Interplanetary Superhighway

rotenberry writes "The current issue of Caltech's Engineering and Science magizine contains the article "Next Exit 0.5 Million Kilometers - A Caltech/JPL collaboration explores the 'Interplanetary Superhighway.'" which describes "...the Interplanetary Superhighway - 'a vast network of winding tunnels in space' that connects the sun, the planets, their moons, and a host of other destinations as well. But unlike the wormholes beloved of science-fiction writers, these things are real. In fact, they are already being used." However, it takes a very long time to get there."

Comments

Of course it takes a very long time.......

[i_want_you_to_throw_]

Because all of these tunnels connect through Atlanta where there is a "change of plane".

There's a bulldozer outside my house

[egg troll]

An Interplanetary highway, eh? Better head down to the pub, in a hurry!

Re:There's a bulldozer outside my house

[whig]

There's a good pub at L5. Called the Libation Point.

Re:There's a bulldozer outside my house

[PurpleBob]

Note to moderators: The Hitchhiker's Guide is funny. Making the occasional reference to it is funny. Quoting random catchphrases from it in response to that reference is not funny.

time for publishers to start...

[trmj]

...getting the rights to the book title "Hitchhiker's Guide to the Galaxy"

Seven Rules For Spotting Bogus Science

[dreadknought]

I wonder if this applies to the seven rules for spotting bogus science?

Re:Seven Rules For Spotting Bogus Science

[vortmax(OU)]

Bogus science? How about this?

From the article:
Ideally, a spacecraft at L4 or L5 will remain there indefinitely because when it falls off the cusp, the Coriolis effect--which makes it hard for you to walk on a moving merry-go-round--will swirl it into a long-lived orbit around that point.

IIRC from physics classes, is the force making it hard to walk on a moving merry-go-round not the centripetal force?? I thought Coriolis was only a pseudo-force, not a real one.

Re:Seven Rules For Spotting Bogus Science

[karlm]

IIRC from physics classes, is the force making it hard to walk on a moving merry-go-round not the centripetal force?? I thought Coriolis was only a pseudo-force, not a real one.

Ehh... you're 3/4 right. Centripetal force is real and coreolis force is "imaginary". Centripital force is force towards the center of rotation, keeping you from traveling in a streight line. Centripital force doesn't make it hard to walk on the merry-go-round; centripital force allows you to stay on the merry-go-round. You're thinking of the "imaginary" centrifugal force that appears to counter-act the centripital force you are applying with your feet.

Centrifugal force and Coreolis force are both imaginary forces used as short hand for taking second time derrivatives (calclating accelerations) in rotating reference frames using polar coordinates . If you're spinning at a constant speed about the merry-go-round, you keep the same polar cooarinates when in fact, a lot of corce is acting on your body to keep it constantly changing direction at a fairly high rate. In the reference frame you ae always at rest, so you don't say that momentum change is balancing out the force you are using to keep yourself "still" in the rotating reference frame, you say that this imaginary "centrifugal" force is acting on you. The two statements are equivalent, but one is a technical gloss.

Now suppose you try moving in relation to the rotating reference frame. You want to travel in a streight line in the polar coordinates. Well, since the frame of reference is rotating, a streight path in non-rotating space is a curved line in the rotating reference frame, and the amount of aparent curvature is dependent on speed of travel relative to the rotating reference frame. So when you try and walk in a streight line on the merry-go-round with out correcting for rotation, you more or less walk in a streight line in the non-rotating reference frame. In the rotating reference frame, your path is curved. The easiest way to do calculations is to make up frorces that would havepushed your path into that curved shape. It's all just short hand so that everything doesn't need to be translated to and from the stationary reference frame.

Even at the equator, you experience the coreolis effect, it's just that your axis of rotation is parallel to the ground. At the equtor, running East appears to make you lighter, running West appears to make you heavier, jumping up appears to push you West, and dropping off a ledge appears to push you East. One explination of why thy always launch spacecraft in an eastwardly-traveling orbit is that that way the coreolis force helps, rather than hinders the spaceflight. In a non-rotating reference frame this is equivalent to saying that it already has a lot of speed in an easterly direction, so blasting off to the west actually means sloing down a lot rather than using the speed it already has due to traveling at the same speed as the ground.

It's all equivalent, sometimes it's jsut easier to do the math one way. If nobody has done the math to figure out how the imaginary forces get added in in your situation, then you need to translate everything into a non-rotaing, non-accelerating frame of reference and do the calculatins and translate them back into your rotating frame of reference.

It's kinda like special relativity. If you forget the formulas, you can re-derrive them by looking at everyhting in a stationary reference frame and looking at a photon clock and a photon yardstick and figuring out what apears to happen to one secodn and what appearsto happen to one meter and what appears to happen to one kg being acted upon by 1 Newton. It's just a lot easier if you remember the formulas Einstein derrived for you instead of having to transate everything to and from the stationary reference frame.

Re:Seven Rules For Spotting Bogus Science

[grumpygrodyguy]

I wonder if this applies to the seven rules for spotting bogus science?

Believe it or not, basic celestial mechanics still has several unsolved problems.

For instance noone knows exactly how to model the formation of ring structures like the Kuiper Belt(a ring of asteroids orbiting the sun), or Saturn's rings.

If you don't believe me check out this link.

Re:Seven Rules For Spotting Bogus Science

[dillon_rinker]

Good on #2, but not quite on #1. Centripetal and coriolis forces are quite real and entirely valid. Centripetal forces are obvious in a static frame of reference, while coriolis (and centrifugal) forces are valid in a rotating frame of reference. If you are being rotated, you will experience centrifugal force, and if you try to move you will encounter the coriolis force. Someone watching you from outside the rotating area would chalk it all up to good old-fashioned inertia.

The myth about no centrifugal or coriolis forces exists because it's easier to say that to freshman than to try to teach them to analyze forces within a rotating frame of reference.

huh?

[adamruck]

dont the planets move around the sun at different rates? So how would it be possible to make a fixed structure to "drive" to a planet?

Re:huh?

[dackroyd]

So how would it be possible to make a fixed structure to "drive" to a planet?

It's not. You have to constantly calculate where the low energy paths will be and and then choose one that will take you where you want to.

When the planets move around these paths will change and to get to the same place you may have to take a different 'route' for journeys that start at different times.

Calling it a 'network of tunnels' is a poor simile, lets see if I can do any better. It's more like a set of deep valleys connected to each other over a small rise. The valleys are formed by the gravity of the planets and moons, and the layout of the valleys change as the planets move around.

To get from point A to point B, you can either use lots of energy to go in a straight line up and down the deep sides of the valley or if you follow the bottoms of the valleys and aim carefully at the connection between different valleys you can use less energy to move.

As space is frictionless, not only do you have to spend a lot of energy to get up the side of the valley (ie getting the spaceship up to speed for the journey), you also have to spend a lot of energy to stop from rolling on past where you want to go to (ie slow the spaceship down once it there). This is a problem if you want to send a probe to go and look at several planet/moons in a mission and spend a reasonable amount of time around each one. If you just accelerate/decelerate to get to and from each orbit you'll need a lot of fuel.

What's cool about this is that if you want to, you can bounce around within the valley so long as you don't roll at the low connection to another valley. This means that the spaceship/satellite could stay in one orbit around a moon for a while, and then when the time comes to move on, it can fire its rocket for a very short time just to aim at the low connection to the next valley. This will then make the ship move into orbit around the next planet/moon and it will be in a stable orbit around that until it decides to move on again.

Re:huh?

[Anonymous Coward]

The 'network of tunnels' analogy is actually quite fitting. There are manifold surfaces in space which, once you are on them, you automatically fall to a destination lagrange point. That is where that analogy comes from.

(Of course, the manifolds do not just have coordinates in space but have required velocities at those coordinates. But once you are "on" the manifold in the sense of being in the right place with the right velocity, then it works exactly like a tunnel connecting you to somewhere else because you simply "fall" there without having to do anything else.)

Gravity Hitchhiking, Pure and Simple

[weston]

That's what this is. You don't get quite the comfy ride in the back of a Vogon Space Cruiser or anything, but it's still hitchiking.

Now if only I could get a free ride to the Midwest or East Coast this way.

yes, it takes a long time.

[Quasar1999]

Of course it takes a long time... you forgot rule #1... the shortest distance between any two points is a straight line... err... is it a curved line? no... wait... ahh screw it...

Ok... it's a friday night... I'm sitting at home, with nothing better to do than try and be a smartass on slashdot... Oh lord, I've wasted my life...

Re:yes, it takes a long time.

[gilroy]

Blockquoth the poster:

rule #1... the shortest distance between any two points is a straight line

... but if the spacetime metric is not flat, the "straight" line might be curved... (Think great circles on the surface of spheres.)

Re:yes, it takes a long time.

[Tony-A]

Ok, I'll bite. Yes, the shortest distance between any two points is a straight line. That's because a straight line is *THE* path between the two points with the shortest distance. (You can have some fun with equivalence classes if there's more than of of 'em;) A straight line on a 3-d sphere goes through the sphere, not on the surface. A straight line on a 2-d surface of a sphere will not look straight when projected onto a flat map. A straight line on a Mercator projection is not the shortest distance on the represented 2d-surface, but does have the advantage that you can pick a heading, stay on it, and get there eventually.

It'll Never Pan Out...

[Quaoar]

The project is a failture from the start...what good is it when this "highway" doesn't deliver porn?

Re:It'll Never Pan Out...

[m1chael]

yes it can, it just takes a long time to come.

This Reminds me of Doug Adams

[Montgomery Burns III]

"The Universe is big. Really big. You might think that it is a long way to the chemist, but that is nothing comapred to the universe."

how this works

[Anonymous Coward]

What this is about is mapping out stable and semi-stable manifolds (paths) in space between planets. That is there are places in the solar system if you put an object, it will naturally draft toward certain other positions. For NASA, JPL, etc. The important paths are those linking the planets and other destinations of interest hense the high way metaphor (which is just a metaphor, not even a precise one at that. A embeded manifold is the precise mathematical term) These manifolds are created by the interaction of the planets and because of that can be thought as fixed relative to them, or as moving with them. (Which is why manifold is more precise term sense it does not denote fixed position nor one dimensionalness)

for those who didn't read the article...

[PissedOffGuy]

it's talking about how the gravity wells of planets make for low-energy paths from place to place, like how we choose to launch a mars probe when earth and mars are at certain positions relative to each other, maybe using the moon along the way. a well-known concept but the article has lots of flashy language.

We have one person to thank for this...

[commodoresloat]

Al Gore.

Oh they had better not....

[Anonymous Coward]

someone had better tell them to wait 5 damn minutes, because if I don't find out what the friggin question is, im gonna go insane, or, well, as insane as someone who was just blinked out of existence can be...

Oh the taxes

[krray]

When do the tolls go into place? Would we have to STOP even though the system will probably automated? We do have to be human sometime and make it counter-productive...

The structures aren't fixed

[Macrobat]

The structures aren't fixed. The basic idea is, though, that the most fuel-efficient way to get to another planet/moon is not just to wait until it's reached it's closest point and blast off, but to calculate when and where the gravity wormholes offer the most aid/least resistance. They are akin to the Lagrange points between the earth and the moon, where the pulls from the two sources create an area where the least resistance still keeps an object in place, sort of like a patch of dirt on an icy surface. (That's an analogy for what happens, not how it happens.)

The thing about the wormholes is, though, that they're governed by non-linear dynamics, and are therefore extremely convoluted and difficult to calculate. But that doesn't imply that they're static, just that they're usually not the shortest distance between points A and B.

Re:The structures aren't fixed

[kfg]

Just as if one wants to travel from England to NYC entirely by sail it is faster to sail south to the Canary Islands off the coast of Africa, across the Atlantic to the Caribbean, then up the east coast of North America, because that way you are traveling with the currents and prevailing winds the whole way, rather than against them.

These are even often refered to as "Highways on the Sea," and calling these "Interplanetary Superhighways" is no doubt derived from this.

Of course there is no actual structure.

The only real difference is that in space the "continents" are in continuous and *rapid* movement as well, and thus the "currents" and "winds" are in a constant state of flux.

Other than *that* Mrs. Lincoln. . .

KFG

Re:The structures aren't fixed

[LMCBoy]

It's not a material structure at all, and the parent poster shouldn't have called it a "wormhole", either. It's simply the least-energy trajectory from A to B through the Solar system, given the gravitational effects of the planets. The paths are always changing (quite chaotically), simply because the planets are in moion.

NASA's been taking advantage of such "gravity assist" trajectories for a while. How do you get to Jupiter? Slingshot around Venus, flyby Earth twice, then you're on your way. It seems roundabout, but sometimes, paths like that are the easiest way.

Re:The structures aren't fixed

[Anonymous Coward]

No, these are very different from normal gravity assist manuvers that have been used in many interplanetary missions. Those are still spliced together from ellipse like pieces, whereas these "superhighway" paths are simply not. Of course, 3rd body effects must usually be numerically calculated and accounted for in any real mission, but in this case they are part of the trajectory design to begin with.

Any distributed computing people listening?

[asparagus]

Here is a project I would love to support.

Massive amounts of numbers to be crunched, tons of routes to be discovered, and all by lowly computers with nothing better to do.

Proving that some ungodly number of ProcHours can figure out a RC-72 bit key is meaningless to me.

This is the sort of science humanity is interested in. Onward to Mars!

-Brett

Re:Any distributed computing people listening?

[La Temperanza]

Have you taken a look at DistribFold? I mean, these things and SETI@home are cool, but folding proteins actually helps people now.

Poincare Conjecture

[Professor_Quail]

I read the article and understood most of what they were talking about...but I knew I had heard something related to this before.

The Poincare Conjecture

IIRC, solving this problem should make some major advances in this 'tube-theory'. Can anyone explain how though?

---

Re:Poincare Conjecture

[Anonymous Coward]

IIRC, the Poincare conjecture has to do with being able to map the number of 3-dimensional simply connected (no holes ala the donut), compact (think finite expanse, although that isn't correct; the definition of compact is a bit more technical), boundaryless (maybe) manifolds (surfaces) to the 3 sphere.

The article has nothing to do with this. The article is simply discussing searching for trajectories whihc minimize the energy to get from A to B. The tube/wormhole terminology seems awful, if not incorrect (wormholes are very different beasts).

Wait a minute... how long?

[RumGunner]

Like most Amerikans, I want it all, and I want it NOW.

Plus, those gravitational speed ups are slowing down the planet! Eventually, we'll suck up so much momentum to cause the earth to stop revolving around the sun, and we'll burn up!

Act now to fight the destruction of our gravitational resources!

Re:Wait a minute... how long?

[TheRealBlueEAGLE]

This might seem like a joke, but in the very end it is a point. It's like the atmosphere or the oceans. Since there's a lot of it it doesn't matter if we dumt this and that into it.

Hopefully we'll find other ways to explore the space before we slow down so much that we crash into the sun. :)

Gravity drive

[gmuslera]

Is like driving a ballon, wasting a very little energy to go to up or down the next "wind" that goes in the rigth direction. With gravity forces, inertia, and a bit of calculus to find where is the best moment to start the ride, you can go very far without wasting combustible or whatever you use to move, just letting gravity to do their job.

Bus, as far I understand, that "highway" must be very dinamic, is like saying that in a year, 6 months and 3 days there should be a "road" to Pluton, but if you try this every other moment it will be very costly or the trip will last 4 months more.

And, well, this "highway" is beloved as well for good hard sci fi writers, taking advantage of gravity to do "impossible" tricks is very used, and is funny to see everyone surprised in the story of that kind of tricks

for those who didn't understand the article ...

[Heisenbug]

I am not a rocket scientist, but I think this article uses flashy language because it's talking about something way more complicated than using the moon along the way. They mention, for example, that the Earth to Mars path is much harder to figure out than Jupiter to Saturn (and I got the impression that it would take thousands of years).

This isn't just a way to get from planet to planet using less fuel -- it's a way to get around using no more than a shove in the right direction, starting from between the Earth and Moon and ending up anywhere you want. That's not your father's rocket science, and it's bloody cool -- flashy language or not.

Re:for those who didn't understand the article ...

[chaotician137]

Thanks Heisenburg! It's good to know some people appreciate our work. It's bloody hard to explain to NASA managers, much less the general public. This article is a sort of first attempt.

Although I guess I am in some sense a "rocket scientist," I think the truly cool aspect of the work is the light that it sheds on the mechanisms of "interplanetary cross-fertilization." This understanding contributes to fields such as astrobiology, for example, where comet impact rates are key for determining the delivery of water to the Earth and impact ejecta exchange rates are important for investigating the transportation of microbes between Mars and Earth.

By the way, the fastest that a piece of impact ejecta has been able to get between Earth and Mars in any simulation is 10,000 years. This would be a piece of debris which, due to nonlinear effects, repeately encountered Mars and Earth with just the right geometry that it made the trip in the fastest time. The average transit time for bits of debries is a few million years.

Lagrange Points

[LuxFX]

This technique uses a concept called a Lagrange Point, where gravity from multiple bodies (usually in a orbiting situation) cancel each other out -- which results in a place where a parked object can sit and stay in place in relation to the orbiting system.

This technique is used to keep the SOHO sun observation satellite at Lagrangian point 1 in the earth/sun system, so that it keeps a constant view of the sun.

The concept behind this is extended in this instance to reveal tunnels which offer the 'path of least resistance.'

In fact, this has been discussed on Slashdot before. Slashdot users have also discussed Lagrangian points in relations to one or both of Earth's sub-moons.

Re:Lagrange Points

[Dyolf Knip]

But these are Lagrange Points for systems with more than 2 bodies. They're extremely dynamic and move along some very convoluted and lengthy paths. If you stick your ship in one at the right time, then you basically get taken for a free ride courtesy of Gravity, Inc. But the "tens of thousands of years" needed for an Earth-Mars trip doesn't strike me as being particularly useful anytime soon. Maybe for moving large asteroids out amongst the gas giants, but in this neighborhood the free ride just isn't worth the wait.

Evidently the research is more immediately useful for the techniques learned in complex multi-body interacting systems problems, which fluid dynamics guys are also fascinated in.

You are so full of crap

[p3d0]

The article says a whole lot more than that, my dear whore. It has a lot of cool ideas if you would take the time to skim it.

They have discovered a new type of route throughout the solar system, besides the conic sections typically used today, requiring orders of magnitude less energy. They can also predict up to 100 orbits into the future, with multiple ports of call on the itinerary, which is much more sophisticated than the simple slingshot method you're alluding to.

They are using chaos theory and orbital instability to their advantage. That is something most certainly not done in traditional conic orbital maneuvers, which are of such a short duration and simple nature that chaos and instability don't enter into it.

Where's LTOOL?

[Jeremy Erwin]

Raise your hand if your first reaction to this article was to try to find a copy of Ltool...

Some day...

[DoraLives]

Some day, somebody is going to grapple a surprisingly large freely-orbiting body of mostly nickel-iron, with perhaps some very valuable other transition metals in there too.

It'll get nudged this way and land in the back yard of the lucky (corporation, government, fill in the blank) via these EXACT orbital pathways.

When it does, you can tell the grandchildren, "Bah, that's OLD news. We were talking about it on slashdot before your PARENTS were even born."

The problem with nerds...

[ehudokai]

... is that for the most part we have too much information in our heads, but no common sense to use it. This article does a wonderful job of illustrating, in a relitively reasonable manner, how we can do a lot of work traveling between planets without expending much energy!

BRAVO!!!

They have managed to move beyond their meager geekness and actually apply concepts that come from Lagrange, chaos theory, etc... and use them to better mankind and also explain previously unexplained phenomena.

I know way too many nerds who cannot do this for the life of them. They have lots of knowledge, but they are useless!!!

A bit of a rant... I know, but it's frustrating to read all the comments by idiots who can't even read the article before they reply...

Duplicate article from July 20, 2002

[Arcturax]

Here is a previous discussion of this subject.

oh dear

[gid13]

you know you've been reading too much slashdot when you think it says "...these things are real. In fact, they are already being SUED"

Hmmm...

[breon.halling]

A Caltech/JPL collaboration explores the 'Interplanetary Superhighway.'" which describes "...the Interplanetary Superhighway..."

Am I the only one who finds this redundant?!?! =P

Re:Home On Lagrange

[Krellan]

Oh, give me a locus where the gravitons focus
Where the three-body problem is solved,
Where the microwaves play down at three degrees K,
And the cold virus never evolved.

(chorus)

We eat algea pie, our vacuum is high,
Our ball bearings are perfectly round.
Our horizon is curved, our warheads are MIRVed,
And a kilogram weighs half a pound.

(chorus)

If we run out of space for our burgeoning race
No more Lebensraum left for the Mensch
When we're ready to start, we can take Mars apart,
If we just find a big enough wrench.

(chorus)

I'm sick of this place, it's just McDonald's in space,
And living up here is a bore.
Tell the shiggies, "Don't cry," they can kiss me goodbye
'Cause I'm moving next week to L4!

(chorus)

CHORUS:
Home, home on LaGrange,
Where the space debris always collects,
We possess, so it seems, two of Man's greatest dreams:
Solar power and zero-gee sex.

--Home on Lagrange (The L5 Song)
© 1978 by William S. Higgins and Barry D. Gehm

http://www.jamesoberg.com/humor.html
(from very bottom of page)

Hmm.. who wants to start a project on sourceforge?

[bigattichouse]

All the math makes me brain spin, but it would be seriously cool to have a linux-based "navigator".. give it the current date and your position and find the nearest routes to Jupiter.

You know I wonder if this idea opens the thoughts for an interplantary positioning system (IPS)... in order to know where you get off, you'd have to know where you are.

Interplanetary SuperHighway

[TREETOP]

Where's my flying car. I want a flying CAR! This gives new meaning to the name "Disney World".

Cant we just walk?

[rosewood]

With this stuff talked about in another slashdot article, it seems that I could just use my super-human blood to hold my breath as I walk the distance and never get tired!

Re:Deflect killer astroids, gather comet dust?

[chaotician137]

As one of the scientists mentioned in the article (my website), I think the author of the article, who's a journalist and not a dynamicist, is slightly wrong about material "collecting" at L4.

Material typiclly doesn't come from elsewhere in the solar system and get stuck in some system's L4 points (like the Earth-Moon L4 or L5 points). The material that is there, if any, would have existed in that location since the formation of the system, i.e., anything near the Earth-Moon L4 or L5 points was there when the Moon formed.

Regarding the killer asteroids, you're totally right about deflecting them with small forces. There will be a conference next year, Planetary Defense Conference: Protecting Earth from Asteroids, where people will propose technical plans associated with defending Earth from approaching near Earth objects (comets and asteroids). The threat will be approached from three warning levels: short-term (less than ten years warning); medium-term (ten to 30 years warning); and long-term (more than 30 years warning). The more time we have to deflect it, the smaller the force needs to be.