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Road Trip On The Interplanetary Superhighway
eegad writes: "CNN has an article about a new idea from NASA springing from chaos theory called the interplanetary superhighway. It will purportedly allow easier space travel by steering through regions where the net gravitational force exerted by nearby bodies is smallest. The actual NASA news release is here. Sounds like an interesting concept but it is unclear how the scientists will account for every source of gravity, including the elusive dark matter."
This actually sounds a lot like the theories exhibited in the star trek series about warp travel and how different vessels in warp flight have to adjust their courses to travel between the stars to minimize gravitational distortions affecting their flight path. Personally I think it's a great theory and very logical. Especially since gravity creates friction and drag and those are both bad for travel in space or not.
Dark Matter?! Absolutely negligible on interplanetary scales.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
Who cares? The key here is *interplanetary*.
Dark matter is only important on galactic scales. We know where all the (important) mass in the solar system is.
let's look at the facts: Big government bureaucracy. Foul smelling, funny looking employees. Interplanetary highway construction. It's all there in black and white.
NASA is run by the Vorgons.
There are some people that if they don't know, you can't tell 'em.
Great! This finally explains why the Vogons had to destroy earth for a hyperspace bypass.
According to MOND there is no dark matter. So you wouldn't have to worry about its gravitational effect. You also wouldn't have to worry about bumping into it.
The Moore-Murphy Law: The number of things that will go wrong will double every 2 years.
As much as I love to hear theorys like this out of NASA, and as much as I love NASA, I think they have a few other bugs to iron out first.
While this is a great idea.. and something that has been proposed since the earliest days of Sci-Fi, (using heavy masses as centerpoints for gravitational slingshots, among other things), we
need to get a lot of other things settled first.
People back on the moon looking for raw materials, some actual exploration of Mars, the ISS up and running properly and actually doing something that John Q Public cares about, would be a good start.
This is really coool, and Hubble will probably help a lot, as well as that Muckin Huge Telescope they are building, and SETI may even factor in, as it picks up signals from objects that we cant see, but we can hear.
Its good to see that even in times of "national trouble" NASA is forging ahead and is out on the edge with theorys and predictions, but unfortunately, thats all they are, or are likey to be, unless the Gubmint gets serious about funding space travel. Or NASA becomes self sufficient.. which they could be, if only they collected royalties on the mundane uses of some of the hundreds of things that have been invented/developed by them for the space program.
*sigh*
in a perfect world...
Maeryk
Feminine Protection? What is that? A chartreuse flame thrower?
The research is about finding low-cost paths through the solar system, not interstellar space. The dynamics of the solar system are very well understood, and all of the important gravitating bodies are known (there isn't any significant dark matter inside the solar system, by the way). You just have to do some heavy-duty computations to take advantage of all that.
Interesting concept but doesnt the slingshot effect use the gravity of planets (hence zero fuel ?) for travel ? Hence a path with nett gravity pulling the body to its destination would be of more use I think. Already the cassini mission used this principle to propel the craft to saturn (since the spacecraft lacked the fuel and the engines to propel itself to saturn).
-Dracken
You're right in that we (so far) cannot solve (in the sense of a mathematical proof) a 3 body problem using nice neat equations like we can for 2 body problems. However it is possible to calculate a trajectory and has been for some time. Takes a reasonably large amount of computing horsepower and a good idea of the initial conditions but a useful approximation can be calculated. Not an elegant or exact method but does work.
i am sure this can be empirically figured out. send hundreds of thousands of little probes all over the solar system and track their movement. each probe only need to be a beacon w/ a solar panel so they should be make very, very light. (prefabbly something degradable so no more space trash! -- or crash all of them into jupiter later, so something).
this way you can figure out to a good degree what the gravimetric forces are within a good error margin.
p.s. there is no accepted theory on what, or where dark matters exist. frankly so far their interactions we can see is on a galaxy-level. hence their existance, or effect within something as small (ha!) as the solar system is not well understood; and since we pretty much sent all the other probes etc (say, voyager) on their routes fairly predictably, i would say contemplating about dark matter interactions within the solar system is unnecessary.
but, if you really wanted to, you could ;-)
My life in the land of the rising sun.
Uh, just back up a minute there. Chaos theory also punches a massive hole in the idea which none of the articles seem to address. To be able to utilise this idea, you need to know in advance exactly where the planets will move to. Chaos theory states that this isn't possible, since you would need a tremendous amount of precision (down to inches) to be able to predict how and when all of these planets will be just right such that you are in a zero-gravity path. If you're wrong, you have to burn fuel to get onto the path, assuming you aren't too far off in the first place. After all, predicting where planets move requires a "complex iterative model", and if your starting data is even slightly out, then it will drift far away from the correct answer over time.
Each planet and moon has five locations in space called Lagrange points, where one body's gravity balances another's.
Right. So what you're saying is if I have the Earth and the Moon, there will be five points where the gravitational forces from the both of them cancel out. Uh, wouldn't there be *TWO* such points? Think about it.
Note to M1-ers: a curt but otherwise insightful message is not "Flamebait" or "Troll".
any "effect" where you use grvity to move with zero fuel is called falling.
no need to give it fancy names.
The idea of using gravitational forces of other bodies in the solar system is neither new nor wasn't used yet.
Modern computational power allows to drag in the forces of several bodies, making better result possible, but that's hardly surprising.
And the "chaos theory" probably means that they just considered the stability of their trajectories. This is hardly very exciting. The problems of unstable trajectories should be known to any maths undergrad.
So it just boils down to the mad buzzword attack on the holy quest for more govermental funding.
Owner of a Mensa membership card.
A similar idea was proposed many years ago (and used for one of the satellites studying the moon). Do a google search for "Earth-Moon fuzzy boundary" for references to that particular application.
The idea is that you can more or less coast through regions where the competing gravitational effects of many bodies cancel out, making part of your path from point a to point b less expensive than the standard transfer orbit.
The article describes an extension of this idea.
"Highway to Uranus"?
;-)
Forgive me
Whoever designed level 61 in Frozen Bubble is a sadistic bastard.
Go to the website here:
http://www.genesismission.org/
includes pictures, decent diagrams, etc.
"It is a greater offense to steal men's labor, than their clothes"
Scientist1: Well, it appears that there's some parts of space where there's no gravitational pull. So, if we chuck the craft along one of these paths, it will umm...
Scientist2: It will probably need less energy.
Scientist1: Right. Since it doesn't have to do any work counteracting any gravity.
Reporter: Makes sense fellas. Now, you called a press conference. What's that all about?
Scientist1: Well, that was it.
Reporter: (short pause) I see. (another longer pause - an uncomfortable silence, actually) Now, seeing as you just worked this out, how did you fly craft before then?
Scientist2: Well, gas was so cheap and all...
(Scientist2 slaps Scientist1 and NASA lose what funding they have left)
IN RELATED NEWS: Liberal Arts graduate? Want to work for the JPL? We're hiring! Call NOW!
Blearf. Blearf, I say.
The reference to "dark matter" makes no sence to anybody ever studied general relativity. External gravitational field doesn't vary significantly in the Solar system, therefore it's irrelevant. Even if we all accelerate in the gravitational field of some dark matter, we do it uniformly.
I'd hate to take the written exams to pilot one my own space wagon, though.
You are at an intersection of 17 interstellar space lanes. You will now listen to the astrogation control channel for 30 seconds. Choose an entry vector to the roundabout, calculate a trajectory towards the Hyades Cluster, and engage warp drive. Remember to follow the astrogation control channel protocol. Refer to the attached astrogation table for nearby mass concentrations. You have two minutes to complete the procedure.
The driving test should be much better: you just grab the joystick, stamp on the warp pedal, and hope for the best.
"I have opinions of my own, strong opinions, but I don't always agree with them." -- George H. W. Bush
It certainly seems like as the position of the planets change, the highway itself would alter radically, closing routes entirely in certain circumstances. So, 6 month trip to Mars until February, then no (special) route until two years later.
;).
I wonder what relationship, if any, this highway bears to the routes that Voyager and Pioneer missions took. Maybe a slingshot route is a continual HOV lane
If your bitterest enemies are people who hack the heads off civilians, then I would say you're doing something right.
How dare you suggest monkeys be used for such a thing, you insensitive monster. I would recommend loading a rocket full of linux geeks and firing it into the sun.
the dark matter effect is insignificant within our solar system.
With the slingshoting spacecraft around planets, the goal and effect is to increase the speed of a spacecraft by passing it by a planet in a special trajectory so that the spacecraft takes some of the planet's momentum. There is an upper limit to how fast a craft can get, because the higher the difference in velocity between the planet and the craft, the closer the craft must come to the planet's centre of gravity. If you're too fast, a collision would occur.
This method of space travel is quite different, much lower speeds are involved, and the trade off is that one can travel the 'space lanes' indefinately, and the craft is essentially coasting anywhere it wants to go. The only fuel needed would be for minor corrections, and to actually get on/off the lane at the beginning and end of the trip.
Put in short, the slingshot effect is at much higher speeds, and is limeted in use, while this method using lagrange points is slower, more reliable, and can be used indefinately.
Bork!
CHAOS THEORY...
It does apply to everything, but the little bit that is applies to really big things like planets and their effect on a space craft is negligile.
SLING SHOT...
A lot of people are talking about using gravity to propel a space craft, but don't seem to understand exactly how it works. When a space craft sling shots around a planet, what happens is this. The SC is captured by the gravity of the planet. The SC begins to fall towards the planet. However, it is falling at such an angle that it will never hit the planet or a significant portion of its atmosphere and is therefore release back into space. Now, conservation of energy applies and says that the kenetic energy gained by falling towards the planet is lost when it escapes on the other side. BUT (this is the heart of how the sling shot works) the planet is orbiting the sun. When the SC begins falling towards the planet, it also gains some of the energy from the planet itself. The SC picks up a significant portion of the velocity of the planet in it's orbit around the sun. When you apply the law of gravity for 2 bodies, you will figure out that the planet actually slows down because some of its energy is given to the SC. The end result is a SC that is going much faster and it didn't have to burn any fuel.
SPACE CRAFT'S FUEL...
several people are saying that the SC doesn't need to use fuel. If we could calculate exactly where everything is in the universe, then we could do it with almost no fuel. But we can't. Also, as all the calculations are only a pretty good estimate, the SC carries enough fuel to make in flight corrections.
LAGRANGE POINTS...
There are 5 points where gravity cancels exactly.
1. directly between the earth and the moon.
2. leading both the earth and the moon. It is in orbit around both the earth and moon, but does not move realtive to them because it can't fall around both.
3. same as 2, but trailing instead of leading
4. on the opposite side of the earth from the moon
5. on the opposite of the moon from the earth.
HOWEVER, only 2 points are STABLE. Points 1,4 and 5 are unstable, points 2 and 3 are stable. If you solve the problem, you realize that points 1,4, and 5 are sources and points 2 and 3 are sinks.
Now to qualify myself. I've only had 2 astro engineering courses (taken for fun) a few years ago back in college, so if i've made any mistakes, please forgive me and correct me.
If I drive fast enough at the red light, it'll appear green.
Does anyone have a rough estimate about the difference in time-of-flight for an object taking the "interplanetary highway" versus the old-fasioned fuel assisted "off-road" travel? I would imagine that in some cases the fuel and gravity assisted flights, while more expensive, would be able to reach its destination faster than some of the roundabout pathways of the highway.(?) Or is the travel time difference not very substantial for an interplanetary mission because the old-fasioned travel methods involved their own roundabout gravity assists from various intermediary planets along the way to its real destination?
I recently read and interesting article in SCIAM proposing an alternative to the mysterious dark mater. He calls his theory MOND (Modification of Newtonian Dynamics) where he states that for extremely weak gravitational fields (a < 10E-5 m/s^2), F approaches ma^2. Apparently, his equation is able to explain the stability of may galaxies well without having to use dark matter. It remains to be seen whether his theroy will hold up to serious scrutiny but already, astronomers are using it to model galaxies (using it as a calculation technique instead of an actual law of nature). He has yet to incorporate it in relativity.
More information is available at http://www.astro.umd.edu/~ssm/mond/litsub.html
Lord, bless my users that they may stop being such fucking idiots!!
In my day, we didn't have no inter-planetary sup-er high-way. We got to Triton O-45 the old fashioned way, and it was up a gravity well both ways!
Some scientists theorize that a killer asteroid traveled along the highway when it smacked into Earth and wiped out the dinosaurs 65 million years ago.
Oh my gosh! Interplanetary superhighways facilitate terrorism! Tear it down! Think of the children!
Gravity does not cause friction. Friction converts kinetic enery into heat which cannot be feasibly recovered. Total energy (potential + kinetic) in a gravity field is strictly conserved. Friction will most likely be greater in the "Super Highway" as interplanitary dust will collect in these gravity wells.
Probably I just know too little about this to make any sense (kinda like how I couldn't understand Enron's bandwidth trading operation) but isn't this sort of like what Benjamin Franklin did with studying the Gulf Stream and other oceanic currents? Only this time, the ship makes its own current and just steers itself away from things which would slow it down. Hm. Maybe it isn't quite like that.
Maybe it is more like get launched, then just coast and steer. I kinda don't see why this is such a big deal... Wouldn't some kind of gravitational radiation antenna be able to just figure out where the gravitation is lowest?
Somehow, I don't think I'm qualified yet for the space pilot position. (Also, for some reason, probably the coast and steer part, I was thinking about Japanese pagodas, with the central stability beam and all the layers resting on each other, but not using the beam for structural support, only stability. Maybe just randomness...)
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Contrary to what you say, the position of the planets is known to astonishing accuracy- it's only over millions of years that they move significantly chaotically, over a few months their position is entirely known.
A small body bouncing around between them is rather different however- that can be very chaotic.
Plotting a course through the solar system is quite routinely achieved. Remember Voyager?
Uh, wouldn't there be *TWO* such points? Think about it.
Do a web search on Lagrange points, you'll find it. There's 5. One between the earth and moon, one the other side of the moon, one opposite from the moon, one 60 degrees ahead of the moon and one 60 degrees behind.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"The Royals! KC Rocks!!!
It is actually Karl Sundman, not Sundham. The general n-body solution is also known.
See here for some references that you should be able to locate at any good university.
Being that humans tend to overdue things, I imagine that eventually we will start stealing momentum from some of the planets to such a degree that their orbits will be noticably different, possibly throwing off orbit frequency balances [1] that have been acheived over billions of years, and asteriods in otherwise stable circular orbits will start to go wacko.
I am sure they laughed at the idea that cars and factories could ruin (alter) the Earth's atmosphere. But, we did it. Maybe it will take longer to bust Jupiter, but I woudn't put it past us. If we can harness the energy of the sun from places beyond earth, then we have the potential for *huge* population growth. The energy falling on Earth is a speck compared to all the energy potentially capturable via solar panels made from asteroid materials, etc. The raw materials are all out there and so is the energy. It is only a matter of time until we learn to combine the two.
[1] I forgot what they call that. Synchronicity? Orbit Ratio patterns? Orbital Vibration? stumpage.
Table-ized A.I.
This is what will happened
. .
1 Civilized Voles leave their main camp near the Gap Chasm.
35 Second Wave occurs, killing men and children of First Wave.
200 Third wave occurs several generations later.
202 Magician Roogna delivered to Third Waver.
204 Magician Merlin becomes first king of Xanth. Talent = knowledge.
* Fourth wave occurs. Women surviving the Third Wave kill their rapist husbands and bring in better men.
206 King Merlin marries Sorceress Tapis.
207 Magician Jonathan, the Zombie Master, delivered to Merlin and Tapis.
216 The Princess is delivered to King Merlin and Tapis. Princess Taplin
219 Millie the Maid delivered in West Stockade.
224 or 225 Electra delivered to West Stockade
226 King Merlin vacates throne and goes to Mundania.
228 Roogna crowns himself king.
233 Electra goes to the Isle of View to help the Sorceress Tapis by making
the Heaven Cent.
236 The Princess goes to Tapis to have a coverlet made for her Sleep. Taplin
* Altercation between Magician Murphy and Sorceress Tapis at the Isle of View.
Murphy's curse causes Electra to bite the apple and start the 1,000 year sleep scheduled for the Princess.
* Fifth Wave advance scouts enter Xanth.
* Dor's adventure in Fourth Wave Xanth, wherein he detonates the Forget Spell in the Gap Chasm.
* The great Goblin/Harpy War occurs
* Prince Harold Harpy released from Brain Coral storage, and the spell on goblin females is revoked.
* Topological transformation of Millie the Maid into a book titled The Skeletin in the Closet.
Neo-Sorceress Vadne exiled to Brain coral storage.
The Zombie Master zombies himself.
* Tapis and the Princess go to Castle Roogna, and the Princess marries King Roogna.
237 Magician Murphy retires to Brain Coral storage.
* Fifth Wave proper begins.
267 Jonathan Zombie encounters a phantom at Specter Lake.
286 King Roogna dies in battle with the Sixth Wave.
* Sorceress Rana becomes first female king. Talent = Creation
325 King Reitas' reign
350 Rune, Rana's son, becomes king. Talent = Evocation.
378 Seventh Wave. Rune dies.
* Jonathan becomes first zombie king.
400 Talent Research Group established: Bond 007
402 Team talent of Cursing developed: modification
405 Secret of expanding talents
410 Loudspeaker destroys opposition except for Hydrogen
411 Air attack
412 Earth encounter
413 Fire fight
414 Water war
415 Void violation
478 Magician Vortex becomes king after the Zombie King abdicates, finding the job too rotten. Talent = demon summoning.
495 Simurgh's egg delivered.
500 Roxanne Roc starts penance at the Nameless Castle, egg sitting for the Simurgh.
548 Magician Neytron assumes throne. Talent = bringing paintings to life, including those of women or food.
575 Magician Nero assumed throne. Talent = animating golems.
591 Stork brings Magician Gromden. Talent: perceives the history of any object he touches.
623 Magician Gromden assumes the throne.
657 Stork brings Magician Yin-Yang.
658 Stork brings Threnody as the result of the mischief of a demoness (Metria) with King Gromden.
659 Stork brings Jordan the Barbarian to Fen Village.
677 Jordan commences his adventure in medieval Xanth.
* Jordan has a tryst with Bluebell Elf.
* King Gromden dies; Castle Roogna deserted.
* Magician Yang assumes the throne.
* Jordan becomes a ghost.
* Threnody marries King Yang.
681 Threnody becomes a ghost.
682 King Yang remarries.
684 Stork brings Lord Bliss, son of Yang.
689 Stork holds nose and brings Evil Magician Muerte A. Fid.
698
Eighth Wave.
704
Lord Bliss marries Lady Ashley Rose.
705
Stork brings Rose of Roogna to Lord Bliss and Lady Rose.
719
King Yang assassinated by poisoning.
*
Muerte A. Fid, Magician of Alchemy, assumes the throne.
721
Lord Bliss receives poison pen letter.
725
Lord Bliss dies. Rose sent to Castle Roogna for safety.
*
Demoness Magpie helps care for Rose
753
Ninth Wave.
*
Magician Quan, Herbalism, Fid's nephew, assumes throne.
797
Tenth Wave.
*
Sorceress Elona, Longevity, becomes second female king.
866
Eleventh Wave.
*
Ghost King Warren, Solidifying. Killed by Fid Also, creating ghosts.
883
Stork brings Magician Ebnez.
897
Mare Imbrium foaled as night mare.
*
Forrest Faun adopts a seedling sandalwood tree.
909
Magician Ebnez takes the throne, after Ghost King exorcised by people.
917
LastWave (Twelfth)
932
King Ebnez adapts the deathstone into the Shieldstone to protect Xanth from Mundane Waves.
933
Stork brings Humfrey.
*
Stork brings MareAnn, later Humfrey's Wife #5.5 in 1090.
949
Stork brings Storm Magician
*
Humfrey hired by King Ebnez to do a Xanth census of talents, as Royal Surveyor.
952
King Ebnez dies.
*
Humfrey declared Magician and assumes throne.
*
King Humfrey marries Dana (Dara) Demoness: Wife #1.
953
E. Timber Bram appointed Historian of Xanth.
954
Dafrey delivered to King Humfrey and Dana Demoness; Dana takes off. Son #1
*
Humfrey marries Maiden Taiwan: Wife #2.
955
Tics mutate.
969
Magician Arnolde Centaur delivered to Centaur Isle.
971
Humfrey abdicates throne. Maiden Taiwan abdicates their marriage.
*
Storm Magician Aeolus assumes the throne.
*
Humfrey rediscovers Castle Roogna.
972
Humfrey achieves Degree from University of Magic and becomes a true Magician of Information.
972
Magician Humfrey marries Rose of Roogna: Wife #3.
973
Rosetta Bliss Humfrey--"Roy"--delivered to Magician Humfrey and Princess Rose. Daughter #1
975
Storm King decrees that any resident without a magic talent will be exiled from Xanth.
986
Girard Giant rolled to Giant Village by battalion of storks.
994
Rosetta marries Stone.
*
Cherie Centaur foaled south of North Village.
997
Stork brings Magician Trent to North Village.
1000
Rose goes to Hell in a Handbasket.
*
Magician Humfrey takes 80 years worth of Lethe Elixir.
*
Magician Humfrey marries Sofia Mundane: Wife #4.
1001
Stork brings Sorceress Iris to an unwary family.
*
Jethro Giant delivered
1002
Crombie the Soldier delivered to Magician Humfrey and Sofia. Son #2
1005
Magician Humfrey trains Magician Trent.
*
Cynthia Human delivered to North Village
1007
Magician Humfrey trains Sorceress Iris.
1017
(Magician) Bink delivered to north Village to Roland and Bianca.
1021
Magician Trent transforms the fish in Fish River into lightning bugs.
Also others, including Cynthia, a winged centaur filly who flees to
Brain Coral's pool.
1022
Evil Magician Trent attempts a coup d'etat. Transforms Justin into a tree. Is betrayed and exiled to Mundania.
*
Stork delivers Chameleon to Gap Village
1024
Sorceress Iris betrays the Master Slaver
1025
Stork brings Gorgon and Siren, twin sisters.
1027
Bink loses the middle finger of his left hand in a nonmagical accident.
1033
Herman Centaur exiled from the herd for having magic.
1035
Sofia (Wife #4) returns to Mundania.
1036
Sea Hag takes over a body in historical times.
1039
Grundy Golem animated by Good Magician Humfrey.
1040
Donald becomes a shade.
While the CNN article is truely hyped and mostly fluff there is an informative paper here.
In summary: If you find yourself in orbit around a Lagrange point you only need to change your velocity a little to change your orbit radically (thats the chaos part). The orbits you can enter in the Sun-Earth system is forming two horseshoes with the Earth placed in the gap (or perhaps more precisely: Like the figure 8 with the smallest of the loops folded within the larger one and the Earth placed in the cross between the loops). One of the orbits lies within earths orbit. The other lies outside of Earths orbit.
What makes this particular interesting is that the horseshoes of the Sun-Earth system overlaps the horseshoes of the Earth-Moon system. So, if you're travelling along one of the horseshoes in the Sun-Earth system, you can pull the trick again when you cross the horseshoe of the Earth-Moon system and enter an orbit around earth with virtually no fuel consumption. It works the other way around too: If you place a spaceship in one of the Lagrange points of the Earth-Moon system you can reach far into the solar system for almost free by entering the horseshoe of the Sun-Earth system at the right time. The only catch is that you're travelling pretty slow.
Now the CNN article talks a lot about interplanetian travel, but the reality is that the mechanics have only been worked out for the earth-moon-sun system and the Jovian system. Interplanetarian travel requires heavy computatios and is still in the works.
And to dispell some of the confusion in this thread about the nature of the Langrange points this page gives a good explanation.
The Slingshot effect (i.e. the Gravity-Assist) is for trajectories at much higher energies. The Interplanetary Superhighway method is useful at lower energies.
What will be cool is when we can tie the two methods together and use gravity-assists to get someplace quickly and then use lagrange points to move around after we get there... say to design a mission to orbit each of jupiter's moons one by one.
There are 10 types of people in this world, those who can count in binary and those who can't.
http://www.amazon.com/exec/obidos/ASIN/0805059857
http://www.islandone.org/Propulsion/ProjectOrion.h tml
I personally favor building big manly throbbing Orion rockets, but that's because chaos theory makes my brain hurt and because things that explode are cool.
cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
Another guy from JPL had a Berkeley dissertation circa 1965 on this topic; the minimum energy orbits are called Hohman transfer trajectories. They neglect the rest of the planets, but those are minor perturbations -- that's what the "tubes" are about.
There are five orbits around the Earth-moon neighborhood where the derivative vanishes, the Euler points and the Lagrange points; the forces [including momentum!] all balance out, but they aren't necessarily stable [the 60 degrees ahead/behind in the moon's orbit are, if some mass ratio condition is satisfied, cf "trojan asteroids" in Jupiter's orbit].
The guy may know something, but NASA is a big organization, and the press release writers in any such were typically English majors. The chaos theory angle is largely bullshit [but heaven forbid I should utterly squelch young spirits, as one of my professors used to say:]
If this leads someone to learn the math, great, but it's really a crock (tm).
CHAOS THEORY... It does apply to everything, but the little bit that is applies to really big things like planets and their effect on a space craft is negligile.
There are places where the gravity from the Earth and the Sun pull on your spacecraft at almost the same amount (near Lagrange points) in these places small maneuvers can put you on vastly different trajectories... small actions have big effects... and this is where you can use chaos theory for trajectory design.
There are 10 types of people in this world, those who can count in binary and those who can't.
I never much liked the theory of dark matter. "Our calculations indicate a bunch of stuff we don't observe...must be invisible stuff." Uh, yeah. It's the ether, guys, and planets spontaneously generate from it.
Seriously, though, when a calculation doesn't match up with oberservable fact, you're supposed to adjust the calculations (chaos theory, heisenberg, quantum mechanics), not invent something. And there's a theory right now, explained in the latest scientific american (you ARE a subscriber, right? If not, drop the $35 per year, it makes you a better person), that does just that -- adjusts gravitational constants unchanged since Newton's days when matter moves very quickly. I kind of like it...it makes more sense to me than this "hey, 95% of the galaxy is invisible and undetectable and that's why things spin in wierd directions!" crap.
Dark Matter. Feh. In another 70 years it'll rank with phrenology, dowsing and psychoanalysis.
Hey freaks: now you're ju
Sounds like an interesting concept but it is unclear how the scientists will account for every source of gravity, including the elusive dark matter."
They won't. They'll do the astrogational equivalent of firing a shotgun out in front of the ship, waiting a week and seeing which particles have had their trajectories distored most severely.
Those that don't get pulled off course met the least accelleration due to gravity and friction.
(Transverse redshift, blah blah blah.)
Problem solved.
(Jeez, people. Computers aren't always the best solution. Get out from behind your desks, once in a...
Right. Slashdot. Got it.)
And no, this isn't off-topic. I'm commenting on the post I'm replying to.
(still laughing from post)...
Donate background CPU time to fight cancer.
I thought Al Gore invented the interplanetary superhighway?
Nowhere did Mr. Lo describe in his paper that the gravity cancels out on these paths (only that they were minimum energy and connected the Lagrange points).
;^)
The whole idea of a minimum energy paths through the solar system is that it's a dynamical systems of greater than 2 dimensions. The weird thing about dynamical systems of 3 dimensions is that trajectories in some of these systems exhibit a type of predictability called a "strange" attractor.
Strange attractors for trajectories are different than the attractors you normally see in 2 dimensions (like local minima or orbits that retrace themselves) in that small pertubations can cause greatly divergent behavior. Even though the behavior appears chaotic, in some systems, the behavior can still be described as nearby a "strange" attractor. This is effect is often called chaos, and the study of strange attractors is called chaos theory.
Apparently Mr. Lo has worked out a theory where the minimum energy trajectories under this complicated dynamical system (planetary gravitational attraction) exhibits attractors that looks like "tubes" that exhibit the chaos-like behavior of strange attractors.
At first glance, these tubes appear to have the dynamical structure similar to n-body orbits (this factoid about orbits was first discovered by Michel Henon in the 60's). "orbits" in n-body systems don't actually retrace themselves, but sort of looks like a coiled up extension cord. The envelope or attractor of the orbits look sort of like a mis-shaped torus (squished donut), where the orbits can pretty much be anywhere on the surface of the donut (the attractor), but the path it takes is somewhat unpredictable (chaos) and highly dependent on initial conditions. There are more complicated attractors (some involving little islands of stability inside the donut) depending on the energy level, but this is the basic idea. This discovery seems to extend this known factoid about orbits to the structure of minimum energy trajectories in n-body gravitational fields.
All this will be moot, however, when in the 2004 election, Al Gore wins the presidency by taking credit for inventing the Interplanetary Super-Highway while giving a campaign speech for an increased budget for Nasa leading all the l337 geek-crackers to rig the newly approved, non-tamperproof election computers... I boldly predict this will be henceforth called the "butterfly-ballot" effect... But I digress...
Basically what happens is that there are certain points near to the earth and every other body in the solar system called the Lagrange points. The researchers have worked out a way of calculating a route that passes through the regions around the Lagrange points to jump from planet to planet with almost no expenditure of fuel.
The only downside to this is that the route is probably going to be slow; several years to go from place to place. Still, the implications of being able to move cargo/fuel to say, Mars ahead of human habitation cannot be overestimated. The other downside is you have to be fairly high above the earth initially to be able to reach the 'superhighways', so don't expect the program to give directions from route 66 ;-)
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Oh yeah, one other thing...
This is an interesting discovery since it's not obvious that the minimum energy trajectories between lagrange points follows a strange attractor (and aren't simply random or divergent). This means that if the trajectories are truly chaotic (i.e., follow tube-like strange attractors), once you get near the attractors (matching position/velocity vectors), maybe you can't predict exactly how you are going to get there, but you can be pretty sure that you will stay near the attractor so you needn't waste all your manuvering fuel trying to make minor course adjustments to try and stay on a specific trajectory. If it all pans out, this would probably turn out to be a pretty important discovery for inter-planetary minimum energy trajectories...
What this paper states (incorrectly) is that it is not the gravitational forces alone that cancel each other out, but the combination of gravitational forces and centripetal acceleration cancelling each other out.
Suggest you do a google search on the Circular Restricted Three Body Problem (CRTBP)
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
In 1845, a mathematician at Cambridge proposed the existence of another, unseen planet, due to pertubations in Uranus' orbit that couldn't be accounted for. He calculated its position, and Neptune was discovered the following year.
On the other hand, problems with Mercury's orbit turned out to be the effects of relativity, not an unseen mass.
So both approaches have historically worked. The idea of unseen mass distributed throughout the galaxy is not that far-fetched. After all, from light years away, nearly everything is invisible.
-Jed
Absolutely fascinating work by Martin Lo. If highway coordinates are publicized this might be the best place for spaceguard and amateur asteroid searchers to look. Currently amateurs are discovering asteroids very frequently.
I also wonder if this implies a similar superhighway among the stars which could determine where a stream of matter might be coming over the millenia from outside the solar system. (i.e. where are the off-ramps to our solar system?)
The interview with Lo is much more interesting; he believes we are on a cusp of where advanced theoretical mathematics is going to inform a new generation of engineering.
I would like to understand the math better, specifically to see if it might have applications to software. I'd also like to plot the superhighway, or understand how they are doing it. But only have a year of college math. Where is a good and free place to learn about it online? Been to Mathematica.
This has already been done before -- see the section on "CHAOS, ORBITAL DYNAMICS, AND FUZZY BOUNDARIES" on this page. I know it was detailed in Scientific American back in the mid/late 90's.
blog |
The inventor of the Flying Saucer propellantless
propulsion is asking people not to be afraid
if they happen to see his Flying Saucer going
across the skies in the next years.
He say his IFO " Identified Friendly Object"
should not be the target of the military or others.
He hopes others will copy his lead in developing
other propulsion technologies in competition with
NASA's lack of vision for future space travel.
http://colossalstorage.net
This kind of thing should have been identified long ago. Not knowing that, I'm sure that it was, for some reasons.
1, NASA uses all kinds of math to plot orbits and trajectories. If you look at the math long enough, it can only naturally occur to you to find "paths" through space for various criteria: fuel, time, locations. Unfortunately, the question most implied by default is "What is the minimum time path?", since Mission Control is not a generational job.
2, NASA already knows about certain types of paths that are unconventional. One particular one that I recall has a spacecraft whipped at the moon; the craft has a close encounter with the Moon (pun: the Moon is grey); it ends up making a relatively huge ellipse away from the Earth-Moon system; and finally the craft comes back to Luna and makes a puny insertion burn to orbit. Total fuel cost is lower than just doing the Apollo route; but you traded time and Lunar inertia for it.
The "interplanetary superhighways" thing is the usual type of innovation that in retrospect was a no-brainer. If I had spent time plotting orbits and trajectories for various spacecraft, I would have seen that set of solutions soon enough. But will the politics and optimizations of spacecraft launches and travel allow these solutions to be used, much less become more public? For example, just think on how cheap in fuel terms it will be to send out probes on solar sails; with fuel being free and stored off-craft, more cheapness arises in the double-increase of spacecraft mass, getting more done for the money. (I say double-increase due to no main propulsion, which opens mass for instruments, and "infinite" fuel, which means you can make the craft about as heavy as you want (limited by sail size, 'course).) Sail-driven craft will take a bit of time to get where they are going in the Outer System; instead, we chose what are essentially launched and boosted billard balls for those jobs.
[also misbehaves on Kuro5hin as Peahippo]