Hi Can one of you with astrophysical smarts tell me. If i put a lunar size mass in earth/moon l4 or l5 points. Will the arrangment hold stable? Occam
You're going to upset the orbits of everything in the solar system. All these planets currently rotate around the sun in well defined orbits. This is a result of the natural equalizing that occurs over time between celestial objects. Much like magnets floating against each other's force field. Compare this with the timing on a car engine. When the timing is right, things run smooth and quiet. When the timing is off, damage to the engine may occur. In this case, the insertion of a large gravitational force is going to displace those steering forces that define current planetary orbits. Change that, things are going to start colliding with one another again until another equalization is found. Larger, more dense planets would see a huge increase in meteor activity. So no, it wouldn't hold stable, nor would it be reversable once started.
Now, if you mean a lunar sized mass, but hollow like a balloon, the effect would be negligible. It is the density that matters in gravity, not physical size. A particle of black hole matter, no larger than a grain of sand, could weigh a trillion tons and affect the orbits of small planets. x
Xenon.. The question relates to an idea for an SF story. The mass would be ~7 x 10/22 Kg. But.. being mostly neutron star density [neutronium], would only be a few Km's in diameter. The make-up[form of mass] is irrelevent. Wanted to know is stable orbit will hold in trailing or leading Lagrangian points. As they would will small masses like O'niel colonies and such. With larger mass equivalent to moon or approx. Did not think that such as our moon would have influence on venus/mars orbital dynamics but for a few meters here and there. ?? Occam
A few meters isn't much on the scale of things. But once you factor in other gravitational tugs in the course of an orbit, you are playing with close tolerances. The effect may not manifest itself for millions of years or you could have a collision with something in a few years. You have to remember that everything in the cosmos is in motion. This means that there is a never ending balancing act going on between gravitational bodies of any size. They push and pull off one another in a subtle way giving a rough alignment and structure respective of their individual solar systems. To drop a gravitational force in that balanced system, is to displace the alignments of everything within that system. Unless of course, you wrap it in an anti-gravity envelope. x
xexon LOL. Well literary license unbound . I suppose a technology that allows a ship with a singularity wraped in a neutronium shell could achieve just about anything.. will give it some thought.. thanks for the input Occam
Something that small and dark would be hard to find. And while the moon is a respectible mass, if it were at L-4 of the Earth's orbit (it orbits the sun not the earth), it gravitational influance might go unnoticed. Heck, at Jupiter's L-4 the gravitational effect of a lunar mass on the solar system would be even less. AND the lunar/Jupiter mass ratio would be small enough that it would be stable in that position. (According to my Jim Kirk calculating phaser).
What? You don't believe what I say? Within the nuclear structure of all matter, there are subtle forces which can be isolated and concentrated. Some of these forces have a direct connection with gravity itself. You've seen those noise cancelling headphones on TV? Same principle can be applied to gravity. You can use it against itself to achieve zero gravity. A gravitational parity, where attraction and repulsion are held in equal measure. Its going to be a few years before scientists understand this. The ancient yogis understood it well though. A neutronium ship? Nah. Thats the hard way. You just raise the atomic vibration of the ship to the point it no longer interacts with physical matter. Silly boy. x
xexon No.. You have it wrong. Have before your examples known of many who say exactly same thing. Our solar system is fragile ballance of gravitic masses. Poetic license was about 'my writing skill' not your position. Which seems entirely accurate. As to your postulations on gravity.. Humans, including you, have no idea what gravity is. Just it's effects. Ps. the neutronium shell is a stabiliser for the sub solar mass singularity at core which allows FTL travel. As a speculative writer it seems i have a more 'realistic' grasp of our universal laws than you. Yogi's ?? Come on man. Occam
Yogis were the first particle physicists. Instead of using equipment, they used their ability to perceive. They understand more than any scientist, about how the universe "works". Science will be centuries in catching them. Gravity, is the sea in which all of creation sits. It has currents and eddys, depths and shallows. It even has storms. It is the creative force that acts upon matter to make the world around you. It has a frequency thats higher than what you can deal with right now, but it won't always be that way. One day, somebody will stumble upon something that will make gravity give up all it's secrets. Within ten years of that day, the wheel will be almost obsolete. x
O'Neil proposed putting space stations at the L-4 and L-5 points of the moon's orbit, whence the "L-4 Society" and the misnomer that L-4 and L-5 refer only to points in the moon's orbit. Legrange (the "L" in L-4) solved Newton's gravitational equations for the three body problem. His fourth and fifth solutions are the only stable ones that he found. Any body orbiting a larger body has L-4 and L-5 points. Many SF authors (including Niven) wrote stories that had space based civilizations. All of them had "cities" at the L-4 and L-5 points because asteroids (resources) are denser there. Astronomers have found that Jupiter's L-4 & 5 do indeed have clusters of asteroids.
MikeE Thanks. Yes L4 and 5 are to me from SF. It teaches and entertains. Yes was aware it holds for jupiter and other situ's Niven is dmn good. reading ringworld children now. I asked because MASS was large. Two moon mass objects in earth orbit.. Seems there would be instabillity. Does Lagrange math on 3 bodies still hold? Earth with 2 lunar masses? Maybe it should be 3 lunar masses. each 33.3 deg around orbit.. Dunno.. but it's interersting. Occam
So Razor what was your original question? Orbits of one object in another object's L4/L5 Langrange points are stable. This is solved with nos as much as the three body problem but rather by solutions to Roche lobes with equipotential gravitational points. For instance, at 60 degrees in front of and behind Jupiter there are groups of asteroids known as Trojan asteroids. For the L4/L5 Earth Lagrange points, there is some dust, but nothing substantial. Space stations could indeed be placed there in the distant future though.
heart That was my question..As clearly stated in 1st post, cant u read......? If a lunar mass was placed at l4/l5 ? Would it destabilise moon or earth/ relative to solar orbit. no didnt think so occam
