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### Re: Penetrate Earth

Posted: Mon Nov 06, 2017 4:04 pm UTC
p1t1o wrote:Fire it at the ground at just over escape velocity, and it should exit the other side of the Earth going slightly slower, fulfilling your "through the Earth" requirement. There would be a colossal explosion for sure but I feel like the Earth would remain [largely] intact - since only a fraction of the hole's kinetic energy would be transferred to the Earth at all.

Assuming you catch it on the other side, right? Because if you don't, all that's going to happen is the Earth will be gone and the black hole will be slightly larger.

Why would a black hole move through the Earth, though? Are you just assuming it's so small and moving fast enough that it, what, sucks material up to get it out of the way or something? I'm not too sure why you think this doesn't just destroy the Earth outright and instead punches through.

### Re: Penetrate Earth

Posted: Mon Nov 06, 2017 4:18 pm UTC
SDK wrote:Why would a black hole move through the Earth, though? Are you just assuming it's so small and moving fast enough that it, what, sucks material up to get it out of the way or something? I'm not too sure why you think this doesn't just destroy the Earth outright and instead punches through.

As I understand it, the BH has low enough mass that it's gravitational field is negligible outside of it's immediate vicinity, and it's kinetic energy can be pretty small as well.

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 4:27 pm UTC
SDK wrote:
p1t1o wrote:Fire it at the ground at just over escape velocity, and it should exit the other side of the Earth going slightly slower, fulfilling your "through the Earth" requirement. There would be a colossal explosion for sure but I feel like the Earth would remain [largely] intact - since only a fraction of the hole's kinetic energy would be transferred to the Earth at all.

Assuming you catch it on the other side, right? Because if you don't, all that's going to happen is the Earth will be gone and the black hole will be slightly larger.
If you start out above escape velocity, it'll still have close to escape velocity when it leaves, which means it will...escape. No "catching" needed.

Why would a black hole move through the Earth, though? Are you just assuming it's so small and moving fast enough that it, what, sucks material up to get it out of the way or something? I'm not too sure why you think this doesn't just destroy the Earth outright and instead punches through.
It's a small black hole, for whatever definition of "small" is needed to make this the outcome.

(Honestly, even if it's got the mass of Earth, it would take some time to destroy the planet because just moving that much stuff takes a while. If it's moving fast enough, even such a massive BH would mostly just pass through the planet without causing much widespread damage.)

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 4:32 pm UTC
We can't make it too small though - it is going to be absorbing material on its journey through the Earth, and any material it does absorb will slow it down equal to that material's momentum. So it's got to be big enough that it can actually have enough speed to reach the other side.

And you do need it to absorb material, because if you don't, you have an impact. I'm not sure that's even possible (to avoid an impact by absorbing material as you approach), but if you don't avoid impact, all your kinetic energy is lost to the resulting explosions.

Or is it just the case that black holes cannot impact anything in the traditional sense since explosions can't leave the black hole anyway? Is that what I'm missing?

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 4:38 pm UTC
Above escape velocity with a black hole, and having enough force to destroy the earth otherwise?...Yeah, this is too destructive for my taste. If the bullet is definitively going to go relativistic, could the design of the bullet be different to not need any of that?

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 4:44 pm UTC
SDK wrote:We can't make it too small though - it is going to be absorbing material on its journey through the Earth, and any material it does absorb will slow it down equal to that material's momentum. So it's got to be big enough that it can actually have enough speed to reach the other side.

And you do need it to absorb material, because if you don't, you have an impact. I'm not sure that's even possible (to avoid an impact by absorbing material as you approach), but if you don't avoid impact, all your kinetic energy is lost to the resulting explosions.

Or is it just the case that black holes cannot impact anything in the traditional sense since explosions can't leave the black hole anyway? Is that what I'm missing?
I think mainly what you're missing is how much denser a small black hole is compared to anything familiar.

A 1 cm2 hole through the Earth contains about 7000 tonnes of material. A black hole that size has a radius of 10-20 meters. Its gravity at a distance of 5mm is 0.01g, so it won't actually be pulling in anything that far away. It won't even pull in everything it affects with stronger gravity than Earth's, because at that size other forces greatly outweigh gravity. But even if we assume it sucks in everything from the region where it's gravity is higher than 1g, that's only 1/100th of the mass of the black hole itself, so it won't have a significant effect on its speed. Start it off about 1% higher than escape velocity and it'll have about escape velocity when it comes out the other side.

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 5:45 pm UTC
Ok, sure, that makes sense. It's hard to rationalize how something that weighs so little can still have a lot of gravity immediately next to it. Thanks.

### Re: Penetrate Earth

Posted: Mon Nov 06, 2017 6:17 pm UTC
andykhang wrote:So, I have asked for a Matter-Antimatter Anti-Structure Sniper Rifle earlier in this thread. Now, I wanted to test this, and to do that, I need a target, a huuuuge target. So, I decided to aim it down, lock and loaded, and it's time to penetrate Earth. Supposed I aimed it straight down, and used the same indestructable bullet last time, what speed do I need to achieve to do that?

1) Define "penetrate the Earth" as "get a bullet from the Earth's atmosphere into the Earth's mantle" for purposes of this test.
2) Take your vibranium rifle and ammo to Iceland.
3) Follow the mid-Atlantic rift until you find an active spot.
4) Set up your rifle on a really big tripod that can straddle the rift.
5) Retreat.
6) Remotely fire the rifle.
7) .....
8) .....
9) .....
10) .....
11) .....
12) You now have a successfully tested indestructible rifle that isn't encased in basalt and isn't too hot to hold. Congratulations!

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 9:36 pm UTC
If your bullet is small enough, you can shoot it through the Earth with no problem.

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 9:54 pm UTC
It also needs to have no electric charge.

### Re: Science-based what-if questions

Posted: Mon Nov 06, 2017 10:25 pm UTC
Yeah, if your bullet is not a neutrino, you may run into problems. Maybe you could find something in the dark sector that works.

### Re: Science-based what-if questions

Posted: Tue Nov 07, 2017 9:35 am UTC
How about I put a spin in it? A really fast spin. This being the indestructable bullet and all, I don't really have to worry about centripedal force tear itself apart.

Edit: Also, making a bullet drill-like.

### Re: Science-based what-if questions

Posted: Tue Nov 07, 2017 1:15 pm UTC
If you're talking about the black hole, spinning it won't make an important difference.

If you're not talking about the black hole, you'd need something to keep it spinning for it to be drill-like, because otherwise it will lose its angular momentum too quickly to do any good.

### Re: Science-based what-if questions

Posted: Tue Nov 07, 2017 3:46 pm UTC
Even when the spin itself is relativistic?

### Re: Science-based what-if questions

Posted: Thu Dec 07, 2017 1:41 am UTC
Solar Von Neumann
How long would it take a fully-automated solar panel factory to produce enough solar panels to power itself? (Using as few fossil fuels and fossil fuel products as possible)

### Re: Science-based what-if questions

Posted: Thu Dec 07, 2017 2:20 am UTC
That might be as 'simple' as finding out what power requirements a "one small solar panel at a time" machine needs to use, determine the rate of product completion and the fraction per that production that such a single panel provides.

Though selling the panels, reinvesting in further (larger?) panel-makers and only later stopping the exponentially increased sales1 and suddenly diverting production into self-supply might be quicker. Depends upon the parameters of the various dependent costs. Which will take true Randalesque research to nail down. Especially with assumptions of improving technology (requiring or not newer fabricators to take advantage of) and degradations of the seedcorn panels as time passes (if not initially just sold on).

1 With or without a price-depression curve as a state of oversupply is approached, for an additional kink.

### Re: Science-based what-if questions

Posted: Thu Dec 07, 2017 2:41 am UTC
Sounds like the next big clicking game.

### Re: Science-based what-if questions

Posted: Thu Dec 07, 2017 3:30 am UTC
Sizik wrote:Sounds like the next big clicking game.

I was thinking that, myself. Daily raw material drops, limited energy other than the self-production options, buy/sell/store/use options on output (with dynamic P2P-market demand controlling prices), level-up individual aspects to access (create or buy) bigger/better/buffed versions, and drive up the player rank to expand various options

The only thing my ideal idea is missing is the Real Currency Bonus-Pack market, direct or via an otherwise trickle-through fiat currency like 'jewels', because (though I see the value, and the raison d'etre to developing and marketing the game at all), I'm too much unmercenary to do this myself.

### Re: Science-based what-if questions

Posted: Thu Dec 07, 2017 5:15 pm UTC
I think you have other costs to take into account as your factory grows: land costs money, sprawling wider needs more land, building higher needs deeper and thicker foundations, upgrading foundations costs a lot more than laying better ones in the first place but laying foundations for a 50-storey building right away would cost more in setup phase, if your site gets really big the internal transport system starts getting expensive and if you build tall you're increasing your power consumption per hectare. The further from the Equator you get, the more benefit you get from vertically series of panels and the less you get from horizontally spread panels, so near the Arctic or Antarctic Circle a tall, slender building aligned east-west is probably better than a flat solar farm but near the Equator you're pretty much stuck with spreading horizontally. If you fill your initial site and the land prices around it are prohibitive, you may need to split your site, which is generally not efficient but could allow you to ship away from a host city without having to ship through it.

If this is Sim City, you'll also want to disabled disasters, because otherwise components with 50-year lifespans will explode within 20, making the whole place more debris-strewn, radioactive and on fire every month until you have to exploit a glitch to even build replacements, and then there's an earthquake during a hurricane and Godzilla shows up.

### Variable Engine

Posted: Fri Dec 08, 2017 9:42 am UTC
What would you do with a Variable Engine, A.K.A: An engine that could convert any type of energy into any type of work, regardless of absurdity, and vice-versa? (The engine and work is equivalent, btw, so you can't make it a Perpeptual Engine yet)

Edit: Also, what do you think is the basic requirement for the type of engine I describe? You could assume it that it only take certain type of energy and/or certain amount as the same time to make it easier.

### Re: Variable Engine

Posted: Fri Dec 08, 2017 10:53 am UTC
andykhang wrote:(The engine and work is equivalent, btw, so you can't make it a Perpeptual Engine yet)

You say that as if you mean "no gain", but are you also intending there to be no loss? If you can convert without loss (or without the losses existing in the one or more current methods necessary to convert from end-to-end) then that's also an instant bonus.

Solar energy direct to mechanical (rather than through PV to electricity (in and out of battery) to motor, or solar furnace to steam and turbine and thence mechanically-geared or to generator to electricity to motor, as before) might be a Holy Grail for various current problems.

Or somehow create a direct conversion of any energy you want (however slow and trickling) towards potential energy to create a beanstalkless "space elevator". If your question is as open ended as all that.

### Re: Science-based what-if questions

Posted: Fri Dec 08, 2017 11:02 am UTC
You need to give it some restrictions. If your engine can take any energy and turn it into useful work, I would just gradually convert the entire mass of a hunk of material in my reactor into electricity, kinetic energy, or whatever. Spaceflight would be trivial, since you would have a reactionless drive. Cooling would also be trivial, since your magic engine can just extract the thermal energy from something and turn it into work, against all laws of physics. So I could have a megawatt CPU if I want, and it will cost practically nothing to operate and will never overheat. This makes computing trivial.

When you have essentially unlimited energy, computing power, and range, there isn't much you can't do.

### Re: Science-based what-if questions

Posted: Fri Dec 08, 2017 11:18 am UTC
andykhang wrote:What would you do with a Variable Engine, A.K.A: An engine that could convert any type of energy into any type of work, regardless of absurdity, and vice-versa? (The engine and work is equivalent, btw, so you can't make it a Perpeptual Engine yet)

Edit: Also, what do you think is the basic requirement for the type of engine I describe? You could assume it that it only take certain type of energy and/or certain amount as the same time to make it easier.

This question boils down to "What would you do if you were a god?"

I would use it to bring cheap electricity to the entire world, undercutting all energy providers globally and collapsing the oil-based economy - which I would replace with one based on copious amounts of almost-free energy from me, installing myself as the de-facto ruler of the world.
Then the real fun begins.

### Re: Science-based what-if questions

Posted: Fri Dec 08, 2017 11:25 am UTC
Eebster the Great wrote:You need to give it some restrictions. If your engine can take any energy and turn it into useful work, I would just gradually convert the entire mass of a hunk of material in my reactor into electricity, kinetic energy, or whatever. Spaceflight would be trivial, since you would have a reactionless drive. Cooling would also be trivial, since your magic engine can just extract the thermal energy from something and turn it into work, against all laws of physics. So I could have a megawatt CPU if I want, and it will cost practically nothing to operate and will never overheat. This makes computing trivial.

When you have essentially unlimited energy, computing power, and range, there isn't much you can't do.

Or creating a bomb that could slowly convert the planet in anyway you want. Or if you want to be bold, convert matter into special spacial energy that could create a singularity or a big rip to a planet you're standing in, or simply turn it into pure computational power (as absurd as you want, remember?) to turn matter into intelligent...and i just think of the good story idea haven't i?

Yeah, best to restrict it...How about just a energy-matter converter, and limiting it to the form of energy that we known of?

### Re: Science-based what-if questions

Posted: Fri Dec 08, 2017 11:31 am UTC
'just'

'limiting'

### Re: Science-based what-if questions

Posted: Fri Dec 08, 2017 11:42 am UTC
You better thank you're lucky star I didn't including work to change a regional fundamental law and straight up magic, my man .

### Re: Science-based what-if questions

Posted: Fri Dec 08, 2017 12:11 pm UTC
andykhang wrote:You better thank you're lucky star I didn't including work to change a regional fundamental law and straight up magic, my man .

Ooh, expanded powers!

In this case, first I would ascertain if there is an afterlife.

Then, if there isnt one, construct one.

If there is one, conquer it.

Bish-Bash-Bosh, Im God-emperor of Dune the Universe.

Then the real fun begins.

### Re: Science-based what-if questions

Posted: Sat Dec 09, 2017 3:13 am UTC
Yeah, that's still not particularly limiting. It's nice that now you can't just take waste heat and recycle it to do more work, but you can still just pick up a handful of dirt, chuck it at your engine, and make any substance or structure you like appear before your eyes. The laws of physics governing everyday life are completely understood. There are no forms of energy relevant at that scale that we don't know of. If you can just "convert" a lump of matter into any type of energy you want, that should include chemical energy, gravitational energy, and all other conventional types of potential energy that give everyday objects their structure; there is no reason you couldn't even transmute elements if you wanted to.

So, sure, you're still eventually vulnerable to the heat death of the universe, but you can get a lot done before that point.

### Re: Science-based what-if questions

Posted: Sat Dec 09, 2017 5:54 am UTC
Limiting it again huh...How about just a inertia converter, in which you convert simple kinetic energy into electricity, with no waste, and applied with anything?

### The Big Gaia

Posted: Mon Dec 11, 2017 5:43 pm UTC
Supposedly, I want to make a cake. A cake so big, it's literally the size of the Earth: The Big Gaia, if you will. Supposedly that it's at least safe for human comsumption, what should it look like, and how should I make it?

### Re: Science-based what-if questions

Posted: Mon Dec 11, 2017 5:52 pm UTC
You can't make it - there's not enough materials for it on Earth.

### Re: Science-based what-if questions

Posted: Mon Dec 11, 2017 5:56 pm UTC
If you want it to be safe for human consumption, make it out of cake.

The parts in the middle will get sort of squished together, though.

### Re: Science-based what-if questions

Posted: Mon Dec 11, 2017 6:23 pm UTC
Zohar wrote:You can't make it - there's not enough materials for it on Earth.

Who said I would just take it on Earth alone? Let just supposed I got at least an Earth amount of ingredient and a way to process them all (Probably a giant mixer powered by black hole or something)

@gmalivuk Or that the cake would be realy puffy.

### Re: Science-based what-if questions

Posted: Tue Dec 12, 2017 9:29 am UTC
Heres my proposition.

You cant make it a sphere, because the central layers will be heated and compressed out of recognition, it will no longer be cake. It may be a good way to manufacture crude oil en masse though.

I suggest making a giant plane-like sheet of brownies. But not a flat sheet, a sheet rolled up into a tube and gently spun up (only enough spin to counter its own gravity is required) like an O'Neil cylinder. I think this might facilitate cooking (filament-like heat source running centrally) and preparation. And consumption.

### Re: Science-based what-if questions

Posted: Tue Dec 12, 2017 10:45 am UTC
Hm..that could work. The speed of it spin is a problem though, as it will determine the type of binding agent that giant waterpipe of a cake is needed, and you can't have too tough of a binding agent (unless you want it to be scooped out of a power excavator or a drill and diluted it in special agent again to eat)

### Re: Science-based what-if questions

Posted: Tue Dec 12, 2017 11:24 am UTC
Would it be cheating to use a planet-sized baking dish?
It'd be easier if we could line a tube with brownie, instead of the brownie needing to be structural.

### Re: Science-based what-if questions

Posted: Tue Dec 12, 2017 12:22 pm UTC
If by extent, loads of empty space, perhaps start thinking along the lines of a soufflĂ©? If by mass and/or volume (give or take density), hollow tube self-supporting (radially) by its own spin is a start, but questions about the longitudinal pressures amount. But make it very wide and not so longâ€¦ At an extreme (especially if ambitious regarding the planet size or picking the righr body to construct around), consider going full Dyson Ring, and choosing your parameters wisely can even cook the thing for you, more or less through (or go for something like an inverse baked-Alaska donut!) before sliding it off ready for the next lot of mix to be laid out, because just making one cake is being greedy. There's neighbours'll appreciate cake, too, and it never hurts to make friends of your neighbours. Especially if you might ask for a cup or two of sugar at some point.

### Re: Science-based what-if questions

Posted: Tue Dec 12, 2017 12:50 pm UTC
...Never said anything about the whole thing need to be eatable, so alright then. Next is what kind of flavor that could survive the radiation bombarment from space, or do we lay out an atmosphere as flavor dust?

### What happened to my duck?

Posted: Wed Dec 13, 2017 4:06 pm UTC
If me and my pet duck, who weighs next to nothing, were placed far away from any gravity source and in such a way that our mutual attraction was negligible, would I see my duck accelerate away from me? If so, how fast?

### Re: What happened to my duck?

Posted: Wed Dec 13, 2017 6:35 pm UTC
DRAirey1 wrote:If me and my pet duck, who weighs next to nothing, were placed far away from any gravity source and in such a way that our mutual attraction was negligible, would I see my duck accelerate away from me? If so, how fast?
You mean because of the accelerating expansion of the universe? The duck would have to be extremely far away from you for that to have a greater effect than the mutual attraction between you.