Jump to content


  • Posts

  • Joined

  • Last visited


9,543 Excellent

Profile Information

  • About me
    Kerm Telegraph Maintenance Engineer
  • Location
    The North Grove, Duna.

Recent Profile Visitors

12,603 profile views
  1. Late to this party but I, for one, welcome our RoboTurtle overlords.
  2. Probably best not to imagine what happens if someone lets the balloon go and all the air shoots out of one end.
  3. This is not my analogy but I quite like it. Imagine a balloon. Paint a bunch of dots on it to represent stars (or galaxies - whatever). Now inflate the balloon. The radius of the balloon represents the time axis. The surface of the balloon represents 3D space. As we move forward in time, all the stars move away from each other but they’re not moving away from any single point in space although they are moving away from a single point in time.
  4. You’d need a very big tube if I’m understanding your description correctly. Let’s assume a 40,000 km acceleration tube (circumference of the Earth to a reasonable approximation). Let’s assume constant 4g acceleration and deceleration, so half of that tube is used for charging the Drive. Starting from rest, s = 1/2 at^2. Solving for t, I get 1000 seconds, approximating 4g to 40ms^2. So a fully charged Drive can accelerate for 1000s at 4g. So what delta-V does that give? Delta-v = a.delta-t Solving for v, I get 40km/s. Thats… curiously unimpressive for the infrastructure involved. So much so that if someone could check my maths, that would be appreciated. For reference, the Saturn V could accelerate the Apollo CSM+LM stack to around 10km/s.
  5. Just for comparison purposes, according to Wikipedia, the world Maglev speed record is 603 km/h, achieved on an 18.4 km track. That's from rest to full speed and back to rest. A little bit of back-of-the-envelope maths gives me an acceleration of approximately 0.15g and a time to reach maximum speed of 110s or just under 2 minutes. Put a Maglev in a vacuum tube so that it can keep accelerating and you very quickly get to some pretty ridiculous speeds even at .15g. Again, for comparison, commercial passenger jets travel at about 600 mph (from a quick online search) or 965 km/h. The above Maglev in a vacuum tube would hit passenger jet speed in about 3 minutes and about 14 km into its journey, assuming my arithmetic checks out. In that context, accelerating at 1 or 2g looks a bit like overkill. Edit: This is a very rough calculation of course - for one it ignores air resistance completely and, for two, it assumes a constant acceleration to the half way point and then constant braking to rest. But I think it gets the main points across - it should only take a relatively modest constant acceleration for a vacuum tube train to comfortably beat out commercial air travel for raw speed, and those kinds of acceleration are quite achievable with current technology. Whether a vacuum tube train can be made as reliable and safe as commercial air travel is another matter.
  6. Good to see this one back! Glad college life is going well too!
  7. I, for one, find it mighty suspicious that they cut the audio feed when the dolphin turned up. I bet it was whistling the Star Spangled Banner.
  8. This. So very, very much this. Arnie in his prime, special effects that were there when they needed to be rather than gratuitous 'LOOK - A SPECIAL EFFECT' shots, and probably one of my all time favorite sci-fi movie scenes of all time. And best yet, my godson is almost old enough for it and old enough to appreciate it. On a completely different note, I recall Short Circuit 2 being as good as, if not better, than the original. Unsure if either movie will have stood the test of time though.
  9. Depends how that person is flying. If they’re relying purely on wing flapping for propulsion then probably very slowly. On the other hand it might be possible to let gravity do the work, depending how the antigrav pack works. If it’s capable of letting a person rise against gravity and can also be adjusted to provide various amounts of lift then it might be possible to go vertically upwards under antigravity power, turn the pack off (or ‘throttle’ it way back) and dive to gain speed, set the pack to neutral to avoid lithobraking and glide as far as you can until air resistance slows you down. Repeat as necessary.
  10. Elephants are the obvious example of ‘tentacle manipulators’ and, thinking about it, an excellent counter example to my previous post where I thought that tentacled critters using tentacles as both ‘arms’ and ‘legs’ would be more plausible than something that mixed up articulated limbs with tentacles. So - scratch that comment. I was curious about octopuses as another possible example of ‘tentacle manipulators’ though and found this paper: https://www.cell.com/current-biology/fulltext/S0960-9822(09)01914-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982209019149%3Fshowall%3Dtrue It describes an interesting - for this discussion - ‘stilt walking’ behaviour which a certain octopus species will use when carrying coconut shells around. ”To carry one or more shells, this octopus manipulates and arranges the shells so that the concave surfaces are uppermost, then extends its arms around the outside and walks using the arms as rigid limbs.” (emphasis added) Admittedly ‘stilt walking’ is pretty cumbersome but I thought the rigid limb thing was relevant to this discussion, as an example of a soft bodied critter being able to rigidify(sp?) itself if required. On that basis I could imagine a soft bodied tentacular alien being able to rigidify itself if it needs to brace for tool manipulation.
  11. The one drawback I can think of for hands is that they're relatively fragile with a lot of moving parts and so there's quite a few ways they can go wrong or be impaired. A tentacle might be more robust (so 'better' in one sense) but wouldn't be quite as versatile as a hand for manipulating tools. However a tentacle would be a much more flexible and versatile carrier for that tool manipulator than an arm is for a hand. A tentacle with some kind of receptacle in the end (think of an elephant's trunk) would be reasonably capable as a manipulator whilst being considerably more flexible and versatile than an arm. It could grasp a handle with ease (an octopus would have no problem holding a hammer), the receptacle at the tentacle tip would allow for holding smaller tools or manipulating 'poking' tools like bradawls or punches (or daggers). About the only thing I can think of where it would seriously struggle would be with scissors and related tools where having multiple digits to operate multiple parts of the tool simultaneously is an advantage. One could operate a pair of scissors two-handed but it would be clumsy. Perhaps a bifurcated tentacle then, with each tentaclet(?) having a receptacle at its tip? Something else to think about when considering alternatives to hands is that you're also likely to be considering alternatives to feet. In general nature seems to be quite good at coming up with symmetrical body plans or body plans where similar structures can be pressed into service for different roles. Arms and hands vs legs and feet for example. I would find an alien creature with tentacle manipulators which walked on another set of tentacles to be much more believable than some half-and-half critter with humanoid articulated legs and tentacular arms. Of course - as you've mentioned before - 'aliens' could be the product of human biological engineering, in which case all bets are off. From a worldbuilding perspective, I'd find it interesting to write about a fictional race of tentacle critters. How would that reduced dexterity (compared to hands) affect their approach to every day matters. Take clothing for example - I imagine that manipulating buttons or zips with tentacles could be a real pain, so they might favour clothing with as few closures as possible, and perhaps rely on toggles or overgrown cufflink style closures (longer, easier to grip with a tentacle) than buttons. Hook and loop fasteners would be significantly easier to use, so perhaps all their clothes would rely on alien Velcro. Likewise for spacecraft controls - they might depend more on buttons and biggish levers rather than fiddly small switches, assuming that their spacecraft are still flown with manual controls. Or, what would arts and crafts look like for these critters? I doubt they're going to be much good at needlework, so anything hand-stitched might be the mark of a true crafts-critter. So much so that human crafts like embroidery or tapestry work would completely knock their socks ( or other tentacle-tip protective garments ) off! Maybe that turns out to be the basis for their peaceful artistic and cultural exchange with humanity? It's those kind of small details that I think would make this fictional race feel really alien rather than humans-by-another-name.
  12. For those about to sleep. We salute you.
  13. Nah - Elastic Failure are prog rock. They probably have a theramin player who can also knock out a kicking kazoo solo if the mood takes her. Now CatastrophicFailure on the other hand or, more probably CataströphicFailure? That's your thrash metal band right there.
  14. I, for one, look forward to our oddly shaped, Dayglo music storage media. Although warp drive would be pretty neat too.
  • Create New...