scientists do not understand

nec208 · Jul 10, 2007

I have 3 questions one if there is a asteroid coming to earth what can they do to stop it? And are the scientists working on a solution. And 2 what causes gravity is it mass and 3 why do scientists who work on anti-gravity is look down on by other scientists or like many people on this group who flame others for talking about it? May be it take 5 years or 100 years to one comes up with a anti-gravity .Well the same goes for plasmas weapons prove to be before we look into it , but this not the case with plasmas weapons. I know no grade 9 book in school that talks about what is gravity and all we know is the effects of gravity . My science is at a public school level , I just do not understand the high school science .. <div class="Discussion_UserSignature"> </div>

MeteorWayne · Jul 10, 2007

1 Perhaps. It depends on how far in advance we know the asteroid is coming. If it's a few days, there's nothing we can do. If it's a few orbits (i.e.years) we may be able to do something, though we do not yet have a plan. We have ideas that should work. 2 What "causes" gravity? That's a good question. According to Einstein, it's the bending of space-time. I'd say we don't know for sure. You can predict how much gravity there will be by the amount of mass. 3. Anti gravity. Well, no one works on it because it doesn't exist. There is no viable physics to state it could exist. There are some wacky theories, without even a consistent mathamatical proof. No one gets flamed for talking about it. They just get banished to phenomena where discussins of physics that do not exist belong. Wayne <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

deapfreeze · Jul 10, 2007

Sounds like a pretty good explanation to me MeteorWayne. We should however try working a little harder at comming up with a plan for asteroid protection. <div class="Discussion_UserSignature"> William ( deapfreeze ) Hooperhttp://deapfreeze-amateur-astronomy.tk/ </div>

billslugg · Jul 11, 2007

nec208 The reason that some scientists are looked down upon is that they make outlandish claims yet they do not provide evidence to support the claims. Lots of times we will give someone the benefit of the doubt. Because they are esteemed and have a good track record and have never let us down before, we will say "OK - could be true, you are a credible source, I'll believe it for now." But proof is eventually expected, or the claim must be withdrawn. Anti gravity is not simple levitation, where power is applied and an object is raised against a gravitational field. There are magnetically levitated trains that float above the ground, yet no one laughs at them. The reason is that they paid their energy debt. They injected energy into the system and raised the train against the gravitational field. Work was done, potential energy was gained, the train came back down, the debt was repaid. No laws were broken. Anti gravity believers think you can somehow raise a mass against a gravitational field without having to input energy. This would be a violation of the first law of thermodynamics which says that energy can neither be created nor destroyed. It is the most tested, most verified law of physics. It has never been broken. If we could find a way to make free energy we would all be very wealthy. Whomever managed the feat would be more famous than Jesus. Don't you see that some people might be dreaming the impossible dream? Don't you see that some other people see a possible way to make a buck if they could just convince the world that they were almost at the solution but just need a few more developmental dollars? We should not laugh at people who really believe in it. We should simply help them to see the error in their ways. We should not tell them it is impossible, because they will not believe it and, frankly, that is not true. It IS possible that someday the law may be broken. No one can tell for sure. As for those who <div class="Discussion_UserSignature"> </div>

oscar1 · Jul 11, 2007

Perhaps this sounds silly, but couldn't we capture an asteroid, park it in Earth' orbit, fit it out with small rocket engines, and use it to smash into the rock that is coming for us if one does at some point in the future?

nec208 · Jul 11, 2007

They can't use nukes it will brake it up in too many small asteroids and it do more harm than good. And there is no space craft that they can send. <div class="Discussion_UserSignature"> </div>

nec208 · Jul 11, 2007

Anti gravity is not simple levitation, where power is applied and an object is raised against a gravitational field. There are magnetically levitated trains that float above the ground, yet no one laughs at them. The reason is that they paid their energy debt. They injected energy into the system and raised the train against the gravitational field. Work was done, potential energy was gained, the train came back down, the debt was repaid. No laws were broken. =============================== Yes basic rules energy = work and no energy = 0 work. What I'm trying to get at if they can some how come up with a anti -gravity device with out braking any laws. And there is no point asking anyone on how one can make a anti -gravity device because no one has any idea at all. <div class="Discussion_UserSignature"> </div>

nec208 · Jul 11, 2007

What "causes" gravity? That's a good question. According to Einstein, it's the bending of space-time. ============================ I will need more information that is not much .. All I can find on good old wik not much... wik In physics, spacetime is any mathematical model that combines space and time into a single construct called the space-time continuum. Spacetime is usually interpreted with space being three-dimensional and time playing the role of the fourth dimension. According to Euclidean space perception, the universe has three dimensions of space, and one dimension of time. By combining space and time into a single manifold, physicists have significantly simplified a large amount of physical theory, as well as described in a more uniform way the workings of the universe at both the supergalactic and subatomic levels. wik But using the fourth dimension will only tell where the object is in space <img src="/images/icons/shocked.gif" /> <div class="Discussion_UserSignature"> </div>

derekmcd · Jul 11, 2007

"The reason that some scientists are looked down upon is that they make outlandish claims yet they do not provide evidence to support the claims. Lots of times we will give someone the benefit of the doubt. Because they are esteemed and have a good track record and have never let us down before, we will say "OK - could be true, you are a credible source, I'll believe it for now." But proof is eventually expected, or the claim must be withdrawn." Exactly. Let's use the Higg's Boson as an example. A theoretical particle that is the essence of mass of all other particles. Find a way to shield the effects of the Higg's field and you might just find how to negate gravity. Highly theoretical. Well, not even theoretical... but an interesting thought. <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

derekmcd · Jul 11, 2007

"The reason that some scientists are looked down upon is that they make outlandish claims yet they do not provide evidence to support the claims. Lots of times we will give someone the benefit of the doubt. Because they are esteemed and have a good track record and have never let us down before, we will say "OK - could be true, you are a credible source, I'll believe it for now." But proof is eventually expected, or the claim must be withdrawn." Exactly. Let's use the Higg's Boson as an example. A theoretical particle that is the essence of mass of all other particles. Find a way to shield the effects of the Higg's field and you might just find how to negate gravity. Highly theoretical. Well, not even theoretical... but an interesting thought. <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

oscar1 · Jul 11, 2007

The sheer velocity of the incoming rock would reduce a nuclear blast to no more than a pinprick. But I am referring to a major collision (no nukes involved), whereby a required portion of the mass of the projectile is [hopefully] instantly converted into 'path altering energy'.

MeteorWayne · Jul 11, 2007

It's not a bad concept Oscar, though obviosly not something we could achieve now. The biggect problem of course, is where can you get, and how do you harness the energy required. It's not like accelerating a spacecraft. It's like accelerating 1,000,000,000,000,000,000,000 spacecraft all at once. acelleration= Force/mass. And the mass of an asteroid, even a small one, is very big (it would also have to be or wouldn't work for what you suggest) If you can reach it, applying the same force directly to the incoming asteroid (with a mass driver, or massive ion drive) would be more efficient, IF you have enough time. Wayne <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

vandivx · Jul 11, 2007

that mass is the cause of gravitation of matter is only an assumption albeit as sure an assumption as that one that the sun will rise and go down in the evening for example reason is that no 'mechanism' of gravitational force is not known, we don't know how the mass is bending space and so it is I think just an assumption although it is as strong link (btw mass and gravitation) as it gets and you can take is for a fact unless you work on the theory of gravitation trying to show what the real mechanism is, in that case you consider the subject as open and call that an assumption mass is the measure of inertia of matter and it so happens that if you double the amount of matter and thus double the inertial resistance it gives to acceleration you also get double the gravitational force - this is often illustrated by that famous experiment in which a feather falls in a vacuum as fast as one kilogram ball of iron say as for antigravity I think it can be discussed even here if one keeps it within bounds of valid physics but then again you don't get too far that way I believe we need to understand the 'mechanism' of gravity before we start considering antigravity, at least as far as theory goes, experimentalists may stumble onto something but that is not too likely IMO once we understand how gravity works in the first place we might see right away how likely it might be that antigravity could be realized and it doesn't have to always violate some energy conservation laws, I mean we could input lots of energy to set up some block of matter to antigravitate (perhaps for limited time only) or more likely setup some cylindrical region of space reaching out into orbital space at great energetical cost in such a way as to 'unbend it' and rocket placed into such area of space might leave the Earth gravitational field using just engines to overcome its inertia to get moving... it would cost tons of energy if it could be possibl <div class="Discussion_UserSignature"> </div>

oscar1 · Jul 11, 2007

I know what you are saying, that is if we are looking at, relatively speaking, an 'instant defence'. Yet if we would gradually interfere (step by step) with the trajectory of a chosen asteroid, we might eventually get it into the required orbit. This may take quite some time, and would be too late to start doing, of having started doing, if some rock decides to come our way in the interim period, but would at least represent us doing something vs us currently doing nothing. We could even decide that a tiny portion of our defence spending should be channeled in the direction of this project, since we are talking here about a clear case of 'defending ourselves' against possible attack (we can only die once, no matter who or what causes it). It would also be very good for science, and wouldn't have to lead to anyone currently deriving income from defence spending to lose that income.

MeteorWayne · Jul 11, 2007

As I stated in another thread, our current focus needs to be threefold. 1. examing space for asteroids that might impact us. Nothing else would provide such intense motivation to address the actual issues of deflection as knowing an impact is coming a decade or so down the road. 2. Charachterising the structure of asteroids and comets. So far we have visited less in total that one person's fingers and toes. Each time we learn someting about an object's mass and structure. This will be crucial when it comes time that we need to attempt a deflection. Every comet and asteroid we've visited has been different in these qualities. 3. Time to get some of the more manageble concepts, at least, off the drawing board into some hardware. Unfortunately, without #1, there's not enough motivation to spend the time and money. So we "ostrichize" <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

oscar1 · Jul 11, 2007

OK, I'll retreat, and go back to hoping that we will have a Harry Stamper available to moment we need his services. <img src="/images/icons/wink.gif" />

kyle_baron · Jul 11, 2007

They just get banished to phenomena where discussins of physics that do not exist belong. /i> You make it sound like Phenomena is a bad place for a topic to be discussed. <img src="/images/icons/tongue.gif" /> It's just a topic, that is not scientifically (politically) correct. So that the "purists" (with their noses held high) in the scientific community, are not offended or tarnished. <img src="/images/icons/blush.gif" /> <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> </div>

MeteorWayne · Jul 11, 2007

I'm not suggesting you retreat, Oscar. As I said, you make a lot of sense, we all just have to work on figuring out how the get the "rocks" that run our countries to become serious enough about the issue! <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Jul 11, 2007

I didn't say it was a bad place, just that it was where it probably belonged. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

lukman · Jul 11, 2007

<blockquote>In reply to:<hr /> why do scientists who work on anti-gravity is look down on by other scientists <hr /></blockquote> Gravity were generated at sub atomic level, where normal physics law is invalid, time is not relevant, it is the place where uncertainty happens. How one can anti the gravity using physics law? Until human truly understand how those fundamental forces work, else we cant make anti any of those forces. We understand matter, we can make anti matter, at a very inefficient and costly way -P <div class="Discussion_UserSignature"> </div>

tony873004 · Jul 11, 2007

I like the idea of nuking the asteroid, as long as we can do it a few years before impact. If they're loose piles of rubble, barely held together by their own gravity, as their densities suggest they are, then a nuke on an asteroid would be like a firecracker on a dirt clod. After nuking it, as the fragments spread out, it won't be long before the average spacing between then exceeds 1 Earth diameter. Then it is likely that none of them will hit us.

MeteorWayne · Jul 11, 2007

Sorry, but it is clear you do not understand the magnitude sizes, masses and velocities involved. Too many movies and TV, not enough physics. Sorry if that sounds tough. A nuke (even the most powerful on earth) will barely blast dust off the surface of an asteroid. The best chance is to change the speed by a millimeter a second far enough in advance that it will make the asteroid miss us. A nuke MIGHT be large enough to do that if placed in the right spot, where the force and mass will cause that change in velocity. Other methods have a more reliable and predictable chance of success. Too many unknown variables with a nuke. Wayne <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

tony873004 · Jul 11, 2007

I don't understand the magnitudes and masses? "It's not like accelerating a spacecraft. It's like accelerating 1,000,000,000,000,000,000,000 spacecraft all at once." Your figure exceeds the mass of the Moon (assuming the spacecraft you're talking about is more than 70 kg). All Earth-crossing asteroids are significantly less massive than this. For example, Apophis is about 20,000,000,000 kg. Apophis' surface gravity is only 0.00001 that of Earth's surface gravity (assuming 125 meter radius and 2e10 kg mass). You couldn't even walk on its surface as even your most gentle step would accelerate you well beyond its escape velocity. The Castle Bravo nuclear test (15 megatons or 6e16 Joules of released energy) produced a crater 6500 feet in diameter, roughly the size of Apophis, and 250 feet deep. Why would something that can produce an Apophis-sized crater on Earth barely blow dust off an asteroid with negligable surface gravity? And the crust of Earth, at 2.7 grams per cubic centimeter, is more dense than an asteroid. Apophis is estimated to be about 2.4 g/cc which is why it is theorized to be a loose pile of rubble, rather than solid rock. The best chance is to change the speed by a millimeter a second far enough in advance that it will make the asteroid miss us. A nuke MIGHT be large enough to do that if placed in the right spot The strategy behind a nuke is not to nudge it by a mm/s, but to break it into fragments, each carrying off momentum. When the spacing between the fragments exceeds 1 Earth diameter, Earth will simply pass through a debris field possibly getting hit by a few negligable fragments, but much more likely not getting hit at all. Another advantage of nuking it is that we don't have to worry about the error bars on our orbit calculations. Since the nudging methods work best a few decades in advance, and we might not know to a precision of a few thousand kilometers where this

CalliArcale · Jul 11, 2007

<blockquote>In reply to:<hr />The strategy behind a nuke is not to nudge it by a mm/s, but to break it into fragments, each carrying off momentum. When the spacing between the fragments exceeds 1 Earth diameter, Earth will simply pass through a debris field possibly getting hit by a few negligable fragments, but much more likely not getting hit at all. <hr /></blockquote> The problem is being able to spread those fragments out sufficiently such that you don't end up just turning a single slug into a shotgun blast (so to speak). You are correct that it may be possible to break up Apophis and scatter the fragments, but I don't have the math to be confident that it could a) reduce Apophis to fragments sufficiently small as to burn up safely in the atmosphere, and/or b) spread the fragments out sufficiently that there is negligible risk of any of them hitting Earth. I still think it would be easier to divert the intact asteroid than to break it up and essentially divert all the bits, but I do confess that I lack the skill to prove this mathematically. It's just a hunch. <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

oscar1 · Jul 12, 2007

The size of the asteroid, comet, or whatever, is really secondary to its velocity. Where exactly are you going to detonate that nuke, when the rock covers a distance of say 30 miles each second? That moment the nuke is detonated next to the rock, is a moment too long, for the rock is within that moment already 10 miles away. If the nuke is detonated in front of the rock, the kinetic energy of the rock and its velocity, will most likely be far greater than the energy concentrated within the blast, and will the rock shoot through the bast like an aeroplane flies through a tiny cloud; it would hardly notice it! There are really only two ways to avoid a collision between a threatening rock and Earth, and that is indeed to gradually change the trajectory of the rock over decades, or to alternatively make it collide with another rock (which we would have to long before have placed into a strategic orbit), and make use of the kinetic energy to rubble it. Either way, we will need decades.

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