeshot (many small chunks of asteroid). It is highly unlikely we would obliterate the asteroid in question, meaning the chunks will still be flying toward us per the laws of motion, and now we have many more target to attempt to deflect. The best solution is gradual changing of the asteroids course by gravitational nudging or other means. It isn't sexy, and it isn't going to be a major motion picture, but it would work a heck of a lot better than trying to blast the bejesus out of an asteroid only to have its bit still hit you.
Harcourt, the shotgun effect doesn't apply here. You will never have a situation where smaller chunks are more destructive than a whole. Whoever came up with that idea never sat down an realized how small a meteorite needs to be to cause extensive damage, it very quickly ramps up.
And we really weren't discussing delivery mechanism past the point that it needs to be developed. However, if push comes to shove, you'd take warheads and place them on Delta's or something like that.
And as mentioned several times above now, we do know the best plan is to simply make it miss us in the first place, but we cannot guarantee that there will always be enough time for that.
Mitchell
Funny this came up - I just finished re-reading "Lucifer's Hammer" for about the 8th time. Niven supposes that a 4 1/2 mile wide comet breaks up and hits Earth "as a series of flying mountains". In developing an analogy, some of the characters compare the comet to a gigantic hot fudge sundae - a relatively soft, slushy interior surrounded by a thin frozen crust, and of a similar density. In supposing that Earth is struck by a cubic mile of hot fudge sundae, they estimated the energy release at approximately 2.7 x 10E28 ergs.
Doesn't really help Earth, as it's still mass times acceleration. Several dozen major strikes, earthquakes, tsunamis, planet-wide rain. Same energy as a single impact, just distributed differently.
Great book, btw - I highly recommend it and most everything else by Larry Niven. It's a shame the "Armageddon" and "Deep Impact" folks didn't read it.
I am not with the blasting it to bits theory. On the flip side, gravitationally guiding it would need time, and more time if it was faster or denser. I have said many times (here as well) that one of a civilizations milestones is the ability to deflect a killer rock. Of course ability and success are not the same. I agree the comet from beyond would be faster, but if it was mostly ice then going thermonuk as the above poster suggests, would very well be the correct answer....almost...that would be some valuable water, in any event if we decide to experiment, let's do it inside venus's orbit not out here were we carbon infestation units are.
We know that there are large magnetic currents in our own solar system. We CAN generate large electric fields, even remotely, and if nuke is your color green, imagine a set of thorium reactors that we set on a wayward rock (nine hours to rama? boy they would hate this manuever!!). Since we know more than is good for us about repulsion, attraction, magnetism and electricity, it's a only a small theoretical stretch to use the available magnetic fields for propulsion, to interact with the solar systems magnetic field lines we either need big magnetics or, next best thing, big electric generators (hence the Th) and just a leeetle bit of control for steering. I would say mankind has the ability to hit the first class a civilization status (just barely, and mostly by luck and serendipity but that's another composition).
I purpose, again, an offworld observation network (manned would be nice, with ion guns and a whole lotta reserve) AND a new mapping project, one that gives us a much, much, MUCH better picture of the magnetic currents swirling through our solar system....after all, those magnetic currents are exactly HOW we will get to mars in less than two weeks......just as soon as we either educate some democrats on science or at least get em to spend a few real bucks......well, ya know my fellow blues ain't gonna let me tote no big ole ion gun on out to IO for target practice, right?
Interesting ideas, Ray. I haven't researched much into mag currents for propulsion, but the idea sounds intriguing. Thanks for the input.
The idea that magnetic fields can be used for spacecraft propulsion is physically untenable. While magnetic torque devices have been used on satellites to make attitude corrections (just orbiting satellites) - it takes a long time to get a satellite to move just a few degrees... and that is in Earths magnetosphere, which is orders of magnitude greater than inter-planetary fields. The solar wind does have stronger magnetic fields, but there are only a handful of large events. Deep-space magnetic fields have been measured by Voyager, ACE (just go to almost any space weather website to look at the data), and a number of other spacecraft.
Magnetics might not do the trick, but solar wind or just the radiation energy might. The trick is to use our knowledge to divert the object.
What 'magnetic currents' do you refer to? If you're considering interacting with the magnetic fields of The Sun or Earth...that's nice if you're a charged subatomic particle, but neutral macroscopic objects?
You might as well try to catch a speeding car with spiderwebs...
A mega volcano out of Yellowstone is as likely as a large hit.
...or any of the other mega-volcanoes. However, we have the technology now to detect and, most likely, prevent threatening asteroids from hitting us.
We can't affect volcanoes now or in the foreseeable future. All we can do is try to give adequate warning before they blow.
We could affect asteroids and comets if we really tried, however. A civilization that does nothing deserves whatever happens to it.
There's an even better idea - be somewhere else when it hits! Bet it would make a great show from the Moon, or Mars, or the Asteroid Belt. We need to get off this rock!
About cue balls, luna could be our source of interceptor material. We also could use lunar based observations to improve detection, and yes thorium based energy sources could supply safe power for long lunar nights.
Not that we have a 'choice' in what we get hit with, but I believe that a comet would be far more destructive due to the higher velocities and water content that would vaporize, and through thermochemical cycling, generate far more heat. It would behave more like an atmospheric nuclear device in terms of blast effects (as was shown in Tunguska).
Most rocky/metallic asteroids would be far more narrowly focused and more of their energy would be dispersed in the formation of a crater (or craters if they break up).
In any case, it's bad either way for someone.
Except there probably wouldn't be a crater because it would in the ocean and create the mother of all tsunamis. You hodads keep your boards waxed and ready.
I think that will depend on how much water volume gets displaced by what was left of the leading shock wave and the asteroid itself after slowing in the atmosphere. If an asteroid hitting us were big enough to cause a major tsunami hitting the ocean, it would probably be on the level of a state or country destroying size... my point was that if they are equal in size, the comet would do more damage.
If anyone thought that the government would tell the people that an asteroid or comet was on a collision course is a FOOL
I'm a planetary astronomer. Anyone who thinks that "the" (as if there is only one) government could hide such news is beyond foolish.
There are thousands of astronomers in dozens of countries; any of whom can see the sky, and all of whom collaborate on a daily basis. There is no way that such news could be kept secret, even if there was anyone motivated to do so.
Has there been an increase in the number of conspiracy theorists, or have they just now learned how to use a computer?
And why hide it?
Assuming we can't stop it, does it really make a difference if people 'panic' now, or say, six months from now, when it's a naked-eye object...?
Even if there was some way that ALL the world governments decided they would try to hide it, it would be a major FAIL. Heck - they can't keep a gun sale to a third world country secret. Whatever would make someone think they could keep something like this secret? lmao!
I see your "silent world governments on potential killer asteroid" and raise you a "we never landed on the Moon and everyone including the Soviets are in on it" as proof that the tin foil hat brigade is procreating at a rabbit's pace. Next time, Buzz needs to punch a little lower, and a little harder.
Sky Dog: Yes.
Sadly, it's both.
So, the bottom line here is if we get the last call alert, we have to dive under the bed, or better yet, if there are some backyard bomb shelters left over from the cold war, some might have a chance to survive for awhile after the hit of a big asteroid.
No. The bottom line here is - we need to find them, we need to find them early, and we need to do something about it.
You are welcome to hide under your bed SNG; I'd much rather stand with the people who will actually DO SOMETHING ABOUT IT.
Unlike volcanoes and hurricanes and the like, THIS IS A COMPLETELY PREVENTABLE DISASTER.
Not sure I agree that it is "completely preventable" as that implies we have the knowledge, systems and technology to detect and affect changes to avert an event, or escape an event that we can't avert.
Finding them alone is a huge challenge without a large ongoing, highly coordinated effort and supporting tools. Then the technological aspects need to be addressed. We can't even agree that one methodology will work over another because we have neither experience to guide us, or enough data about the make-up of these objects (i.e. loosely packed cometary or granuals vs. rocky packed vs. solid, etc.) and how they will behave under various scenarios to tell us whether destroying an object is possible or it will be better to divert it or to leave the planet entirely.
This becomes a lot like the AGW/Climate change debate... there will be those who feel that it is worth the cost and effort to focus significant resources in this area, and those who believe that the probablity of something happening in their lifetime makes it a complete waste of time (i.e. money).
Maybe, if the asteroid mining industry really takes off, we'll be closer to being able to answer a lot of the open questions and be able to make it completely preventable.
"Maybe, if the asteroid mining industry really takes off, we'll be closer to being able to answer a lot of the open questions and be able to make it completely preventable."
All the more reason to support that (and any other form spacefaring infrastructure), so that if a rock is found with our name on it, it becomes a simple matter of calling Planetary Resources, Deep Space Industries, a space patrol/rescue force, or anyone else who has the already existing capability:
"Hey, can you guys spare a ship to go X coordinates, and just nudge that object Y amount, in Z direction? What? Sure, we'll pay the usual rate for your time, and you're entitled to anything useful it may contain, once you do..."
Hopefully, the mining company will not nudge it the wrong way; or if they do, they are insured for any losses they may cause. Not to worry though, the mining industry is known for its dedication to high safety standards.
"Hopefully, the mining company will not nudge it the wrong way..."
If you've already determined that it's going to hit Earth if left to itself, then anything else is the 'right' way...
Well, we can always be beamed up to the Enterprise, if it is built soon enough.
The Enterprise, can use it's tractor beam to move hurricanes, and bad asteroids, out of harms way.
A smart race of beings would have ready on the moon several missles capable of delivering a 100 megaton nuclear bomb or even a 500 megaton nuclear bomb which with Moons lower gravity that should be achievable. Then they can quickly launch to intercept those 500 foot and smaller State busters. A 500 megaton nuke would vaporize a 500 foot rock or at least push it away from it's orbit towards Earth. That's 10 times bigger than the biggest nuke ever set off by Russia (50 megatons).
Not allowed due to treaty.
And in addition to the above, it's easy to throw those explosive yields around, but those would be big bombs, and unnecessarily so. The largest nuke ever detonated was a Russian 57 megaton device (though it's said that it was deliberately held down from a potential 100 megaton yield), and it was a physically BIG device. Even with today's technology, it couldn't be made much smaller.
Most strategic nuclear weapons today are 1 megaton, or less. Greater accuracy has reduced the need for crazy yields, and effects don't scale linearly, they're proportional to the 2/3 power of the weapon yield. (Going from, say, a 1 megaton to a 10 megaton device, doesn't have 10 times the effect/damage, but about 4.4 times the effect. But all other tings being equal, weapon mass does increase in a more linear manner. You soon reach a point of diminishing returns.)
So, if we could set of this mega nuclear arsenal on the Moon (yeah, we'll all sleep easier knowing that it's up there, potentially pointable somewhere else...), it means we also have the spaceflight capability to set up automated asteroid search systems, spot threatening objects, and (Test Ban Treaty not withstanding) smack the thing with a 1-kiloton device (stored on Earth until/unless needed) early on, push it on a comfortably safe path, go back to bed...
We don't even have the capability of putting our own astronauts into space right now. How do we expect NASA to intercept an asteroid or comet? Think about how much greenhouse gasses would be released by a missile launch.
There are even more greenhouse gases on/floating about the deep ocean floor than we've ever produced. If an asteroid of fair size stuck the oceans the heating from it alone could create a greenhouse effect that would last for centuries. Not to mention suffocate most life on the planet.
You'd be amazed what people can do, when the heat's on. And besides, this would more likely be handed off to the Department of Defense (which has the nukes, after all), with NASA only in a support role.
I have little doubt that an EELV (or maybe Falcon) being prepped for something else, could be pressed into service for deflection purposes. Life's a lot simpler when you're essentially 'shooting' at something, rather than sending people to it...
Ummm. We do, in fact, have the means of putting our own astronauts into space. Just not on our own ships. But that will be the case sooner rather than later.
But I do agree - we'll need to have some heavy-lift options in order to have any chance of intercepting anything. LEO just ain't gonna cut it, if we ever do find something headed our way.
Define 'heavy lift' for these purposes. The payload is only a warhead, guidance and terminal propulsion.
Doubtful that we have anyway currently to do anything about an asteroid and even less about a comet. The best is to hope neither is that large and we can move as many people out of the way if the asteroid or comet is to hit land. The problem is that the asteroid or comet has the greatest chance to hit in an ocean. If it hits the ocean, the an extremely large tsunami is goint to wipe out many many cities. Imagine a tsunami 3,000 feet high.
1. Purchased lifetime supply of Face masks for CO2 - pollution. Check
2. Purchased lifetime supply of Gas Masks for biological warfare. Check
3. Built boat in garage (for rising sea levels) which is too big to get out. Check
4. Have entire 2nd floor of home filled with gallons of bottled water for droughts. Check
What to buy/do for Cosmic threats?
This is EXHAUSTING and a full-time job!
LOL. That is too funny.
The correct answer finally dawned on me as I was reviewing some other material. Tholians web!!
Personally, I've never even seen an asteroid or comet. I'm not all that sure they even exist.
I have no fear of comets or asteroids striking the earth. It is what it is. Man made issues are far worse.
Donate your plastic bottles and plastic bags to planetary defense, everyone! - RC
About the worst case scenario would be a cometary impact in a major ocean. Water waves well over a mile high would likely destroy every major city that sits on the coastline of that affected ocean. The oscillations of such an impact would have those waves surging through the ocean for days. It's likely that the affected areas would be scoured of every man made structure now in place. Subsequently, mud, debris, and bodies would coat the land to immense thickness as the water reversed course and was sucked back out to sea. Then of course, you have to deal with the effect of hundreds of gigatons of seawater being vaporized by the impact. As that water "rained-out" of the atmosphere, we would see storms and flooding on a scale previously unknown in human affairs.
Interesting. Maybe the story of Noah involved a cometary impact in the Mediterranean Sea.
Maybe I missed something, but why are hemorrhoids and vomit threatening Earth?
Keep an "EYE ON THE SKY" Folks. It could happen at ANY TIME. THAT THEY FIND ONE ???? or then again WE ALL GO BOOM!!! No time to say "GOOD BYE ALL".
Hey its all part of the Big Bang Theory...Dinosaurs were here on earth millions of years before man..We have only been here a short time...and we can easily be replaced and probably will..Nothing lasts forever not even man. We think we are special but we are not we are as ants on an anthill...
Except ants survived the last couple of extinction events.