What if the Event Never Happened? - And Mars is still a blue planet!

Wim · 2003-11-18 13:39:50

Humans going to other planets is unavoidable. The humans race is like a virus, it spreads. Or did I get this from Mr. Smith in The Matrix.
What I want to say is that those who are against it, will never be able to stop others from spacetravel.
Those who think hunger will once be 'cured' think wrong.
Those who think once there will be total peace think wrong.
Doing something against war and hunger will take a lot of time (read forever) and money (read zillions) but waiting for it until it is solved before pumping time (read forever) and money (read zillions) in spacetravel is ... wrong.

Shaun Barrett · 2003-11-19 02:30:36

My two cents worth:-
I agree with just about everyone in this thread ... except Free Spirit.

Saying space is "not a place where we belong" could have been applied to all sorts of situations throughout human history. There's almost nowhere on this planet that hasn't been invaded and occupied many times over the millenia and almost every ethnic group has had a go at it.
It's been mentioned already that early humans left Africa, so current wisdom has it, and spread out all over the world. If Free Spirit's way of thinking had held sway, we'd all still be on the African savannah wondering what the rest of our own planet looked like!
Even the North American indians are thought to have 'invaded' North America from Asia some 15,000 years ago (I believe), via a land bridge now submerged. Did they have to annihilate any humans who had found that continent earlier? So far we don't think so but it wouldn't surprise me a bit to find out that was the case. Either way, using Free Spirit's logic, you could say that they they took over a place where 'they didn't belong'.
Today's polynesian islanders have only been on their idyllic tropical islands for a few thousand years, having spent many weeks in open boats to get there from places in Asia. Often the journey would have been an act of faith since the Pacific Ocean at the time was more unknown and therefore more dangerous than interplanetary space is to us at present. Again, those people were taking risks and suffering hardships in order to go where 'they didn't belong'. These days everyone is perfectly happy to call them South Sea islanders and nobody disputes their right to be where they are.

I may be wrong, but I suspect Free Spirit is harbouring more than a little disgust for his own species, perhaps for reasons Cindy has pointed out. But, as she rightly says, brooding in bitterness and guilt for perceived past crimes is a negative, self-destructive, and entirely useless activity.
For my money, I think Free Spirit would do well to shake off such feelings and look at the good things humanity has done and is capable of.
Space is our next frontier. It's a place of hope for the future and should be seen that way.

Gennaro · 2003-11-19 03:41:18

That passage above illustrates the most important reason not to stretch our human empire too far, the reliance on ultra energy-dense substances like anti-matter and other nuclear fuels is dangerous. When you consider that 2 grams of plutonium can kill millions of people, it seems rather irresponsible to launch 72 pounds of it on Cassini with a rocket that has a 10% error rate. Imagine how much that type of thing we'd be launching on a constant basis if we had to keep space bases fueled up. I just see no reason for sending people into space. It's not a place where we belong

Free Spirit,
everything big and powerful is dangerous. Fire, metallurgy, horseback riding, architecture and large society formation was dangerous to the first humans who took it in their service. Those who didn't however got swept away, one way or the other.
Yet if it is the use as weaponry you are worried about, what better option do you have than expanding the playing field? Not that war is a part of the future if we expand into space and that for the very same reasons: too dangerous and unnecessary since there will be an abundance of resources for all. Something that will not happen on this Earth if we choose to stay in its increasingly cramped confinement and zero sum competition for limited resources.
By the way, massive antimatter starships have nothing to do with Earth. They won't be built or fueled here but in interplanetary space. Do you know how big a place that is? To make an analogy: if the Sun was a huge inflatable beach ball, located some 40 meters away, the Earth would have a diameter not larger than the screw heads holding your PC together. Everything you know about, the emotions of all Terran beings and the entire history of the human species thus far can be fitted on a screwhead.
The best thing that can be said about your neck-breaking example of Cassini is that it's seriously flawed. How do you suggest that a launch failure could kill "millions of people"? If a RTG would break up in the atmosphere the radiation released would equal something like a 1/10 000 part of the global effect of an ordinary nuclear bomb test. Get a grip.
As for humanity not belonging somewhere, I can only say that we-belong-in whatever-environment-that-we-conquer-and-master. If we were "meant" for a certain lifestyle and had stayed in it, we'd still be in central Africa, eating carcasses and getting oppressed by the silverback who has exclusive rights to all the females. Until the marginalized males revolt that is and some equal competitor topples his power, in which case the society descends into mass rape of all the sub-males' mothers and sisters for a while, until hierarchy is restructured by the revolting leader claiming power, biting the children of his predecessor to death in the process. That's your leftie Rousseauist Eden for you.
Natural law and nature's rights: a lie and an injustice. Something to be overcome.

Mad Grad Student · 2003-11-20 20:45:25

Gennaro, what you said about antimatter being the propultion of a colony ship was a good idea, but where did up to or past luminal speeds come from? The fastest speed that I think would be possible (While maintaing a margin of safety) would be about 5% of the speed of light. This would put a colony ship in orbit around a star like Delta Pavonis in only 800 years or so.

What's important to remember here is that the absolute fastest a ship could accelerate and still allow normal activity inside is about 1.8 g's. This acceleration would first be achieved through the use of solar sails or M2P2 drive, and after leaving the heliosphere would be maintained through antimatter drive. I haven't gotten to calculus or differential equations yet, but by my (semi-)educated guesses, the ship would reach 5% of luminal speed in 1-2 years. I have absolutely no idea if this is accurate, so could someone inform me on what it really would be?

When talking about stellar colonization, it's important to remember that right now we're at the point flight was at in the rennisance. Da Vinci was scorned for his ideas about flight, but sure enough we did that in only 400 years. Granted, his ideas about ornithopters were pretty flawed, but that's another story altogether. We'll reach for the stars eventually, but whether that will be half a century, a century, or two is beyond my say.

Shaun Barrett · 2003-11-21 06:12:04

Hi Mad Grad Student!
1.8g is actually a very respectable rate of acceleration. According to my calculations, at 1.8g, 0.05c would be achieved in about 236 hours or just under 10 days.

Byron · 2003-11-21 07:09:11

Hi Mad Grad Student!
1.8g is actually a very respectable rate of acceleration. According to my calculations, at 1.8g, 0.05c would be achieved in about 236 hours or just under 10 days.

That's some pretty heavy-duty acceleration there...I don't know if I could withstand that heavy of a gravity for even as short of a period of 10 days. Why not just go for a quarter gee for a full year, which would get your speed up to maybe 50% of c? Of course, you would need to spend another year at the other end decelerating...lol. The real problem is how to cope with the longitudal accelerations inside the spaceship in conjunction with maintaining artificial gravity during the long coasting portion of the voyage. Personally, I think you would only want to accelerate at something like .05 gee for one half the voyage, and turn around and brake for the entire second half, but this would take a lot longer I imagine...

B

clark · 2003-11-21 11:11:11

Beyond the heliopause, what do we know about the substance of the universe? There's been some talk lately about this since we have some probes nearing this place, so new discoveries may change our long held assumptions on the effectiveness of these sub-liminal? speeds.

A sphere inside a shphere inside a sphere inside a sphere....

from atom on up, we see a pattern. I wonder if there is anything to it. Anyone more knowledgable care to speculate?

Gennaro · 2003-11-21 17:43:42

Gennaro, what you said about antimatter being the propultion of a colony ship was a good idea, but where did up to or past luminal speeds come from? The fastest speed that I think would be possible (While maintaing a margin of safety) would be about 5% of the speed of light. This would put a colony ship in orbit around a star like Delta Pavonis in only 800 years or so.

Superluminal was a bit over the top, but 40% lightspeed should be a possibility.

What you need is a Beam Core Antimatter Drive:
"The Beamed core drive would have an exhaust velocity of near light-speed. Allowing (with sufficient amounts of antimatter) acceleration up to almost any arbitrary percentage of the speed of light."
http://ffden-2.phys.uaf.edu/213.web....re.html

I don't think that now is the time to name specific star systems to go to.

- Why not, it's fun.

Besides, you're right about Tau Ceti being rather metal poor, but as far as I can tell, the Sun seems actually to be located in the upper end when it comes to heavy element abundance for nearby stars of its class. It's no ordinary star. I didn't take the time to check with my sources, just threw out a couple of potential destinations from the back of my head. Question is what percentage of heavy elements is necessary for rocky planet formation and/or potential biospheres. Will 50% of the Sun do? I have a hunch that it will, although it might be a close call.

Tau Ceti:
http://www.solstation.com/stars/tau-ceti.htm

Cheers!

Mad Grad Student · 2003-11-22 15:25:44

I hope that last post I made didn't hurt my credibility too much, it was just the product of not actually bothering to look up a referance. According to an old popular science I dug up, disregarding relativity, if you could accelerate for a year at one g you would reach 90% of the speed of light.

I think it's reasonable to think that M2P2 could allow you to reach 40% of light speed before the ship exits the solar system. Although, you have to realize when doing uneducated guesses like that by the time you reach 33% of the light barrier you're traveling at one AU every 24 minutes. Starting from Earth that will take you beyond the heliopause in 40 hours. Come to think of it, that's probably enough time to reach 40%.

Moving at that rate, the 19.9 light-years between here and Delta Pavonis will be behind the ship in a mere 50 years. Add in a year for acceleration and decceleration, maybe three at the end for maping, examining, and low-end terraforming if necessary, and the time from departure to our first steps outside the solar system comes to about 55 years. Considering that the people picked to go will be in prime condition and their youth, most of the first generation will still be around, but the second, born and raised in interstellar space, would do the majority of the work.

I like using M2P2 as a drive system because no matter what, antimatter is extremely dangerous, and will so remain, even 500 years from now. By the same token, nuclear waste is still dangerous now, even though disposal technology is always developing. Solar sails wouldn't be as versitle because they're simply a big pain in the neck to erect and use, and flying a hundred-mile-across, 50-micron-thick mylar sheet over 20 light-years of god knows what kind of space is just asking for trouble. M2P2, by contrast, is compact, energy efficent, non-volitile, and might get rid of some of the risks of cosmic radiation. For more info check out this.

As for the question of which star system to go to, I say Delta Pavonis because it's about the sun's size, is very enriched in metals, and seems about the right age. However, I've just read that it might be about to become a giant star, and who would want to go to a system like that? Epsilon Eridani seems like another promising system to me, and it's much closer. By contrast, Eridani's problem might be that it is too young, and still in the protoplanet stage, like Vega.

Tau Ceti might actually have planets, but it's doubtful that it would be a system like ours. It only has enough metal to make one or maybe two small terrestrial planets, but if one of the gas giants is close enough to the star, its moons just might harbor life as we know it. Titan is very similar to how Earth used to be, and had Saturn formed about 1-1.5 AU from the sun it could have been the primary seat of life in the solar system, so I think life on moons is just as plausible as life on planets.

Gennaro · 2003-11-22 21:45:24

The real problem is how to cope with the longitudal accelerations inside the spaceship in conjunction with maintaining artificial gravity during the long coasting portion of the voyage.

- Byron, when I started getting seriously interested in interstellar travel, I actually gave this problem some thought.
Here's my solution (it's all about architecture!).
The way to create artificial gravity by centrifugal force during the coast period for a massive interstellar ship, would in this case be the traditional huge cylinder fitted longitudinally along the fuselage.
If you set the spin to conform to Earth gravity, 1 g would naturally only be achieved in the outer decks of the cylinder. The closer you get to the central axis the less gravity would be generated. Consequently you'll end up with a lot of space in the middle of the life support section serving no apparent purpose. Now here's what you do.
Let's say that acceleration is also 1 g, meaning that the inertial force of linear acceleration is pushing you backwards in the ship in relation to that factor, why not just fill up the center section of the cylinder with floors from the direction of the engines up, much like in a skyscraper?
During the acceleration and deacceleration phases of the journey, the crew would use this inner section of the cylinder and during the coast periods they would just move to the outer revolving "onion scale" layered floors and in both cases they could move about as happily as on terra firma.
The duplication of living areas, while wasting mass, would actually not pose a wastage of space problem, because that inner section could not be usable anyway during the coast phase.
Neat, ha?

Mad Grad Student · 2003-11-22 22:21:30

As far as ship layout goes, here's my idea. The actual habitation area would be laid out in a donut-shaped pattern made out of 12 or 14 cylindrical modules. The modules would be joined by a flexable rubber (Or something thereof) joint similar to that in jointed buses. During the acceleration phase, the modules would be oriented so that you'll be looking down through the floor at the engines. Once the coast phase begins, they will all be twisted 90 degrees and the whole assembly spun at about 3 rpm to creat one-g. That way, nobody gets spacesick, there's no irreprable bone loss, so we're all happy (Just don't ask "are we there yet?").

As for the space in the middle? That would be were you put all of the essential equipment for the journey and journey's end. In it you will find four miniature fusion reactors (One for the trip, one to make helium-3, one spare, and one for the trip's end), enough carbon nanotube rope to string down a space elevator, several large trans-atmospheric aircraft, 10 VTOL aircraft, 60 landsat and GPS satelities, you could have a pretty good weekend in Vegas with all that stuff, no?

All systems to keep the passengers alive (aka trees) would be contained on the hab deck, in a biosphere layout. If you sent three ships, one could be temperate, one desert, and one tropical so that you have the most variety at the trip's end. Now all we have to do is pick the one lucky planet to get colonized!

Shaun Barrett · 2003-11-23 18:35:38

Mad Grad, I love your optimism! You've almost got me convinced.
Where do I sign up for the maiden voyage?!!

:laugh:

Mad Grad Student · 2003-11-27 20:57:32

Okay, so I might have been a little overeager about going right now, but my point remains that though launching an interstellar U-Haul operation would be difficult, it would also be doable. After I read the detailed Mars Direct plan for the first time, I started musing about what such a mission would look like with only today's tech, on a budget of less than the US's monsterous Iraq plan. Granted, no one would launch this mission, there are too many unknowns as of now, but if we really tried, the human race could travel to a nearby star for only around $60 billion. I think that's a nice bargain for a species-wide insurance policy.

Okay, I haven't done the math yet, so these numbers our pretty rough but here goes. You start by launching about 30 20-ton payloads on Protons from Baukinur. 20 of these are hab modules, each containing a self-sustaining biosphere for six people. Additionally, there are some for a fission power plant and a few back-ups, support and scientific equipment, etc.

The modules are linked in groups of ten surpassing the ISS as the most costly and ambitious scientific project ever undertaken by humans. The three ships each contain 40 people, a self-sustaining nuclear reactor, and enough ion engines to supply about 5,000-lbs of thrust. Should one run into trouble, the others can assist it. Obviously, the crew have been intensively screened for a history of genetic disorders to avoid problems like hemophelia, colorblindness, and Sickle Cell anemia.

Once completed, the ships would be launched on a Voyager trajectory out of the solar system aimed at Tau Ceti and its Earth-like moon Delos (Don't you love making up names for ficticious moons?)

The ion engines are able to apply slow but steady power up to 10% of c. A M2P2 bubble protects from cosmic radiation. At that speed, Tau Ceti is reached in 110 years, with the third generation in command. The crew point the Mayflower, Challenger, and the Beagle (More naming fun!) around and make a second ion burn. Even if only one ship makes it, that will be enough to settle Delos.

Once there, three of the modules break off of each remaining ship and truck the material down. Included will be things like mining equipment, a pocket refinery, and seeds and embryoes of thousands of Earth species to be spread across the land. The modules will be arranged as the start of the first extraterrestrial city. Intriguing, eh?

Of course, this mission will not be launched untill an Earth-like planet or moon is actually found. It will still have to wait untill there's enough support behind it, and by then we will have far better technology, but I guess my point was that anything is possible, if you can imagine it!

As for clark's question, the reason that spheres, spirals and other circles so proliferate the universe is because that's the basic shape that will be formed under force. Anything that expands evenly from one point or is compressed under even gravity will become a sphere, it's just how physics work. At least, that's what I've been told. Btw, I chose Delos as the name for the new Earth because in Greek mythology no land would recieve Leto, the mother of Artemis and Apollo, out of fear of Hera's wrath except the tiny island of Delos. After she arrived it blossomed into an island paradise, so it seemed appropriate. Any other suggestions?

Gennaro · 2003-11-30 11:15:05

Mad Grad,
like your idea about 12-14 turnable habitation modules on a wheel. Very elegant, and certainly more mass conserving than building a double set of residential areas, which my design essentially amounts to. Perhaps I should point out though that all of the in-between space in my design does not have to be "filled out" with living quarters nor must it have an equal floor square size, since most of the journey will be coast anyway, even for interstellar missions where you will accelerate/deaccelerate for many months. Life support reactors, machinery, stores and hydroponics systems would not need to be duplicated either, but could be conveniently placed someplace near centre axle. It was just a simple way of explaining the principle.
Anyway, regarding your layout, I have a few comments. Flexible 'rubber' joints, reminiscent of jointed buses, are nice, if such mega engineering could be reliably combined with needs for radiation shielding etc (in any event certainly easier than building an antimatter drive, I admit), but there is an even simplier solution.
Why join the modules together at all? If you want to move from one module to another (I take it they are of considerable size, like small seperated towns) you could just take the spoke elevator down to midships, float in zero-g to the next spoke elevator in order to ascent to the next door module.
Secondly, cylindrical modules will not be optimal from a space utilization point of view, but that's a minor point.
Thirdly, and I'm not sure of the extent of this (which is also dependant on the wheel radius), but since you are concievably using plain floors inside the modules (how else could you stand straight while in the acceleration mode?), the floor will not conform exactly to the curvature of the centrifugal force after you have "twisted" the wheel 90 degrees into spinning mode. So depending on where you stand inside the habitation module, different effects will occur (in regard to coriolis etc), because the angle/direction of centripetal acceleration will vary.
It could be that you need some way of 'bending' the residential section into a slightly arched or curved form in order to conform with the circular shape of the wheel.
To get the right 'cheese doodle' shape, maybe we could try some more bus joints?

Btw, I chose Delos as the name for the new Earth because in Greek mythology no land would recieve Leto, the mother of Artemis and Apollo, out of fear of Hera's wrath except the tiny island of Delos. After she arrived it blossomed into an island paradise, so it seemed appropriate. Any other suggestions?

"Delos", I love it! :laugh:
Personally though, I hope there's no gasgiant in a Jupiter orbit that close that Tau Ceti and that Delos rather is an earthlike planet at 0.68 AU (or whatever is optimal from a liquid water point of view in that system) instead of a moon.
Of course, when Jane Fonda went to Tau Ceti in "Barbarella" (1968), the home planet of the wicked queen was known as "Iythian".
Geez, why do I know these things?

Come to think of it, there is already an island called Delos in the Aegean Sea. ???

Mad Grad Student · 2003-11-30 17:29:40

For the fist time, I actually did the numbers, and for 500 people a ship would not have to be THAT big. I read in an old book I have that Princeton proffesor Gerard O'Neill's origional plan for a space colony would be a mile-wide ring habitat capible of supporting 10,000 people. Of course, this book also claims that Voyager 2 will fly by Neptune in about six years, but that's beside the point. Anyway, if you scaled it down to my size, you'd need 12 cylindrical sections 300X360 feet to support 500 humans. The modules would form a ring 1,375 feet across that could spin four times a minute for a comfy 1 g.

I would assume that the floor plan for this would involve puting a floor/ceiling the bottom and top of the cylinders, making a floor on the bottom and a housing for equipment and lighting on the top. Your point that gravity would not be straight down at the tips of the sections is valid, but the maximum inclination you'd feel would be 15 degrees, amounting only to a slight downhill feeling.

One major problem you have to face no matter what layout you use is lighting. People often don't realise that Earth's biosphere is nothing resembling a closed system, it's powered at every turn by the sun. The only exception to this is at deep sea vents, but that won't be of much use to anyone other than interstellar tube worms. The simplest solution is to make standard electric lights, but these tend to wear out quickly. I like the idea of using nothing but biological systems because they have one universal advantage over artificial ones, they go on forever. I say genetically engineer some species like fireflies or anglerfishes to shine brightly all the time on a low calorie intake, and stuff a bunch in a mini-biosphere on the ceiling. Hey, by the time we have antimatter, genetics will be old hat!

Going back to names, there are a few I'll bring up from the only sci-fi novel I've read so far that involves interstellar colonization, Chasm City. The five ships in their flotilla are named the Islambad, the Palestine, the Santiago, the Brazillia, and the Baghdad. Of course, the Islambad and the Palestine have some nasty accidents with antimatter, not very good for them. The planet they colonize at the end, around 61 Cygni A is named Journey's End first, nice and simple name, but is renamed Sky's Edge, out of circumstances you have to read the book to get. In two other colonization forrays, they name a moon in the Epsilon Eridani system Yellowstone, and a nice little planet around Delta Pavonis Resurgam.

I just want to say to anyone who's going to try to think of some names, don't mention anything like Tatooine, Courecant, Naboo, etc, just on basic principle. We're trying to be serious here, folks.

clark · 2003-12-01 10:58:25

Instead of complex biological creatures, take basic single celled whatever and splice and dice them to produce 'light'. A few billion in a test tube ought to make you a nice shining 'bulb'. Run a solution through the tube for them to feed on. Viola.

Complex biospheres take care and understanding to make work properly- keep it simple.

Mad Grad, are you a grad student at Princeton?

Mad Grad Student · 2003-12-01 21:27:39

Mad Grad, are you a grad student at Princeton?

Hmm, not that it wouldn't be interesting to live an alternate persona as a grad student (With disonesty on my gender, height, weight, etc why not?) here at these forums, but I think I'll be honest. No, I'm not a grad student at Princeton, I haven't even gotten my high school diploma yet. That would seem rather embarrasing except when you take into account that I've only been at the legal age to solo in a glider (14) for nine months now. I am actually a high school freshman in Phoenix, Arizona, with (Perhaps unrealistic) aspirations for going to MIT. If you noticed, I mentioned earlier that the highest math level I've taken so far is trigonometry, and it would be pretty chagraining if I managed to reach graduate school without several years of calculus and differential equations.

So, now that I've made everyone else feel old, I like that idea about using bacteria as a light source. Is there anything those little single-celled monerans can't do!? While the biosphere would be a handfull to keep under control, it would be much easier than dealing with mechanical systems for 50+ years on route. Anyone who's tried to do work on a Macintosh can attest to this. :laugh:

Shaun Barrett · 2003-12-02 02:36:46

You have no right to be submitting such intelligent posts at the tender age of 14 ... you oughta be ashamed of yourself!

Gennaro · 2003-12-03 10:18:51

Your point that gravity would not be straight down at the tips of the sections is valid, but the maximum inclination you'd feel would be 15 degrees, amounting only to a slight downhill feeling.

Hey, I'm such a dumbass.

Taking a bath it suddenly dawned on that turnable habitation modules on a wheel need not be configured along the direction of the spin, but rather should be placed parallell to the direction of travel. Meaning that in coast mode, they would resemble elongated rectangular 'bars', in line with the ships' hull/fuselage. That way the inclination effect at the "tips" will be minimized.
In acceleration mode, whether mounted on an actual wheel or on spokes only, the hab sections will resemble solar rays or the petals of a flower, spreading out from the centre of the ship.
There will be no need for "flexible rubber joints", since the wheel will function as a fixed frame upon which the habs are turned 90 degrees to change travel mode each on its own. Movement from hab section to hab section and hab section to fuselage, can be performed along corridors inside the wheel and up and down shafts in the spokes.

Hab sectons could be outwardly designed with an architectural mind and would lend themselves nicely to pleasing aesthetic principles, I think. Missile shapes and spead streaks underlining the directed velocity and power of the whole assemblage for instance, and with magnificent panoramic views fore, side and aft.

Bill White · 2003-12-03 15:13:09

The modules would form a ring 1,375 feet across that could spin four times a minute for a comfy 1 g.

4 rpm? I have read that this rate of spin can lead to disorientation, especially upon rapid head movements that add to or subtract from the centripetal acceleration.

Also, depending on the radius of the motion, different gee forces will be experienced at relatively close proximities. In other words, your head would truly eb lighter than your feet and doing somersaults would play havoc with the inner ear.

1 rpm is said to be the accepted safe threshhold.

Links to follow - bug me if I forget.

Mad Grad Student · 2003-12-03 22:15:37

I like your idea, Gennaro, although one problem is that the modules' gravity would be greatly reduced close to the to the hub. However, I doubt that very many people would complain about weighing less. The reason I chose the wheel design is because of 1) lack of origionality, I have plenty but just decided not to use it here, and 2) it carries a certain elegance, you have to admit. Elegence never gets you anywhere in space, though, and I think the sunflower layout is a good comprimise that should stay intact the whole trip.

Actually, Bill, 4 rpm wouldn't have too great an effect on your inner ear when you're situated at least 688 feet away from the center of motion. Even if the effect was noticable, it would be a tiny hassile at most, and the inhabitants would quickly adapt to it. Come to think of it, aren't there bigger problems to an interstellar voyage than centrifugal force, and what does all of this have to do with a blue Mars? ???

Gennaro · 2003-12-03 23:16:28

I like your idea, Gennaro, although one problem is that the modules' gravity would be greatly reduced close to the to the hub.

- Hub? No it wouldn't. Are you sure you understood it? Sorry, if my way of explaining is so poor (comes with the foreign language, I guess), but it's still essentially about your idea of "twisting" the habs 90 degrees, which by the way, if you haven't read it in a book, I think was real smart.
Read again and you'll see!

Mad Grad Student · 2003-12-04 22:25:29

Oops! For some (probably dislexia-tied) reason I thought that you meant that the modules would be in a sunflower pattern in cruise mode and aligned with the direction of travel while accelerating. The other way makes sense, except for the minor problems that during cruise mode the modules would need to be spun faster for the same amount of gravity and the joint would be under a lot of stress during acceleration.

Btw, what foreign language is that you mention? It probably doesn't matter, the most I know of any other language is how to order food and say where I'm going in French. Maybe after eight semesters of it I'll understand more.

Shaun Barrett · 2003-12-07 07:28:37

Hi Bill!
We had long discussions here at New Mars about rotating tethered spacecraft a while back but I don't remember where. From memory, humans can adapt to rotation rates up to about 4 rpm but, as you suggest, there are certain problems with the Coriolis effects.
I've always thought keeping the rotation rate down to 1 rpm would be ideal. However, if you want a full 1 g environment for the crew and only 1 rpm, you need a 900 m radius of rotation - the advantage with this being the almost undetectable Coriolis difficulties.

Mad Grad Student · 2003-12-12 17:42:27

Right, steering the discussion back on topic, I've recently heard more and more evidence that Mars is dead because it's simply too small to keep the tectonic cycle circulating for more than one or two billion years. I don't like, and I use that word tentatively, this idea, because what it means is essentially that an Earth-like planet has to be above a certain size to maintain Earth-like longevity. Of course, you can't pick and choose evidence based on what you like and dislike, facts are facts and that's the foundation of science.

I'm not quite sure how we can tie this into the topic discussion, because under this scinerio there is no singular event that we can ask "What if" about. However, after I got the creative juices going I managed to think of one absurd event that could have gone differently and give us a different Mars today.

Okay, there's mounting evidence that Neptune formed much closer to the sun than it is today, and as it ventured outward its tidal forces greatly influenced the growth of the solar system. So what if as Neptune was forming it got into a slightly more eliptical orbit? Now, let's just suppose that this new orbit sent a chunk of material about the size of Europa towards Mars. If it happened to be on a certain orbit, it would intersect with Mars, areobrake, and go into orbit around it. Stranger things have happened, like Uranus tipping over or Earth getting its moon.

I estimate that a Europa-size object would exert such huge tidal forces on Mars, that shearing alone could keep the core running. Of course, it's entirely possible that this is an insane idea only a poorly-educated freshman would concoct, but let's assume it were possible. With Mars' core buring strong to today, it could keep the sillicate-carbon cycle running and stay at a comfy Earth-like temperature. Imagine what that would be like for Lowell and the other astronomers to look through their telescopes and see vast oceans and forests, the inner system would be a very different place under this scinareo.

I actually enjoyed talking with you guys about interstellar transportation, but that whole thing is kind of off topic in here. Perhaps we should move that into the "interplanetary transport" forum.

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#26 2003-11-18 13:39:50

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#27 2003-11-19 02:30:36

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#28 2003-11-19 03:41:18

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#29 2003-11-20 20:45:25

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#30 2003-11-21 06:12:04

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#31 2003-11-21 07:09:11

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#32 2003-11-21 11:11:11

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#33 2003-11-21 17:43:42

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#34 2003-11-22 15:25:44

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#35 2003-11-22 21:45:24

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#36 2003-11-22 22:21:30

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#37 2003-11-23 18:35:38

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#38 2003-11-27 20:57:32

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#39 2003-11-30 11:15:05

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#40 2003-11-30 17:29:40

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#41 2003-12-01 10:58:25

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#42 2003-12-01 21:27:39

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#43 2003-12-02 02:36:46

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#44 2003-12-03 10:18:51

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#45 2003-12-03 15:13:09

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#46 2003-12-03 22:15:37

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#47 2003-12-03 23:16:28

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#48 2003-12-04 22:25:29

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#49 2003-12-07 07:28:37

Re: What if the Event Never Happened? - And Mars is still a blue planet!

#50 2003-12-12 17:42:27

Re: What if the Event Never Happened? - And Mars is still a blue planet!

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