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1. Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 03:34:29 JST Foone🏳️‍⚧️

   In Portal, using the portal gun to get to the moon is the obvious space travel usage, but I think people are overlooking how it'd let you trivially break the rocket equation.

   Hell, you could build a >1g torchship using nothing but the ocean.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 03:36:28 JST Foone🏳️‍⚧️

     in reply to

     I'd do the math on how much thrust you'd get out of sticking one portal at the bottom of the Mariana Trench and the other in a ship, but I think it'd maybe be slightly tricky because you've got yourself an inertialess thruster right there, which is slightly illegal according to physics.

     The Einstein cops are gonna show up and impound your spaceship

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 03:39:00 JST Foone🏳️‍⚧️

     in reply to

     And that's just thinking about a static arrangement of portals. You could also use a dynamic arrangement where you use gravity to accelerate mass to arbitrarily high speeds and then fling it out the back

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 03:51:59 JST Foone🏳️‍⚧️

     in reply to

     If you could make portals bigger you could also have a fun setup where you build your spaceship and then just let gravity accelerate it though a portal-loop.
     You get going as fast as you want, then just swap the portals so you're now aimed at Mars.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 03:57:40 JST Foone🏳️‍⚧️

     in reply to

     Anyway the lazy, boring way to use a portal and pretend you aren't violating a bunch of physical laws is to just use it for fuel transport.
     You have a bunch of fuel on the ground, a tiny tank on your rocket, and you keep topping off the rocket's tank by piping in the fuel.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:21:20 JST Foone🏳️‍⚧️

     in reply to

     BTW, as a variant on the kzinti lesson, the portals are extremely dangerous as a weapon, because of how good they are as a weapon.

     Ignoring the obvious ways to fight with them like opening a portal on the enemy's hull, shoving out a nuke and then closing the portal...

     You could also just have a rock that you're letting accelerate to arbitrary speeds in a vacuum. That's free unbounded kinetic energy, the only limitation being the "charge" time.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:25:11 JST Foone🏳️‍⚧️

     in reply to

     This isn't a ship-destroying weapon, this is a civilization-ender if not planet-killer.

     You've got a projectile moving at a significant fraction of the speed of light. This is a relativistic weapon: it's going to hit harder than if it was a nuke.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:31:53 JST Foone🏳️‍⚧️

     in reply to

     You can also make it bigger by not using a roughly round rock and instead using a long rod of the densest material you can get your hand on.

     But mass you pay for, speed you don't.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:38:43 JST Foone🏳️‍⚧️

     in reply to

     Like, the worked example from Atomic Rockets has 7 kilograms of cat litter moving at 90% of lightspeed hitting a stationary target with 195 megatons of kinetic energy.

     https://www.projectrho.com/public_html/rocket/spacegunexotic.php

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:44:56 JST Foone🏳️‍⚧️

     in reply to

     But yeah this is the ultimate doomsday weapon. You can accelerate indefinitely for free, you just have to wait.
     (and if you can put your portals in orbit of a more massive object, you get faster acceleration than 1g)

     So you don't need more than a portal gun, a tungsten rod, and some time to blow the atmosphere off a planet.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:49:43 JST Foone🏳️‍⚧️

     in reply to

     Sir Isaac Newton may be the deadliest son of a bitch in space, but the deadliest son of a bitch in the Half Life universe is Cave Johnson.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 04:51:53 JST Foone🏳️‍⚧️

     in reply to

     The Nihilanth could teleport an entire army to earth, the combine can conquer a planet in hours, the g-man has control over time and space, but Cave Johnson's invention could put a hole in a planet

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 05:00:01 JST Foone🏳️‍⚧️

     in reply to

     Alternate ending to Half Life Alyx where it turns out the scary thing the Combine has locked up in the vault is Chell.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 05:30:01 JST Foone🏳️‍⚧️

     in reply to

     There's also the gravity interaction: an infinitely falling object that never reaches the bigger body is also accelerating the bigger body.

     Your forever falling object is shoving the earth upward, very slowly. That could matter in the long enough term... But it seems kinda meaningless compared to the other ways you could use a portal.

     Still, might be handy if you need to adjust the orbit of a planet and are willing to wait.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 05:38:19 JST Foone🏳️‍⚧️

     in reply to

     It would be a very Cave Johnson thing to try to fix global warming by pushing the earth away from the sun.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 05:45:42 JST Foone🏳️‍⚧️

     in reply to

     The only thing more Cave Johnson would be using relativistic weapons to blow up the sun

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 05:53:36 JST Foone🏳️‍⚧️

     in reply to

     The lab boys tell me that if you dump enough iron into a star, it'll turn off. Well, we don't have that much iron on hand, but what if it's moving at 99% the speed of light?
     They told me that wouldn't help, but I said pack your bags: We're doing it anyway

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 06:29:00 JST Foone🏳️‍⚧️

     in reply to

     Portal 2 does establish that the portal-placing shot moves at the speed of light, but that just raises the question of how fast you move through the portals themselves.

     It basically can't be slower than light, or you'd chop yourself in half if you moved halfway into one and then backed out.

     So it has to be lightspeed: which means, if relativity is still correct, that it's also a time machine.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 06:35:58 JST Foone🏳️‍⚧️

     in reply to

     Maybe not one that lets you trivially violate causality but with moving portals or multiple portals, whoops...

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 06:40:29 JST Foone🏳️‍⚧️

     in reply to

     Anyway once you're flying around the universe with your FTL portal-rockets the next question is what happens if the two ends of a portal are moving at different speeds through time. What if you drop one end into a black hole?

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 06:46:04 JST Foone🏳️‍⚧️

     in reply to

     And what if you put one end on an enemy planet and the other end in low orbit around Betelgeuse when it finally goes supernova?

     How many gamma rays will come through a hole in space about a meter across?

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 06:57:15 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross

     @cstross yeah!
     Or there's that possibility that Europa has more ocean water than earth, why not drain that? You can get there pretty easy with a torch ship...

     Or hell, with free thrust let's just deorbit all the comets in the oort cloud into Mars and use the new Barsoom Ocean as our remass.

   • Charlie Stross (cstross@wandering.shop)'s status on Wednesday, 17-Jan-2024 06:57:16 JST Charlie Stross

     in reply to

     @foone Yes, but if everyone built 1g torchships pretty soon there'd be no oceans! Much better to use Jupiter instead: nobody will miss it, right?

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:01:17 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross

     @cstross (I did think about jupiter more seriously but the problem is that you'd have to build a structure that could withstand the pressures of Jupiter's atmosphere as it falls into the planet. That's way harder than something that can survive the earth's oceans, even if you would get more thrust out of it)

   • ~ (modulusshift@digipres.club)'s status on Wednesday, 17-Jan-2024 07:10:17 JST ~

     in reply to

     @foone I don't think mass exiting through a portal imparts any thrust to the surface the portal is on, so not sure this works. but the remote fuel tank and the "infinitely falling object continuously pulls on gravitational partner" both seem legit to me. as well as the time travel implications.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:22:55 JST Foone🏳️‍⚧️

     in reply to

     • F4GRX Sébastien

     @f4grx yep! It does.

   • F4GRX Sébastien (f4grx@chaos.social)'s status on Wednesday, 17-Jan-2024 07:22:56 JST F4GRX Sébastien

     in reply to

     @foone does the atmosphere (or vacuum) crosses portals? Because it would be a kind of problem...

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:39:55 JST Foone🏳️‍⚧️

     in reply to

     my guess based on how big supernovas are (bigger than that. no matter how much you estimate "that" to be), the answer is "enough"

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:39:55 JST Foone🏳️‍⚧️

     in reply to

     anyway so there's a point in Portal 2 where you fire a portal at a surface that's far enough away that there's noticeable light-speed delay before the portal opens, right?

     but is that based on the distance between portals or the distance from the gun?

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:43:38 JST Foone🏳️‍⚧️

     in reply to

     like, in the game's specific scenario, the distinction is irrelevant, but the portal gun is mobile after all. what if you set up a portal on earth, then hop in a rocket to pluto, then when you land, you fire it at the surface of pluto.
     The distance between the gun and the surface is minimal, but the portal pair you just set up is about 5 light-hours long.

     Does it take 5 hours for the portal to open? or does it open instantly?

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:47:57 JST Foone🏳️‍⚧️

     in reply to

     • Rot Maetrix

     @DotMaetrix awesome!

   • Rot Maetrix (dotmaetrix@chitter.xyz)'s status on Wednesday, 17-Jan-2024 07:47:58 JST Rot Maetrix

     in reply to

     @foone You just so happened to catch me while I had enough gunk in my throat to have a proper shake at the voice

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 07:55:51 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross
     • LisPi
     • Adam Bursey

     @lispi314 @abursey @cstross true, but the fun part of a portal-ship is that there's really no difference between a crewed lander and a remote-controlled doomsday missile.

     if you land somewhere uninhabited and/or friendly, you can drop a portal and then send people through. if it's unfriendly, you open the supergiant portal, and have the portal gun throw itself through a return-home portal that instantly closes. you build another ship

   • LisPi (lispi314@udongein.xyz)'s status on Wednesday, 17-Jan-2024 07:55:52 JST LisPi

     in reply to

     • Charlie Stross
     • Adam Bursey
     @cstross @foone @abursey Backblast might make it a weapon of last resort, though.
   • Charlie Stross (cstross@wandering.shop)'s status on Wednesday, 17-Jan-2024 07:55:53 JST Charlie Stross

     in reply to

     • Adam Bursey

     @abursey @foone A portal gun (with the other end of the portal inside the photosphere of a blue-white supergiant) makes a really neat blaster!

   • Adam Bursey (abursey@me.dm)'s status on Wednesday, 17-Jan-2024 07:55:56 JST Adam Bursey

     in reply to

     • Charlie Stross

     @cstross @foone Peter F. Hamilton also uses the idea in a lot of various ways in his Salvation books. E.g. why deal with complicated propulsion systems when you can chuck the ingress end of a portal into a star and stick the egress end on the back of your ship.

   • Charlie Stross (cstross@wandering.shop)'s status on Wednesday, 17-Jan-2024 07:55:57 JST Charlie Stross

     in reply to

     @foone I seem to recall Larry Niven played with this stuff in his teleportation short stories in the 70s (notably "All the bridges rusting"). And I had fun with it in "Glasshouse".

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 08:21:25 JST Foone🏳️‍⚧️

     in reply to

     anyway the fact the aperture science facility extended so deep underground in portal 2 was interesting.

     hey, you know what a very deep underground facility would be real useful for? dropping stuff through portals and having it fall a long time, accelerating as much as possible.

     I bet there's a borehole we never see that's just top to bottom and has as much atmosphere as possible evacuated from it, to lower air resistance

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 08:36:45 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross
     • adehnert

     @adehnert @cstross unfortunately the Half Life universe has the oceans already having dropped by a significant amount, because someone else (The Combine) is already draining the oceans. So using the ocean as remass is not the best idea, as easy as it is.

     But yeah: you could use it just enough to get to Jupiter or some other source.

   • adehnert (adehnert@mastodon.mit.edu)'s status on Wednesday, 17-Jan-2024 08:36:49 JST adehnert

     in reply to

     • Charlie Stross

     @cstross @foone As long as you only use it sparingly, climate change induced ocean level increase isn't an issue. Probably doesn't help with the rest of climate change, and when we inevitably don't use it sparingly we get fun new environmental crises, but hey.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 09:09:20 JST Foone🏳️‍⚧️

     in reply to

     • Suwul

     @susul I was thinking that the portal would be very short-lived, because the surface you placed it on would be quickly destroyed, but there'd be a short period where the initial gamma rays make it through.
     but yeah, if you can somehow keep it open longer than milliseconds after the instant of the star's collapse, you'd absolutely wreck anything near the endpoint

   • Suwul (susul@misskey.heonian.org)'s status on Wednesday, 17-Jan-2024 09:09:24 JST Suwul

     in reply to

     @foone@digipres.club the gamma rays are gonna be mostly negligible when you get hit with particulate accelerated with a foe of energy

   • Michael Gemar (michaelgemar@mstdn.ca)'s status on Wednesday, 17-Jan-2024 09:13:42 JST Michael Gemar

     in reply to

     • Charlie Stross

     @foone @cstross Don’t drain Europa! It will anger the hyperintelligent squid there!

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 09:13:42 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross
     • Michael Gemar

     @michaelgemar @cstross
     that just provides an episode for our Torchship Explorers show. Captain Laser has to go help some ice miners working to set up a portal farm on the bottom of the European ocean, when their drills keep getting attacked, and the crew has to learn to communicate with the squids and figure out how to stop the miners from just going "fuck it" and poisoning the whole ocean.

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 09:28:34 JST Foone🏳️‍⚧️

     in reply to

     • take me to snurch

     @rolenthedeep valve's got my resume, they're welcome to hire me anytime :)

   • take me to snurch (rolenthedeep@rattodon.nexus)'s status on Wednesday, 17-Jan-2024 09:28:35 JST take me to snurch

     in reply to

     @foone probably the best pitch for Portal 3 so far

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 10:34:47 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross
     • Peaceful Assembly Robot

     @StompyRobot @cstross planet destroying asteroids are the kind of thing that only civilizations without relativistic impactors have to worry about.

   • Peaceful Assembly Robot (stompyrobot@mastodon.gamedev.place)'s status on Wednesday, 17-Jan-2024 10:34:48 JST Peaceful Assembly Robot

     in reply to

     • Charlie Stross

     @cstross @foone
     I seem to recall Jupiter is the reason we only have planet destroying asteroids every half a billion years or so...

   • Foone🏳️‍⚧️ (foone@digipres.club)'s status on Wednesday, 17-Jan-2024 11:43:58 JST Foone🏳️‍⚧️

     in reply to

     • Charlie Stross
     • Aethylred

     @aethylred @cstross not if you've got portals! you can harvest remass from the bottom of a gravity well and transport it anywhere, for free!

   • Aethylred (aethylred@mastodon.nz)'s status on Wednesday, 17-Jan-2024 11:43:59 JST Aethylred

     in reply to

     • Charlie Stross

     @cstross @foone most of the water harvested from Jupiter would be burned getting away from Jupiter and eventually be recaptured by Jupiter because Jupiter is fucking massive