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# NASA to end Global Warming

Cool the Earth and end our dependence on foriegn oil at the same time
 (-10) [vote for, against]

OK, I just made up that part about foreign oil. But it seems like it would be possible to cool the Earth by increasing the distance from the sun. This could be accomplished by increasing the mass of the earth.

(Quick physics lesson: If you have a ball on a rubber string and you swing it in a circle, the rubber stretches to a certain point and stops. This is where the earth is currently. If you add weight (sorry, "mass". I'm on summer vacation) to the ball without lessening the velocity, the circle gets bigger. The rubber band is the sun's gravitational field.)

So we send out specially designed spaceships to go out and mine whatever they can and bring it back to earth. The more stuff we bring back, the more mass we have, the farther we get from the sun.

TA DA! Global warming issue solved.

 — Hunter79764, Aug 12 2006

gravitational slingshot http://en.wikipedia...itational_slingshot
(Momentum gained by a spacecraft is lost by the planet) [ldischler, Aug 12 2006]

Gravity Well http://www.divnick.com/wishing_well.htm
Put your money into plastic gravity wells [baconbrain, Aug 14 2006]

HullaBalloon Hullaballoon
To hold the ocean water out of the way and delay the possible effects of global warming [Hunter79764, Aug 15 2006]

Barycenter http://en.wikipedia...rycenter#Barycenter
Barycenter = Centre of gravity [zen_tom, Aug 17 2006]

Randall's recent take http://www.xkcd.com/1732/
Um... [RayfordSteele, Sep 12 2016]

2019 update https://www.express...sail-space-news/amp
Semi-legitimate work from NASA and the University of Glasgow on a related topic [Hunter79764, Jun 09 2019]

What If The Earth Were Twice As Big? https://www.youtube...watch?v=1bVfzBD-40E
youtube [Skewed, Jun 09 2019]

Increase of mass effect on orbit https://www.physics...ct-on-orbit.172283/
physicsforums [Skewed, Jun 09 2019]

[marked-for-deletion] Good idea, but bad science. Gravity doesn't work that way.
 — ldischler, Aug 12 2006

What do you think would happen if the earth gained mass, ldischler?
 — jutta, Aug 12 2006

well, if this works, it would only be a temporary fix, until the junk in the atmosphere was concentrated enough for warming the earth even at a farther distance from the sun. you'd also need to work out how far away the earth would need to be and how to keep it from intersecting other planets as that's probably not how you'd want to add mass.
 — tcarson, Aug 12 2006

 Actually this could work very nicely, assuming it were possible to transfer the mass to the earth without messing things up. However we would need to come up with quite a bit of mass to pull that off. I would have to guess that a uniform layer of stuff several miles high at least would be needed to gain enough mass(say level with the tip of mount everest) for the effect to be noticable, however you only need to move the earth a little bit(say less than 1 or 2 times the diameter of the planet further out) to have a measurable effect, considering what happens just due to planetary tilt on its axis. I wonder if just lowering a few good size comets a few hundreds of miles across into the ocean might work to cool things off a bit.

 Um [ldischler] last time I checked that is exactly how gravity works. Either increase mass or increase velocity, both will result in a wider orbit. Thats basic newtonian Physics.

 [Hunter] Where do we get the special space ship?

I wonder if adding a second earth orbiting mass might do the job as well, though you would have to be awful careful not to run the two moons into each other. then atleast there would still be surface topography on the planet.
 — jhomrighaus, Aug 12 2006

//What do you think would happen if the earth gained mass, ldischler?//

Gravity is a distortion of space-time. It's not equivalent to adding mass to a ball on a rubber string, as hunter says. Add mass to the earth, and the orbit is unchanged. To change the orbit, you'd have to add momentum. You can do that (as has been proposed) by interacting the earth with other bodies (such as comets). You can gain or lose momentum that way, and this has been used to propel spacecraft to higher or lower orbits. It's called gravitational slingshot. Although, to change the orbit of the earth appreciably, millions of interactions would be required.
 — ldischler, Aug 12 2006

 Momentum = mass * velocity

 however the problem rests with the mass increase, It cannot be performed by any known process.

I dont think youre right about the whole spacetime thing as newtons laws can and do govern planetary motion(how were Keplers laws Proven) Its just not possible to change the mass without imparting an energy impulse on the system. IF you could somehow increase the Mass of the Planet with no impulse THEN the planet would shift to a wider orbit.
 — jhomrighaus, Aug 12 2006

 [Idischler] is quite correct about the workings of gravity.

Let's imagine for a moment you have an object in an orbit around a larger object. (In this example, ISS around Earth.) The object then spawns another object in the same initial orbit with far less mass (a spacewalking astronaut). How does his smaller mass affect his orbit? The answer, fortunately, is that it doesn't.
 — lurch, Aug 12 2006

 [jhom], since when has the question "How would we actually do something like that?" stopped a HB post? Obviously, (this means I am making it up as I go) NASA would work in conjunction with Russia and any other space program that exists and develop the special craft. It would be funded by the UN, because it benefits the entire world.

 I've only taken a few physics classes, but I still see this as do-able. Granted, there isn't the technology and it would be not very feasible, but it could work. As was said, the only way to change the distance from the sun is to change momentum. Also as was said, momentum=mass * velocity. Add mass, add momentum, increase radius of orbit from the sun.

 The idea that you cant add mass without the energy impulse is beyond me, and I will admit that.

The spacewalking astronaut is always tethered to the ship, right? If he followed the same path (orbit) as the ship, it seems like it would be only slightly inconvenient to retrive a lost astronaut because he would only drift as fast as his shove-off from the ship, which would not be very fast assuming he didn't have suicidal intentions. The tether is there because without it or something like it (i.e. an arm, hanging onto the ship) the astronaut would travel fairly rapidly away from the ship. I'm no astronaut (or physics major), but this is how it seems to work to me.
 — Hunter79764, Aug 12 2006

You've only taken a few physics classes, but proceed to give a basic physics lesson that is ludicrously wrong, and then base your idea on it. That's the bakery for you. (And that's why "bad science" is a reason for MFD.)
 — ldischler, Aug 12 2006

 //What do you think what would happen if the earth gained mass, Zeno?//

 Hmm an interesting question.

 First of all I think the effect it will have on the orbit of the moon willl have drastic consequences for the climate. (due to the effect on the oceans that are the belly of the climate)

 Furthermore any change in orbit will change how we (as a mass) interact with other planets.

 These man made changes are abrupt changes (from the point of view of the age old patient brother earth)

 So there might very well be a reaction like the axis would realign or even the crust might change position as seen from the core. Tiny changes in these things would bring about massive changes in the climate.

 These changes would likely bring about a new iceage, not exactly what you had in mind.

 These and other side effects of your idea have a much greater effect then the mere distance from the sun.

[marked-for-deletion] pretty bad science.
 — zeno, Aug 12 2006

Oh, and global warming is a natural fenomenon (sp?) It happened before, it will happen again. There is no proof whatsoever that mankind has anything to do with it. (I say we should not cut down trees, not pollute the environment, treat the earth as a garden and be good and nice to it and to eachother, yes!) But global warming is in effect because we are still warming up since the last ice age, completely natural.
 — zeno, Aug 12 2006

Oh, and your dependence on foreign oil lies more in the economic climate of the world then in you being able to get enough of it.
 — zeno, Aug 12 2006

 While the idea of, for example, taking mass of the moon and putting it on the earthwould have Zero effect on the overall Earth Moon Orbit as the energy transfer from one to the other nets out.

 [lurch] His mass does not effect his orbit because he was on the station and had an inital Angular momentum and when separating from the station a component of the Momentum is transfered from the station to the Astronaut(a change in mass with no change in velocity, then Momentum is the same, Orbit is the same.

 If however he pushes off the station directly along a tangent to the orbit of the station the station will slow minutely and the astronaut will take on a small increase in velocity, so both will experience changes in Momentum but together the changes net out with the changes in Mass and Velocity.

 If the astronaut pushed off perpendicular and to the outside of the orbit, then he will begin to travel a new Orbit that is wider than before and it would not be a periodic orbit(neglecting all outside influences that is) He would eventually spiral out of the solar system. The space station would now begin a smaller orbit that would eventually spiral into the sun.

 WHat is not addressed anywhere in any way is what happens if you instantaneously from nowhere suddenly increased the mass of an object(since of course it is not possible to do it) BUT if you could in your example what would happen to the astronaut if his mass doubled? Would he continue on his path(with a change in angular momentum?) would he suddenly slow down(to Preserve his momentum?) Would he shift to a wider orbit? Or would he be pulled inward due to his increased mass and begin to trace a degrading orbit(non periodic)?

[ldischler] your right that this would not work the way he thinks. But why not try to be more open to the discussion of the topic, so that through the interaction people can become better educated? When I first read this I said sure it would work. Then I started to think on it and the discussion begun and I realized that there were issues with making it happen and have arrived at a deeper understanding of the question. You yourself are not always correct in your evaluation of a scientific question and so could be a little less harsh while others undertake to understand these more obscure questions, From a half baked perspective this is a Fun Idea even if it is doomed to failure, we dont need to draw and quarter everyone for discussing it. IMHO.
 — jhomrighaus, Aug 12 2006

Please, what it means, IMHO?
 — zeno, Aug 12 2006

Orbital distance is dependant on the Mass of the entire system. You don't need to ADD mass to the earth. You need to REDUCE mass from the sun.
 — Galbinus_Caeli, Aug 12 2006

IMHO In My Humble Opinion.
 — jhomrighaus, Aug 12 2006

In agreement with ldischler on the physics, but regardless, can we leave the planet where it is, please? Thank you.
 — theircompetitor, Aug 12 2006

Would you be able to bring back more mass than you've used in propellant?
 — RayfordSteele, Aug 12 2006

 You are just going to have to make up your mind whether you are adding mass that has zero velocity (big thump) or adding mass that is travelling along with the earth.

 // If the astronaut pushed off perpendicular ... it would not be a periodic orbit... he would eventually spiral out of the solar system. //

 Sorry, to get to a "non-periodic" orbit is going to take a *helluvalot* more power than an astronaut's shove. (non-periodic means non-returning, and that only happens if you've reached escape velocity. The astronaut's shove would need to be an instantaneous acceleration to 42100 m/s relative to the ISS.)

 Anyway, to the idea. You decide to, let's say, double the mass of the earth. Doesn't affect the earth's orbit but only slightly (and that in the opposite direction than you wanted, because of the added gravity of the total mass of the earth-sun system) but now the gravity level measured at the earth's surface is 2 g! (Ok, let's not add matter with infinite density, black holes are bad for the environment, so more likely about 1.4 g). Now everything is harder to move, so you need to use more energy and create more pollution for anything you move. That's also backwards from what you want.

 The most remarkable effect, though, would be the rise in the earth's atmospheric pressure, due to the extra gravitation. This would cause water to not evaporate as easily, and you would have a major decrease in cloud cover. Said situation would continue until the temperature rose to a point to regain a new cloud equilibrium - possibly as much as 20 degrees higher than the current temperature.

Pressure-cooked fishbone for you.
 — lurch, Aug 12 2006

Any idea that proposes artificial cooling measures to cope with global warming gets a fishbone from me. Thinking we can just correct any environmental trouble is part of the problem with global warming!
 — EdisonsTwin, Aug 12 2006

 ok, let's assume that [ids] and others are right when they say you'd need to add mass to the Earth *and* add have the Earth interact with our celestial bodies to slingshot us into an alternative orbit.

 Let's assume that's all possible. (Personally, I'd mfd it right there because its theoretically but not practically possible)

 However, I will fish this idea because the mass you'd need to add it so phenomenal, it'd take far too long - it'd be easier to stop our poisoning of the planet now and have it rectify itself.

 Also, even if the slingshot were possible, what's to say it wouldn't push us closer to the Sun?

[Also, I don't care for the US-centric manner in which this idea was written. We're not all American, we don't all rely on 'foreign oil']
 — jonthegeologist, Aug 12 2006

No, jon, you don't need to add mass at all. All you need is to add momentum.
 — ldischler, Aug 12 2006

 I mean, simply, that this is written from a US perspective assuming a 100%US audience. Or at least, that's how it reads to me. No crime. I'm not fishing for that.

 And it appears that physics ain't my subject. Also fine, I'll bow to your greater knowledge.

Truth told, forget the Physics. I dislike the idea because it negates our need, as a human population to change our sorry ways. We all need to take responsibility for global warming and not pin our hopes on NASA or any other institution to save us. *We* need to take responsibility and I fish on those grounds alone.
 — jonthegeologist, Aug 12 2006

 Oh, geez. This idea is badly flawed. I'd love to do a study on why some folks don't see that.

 First, adding mass to it will NOT affect the orbit of the Earth. Think of old Galileo dropping cannonballs off the leaning tower (yes, I know he never really did it). Objects in a vacuum all fall at the same rate, regardless of weight/mass. The earth is falling through space in orbit around the sun. Making it heavier or lighter (massier or less massy) will not affect a damned thing--it's falling. The Sun is making the rules, not the Earth, and its gravity is not like a rubber band. It's more like an inverted cone, and we can't affect its shape.

 Second, adding mass to the earth without affecting its velocity would be rather hard, and a complete waste of time. Collecting asteroids and carrying them back to Earth would be very difficult, but let's call that the halfbaked part of this. Lowering them gently to the ground would be silly--they should be thrown into the Earth in such a way that their momentum adds to the Earth's orbital motion.

But why go get the asteroids in the first place? Take the rockets and use them to push our planet along a little faster, which would move it out from the sun. And which would make our year longer, by the way.
 — baconbrain, Aug 12 2006

 I was waiting for someone to mention the time aspect of this whole thing and how the year would be longer. But hey, we already have leap year... Why not just have it every year and make Feb. 29th a real day all of the time?

 And I hope that none of you seriously think that I would support a program that would waste millions of dollars (or pounds, to be more globally accepted) to retrive asteroids and bring them to earth to cool it. Personally, I am in agreement with [zeno]. We are still warming from the ice age, and will continue for however long until it starts cooling again.

 This idea was not meant to be serious in any way (I thought that the phrase "TA DA! Global warming solved" would make sure of that, but apparently not), any more than an idea to have everyone on the planet jump at the right time of the day to "bump" the earths orbit farther out away from the sun.

I wrote this out at 2 AM because it just popped into my head. It's half baked at best. Probly more like 1/4 or 1/8 or even 1/64th baked. I just enjoy playing devils advocate and I'm sorry if I convinced you that I was an idiot in the process.
 — Hunter79764, Aug 12 2006

 BTW, ice age == global cooling =/= global warming

[zeno]'s bleak prediction would, in fact, prove my idea to be correct...
 — Hunter79764, Aug 12 2006

Oh, no, we can't go increasing the mass of the earth! That would increase the pull of gravity on the earth, and since American standards for obesity are based on a person's weight, rather than their mass, our problems with obesity would skyrocket!
 — ye_river_xiv, Aug 13 2006

 //Momentum gained by a spacecraft is lost by the planet// Yes, yes, it stands to reason doesn't it? Yet the effect is not to be measured, ever. The smallness of the craft compared to the bigness of the planet makes this a quantum effect, meaning it's not really lost at all.

[hunter] I didn't get the tadaa bit at all, you see, I'm gullible(sp?)
 — zeno, Aug 13 2006

 jhomrighaus: "however the problem rests with the mass increase, It cannot be performed by any known process." Huh? I was thinking, get a comet from somewhere, turn it into a spacecraft, and goose earth with it. That should take care of both mass and velocity. Earth is not a closed system.

zeno, about global warming: "There is no proof whatsoever that mankind has anything to do with it."
Oh! That's good to hear. You should really tell that to the scientific establishment. Boy, is their face going to be red.
 — jutta, Aug 13 2006

 I like [lurch]'s annos here.

The mass gain without gaining momentum (no goose) would have to be done magically, through a wormhole or by monolith magic like the mass increase of Jupiter in 2010.
 — bungston, Aug 13 2006

 //I'm no astronaut (or physics major), but this is how it seems to work to me.// Well, that isn't how it works, and your misunderstanding has led to this idea, and to a lot of folks getting confused.

 There have been a couple of annotations above that demonstrate the central flaw in this idea, but I'm going to try again. There was a thought experiment on falling objects that is my inspiration, but I can't credit it properly.

 Major Tom gets launched in his space capsule, strapped securely in his seat. When he reaches orbit, he and the capsule float in orbit. He unstraps from his seat, and floats in the capsule. He then vents all the air, unfastens the hatch, and gently makes his way out the hatch. He doesn't push away from the capsule, just carefully lets go, and floats a second, then grabs hold, pulls himself back in and closes the door. He then floats in the capsule, straps down again, and thinks about his mass, the capsule's mass and the mass of the two together.

 At what point does [Hunter]'s mass-in-orbit effect take place? When Major Tom unstraps? When he lets the air out? When he lets go outside the capsule? The truth of physics is, it never happens. The safety line is slack, as we've seen in pictures, the MMU poses against the sky, and the astronauts float beside the tube of ham paste. Spacecraft rendevous quite happily, despite their differences in mass.

 [Hunter] has made an error, and convinced a few people to follow that error. But let's look at the error his way. His intrepid astronauts have collected a chunk of comet, and bring it to Earth. It weighs a good ton, and fills the hold of the two-ton spacecraft that carries it. Since it is enclosed within the hold, the astronauts didn't strap it down. As it floats free, it assumes a one-ton orbit, and the spacecraft assumes a two-ton orbit. The two orbits diverge, and the chunk touches the side of the hold. Instantly, the craft-plus-chunk assumes a three-ton orbit. The astronauts are thrown from their seats, and assume a two-hundred-pound orbit and a two-hundred-and-fifty-pound orbit. They meet in the middle of the cockpit, clutch each other, and take on a four-hundred-and- fifty pound orbit. In the confusion, they lose some bodily fluid, which assumes a 10cc orbit.

 Okay, that's getting silly, but it makes a point--such a thing never happens. At what point will the one-ton chunk of asteroid become part of the multi-mega-ton mass of the Earth? Or, in reverse, can we lift a mass up off the ground in such a way that it assumes a different orbit around the sun, and wave it goodbye? No, we cannot.

 Sorry, but this whole idea started off from a misunderstanding. Gravity is not like a rubber band. Gravity is like a sloping well. Adding or subtracting mass will not affect an orbit. Adding momentum from another moving mass will appear to affect an orbit, but the total momentum of the two masses must be conserved. If you want to affect Earth's orbit using space debris, you'll have to do it the old-fashioned way, with high-speed impacts.

Oh, and you'll have to move the earth out a few million miles before it starts to cool off.
 — baconbrain, Aug 13 2006

 I think it's always better to depend on baser instincts than on better instincts. So, I'm optimistic that once there's more money in fixing global morning than in causing it, the problem will be addressed.

Governments do have a role to play there, by making sure energy costs are reflected realistically to the population. But oil prices themselves, by reflecting the increasing world tension, are paving the way anyway. It's just never a snap of the fingers.
 — theircompetitor, Aug 13 2006

 [baconbrain] what would be the effect if suddenly with no input from any outside forces, Major Tom suddenly massed 2x what he had before? (which is of course impossible but is a curious question)

 Secondary question

Major Tom and Scotty are out playing Gravity slingshot one afternoon. They are both flying in ships that have equal mass and are following the exact same path, they both zip around saturn and head off on the same path, the next day they decide to go out and slingshot around Jupiter, Scotty however decides to bring Chekov along for the ride so that the mass of Scottys ship is 30% more than Major toms ship, they repeat the manuver accelerate to the same speed and then match orbital paths then shut everything down to enjoy the ride. Do they follow the same path through Jupiters gravity well as they did around saturn?
 — jhomrighaus, Aug 13 2006

//If you want to affect Earth's orbit using space debris, you'll have to do it the old-fashioned way, with high-speed impacts.//
And I keep saying no, that you don't have to do this. You can transfer momentum without adding mass, without any actual contact. NASA does this with spacecraft all the time. In principle, you could shuttle a single asteroid from Jupiter and Earth, subtracting momentum between Jupiter and adding it to the Earth, doing this millions of times, and never a single impact. And thank God, because just one impact would destroy civilization. See the "gravitational slingshot" link.
 — ldischler, Aug 13 2006

 Hmmm, I always thought that gravity was a product of two masses attracting and that adding mass to either would cause greater attraction and actually decrease the orbital distance.

Oh, and isn't the Earth gaining mass daily from "space dust"?
 — 2 fries shy of a happy meal, Aug 13 2006

 I finally got un-lazy and did the math on this one. As it turns out, I WAS WRONG, and I admit it. I based my thinking on the centripital force exerted on the earth by the sun, which is

 Mass(earth) * Velocity^2 / Radius

 without giving too much thought to checking my formula for gravitational attraction, which is

 G * Mass(earth) * Mass(sun) / (Radius)^2

 where G=universal gravitational constant=6.67*10^-11.

It turns out that Mass(earth) cancels out and Radius remains the same. I focused too much on centripital force and not enough on how the gravitational force would vary in this situation. Something like that. Now i have just confused myself. It all made sense a minute ago.
 — Hunter79764, Aug 13 2006

 [jhom] - I once built an orbital simulator. It was created in such a way that I could edit parameters of the orbiting objects during a simulation run. Changing the mass of objects "on-the-fly" was something I did quite a few times. In a system where the orbiting object has negligible mass compared to the total system mass (for example, sun mass=1000000, planet mass=1) and you make a change where the orbiting mass is still negligible (say, planet mass=10) you get a pretty tiny change in the orbital distance (very small decrease).

However, if you have two masses nearly equal (object 1 mass = 1000, object 2 mass = 1000) and orbiting each other, they will be in a nice regular orbit around the center of mass ("barycenter") of the system, and if you double the mass of one of them, it gets pretty lopsided all of a sudden. The object that just got more massive doesn't change path very much, but the other one gets sucked in dramatically.
 — lurch, Aug 13 2006

 so in hunters idea if he ejected a very large mass tangently toward the sun this would result in a slight outward shift in the orbit of the earth.

but what of scotty and major tom?
 — jhomrighaus, Aug 14 2006

 I think they follow the same path. Consider for a minute two spacecraft, of equal mass and at equal velocity, travelling just 1m from each other. On encountering a gravity well, they will follow identical paths through it.

Now connect the two craft together via a 1m rigid beam. The craft now weighs twice as much as it did, but will follow the same path as it did before - strain gauges on the beam will show that the beam is carrying no load.
 — david_scothern, Aug 14 2006

 I haven't had any physics classes, so it's taking me longer than it should to figure out how to explain the issues here. The error in the idea as posted could have been pointed out very easily. If gravity is compared to a rubber band, doubling the mass also doubles the rubber band, gravity--that's basic physics and there ain't a damned thing we can do to avoid it.

 So in answer to a question about somehow doubling the mass of Major Tom and his capsule, nothing will change. The inertia doubles, but the gravity doubles at the same time. The equation balances still.

 The inertia of an orbiting object can be referred to as "centrifugal force". We've discussed that elsewhere on the Halfbakery. The short version is that "centrifugal" means "away from center" and "centripetal" means "toward center". Popular usage makes it sound like centrifugal force is an unique force, rather than a way to refer to inertia. Some physicists, in their desire to eradicate that misconception, have confused other folks into using "centripetal force" incorrectly. This was NOT done above, so give [Hunter] much credit for that and for figuring out and admitting his error. (I've dropped in this paragraph for any who were confused by "centripital force". )

 In the case of an orbiting object, its mass gives it a certain amount of inertia, which would keep it moving in a straight line, moving away from the center of the orbit, "center-fuge-aly". The gravity of the object in the center pulls on the orbiting object's mass, pulling it toward the center of the orbit, "center-pet-aly". The centrifugal force is inertia, the centripetal force is gravity, both depend on the object's mass. Change the mass all you want, the orbit doesn't change. (Until the orbiter gets so big that it starts to move the center object, yes.)

[ldischler], you are absolutely right about gravitational slingshots. My apologies for ignoring that. Gravitational tractors would also work. Both would be a lot less destructive than impacts.
 — baconbrain, Aug 14 2006

Just chiming in to confuse the issue by pointing out that gravity, to all intents and purposes can be thought of, not as a force, but as a shape. It is the shape of the universe, defined by the matter contained within, that quite elegantly (and recursively) goes on to define the motion of the very same mass that brought about its very existance in the first place.
 — zen_tom, Aug 14 2006

 Yes, exactly. It can be regarded as an inverted cone in a gravity field, which is kind of self-referential. I'm putting up a link to a gravity well maker.

From an idea of mine: "A gravity well is a three-dimensional representation of gravity around a planet. From flat space, it slopes downward toward the center, getting ever steeper, like a rubber sheet stretched by a bowling ball. Rolling objects within a solid gravity well exhibit orbital behavior. The Wishing Well link shows the spiral wishing wells that illustrate rolling coins in decaying orbits within a plastic gravity well."
 — baconbrain, Aug 14 2006

I'm all for getting rid of the pesky leap year. Changing the Earth's orbit, so that there are an integer number of Earth rotations in it, seems to be a worthwhile goal.
 — Ling, Aug 14 2006

 //the pesky leap year// Another bit of evidence against intelligent design.

BTW, even if global warming is a purely natural phenomenon, and not the fault of humanity, we still should be looking for ways to control it. If we choose to.
 — baconbrain, Aug 14 2006

 I appreciate it, [baconbrain]. If I learned one thing from my physics prof, it was that the human body is a conductor. But if I learned two things, it was the difference between centripital and centrifugal force. I realize that the rubber band idea was not a very good representation of gravity. I knew it wasn't, but couldn't think of another way to get at the point that more mass would make for a higher inertia and a larger orbit, but as you pointed out, the difference in inertia by adding mass is balanced by the difference in gravity form the added mass.

So now that I realize this could never work (not that I ever thought if would), what would happen if we removed mass from the sun and added it to the earth? We would have to overcome 2g to move around, but other than that, the inertia of the earth would increase without gravity between the earth and the sun increasing. Global cooling...? (And to avoid the whole earth-moon imminent collision thing, we could use asteroid impacts on the moon to increase its velocity, since surface terrain is not nearly as important on the moon as it is here.)
 — Hunter79764, Aug 15 2006

(Side note: To me, leap year is more proof of intelligent design. Just when we think we have it all figured out, we realize we're 1/4 day off and we have to add a month to get our calendars straight again. Let's not even start on photons and quarks and all the other stuff that we thought we had figured out but didn't.)
 — Hunter79764, Aug 15 2006

Now I really am going to confuse you:
The Earth's momentum through space is a result of the mass of the Earth and the average velocity. But the Earth is spinning. Some of the Earth is then moving fast in the orbital direction, and some is moving slow. Then just get rid of some of the slow stuff, and keep the fast stuff.
The equator moves at 1670km/h or 27.8km/s. The average orbital speed of the Earth is 30km/s. This means that one side of the Earth is "only" moving at 2.2km/s, but the other side is moving at 57.8km/s. So ditch some of the slow stuff!
 — Ling, Aug 15 2006

You're a bit off there, Ling. 1670km/h is .46 km/s. (You divided by 60 instead of 60^2)
 — ldischler, Aug 15 2006

Setting the sun aside for a moment, wouldn't increasing the earth's mass also increase it's gravitational pull on the moon. In which case the moon would be dragged closer to the earth and it's tidal effects on the oceans would be increased leading back, inexorably, to worldwide flooding of the earth's landmasses.
 — DrBob, Aug 15 2006

Yes, that's true. (Zeno mentioned that above.)
 — ldischler, Aug 15 2006

//You're a bit off there, Ling.//
Oops, so I am, thanks.
 — Ling, Aug 15 2006

Oops, missed that bit! Can I claim it as an original thought anyway?
 — DrBob, Aug 15 2006

 Sure you can [DrBob].

 [Jutta] about the absence of scientific proof that mankind has anything to do with global warming: To many clear thinkers it is more then obvious that our polution isn't good.

 As for the actual damage it does, well that is very hard to calculate and scientists that believe mankind is responsible for global warming are not able to come up with accurate models of weather changes in strict correlation to polution.

 It strikes me as odd that so many scientists still believe mankind is the sole cause of global warming as it has been clearly established that our polution ties in with natural causes.

 And finally there are many serious scientists that believe and theorise that mankind has nothing at all to do with it.

 The debate alone is hot enough to contribute to the problem.

 My earlier comment was meant to say it isn't as clear cut as one might think.

(sorry, bit off topic)
 — zeno, Aug 15 2006

//To many clear thinkers it is more then obvious that our polution isn't good.//

My view on this is that, regardless of global warming, dumping crap into the ecosystem is very unlikly to produce a good result, even by accident.

Coming back to the moon question though. What would happen if we just jettisoned the moon into space. With the elimination of the moon's tidal influence wouldn't that buy us some time to think of another solution before we get overwhelmed by the oceans? Or how about lifting quantities of water into stable orbit around the planet, then we can fetch it down again when it's needed.
 — DrBob, Aug 15 2006

We could use giant zepplins. Maybe even the HullaBalloon... [link]
 — Hunter79764, Aug 15 2006

A localized warming and subsequent rarefaction of the solar wind of sufficient sized area would create buoyancy. If the effect were created from the 'dark side' of Earth, Earth's system orbit would be raised like fish to the underside of a moving boat.
 — reensure, Aug 16 2006

// [Idischler] is quite correct about the workings of gravity. // No. //Add mass to the earth, and the orbit is unchanged.// That's not correct either.
 — zigness, Aug 16 2006

 Sorry, [zigness], he is & it won't.

 Let me see if I can make it make a little more sense. The property of the orbiting object that makes it want to fly off tangentially to its orbit is its inertia, ie, mass. The property that makes it want to plummet into the orbited object is the force of gravity exerted on that amount of mass, ie, weight.

 At a particular spot in a gravitational field, there will be a specific ratio of mass to weight. We are probably most familiar with the ratio of a 1 kilogram mass at the earth's surface being gravitationally attracted to earth with a force of 2.2 pounds.

 Now imagine yourself standing on a scale, and you ask, how much does a kilo weigh? Well, it doesn't really have anything to do with the fact that you're on a scale. Now someone hands you a bowling ball. Now how much does a kilo weigh? Well, the bowling ball had nothing to do with it, either. You are seen by the scale as having more weight, but each unit of mass you possess without the bowling ball is acted on by the exact same amount of force as that unit of mass experiences while you hold the ball.

 A particular mass of planet in a particular orbit is acted on by a force in direct proportion to its mass. The proportionality determines the orbit, not the mass -- the kilo weighs the same no matter if some of its friends come tag along for the ride.

 Add mass to the earth, and its orbit is unchanged.

It does, however, make it more difficult to change by some other means you might try later.
 — lurch, Aug 17 2006

//how much does a kilo weigh?//
I think it weighs a hell of a lot more when you are trying to lose it.
 — Ling, Aug 17 2006

[lurch]: Do I understand correctly that adding n kilograms to the earth will add to its weight (so the orbital radius should decrease because of gravity) but will also add to its mass (so the orbital radius should increase because of inertia) so the net is zero?
 — angel, Aug 17 2006

 yes [angel] the net has to be zero - because the size of the force pulling the orbiting object inwards is proportional to that object's mass - Likewise, the inertia of the object acting against the gravitational force is also equally proportional to its mass. Result = zero effect.

 EXCEPT! - This is considering a system where the central object that everything is orbiting around is something considerably larger and more massive (so much so that adding a planet'sworth of mass shouldn't make a great deal of difference) We can pretty much consider that object (in this case the sun) as a static.

 However, for gravitational systems (and let's say, to keep it simple, binary ones) who's components are of similar masses; Changing the distribution of mass between one object and another *should* alter the nature of their combined orbits. I think.

 I'm imagining two water balloons in orbit around one another with a connecting stretchy pipe (stretchy, but without imparting any force) where mass can be transferred between one and another. I'm not sure how their orbits would be affected by mass transfer.

 At first glance, altering the mass distribution might make one object (the less massive one) orbit the other more quickly, while the other (the more massive one) settles down into nothing more than a 'wobble' but I'm not sure if this is just a matter of relative observation or not.

 see link re barycenters
 — zen_tom, Aug 17 2006

 There's a much easier way for NASA to counteract global warming. Simply assemble some large sheets of silicon out of lunar materials, maybe a few dozen each of which is perhaps a thousand kilometers across. Ship them into medium-earth orbit around the earth's equator so that at any given time 1-2 of them are blocking/reflecting a few percent of the normal solar radiation (insolation, for you techies) out into space instead of hitting the earth. This will cool the planet with much fewer materials, besides the fact that the merely "add mass" scheme simply doesn't work, for reasons given by others.

This scheme has the added bonus that you could make some of these sheets into solar cells and get electricity out of the scheme; but it'd be cheaper and have the desired cooling effect if they're simply reflective. We could also alter the orbits somewhat to occasionally manipulate the weather, say to kill an incipient hurricane.
 — scottinmn, Sep 07 2006

Fast forward to 2019, and it appears the "smart kids" are looking at gravity slingshots, solar reflectors, and laser beams to increase Earth's orbit [link].
 — Hunter79764, Jun 09 2019

Congratulations, [79764]. It feels good when that happens.
 — pertinax, Jun 10 2019

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