Any professional asttronomers or planet finders out there care to comment?
I'm not a professional in the field (I've used my physics degree to bootstrap myself into engineering consulting), but my field of interest was astrophysics, so I'll take a swing at it. Lotsa questions, though...
Remember, all these observations are INDIRECT. They are estimating the size of the planet by the solar wobble caused by the tug of gravity by these planets on their suns. Now, whose to say that this tug is caused by 1 super-jovian sized planet or 5-11 terran sized planets?
That information comes from the Doppler data: compare the present discovery with a system which has multiple planets. In the first case, you'll see a simple periodic variation in the Doppler shift -- a distorted sine curve, if you will, but one which has a single periodic structure which corresponds to the period of the planet. In the second case, there are three periods -- one for each of the three planets -- so they stack up on top of each other, to form a complex periodic structure. The second plot on that page shows the second and third planets' Doppler curve, with the very short-period inner planet removed; you see a long-period sinusoidal curve (the outer planet's), with a shorter-period curve (the second planet's) making about 5 "ripples" in the long-period curve (meaning that the second planet orbits about 5 times for each orbit of the outer one -- 241 days to 1309 days, in fact).
I won't go into the details -- there's plenty of that on the second link -- but it's just a matter of analysis of the data, fitting a model to it, and making a few wise choices if you find that the simplest models won't do. And BTW, it would take a lot more than a handful of terrestrial planets to equal the mass of a super-jovian -- although Jupiter is about 11 Earth diameters wide, it is much more massive (around 80 terrestrial masses, IIRC -- but don't quote me on that, I don't have a text or a link handy).
Whose to say these Saturn like and jovian like planets don't have moons in orbit that are in a "habitable zone?".
That may very well be the case, but we won't find that out with the present equipment. More reason to keep searching, and to get better instruments!
I wonder if we could detect anything but Jupiter from our ouwn sun's wobble? How big a planet does old Sol's wobble say is in orbit around it - 2 Jupiters or 1 jupiter and 8 to 9 others? How does an Oort cloud or Kuiper belt of material affect these calculations?
Right now, we'd might be able to detect Jupiter and possibly Saturn -- but both of those planets are in more-distant orbits than what we've found so far, so detection would be more difficult. The Doppler method would completely miss everything else in the Solar system. (Again, the mass of the rest of the system, after Jupiter and a bit from Saturn, is trivial...)
The Oort cloud and Kuiper belt don't have much effect at all -- orbits of stuff out there are quite long (hundreds of years and way up), compared to the few days to a few years for all the extrasolar planets detected so far. And as far as we know, the masses of bodies in both aren't very large -- in fact, they don't even detectably perturb the orbits of the planets in the Solar system, and we've been looking for that for a long time. Even if something quite large was out there, it would take hundreds to thousands of years of watching to detect it -- either here or in the extrasolar planetary systems.
Until we have a spaced based interferometer array (which I beleive NASA is trying to get funding for)which can do DIRECT imaging of these planets, we will not know of any reall numbers and sizes.
Actually, we do know one planet's mass and size, because it passed between us and the disk of its star; that allows us to remove the uncertainty in mass (from Doppler data, we only know a lower limit on the planet's mass) because we now know the plane of the orbit, and from the measured dimming of the star's light, we know the size of the planet.
But that's a rare case, and I won't argue that we don't need a space-based interferometer array.
Good questions, all of them -- and I hope I've answered them, at least partially.
While I have to agree that Iridium was a fiasco, and that plenty of people are to blame, I have to disagree with your assessment of Bruce's article.
As much as I like Bruce Stirling for all his nifty science fiction, a quote like "when people realized that the Moon is much less interesting than NASA said it was" simply sucks.
I don't know where you were, Bruce, but I know that I and a whole bunch of other folks never found the moon "much less interesting." You might have been busy having your diapers changed, but I was in the middle of a college career based on astronomy done with orbital observatories, and when Congress cancelled all the programs, my dreams died along with a lot of other people's. It wasn't lack of public interest, but lack of the Cold War push -- simple science wasn't worth it, while military superiority was...
Despite this sort of whining, the space program hasn't gone away -- there are still quite a few people who work in it, myself occasionally included. And while there are still mismanaged (and ill-conceived) programs like Iridium, the dream is not yet gone. We just hacked our way back into it.
Look back in a hundred years, and no one will understand why we didn't do it faster -- after all, we had the technology, all we lacked was the will.
Great, if the gov't gets it's way... we'll have a bunch of smaller misguided bloatware companies running around.
You've actually made a very important point: in the end, if there is a structural remedy which breaks Microsoft up, the resulting components would still need a "monitoring and enforcement plan that doesn't equate to government regulation of the industry" -- to quote Ken Wasch (maybe a bit out of context).
I have looked long and hard at the situation, and it isn't clear to me what a structural remedy would gain us. If you split M$ along functional lines (OS, apps, and internet), you have three very large companies who can still share information, and who have close historical ties with each other. What do you suppose they'll do next? But if you split M$ into three different OS companies, all you've managed to do is make Sun fourth instead of second... what the hell good does that do?
To my way of thinking, there isn't anything other than a monitoring and enforcement plan which can potentially work. The devil is (as always) in the details. So the question is: "What can we do to make sure the monitoring and enforcement plan works?"
I think the answer is to get involved, rather than just bitch.
I based my guess on observations of the only life sustaining planet we know of. The odds of similar conditions occuring elsewhere are not that good.
Ummmm... my point is, how can you calculate odds with a sample of one? We know exactly nothing about terrestrial-type extrasolar planets, so it's hard to say anything about them -- we can only speculate about the odds of one being like the Earth.
For a slightly different viewpoint: when I look at the single example of Earth, I see life modifying the planet to keep conditions adequate for its continued existence... and my "educated guess" is that this will turn out to be more common than not -- with the disclaimer, of course, that the conditions which life elsewhere likes may not be what we enjoy. Evolutionary forces will tend to produce life which interacts with its environment to support its continued existence, which may eventually change the environment profoundly; Earth's oxygen atmosphere is a good example.
And since we have no idea what conditions are necessary for the development of life (instead, we have speculation about what was necessary for the development of life which has now evolved itself and this planet for 3.5 billion years -- not at all the same thing!), it's hard to predict how many planets will have it, much less what the local conditions will be.
Could someone please explain why seemingly impossible things that are the domain of Captain Picard and the boys are getting attention from science when we can barely launch probes properly to Mars.
You're confusing science and engineering, I think. "Science" is basically a method of discovering (or "uncovering") information about the universe; "engineering" is the application of that information for human use. And don't forget that part of NASA's mission is to do the research and low-level work which will enable private industry to apply new technologies too expensive for them to develop from scratch (although NASA sometimes forgets this themselves, it would appear!).
As far as "barely launch[ing] probes properly to Mars," the problem with the last two spacecraft would seem to have been more in the management of the missions, not in the hardware -- even the Polar Lander would have worked if the testing was done properly. This isn't a failure of science, or even of engineering... it's a failure of oversight.
As a friend of mine says, "The way pizza tastes best is when you wake up, reach over the back of the front seat, and grab a slice of pizza and a warm beer."
So, Dr. Cooper, where's the rest of the explanation?
We should all feel fortunate, or blessed, that our solar system and orbit turned out to be so beneficial for the sustainment of life. I can't even begin to calculate the odds against it... That does not seem too common, to me at least.
It's hard to tell how common it is, because the methods we're using to detect extrasolar planets happen to be suited for finding gas giants -- Jupiter size and up, mostly up! It with take either major improvements in our observational technology, or development of new technologies, to find Earth-sized extrasolar planets.
Until then, all we can really do is guess -- which is what you're doing. BTW, I happen to disagree with your guess...;-)
There is a nearly-exact duplicate of the Polar Lander scheduled for launch at the end of this year; it now appears that NASA will not launch it, because it is the same as one that failed (this is actually touched on in the story). Instead, they'll examine the problem in detail, fail to find the real problem, hammer on the engineers whom they will blame for the problem (when it was underfunding all along), then have everyone wear sackcloth and ashes for a few days before they go back to being the same old NASA.
This isn't really engineering, this is politics. I think the world of the NASA engineers, who are damned good, and extremely motivated. My opinion of NASA management, however, is pretty much unprintable.
Unfortunately, they have a very tight grip on the money -- GPLing them is a grand idea, and might even work (if you could avoid the everpresent danger of overworking the problem -- which release do you actually launch?), but it'll never happen.
What we need is some very rich man *cough*Gates*cough* to fund this sort of thing... but that'll probably never happen, either.
In the old days, programs were "cost plus fixed fee" (CPFF)... some of the abuses were astonishing.... So nowadays, programs are fixed cost.... It works pretty well for NASA, so far, so they haven't changed it in the past 6 years or so... but on the contractor end, it leads to two things: underbidding on contracts to insure some profit, and overworking the engineers to maintain performance.
The underbidding almost always comes in the labor category.
Bughunter, you have presented the picture in exquisitely painful detail.
Fifteen years ago, when I first got into aerospace engineering, I remember my boss (the VP of Engineering) telling me that the most important words I could learn were, "Out of scope." He bid the contracts low, just as you describe, and then looked for the minor (but inevitable) changes to the contract that allowed him to go back and ask for more, arguing that they changed the scope of the contract. (I once saw him bundle the monthly progress reports together, write a two-paragraph intro page, and call it the final report -- and in the end, he forced the customer to ante up more money for a real final report.)
Clearly, things have gotten worse since then. The "out of scope" work never gets done, the engineering has holes in it, and there are new, expensive craters on Mars.
I can't deny that there were abuses which led to the present system, but I don't think any rational person could claim that the problem has been solved with the new way. What's been generated is a system guaranteed to generate "surprises" with operating hardware -- not successfully get probes to Mars.
And the outcome: the engineers are labeled "arrogant," because they "overextended their reach." Ironic... and sad.
It will be interesting to see what the actual maximum data density storage is... it might even get as far as using the orientation of quarks to store the data.
I have a hard time imagining that one...
Quarks are incredibly tightly bound inside the neutron and proton; AFAIK (but it's been a while since I got my degree in physics), the only way to get any information about the quarks in a nucleon is through extremely high-energy collisions -- big particle accelerator stuff. I suspect you'd take your data medium apart in the attempt to read it.
But then again, a couple of hundred years ago it was theoretically impossible to do almost everything I manage to do in the course of an ordinary day... so who knows?
The thing that annoys me the most about the loss of the last two missions -- and the thing that is probably not going to be blamed for the losses, in the end -- is that the hardware was actually pretty much up to the job; it's just the handling of the hardware by the humans involved that cost us those missions, and possibly this whole exploration campaign.
The Climate Orbiter was lost because two people (one NASA, one from the contractor) were handling the entire trajectory; they were completely overworked (to the point failing to implement the backup planning which was already on the timeline, and which by itself might have saved the mission), with no one to even do basic sanity checks on their work -- and they missed not only the critical units conversion, but also the fact that their trajectory corrections weren't having the desired results. A college kid on a work-study internship, working ten hours a week, could have saved the mission. But it was faster-better-cheaper , so they didn't hire the kid...
The Polar Lander appears to have been lost over communications failure between two test groups: when the lander legs were dropped, they apparently rebounded and triggered a ground-contact sensor in each leg; this set a bit in the computer, so that it "thought" the vehicle had already touched the ground, and it killed the engine as soon as it took control. The rebound happened regularly during testing, but the group testing the leg deployment didn't look at the bit's value at the end of the test (after all, it wasn't on the ground yet, so it wasn't their job...); and the group testing the final powered descent didn't bother to look at the contents of the register before they started the test -- they just reset the bit, so they'd have a clean test. All it required was some warm body to look at the test sequence as a whole, but no one had the time. Again, that single college kid might have saved the mission... but NASA was too cheap.
What concerns me is this: they're going to spend their time and money worrying over the hardware issues:
...Dr Pilcher said, that in the light of recent events, the timetable was wildly optimistic: "The jury is out on whether we have the technological capability."
rather than pay attention to managing what they've already developed. It's a bit like the aftermath of Challenger, where they went nuts on the hardware instead of looking at the fundamental problem, which was the prostitution of the program for political reasons. The outcome of that is that we now have a NASA which is completely paranoid about public opinion and afraid of its own shadow when it comes to safety, but which still won't look at the whole picture, and still twitches to the political beat.
It just really pisses me off! Pathfinder worked beautifully (despite a scary airbag system, which was what I figured would fail), and probably did so because of the long hours and very hard work everyone did; I know I did my share of 14-18 hour days on the little piece of it I had. It was so successful that NASA said, "Wow! That was really cheap! Let's see how much more we can cut out of the budget..."
So here we are: decent, low-cost hardware, and crappy, low-budget management. But guess which one is going to get the tarbrush?
Problem was... they couldn't make the laser accurate enough to read it at useable densities.
And right now that seems to be the biggest problem they face with this technology, too.
From my point of view, the most interesting thing about this development (and one of the least commented-on, for some reason) is the fact that they're using bottom-up assembly for the recording medium, instead of a top-down process like almost everything else has required. This is a ground-breaking development in the nanotechnology field: instead of using an atomic force microscope to drag atoms into place, they're growing the magnetic domains in their final, self-organized locations.
That was my first response, but it wasn't a joke I thought of...
Years ago, I worked with a guy who got his undergraduate physics degree from Cornell. For his senior paper, he wrote on the concept of an alien race from the ancient past leaving messages to intelligent lifeforms which might evolve in the future, in exons within highly-conserved DNA regions of microbes. While not steganography at all, it's a remarkably similar concept.
As it turned out, my friend showed his paper to Carl Sagan, who was of course also at Cornell. I think it bothered him, when years later he read the punchline in Sagan's new novel, Contact. (I don't think I need to explain that one, do I?)
Ah, I see -- a continuously-powered airship. Which means you have to:
A. Provide a means for refueling, which in the practical world means bringing it back down periodically (this is true even if you use solar, because the solar cells need replacing -- and they're damned expensive, not to mention pretty heavy for this "lighter than air" application!).
B. Navigate through the jet stream altitudes both ways, which means you spend a while coming back to station (airships are not known for being fast). Both of these, BTW, mean that you need spares for this cycle time, to keep the calls coming through.
C. Vent helium (expensive helium!) to keep at the design altitude, while you burn the fuel (read, "ballast") off.
D. Worry about thunderstorms, which peak out a lot higher than you're flying these airships -- which means every now and again one of 'em is going to blow off to Kansas or farther. In this case, spares aren't gonna do you any good, because they'll either not make it to altitude in time, or they'll just join the first one in Kansas. ("I'm sorry, your call can't go through -- it's too windy!")
I hope you'll excuse me if I say this seems rather unlike a "cheaper alternative" -- it looks to me like you've just traded upfront costs for ongoing operational costs, and have a system which isn't particularly robust.
Also, notice that the biggest expense of the airline industry isn't the equipment, but the fuel for it... (not that you're flying that far, but you're flying continuously).
Shouldn't it be possible to make an insulation that would interact with the wire (as a system), so you could run test-pulses down lengths of wire, that would cause different signals if part of the wire was exposed?
Ah... yeah, that would be possible. One way to do it would be to measure the associated capacitance between the core wire and a conductive sheath that's insulated from it. Practical is a different matter... do you have any idea how many miles of wire there are in the shuttle? And how much that little added mass would reduce the payload of the Shuttle (hint: they started leaving the paint off the External Tank, because it saved them something like 6000 pounds!).
Not to mention the complexity of the testing -- I suspect that you'd seriously decrease the turnaround cycle for launches, if you insisted that each piece of wire in the Shuttle be tested between flights... remember, there isn't anything on that bird that's not fly-by-wire! Everything is electrically-controlled. And you'd have to know the precise length of each wire on each vehicle, because a short difference between supposedly-equivalent wires might show up as a small (but potentially significant) insulation fault... or it might mask one.
One of the reasons why this isn't an issue with commercial aircraft is that they have much less wiring than the Shuttle; another reason is that they are built to be refueled and reflown, not broken down and rebuilt between flights.
I think it's easier to solve the problem in the original engineering, rather than to try to come up with some nifty (and expensive!) new technology to cope with the less-than-inspired engineering.
Watch 10 movies. Now I'll show you a 5 second clip of one of them. Now name the movie in 5 seconds. Show me a computer that can do that?
I think the only problem there is how to set up the movie database. Sure, it might take a fast parallel computer to do it within 5 seconds, but there's nothing inherently complex (or intelligent) about that. And insofar as the human brain can be regarded as a computer, it certainly must be counted as massively parallel in structure!
Show me a computer that can throw and catch an egg without breaking it. How many calculations did I just do?
Depends on what you mean by "calculations." I suspect you're doing analog calculations, rather than digital... but again, the real point is this: there's nothing intelligent about that. Unless you want to call the majority of the animal world "intelligent."
I think you see my point.
I see your point, but it doesn't have anything to do with intelligence: I think you redefined some of the basic terms, and are now arguing about something completely different (although I do happen to agree with you that we've not "had computers that "exceed the capacity of the human brain to process information" for at least 40 years now" -- for now, at least, we're much more general-purpose than our computers).
But, if they were supposed to have once held water, they would still have to be self supporting.
Not if the water were frozen... I'll get back to that, in a couple of sentences.
The article actually says, "Water flowing on the surface or underground in channels and later buried by sediments could explain the appearance of the features." So it's not necessarily that the channel was underground when the water flowed, it's just underground now, having been buried. The story on the NASA site appears to say exactly that, with liquid migration through cracks in the rock as the source of the water. There are several things I can't figure out in the CNN article, and I suspect that it's another case of poor science reporting.
It may also be that the channels were the source of the water -- as in ice deposits, or permafrost with a high water content. This fits with the comment that there was a rapid cooling, after which the floods occurred. With geological heating (or should I say "areological?"), the ice would have melted and flowed out of the deposits, which then collapsed; as the water flowed away, it would cut further channels; then all the channels filled with sediment as the flow abated. Matter of fact, the original ice deposits may well have been part of the drainage system (a much slower drainage), frozen in place.
I know that's reading a lot in, but I'm trying to make it consistent with other knowledge of Mars.
That is, unless one wants to theorize that the water pressure was constant and was helping to support the cavity...
If your point is that Bernouli's Law is fighting us, I'll grant that; but lava is also a fluid, and the same would apply to it. Unless you're saying that the overburden would be floating on the lava?
Where I have my problems with 200-km lava channel widths is the width: here on earth, lava tubes form when the surface of a flow solidifies, leaving the still-molten center to flow away. But lava tubes are nowhere near this size -- as I said elsewhere, tens of feet is about it.
The only other subterranean lava flows I'm familiar with are the ones which feed volcanic vents, and even these aren't nearly that large. What mechanism exists on Mars, to melt rock in swaths hundreds of kilometers wide -- and underground, at that? I just can't see it...
I had to laugh at the headline, "Dinosaur Fossils Challenge Theories." They do have a habit of doing that, don't they!
In a field as difficult as paleontology, where the scientists have to rely on the occasional fortuitous discovery of the remains of a critter which was fortuitously fossilized, the theories pretty much have to be sparse in detail compared to the reality. I can't remember ever reading a headline which said, "Dinosaur Fossils Confirm Theories In Excruciating Detail."
That said, this is an interesting find, and it really doesn't challenge everyone's theories: Robert Bakker (for one) has been claiming for years that some of the carnivorous dinosaurs would be pack hunters. Then again, he's made a lot of conjectures which were first soundly rejected, but have since gained widespread support... not that he's always right, but I guess some paleontologists are better cluereaders than others -- or are less hidebound, maybe.
Any suggestions for non-RTG, non-solar power sources for these things? IANAE, but for a Mars lander maybe you could use solar collectors on an areosynchronous orbiter and transmit the power to the surface via microwaves.
That's an interesting concept, but you're still fighting the low solar constant at Mars' orbital distance. Also, you're requiring two spacecraft where one will really do, with the second carrying a large solar array, plus the added microwave power transfer hardware on both ends -- or three of them, if you've got a rover on the mission. And the lander would still have to use batteries for heating during the very cold martian nights (the thermal cycles alone caused much of the wear on Pathfinder, and rechargeable batteries wear out). I think it's probably doable, but not on a faster-cheaper (I still won't say "better") program.
On the other hand, RTG's are inherently hazardous
That's the issue that really bugs me -- RTG's aren't necessarily "inherently hazardous!" The Soviets have had a bad time with them, but the US hasn't. We did have one release its radioactives on a failed launch back in '64, but it was designed that way -- the RTG burned up in the upper atmosphere, as intended (IIRC, the idea was to keep the radioactives from reaching the surface... disperse them up high, and they tend to stay there). Subsequently we've changed philosophies on this, and all RTG's are designed to survive reentry and still retain all radioactives.
We know this works, matter of fact; there've been two "tests" in real life since the new "total containment" policy went into effect. Apollo 13's Lunar Module (the one the crew lived in and used for the critical trajectory corrections, following the explosion in the Apollo Service Module) carried an RTG which powered one of the scientific packages they were going to leave on the moon; the LM reentered the atmosphere at something like 7 miles a second, but the RTG remained intact -- we've monitored the air and water around the Tonga Trench in the South Pacific, where it landed, and there has been no release of radioactives. Even more illustrative of the safety of good RTG's: in 1968, a meteorological satellite booster went bad and was destroyed by Range Safety. The two RTG's on the satellite spent five months on the ocean floor in the Santa Barbara Channel (it was a launch from Vandenberg, into polar orbit); they were recovered intact, and were recycled into other spacecraft!
but maybe the public will eventually get over their fear of one blowing up in the atmosphere once space launces become more routine and the next-generation reusable launch vehicles are on line...
They can't "blow up," so that fear is totally groundless. Nevertheless, I doubt the public will get over it: we used to use RTG's routinely, but don't anymore, because of the very vocal opposition of a few groups whose "science" is definitely questionable. Anti-"nuclear" sentiment is becoming so widespread that truly idiotic things happen -- like the medical use of Nuclear Magnetic Resonance imaging (where "nuclear" refers to the atomic nucleus; the technique uses spin coupling between the nucleus and the orbiting electron in hydrogen, and has absolutely nothing to do with radioactivity) being renamed "Magnetic Resonance Imaging," simply because people were frightened of a word. I don't know what these fears feed on -- maybe guilt over Hiroshima and Nagasaki -- but I do know that people are being deliberated manipulated. But I won't get into that rant...;>
I hope people do get over this: it's hard to do science in the outer solar system without nuclear power of some sort. Hell, it's hard enough to do it with nuclear power! Past Mars, solar is totally impractical; carrying fuel for things like fuel cells is impossible, given the limits of spacecraft weight and the very long mission times (many years just to get there... and I hope the spacecraft keep their habit of working long past the nominal end-of-mission).
The Russians still use them, of course -- but they appear to care nothing about public opinion... say, maybe this was all a commie plot! =8-0
FWIW, stereo photos are routinely made with just one spacecraft. Just take two pictures at different times, and the relative motion of the spacecraft and the planet (or other object) between shots gives the stereo separation. There have been some good stereo photos of the asteroid Eros lately, done just this way.
It's sad that there won't be much chance for future planetary missions to have extended missions like Galileo, and the Voyager probes before it (just to name a few).
Mars Pathfinder is an excellent example: the lander and its passenger, the rover Sojourner, were both designed to use solar energy, despite the fact that sunlight at Mars' orbit has only half the energy density it has here, and the expectation that the solar cells would be covered by dust and end the mission prematurely. But solar power, even though it was marginal (at best) for the mission, was a political requirement. Galileo and the Voyager spacecraft carried radiothermal generators, which is a big part of why they could keep going.
I think that the Pathfinder hardware might still be working, if NASA had been allowed to use RTG's on it... remember, the Viking landers (with RTG's) also far outlasted their design lifetime. But public opinion prevented that -- the Cassini mission might be the last one that we get to launch with RTG's, and there was a lot of pressure to stop that launch simply because of them.
Enjoy it while it can still happen: Galileo and Cassini may be the last of their kind!
I'm sure life could exist on Mars now. But I don't think it very probable that it could have started there in the first place. It probably takes an ocean world for life to appear spontaneously.
I know of two alternative theories for life's origins, neither of which require an ocean. The first is that clay minerals provided the scaffolding for early self-replicating structures, which eventually evolved into nucleic acids and then broadened their living area. The second is that life began beneath the surface of the earth, where it was much more shielded from the nasty surface environment in the early days of Earth's history (asteroid and comet impacts, mostly). We keep discovering terrestrial life in deeper rock, and it's becoming difficult to explain how it got there -- especially since some of the rock is pretty old.
Aside from that, there are some consistent indications that Mars did have an ocean for a while, early in its history. The northern hemisphere has a very thin crust, similar to terrestrial ocean bottom, and is remarkably smooth, also like terrestrial ocean bottom (in fact, the only planetary surfaces that smooth are those two). There have been some pretty good papers on it in the last year; the ones I remember were in Science, but I'm afraid I don't have the links handy. I particularly remember one which identified the drainage basins from which the water would have flowed; the channels which led it to the northern ocean are the ones which were first seen in the old Mariner photos, and which for 30 years have been considered likely to have formed by large flows of water.
Huh. Interesting idea, but if the channels are old lava tubes, how did they get filled with sediment? Especially if there's no running water? (And before you propose that the lava is still in them, I suspect the difference in density between and sediment is detectable gravometrically; this should be easy to check out, and I'd be surprised if the planetologists haven't already done it.)
The size is also a bit large for lava tubes, I think -- all the ones I've seen are tens of feet across, not a couple of hundred kilometers. It's hard to imagine what would increase the size that much; the difference in surface gravity won't do it, for sure.
I know of a couple of proposals for slowing a lightsail starship at the end of its journey, using the original lasers that sent it on its way. I discussed one of these in a post farther down the page (in response to "Screw lightpressure, use Solar Wind"), so I won't repeat it here...
The other is pretty interesting. We know there is a large magnetic field associated with the Galaxy (we can detect it from the polarization of light passing through the field), so it has been suggested that we use that field to turn the spacecraft! We'd first accelerate the starship away from Sol on a trajectory that takes it past the target star, at a considerable distance and with the proper angle relative to the galactic magnetic field; well past the target star, we'd charge the starship electrically, to a huge potential, and use the Lorentz force (the force that bends the path of a charged particle travelling through a magnetic field) to travel in a semi-circle, until it is aimed more-or-less back toward Sol, but on the other side of the target star.
Now it's headed back into the lasers, and it can decelerate into the destination system from the far side.
Admittedly, it makes the journey quite a bit longer (talk about "going 'round Robin Hood's barn!"), but at least you can use the existing laser power to slow down. I think the bigger issues have to do with the configuration of the galactic magnetic field (I don't think it's extremely well-mapped), and with getting the whole "train" of lightsail, spacecraft and Fresnel lens (see the post below) all turned around and properly lined up. But it's probably closer to reality than things like the Bussard Interstellar Ramjet. Coming back... that would still be a problem with this scheme (although the below discussion covers one method of doing that, without the magnetic turn trick). Larry Niven wrote a short story (was it The Oldest Profession?) in which aliens arrived in a lightsail vehicle, and expected us to build them a laser system so they could continue their trip -- and if we didn't, they'd just make the sun go nova and use that light instead.
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I'm not a professional in the field (I've used my physics degree to bootstrap myself into engineering consulting), but my field of interest was astrophysics, so I'll take a swing at it. Lotsa questions, though...
That information comes from the Doppler data: compare the present discovery with a system which has multiple planets. In the first case, you'll see a simple periodic variation in the Doppler shift -- a distorted sine curve, if you will, but one which has a single periodic structure which corresponds to the period of the planet. In the second case, there are three periods -- one for each of the three planets -- so they stack up on top of each other, to form a complex periodic structure. The second plot on that page shows the second and third planets' Doppler curve, with the very short-period inner planet removed; you see a long-period sinusoidal curve (the outer planet's), with a shorter-period curve (the second planet's) making about 5 "ripples" in the long-period curve (meaning that the second planet orbits about 5 times for each orbit of the outer one -- 241 days to 1309 days, in fact).
I won't go into the details -- there's plenty of that on the second link -- but it's just a matter of analysis of the data, fitting a model to it, and making a few wise choices if you find that the simplest models won't do. And BTW, it would take a lot more than a handful of terrestrial planets to equal the mass of a super-jovian -- although Jupiter is about 11 Earth diameters wide, it is much more massive (around 80 terrestrial masses, IIRC -- but don't quote me on that, I don't have a text or a link handy).
That may very well be the case, but we won't find that out with the present equipment. More reason to keep searching, and to get better instruments!
Right now, we'd might be able to detect Jupiter and possibly Saturn -- but both of those planets are in more-distant orbits than what we've found so far, so detection would be more difficult. The Doppler method would completely miss everything else in the Solar system. (Again, the mass of the rest of the system, after Jupiter and a bit from Saturn, is trivial...)
The Oort cloud and Kuiper belt don't have much effect at all -- orbits of stuff out there are quite long (hundreds of years and way up), compared to the few days to a few years for all the extrasolar planets detected so far. And as far as we know, the masses of bodies in both aren't very large -- in fact, they don't even detectably perturb the orbits of the planets in the Solar system, and we've been looking for that for a long time. Even if something quite large was out there, it would take hundreds to thousands of years of watching to detect it -- either here or in the extrasolar planetary systems.
Actually, we do know one planet's mass and size, because it passed between us and the disk of its star; that allows us to remove the uncertainty in mass (from Doppler data, we only know a lower limit on the planet's mass) because we now know the plane of the orbit, and from the measured dimming of the star's light, we know the size of the planet.
But that's a rare case, and I won't argue that we don't need a space-based interferometer array.
Good questions, all of them -- and I hope I've answered them, at least partially.
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While I have to agree that Iridium was a fiasco, and that plenty of people are to blame, I have to disagree with your assessment of Bruce's article.
As much as I like Bruce Stirling for all his nifty science fiction, a quote like "when people realized that the Moon is much less interesting than NASA said it was" simply sucks.
I don't know where you were, Bruce, but I know that I and a whole bunch of other folks never found the moon "much less interesting." You might have been busy having your diapers changed, but I was in the middle of a college career based on astronomy done with orbital observatories, and when Congress cancelled all the programs, my dreams died along with a lot of other people's. It wasn't lack of public interest, but lack of the Cold War push -- simple science wasn't worth it, while military superiority was...
Despite this sort of whining, the space program hasn't gone away -- there are still quite a few people who work in it, myself occasionally included. And while there are still mismanaged (and ill-conceived) programs like Iridium, the dream is not yet gone. We just hacked our way back into it.
Look back in a hundred years, and no one will understand why we didn't do it faster -- after all, we had the technology, all we lacked was the will.
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You've actually made a very important point: in the end, if there is a structural remedy which breaks Microsoft up, the resulting components would still need a "monitoring and enforcement plan that doesn't equate to government regulation of the industry" -- to quote Ken Wasch (maybe a bit out of context).
I have looked long and hard at the situation, and it isn't clear to me what a structural remedy would gain us. If you split M$ along functional lines (OS, apps, and internet), you have three very large companies who can still share information, and who have close historical ties with each other. What do you suppose they'll do next? But if you split M$ into three different OS companies, all you've managed to do is make Sun fourth instead of second... what the hell good does that do?
To my way of thinking, there isn't anything other than a monitoring and enforcement plan which can potentially work. The devil is (as always) in the details. So the question is: "What can we do to make sure the monitoring and enforcement plan works?"
I think the answer is to get involved, rather than just bitch.
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Ummmm... my point is, how can you calculate odds with a sample of one? We know exactly nothing about terrestrial-type extrasolar planets, so it's hard to say anything about them -- we can only speculate about the odds of one being like the Earth.
For a slightly different viewpoint: when I look at the single example of Earth, I see life modifying the planet to keep conditions adequate for its continued existence... and my "educated guess" is that this will turn out to be more common than not -- with the disclaimer, of course, that the conditions which life elsewhere likes may not be what we enjoy. Evolutionary forces will tend to produce life which interacts with its environment to support its continued existence, which may eventually change the environment profoundly; Earth's oxygen atmosphere is a good example.
And since we have no idea what conditions are necessary for the development of life (instead, we have speculation about what was necessary for the development of life which has now evolved itself and this planet for 3.5 billion years -- not at all the same thing!), it's hard to predict how many planets will have it, much less what the local conditions will be.
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You're confusing science and engineering, I think. "Science" is basically a method of discovering (or "uncovering") information about the universe; "engineering" is the application of that information for human use. And don't forget that part of NASA's mission is to do the research and low-level work which will enable private industry to apply new technologies too expensive for them to develop from scratch (although NASA sometimes forgets this themselves, it would appear!).
As far as "barely launch[ing] probes properly to Mars," the problem with the last two spacecraft would seem to have been more in the management of the missions, not in the hardware -- even the Polar Lander would have worked if the testing was done properly. This isn't a failure of science, or even of engineering... it's a failure of oversight.
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So, Dr. Cooper, where's the rest of the explanation?
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It's hard to tell how common it is, because the methods we're using to detect extrasolar planets happen to be suited for finding gas giants -- Jupiter size and up, mostly up! It with take either major improvements in our observational technology, or development of new technologies, to find Earth-sized extrasolar planets.
Until then, all we can really do is guess -- which is what you're doing. BTW, I happen to disagree with your guess... ;-)
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This isn't really engineering, this is politics. I think the world of the NASA engineers, who are damned good, and extremely motivated. My opinion of NASA management, however, is pretty much unprintable.
Unfortunately, they have a very tight grip on the money -- GPLing them is a grand idea, and might even work (if you could avoid the everpresent danger of overworking the problem -- which release do you actually launch?), but it'll never happen.
What we need is some very rich man *cough*Gates*cough* to fund this sort of thing... but that'll probably never happen, either.
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Bughunter, you have presented the picture in exquisitely painful detail.
Fifteen years ago, when I first got into aerospace engineering, I remember my boss (the VP of Engineering) telling me that the most important words I could learn were, "Out of scope." He bid the contracts low, just as you describe, and then looked for the minor (but inevitable) changes to the contract that allowed him to go back and ask for more, arguing that they changed the scope of the contract. (I once saw him bundle the monthly progress reports together, write a two-paragraph intro page, and call it the final report -- and in the end, he forced the customer to ante up more money for a real final report.)
Clearly, things have gotten worse since then. The "out of scope" work never gets done, the engineering has holes in it, and there are new, expensive craters on Mars.
I can't deny that there were abuses which led to the present system, but I don't think any rational person could claim that the problem has been solved with the new way. What's been generated is a system guaranteed to generate "surprises" with operating hardware -- not successfully get probes to Mars.
And the outcome: the engineers are labeled "arrogant," because they "overextended their reach." Ironic... and sad.
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I have a hard time imagining that one...
Quarks are incredibly tightly bound inside the neutron and proton; AFAIK (but it's been a while since I got my degree in physics), the only way to get any information about the quarks in a nucleon is through extremely high-energy collisions -- big particle accelerator stuff. I suspect you'd take your data medium apart in the attempt to read it.
But then again, a couple of hundred years ago it was theoretically impossible to do almost everything I manage to do in the course of an ordinary day... so who knows?
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The Climate Orbiter was lost because two people (one NASA, one from the contractor) were handling the entire trajectory; they were completely overworked (to the point failing to implement the backup planning which was already on the timeline, and which by itself might have saved the mission), with no one to even do basic sanity checks on their work -- and they missed not only the critical units conversion, but also the fact that their trajectory corrections weren't having the desired results. A college kid on a work-study internship, working ten hours a week, could have saved the mission. But it was faster-better- cheaper , so they didn't hire the kid...
The Polar Lander appears to have been lost over communications failure between two test groups: when the lander legs were dropped, they apparently rebounded and triggered a ground-contact sensor in each leg; this set a bit in the computer, so that it "thought" the vehicle had already touched the ground, and it killed the engine as soon as it took control. The rebound happened regularly during testing, but the group testing the leg deployment didn't look at the bit's value at the end of the test (after all, it wasn't on the ground yet, so it wasn't their job...); and the group testing the final powered descent didn't bother to look at the contents of the register before they started the test -- they just reset the bit, so they'd have a clean test. All it required was some warm body to look at the test sequence as a whole, but no one had the time. Again, that single college kid might have saved the mission... but NASA was too cheap.
What concerns me is this: they're going to spend their time and money worrying over the hardware issues:
rather than pay attention to managing what they've already developed. It's a bit like the aftermath of Challenger, where they went nuts on the hardware instead of looking at the fundamental problem, which was the prostitution of the program for political reasons. The outcome of that is that we now have a NASA which is completely paranoid about public opinion and afraid of its own shadow when it comes to safety, but which still won't look at the whole picture, and still twitches to the political beat.
It just really pisses me off! Pathfinder worked beautifully (despite a scary airbag system, which was what I figured would fail), and probably did so because of the long hours and very hard work everyone did; I know I did my share of 14-18 hour days on the little piece of it I had. It was so successful that NASA said, "Wow! That was really cheap! Let's see how much more we can cut out of the budget..."
So here we are: decent, low-cost hardware, and crappy, low-budget management. But guess which one is going to get the tarbrush?
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And right now that seems to be the biggest problem they face with this technology, too.
From my point of view, the most interesting thing about this development (and one of the least commented-on, for some reason) is the fact that they're using bottom-up assembly for the recording medium, instead of a top-down process like almost everything else has required. This is a ground-breaking development in the nanotechnology field: instead of using an atomic force microscope to drag atoms into place, they're growing the magnetic domains in their final, self-organized locations.
This is great stuff!
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Years ago, I worked with a guy who got his undergraduate physics degree from Cornell. For his senior paper, he wrote on the concept of an alien race from the ancient past leaving messages to intelligent lifeforms which might evolve in the future, in exons within highly-conserved DNA regions of microbes. While not steganography at all, it's a remarkably similar concept.
As it turned out, my friend showed his paper to Carl Sagan, who was of course also at Cornell. I think it bothered him, when years later he read the punchline in Sagan's new novel, Contact. (I don't think I need to explain that one, do I?)
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A. Provide a means for refueling, which in the practical world means bringing it back down periodically (this is true even if you use solar, because the solar cells need replacing -- and they're damned expensive, not to mention pretty heavy for this "lighter than air" application!).
B. Navigate through the jet stream altitudes both ways, which means you spend a while coming back to station (airships are not known for being fast). Both of these, BTW, mean that you need spares for this cycle time, to keep the calls coming through.
C. Vent helium (expensive helium!) to keep at the design altitude, while you burn the fuel (read, "ballast") off.
D. Worry about thunderstorms, which peak out a lot higher than you're flying these airships -- which means every now and again one of 'em is going to blow off to Kansas or farther. In this case, spares aren't gonna do you any good, because they'll either not make it to altitude in time, or they'll just join the first one in Kansas. ("I'm sorry, your call can't go through -- it's too windy!")
I hope you'll excuse me if I say this seems rather unlike a "cheaper alternative" -- it looks to me like you've just traded upfront costs for ongoing operational costs, and have a system which isn't particularly robust.
Also, notice that the biggest expense of the airline industry isn't the equipment, but the fuel for it... (not that you're flying that far, but you're flying continuously).
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Ah... yeah, that would be possible. One way to do it would be to measure the associated capacitance between the core wire and a conductive sheath that's insulated from it. Practical is a different matter... do you have any idea how many miles of wire there are in the shuttle? And how much that little added mass would reduce the payload of the Shuttle (hint: they started leaving the paint off the External Tank, because it saved them something like 6000 pounds!).
Not to mention the complexity of the testing -- I suspect that you'd seriously decrease the turnaround cycle for launches, if you insisted that each piece of wire in the Shuttle be tested between flights... remember, there isn't anything on that bird that's not fly-by-wire! Everything is electrically-controlled. And you'd have to know the precise length of each wire on each vehicle, because a short difference between supposedly-equivalent wires might show up as a small (but potentially significant) insulation fault... or it might mask one.
One of the reasons why this isn't an issue with commercial aircraft is that they have much less wiring than the Shuttle; another reason is that they are built to be refueled and reflown, not broken down and rebuilt between flights.
I think it's easier to solve the problem in the original engineering, rather than to try to come up with some nifty (and expensive!) new technology to cope with the less-than-inspired engineering.
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I think the only problem there is how to set up the movie database. Sure, it might take a fast parallel computer to do it within 5 seconds, but there's nothing inherently complex (or intelligent) about that. And insofar as the human brain can be regarded as a computer, it certainly must be counted as massively parallel in structure!
Show me a computer that can throw and catch an egg without breaking it. How many calculations did I just do?
Depends on what you mean by "calculations." I suspect you're doing analog calculations, rather than digital... but again, the real point is this: there's nothing intelligent about that. Unless you want to call the majority of the animal world "intelligent."
I think you see my point.
I see your point, but it doesn't have anything to do with intelligence: I think you redefined some of the basic terms, and are now arguing about something completely different (although I do happen to agree with you that we've not "had computers that "exceed the capacity of the human brain to process information" for at least 40 years now" -- for now, at least, we're much more general-purpose than our computers).
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Not if the water were frozen... I'll get back to that, in a couple of sentences.
The article actually says, "Water flowing on the surface or underground in channels and later buried by sediments could explain the appearance of the features." So it's not necessarily that the channel was underground when the water flowed, it's just underground now, having been buried. The story on the NASA site appears to say exactly that, with liquid migration through cracks in the rock as the source of the water. There are several things I can't figure out in the CNN article, and I suspect that it's another case of poor science reporting.
It may also be that the channels were the source of the water -- as in ice deposits, or permafrost with a high water content. This fits with the comment that there was a rapid cooling, after which the floods occurred. With geological heating (or should I say "areological?"), the ice would have melted and flowed out of the deposits, which then collapsed; as the water flowed away, it would cut further channels; then all the channels filled with sediment as the flow abated. Matter of fact, the original ice deposits may well have been part of the drainage system (a much slower drainage), frozen in place.
I know that's reading a lot in, but I'm trying to make it consistent with other knowledge of Mars.
That is, unless one wants to theorize that the water pressure was constant and was helping to support the cavity...
If your point is that Bernouli's Law is fighting us, I'll grant that; but lava is also a fluid, and the same would apply to it. Unless you're saying that the overburden would be floating on the lava?
Where I have my problems with 200-km lava channel widths is the width: here on earth, lava tubes form when the surface of a flow solidifies, leaving the still-molten center to flow away. But lava tubes are nowhere near this size -- as I said elsewhere, tens of feet is about it.
The only other subterranean lava flows I'm familiar with are the ones which feed volcanic vents, and even these aren't nearly that large. What mechanism exists on Mars, to melt rock in swaths hundreds of kilometers wide -- and underground, at that? I just can't see it...
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In a field as difficult as paleontology, where the scientists have to rely on the occasional fortuitous discovery of the remains of a critter which was fortuitously fossilized, the theories pretty much have to be sparse in detail compared to the reality. I can't remember ever reading a headline which said, "Dinosaur Fossils Confirm Theories In Excruciating Detail."
That said, this is an interesting find, and it really doesn't challenge everyone's theories: Robert Bakker (for one) has been claiming for years that some of the carnivorous dinosaurs would be pack hunters. Then again, he's made a lot of conjectures which were first soundly rejected, but have since gained widespread support... not that he's always right, but I guess some paleontologists are better cluereaders than others -- or are less hidebound, maybe.
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That's an interesting concept, but you're still fighting the low solar constant at Mars' orbital distance. Also, you're requiring two spacecraft where one will really do, with the second carrying a large solar array, plus the added microwave power transfer hardware on both ends -- or three of them, if you've got a rover on the mission. And the lander would still have to use batteries for heating during the very cold martian nights (the thermal cycles alone caused much of the wear on Pathfinder, and rechargeable batteries wear out). I think it's probably doable, but not on a faster-cheaper (I still won't say "better") program.
On the other hand, RTG's are inherently hazardous
That's the issue that really bugs me -- RTG's aren't necessarily "inherently hazardous!" The Soviets have had a bad time with them, but the US hasn't. We did have one release its radioactives on a failed launch back in '64, but it was designed that way -- the RTG burned up in the upper atmosphere, as intended (IIRC, the idea was to keep the radioactives from reaching the surface... disperse them up high, and they tend to stay there). Subsequently we've changed philosophies on this, and all RTG's are designed to survive reentry and still retain all radioactives.
We know this works, matter of fact; there've been two "tests" in real life since the new "total containment" policy went into effect. Apollo 13's Lunar Module (the one the crew lived in and used for the critical trajectory corrections, following the explosion in the Apollo Service Module) carried an RTG which powered one of the scientific packages they were going to leave on the moon; the LM reentered the atmosphere at something like 7 miles a second, but the RTG remained intact -- we've monitored the air and water around the Tonga Trench in the South Pacific, where it landed, and there has been no release of radioactives. Even more illustrative of the safety of good RTG's: in 1968, a meteorological satellite booster went bad and was destroyed by Range Safety. The two RTG's on the satellite spent five months on the ocean floor in the Santa Barbara Channel (it was a launch from Vandenberg, into polar orbit); they were recovered intact, and were recycled into other spacecraft!
but maybe the public will eventually get over their fear of one blowing up in the atmosphere once space launces become more routine and the next-generation reusable launch vehicles are on line...
They can't "blow up," so that fear is totally groundless. Nevertheless, I doubt the public will get over it: we used to use RTG's routinely, but don't anymore, because of the very vocal opposition of a few groups whose "science" is definitely questionable. Anti-"nuclear" sentiment is becoming so widespread that truly idiotic things happen -- like the medical use of Nuclear Magnetic Resonance imaging (where "nuclear" refers to the atomic nucleus; the technique uses spin coupling between the nucleus and the orbiting electron in hydrogen, and has absolutely nothing to do with radioactivity) being renamed "Magnetic Resonance Imaging," simply because people were frightened of a word. I don't know what these fears feed on -- maybe guilt over Hiroshima and Nagasaki -- but I do know that people are being deliberated manipulated. But I won't get into that rant... ;>
I hope people do get over this: it's hard to do science in the outer solar system without nuclear power of some sort. Hell, it's hard enough to do it with nuclear power! Past Mars, solar is totally impractical; carrying fuel for things like fuel cells is impossible, given the limits of spacecraft weight and the very long mission times (many years just to get there... and I hope the spacecraft keep their habit of working long past the nominal end-of-mission).
The Russians still use them, of course -- but they appear to care nothing about public opinion... say, maybe this was all a commie plot! =8-0
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Of course, timing is everything...
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Mars Pathfinder is an excellent example: the lander and its passenger, the rover Sojourner, were both designed to use solar energy, despite the fact that sunlight at Mars' orbit has only half the energy density it has here, and the expectation that the solar cells would be covered by dust and end the mission prematurely. But solar power, even though it was marginal (at best) for the mission, was a political requirement. Galileo and the Voyager spacecraft carried radiothermal generators, which is a big part of why they could keep going.
I think that the Pathfinder hardware might still be working, if NASA had been allowed to use RTG's on it... remember, the Viking landers (with RTG's) also far outlasted their design lifetime. But public opinion prevented that -- the Cassini mission might be the last one that we get to launch with RTG's, and there was a lot of pressure to stop that launch simply because of them.
Enjoy it while it can still happen: Galileo and Cassini may be the last of their kind!
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I know of two alternative theories for life's origins, neither of which require an ocean. The first is that clay minerals provided the scaffolding for early self-replicating structures, which eventually evolved into nucleic acids and then broadened their living area. The second is that life began beneath the surface of the earth, where it was much more shielded from the nasty surface environment in the early days of Earth's history (asteroid and comet impacts, mostly). We keep discovering terrestrial life in deeper rock, and it's becoming difficult to explain how it got there -- especially since some of the rock is pretty old.
Aside from that, there are some consistent indications that Mars did have an ocean for a while, early in its history. The northern hemisphere has a very thin crust, similar to terrestrial ocean bottom, and is remarkably smooth, also like terrestrial ocean bottom (in fact, the only planetary surfaces that smooth are those two). There have been some pretty good papers on it in the last year; the ones I remember were in Science, but I'm afraid I don't have the links handy. I particularly remember one which identified the drainage basins from which the water would have flowed; the channels which led it to the northern ocean are the ones which were first seen in the old Mariner photos, and which for 30 years have been considered likely to have formed by large flows of water.
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The size is also a bit large for lava tubes, I think -- all the ones I've seen are tens of feet across, not a couple of hundred kilometers. It's hard to imagine what would increase the size that much; the difference in surface gravity won't do it, for sure.
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The channels have been filled in with sediment, they theorize. They're not just empty caverns in the rock.
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The other is pretty interesting. We know there is a large magnetic field associated with the Galaxy (we can detect it from the polarization of light passing through the field), so it has been suggested that we use that field to turn the spacecraft! We'd first accelerate the starship away from Sol on a trajectory that takes it past the target star, at a considerable distance and with the proper angle relative to the galactic magnetic field; well past the target star, we'd charge the starship electrically, to a huge potential, and use the Lorentz force (the force that bends the path of a charged particle travelling through a magnetic field) to travel in a semi-circle, until it is aimed more-or-less back toward Sol, but on the other side of the target star.
Now it's headed back into the lasers, and it can decelerate into the destination system from the far side.
Admittedly, it makes the journey quite a bit longer (talk about "going 'round Robin Hood's barn!"), but at least you can use the existing laser power to slow down. I think the bigger issues have to do with the configuration of the galactic magnetic field (I don't think it's extremely well-mapped), and with getting the whole "train" of lightsail, spacecraft and Fresnel lens (see the post below) all turned around and properly lined up. But it's probably closer to reality than things like the Bussard Interstellar Ramjet. Coming back... that would still be a problem with this scheme (although the below discussion covers one method of doing that, without the magnetic turn trick). Larry Niven wrote a short story (was it The Oldest Profession?) in which aliens arrived in a lightsail vehicle, and expected us to build them a laser system so they could continue their trip -- and if we didn't, they'd just make the sun go nova and use that light instead.
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