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Inspired by comments to JBH's answer to The worlds between, the consequences of instantaneous FTL.

The Premise

A technology for instantaneous travel exists, making it possible to travel to any point within our galaxy. Travel time and cost are equal and are not affected by distance. The teleportation devices can operate equally well in space and on the surface of a planet.

The question

Under these conditions, is it better (easier, faster, cheaper) to mine asteroids or planets?

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    $\begingroup$ In such a hypothetical universe, would it not be simpler to just teleport the material you intend to mine to a local facility? Processing a planet or an asteroid become equivalent once a chunk is cut-and-pasted to a different location. $\endgroup$ – Ian MacDonald Jul 16 '18 at 18:37
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    $\begingroup$ @IanMacDonald - for the interest of this question, please assume the teleporter works more like a portal/gateway and less like Star-Trek's transporter - that is, you still need to "cut out" the ore and move it into the teleportation chamber. $\endgroup$ – G0BLiN Jul 17 '18 at 7:24
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    $\begingroup$ @G0BliN, that's actually a very important note to make. Star Trek-style transporters would make mining asteroids much easier than planets, while Stargate-style portals would not work too well on asteroids. In the end, I'm not sure how much benefit portals would be to mining on Earth - it would work great as an emergency system to get people out, but other than that, I think you'll still need all the tunnels to the surface to ventilate the area (unless the portals can do that too), you'll still need supports, heavy machinery, life support... $\endgroup$ – Luaan Sep 18 '18 at 10:42
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One thing to consider is the difficulty of retooling. This is, oddly, a point in the favour of asteroids.

Simply put: when moving your operations from one planet to another you have to consider differing atmospheric conditions, gravities and temperature constraints. You might have to completely redesign your operations to cope with anything from crushing pressure to acid rain.

When mining in space you’ve already engineered for hard vacuum and presumably varying degrees of sunlight. You are (paradoxically) much more in control of the environment and so can simply pull up stakes and move without needing surveys in advance.

As an example: consider the extra complexity you would have to build into a Von Neumann probe (self replicating space probe) in order to allow it to deal with planetary conditions vs just harvesting asteroids.

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    $\begingroup$ +1. To add The only thing will vary a lot is star radiation spectrum and intensity $\endgroup$ – jean Jul 16 '18 at 18:41
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    $\begingroup$ But a planet is way bigger than an asteroid. Mining a single planet may involve scale economy which are never achieved for an asteroid. $\endgroup$ – L.Dutch Jul 16 '18 at 19:11
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    $\begingroup$ @L.Dutch That only applies in a world without instantaneous transportation. For all intents and purposes, all the asteroid facilities are in the same place. It's no more difficult to go from one asteroid to another than it is to go to a facility down the street on the same planet. $\endgroup$ – Nuclear Wang Jul 16 '18 at 20:21
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    $\begingroup$ @Gryphon: While the edit from ‘up sticks’ to ‘pull up stakes’ is perfectly fine as the two are sufficiently synonymous I did actually mean the former. To me up sticks implies taking more along with you than pulling up stakes, though I appreciate it’s such a marginal difference that it really doesn’t matter. Cheers for fixing vacuum though. $\endgroup$ – Joe Bloggs Jul 17 '18 at 9:22
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    $\begingroup$ @NuclearWang: No more difficult to go to, certainly, but you still have to find those asteroids. $\endgroup$ – Matthieu M. Jul 17 '18 at 11:00
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It depends on the cost structure at the moment when you place this.

Mining Asteroids

Pro:

  • easier to move large masses due to lower gravity
  • easier to locate interesting resources

Cons:

  • heat management in lack of atmosphere
  • difficult to hold position in low gravity
  • work in space suit

Mining planet

Pro:

  • heat management in atmosphere
  • work with re-breather possible

Cons:

  • move loads in high gravity
  • mining prospect needed

Once you have an idea of how much can each of the cons cost to be covered, you can determine which is the best option.

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    $\begingroup$ Unspoken pro of mining asteroids: If they're small enough, you might not even mine it. Simply tow it to the nearest refinery to be processed. Even in the larger ones, you're not mining it so much as you're breaking it into small enough chunks to fit in a rock crusher. $\endgroup$ – UIDAlexD Jul 16 '18 at 17:01
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    $\begingroup$ Pro for Planets: With trillions of planets at your doorstep you can probably easily choose planets with a similar gravity to earth - under which conditions humans work the best. (Although for the asteroids only doing small shifts in zero-gravity and teleporting home after every shift will reduce negative zero-grav-effects) $\endgroup$ – Falco Jul 17 '18 at 8:06
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    $\begingroup$ Gravity can also be your friend. If you use explosives for example, to break up your ore, it´ll form a nice pile instead of flying away. Methods of separation like Gold-washing also rely on gravity. And try to drill a hole or use a jack-hammer without the counter-force of gravity ... $\endgroup$ – Daniel Jul 17 '18 at 11:47
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I think that if such technology was available it wouldn't make much sense to mine at all.

The most profitable solution would be to have processing plants in planets with ideal conditions for each mineral and many gathering stations simply looking for the biggest/purest chunks of minerals floating in the galaxy that such factories can process without any mining involved.

If travel time is zero the limiting factor is the processing speed of the factories, the difficulty of discovery of such rocks, and the cost of teleporting

Even collecting very small rocks would be more profitable than mining

If the cost of teleporting is high (lets say it consumes lots of energy) then you should take into account the cost of producing such energy, and compare it with the energy and time cost of mining.

If energy is very cheap, even collecting dust over the galaxy would be more profitable than mining.

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  • $\begingroup$ Exactly. Why even bother mining asteroids, when you can teleport them whole into processing facility? And assuming that teleportation technology is somehow limited in dimensions/mass, in this scenario asteroids smaller size indeed becomes an advantage. $\endgroup$ – Deo Jul 17 '18 at 10:14
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When you teleport something from place A to place B you have to compensate for various differences between the two locations.

For example, the asteroid or planet to be mined will be moving in a different velocity (direction and speed) that the asteroid, planet, or space habitat which is the destination.

In our solar system, the orbital velocity of Mercury is about 47.8725 km/sec and the orbital velocity of Neptune is about 5.4778 km/sec. When Neptune and Mercury are lined up in a straight line with the sun and on the same side they are traveling in parallel directions and the speed difference is 47.8725 minus 5.4778 or 42.3947 km/sec. At times in their orbits when they are lined up with the sun and are on opposite sides of the sun, they are traveling in opposite directions and the difference in their velocity is 47.8725 plus 5.4778 or 53.3503 km/sec. The velocity difference between two different objects in the solar system is constantly changing between minimum and maximum and also changing in direction.

Also, all natural bodies naturally rotate. And all space habitats built by humans will be built as cylinders and made to rotate to provide simulated gravity on the inside of the cylinders, until and unless a method of generating gravity is discovered. And of course, the direction of rotation of a spot on or in a rotating body is constantly changing, and thus the direction of rotation of the minerals that are in that spot.

Therefore the object that is mined and the destination of the minerals will have different orbital speeds and different speeds of rotation, as well as different orbital and rotational directions.

And if the difference in total velocity is small enough, the minerals teleported in will bang around a little without doing any damage. But if the total velocity difference is high enough, the teleported minerals will do a lot of damage. And if the velocity difference is high enough, the teleported minerals can cause an explosion like an atomic bomb.

For example, a stony asteroid about 10 meters (33 feet) in diameter entering Earth's atmosphere at a speed of tens of kilometers per second can create a 20 kiloton explosion - about equal to that of "fat man" at Nagasaki - in the air, and such airbursts are now known to happen about once a year.

The energy in the Tunguska explosion is now estimated to be "only" equal to 3 to 5 megatons of TNT, and thus about 130 to 300 times the energy of the Hiroshima and Nagasaki bombs. It was caused by a small comet or a rocky asteroid about 60 meters (200 feet) wide traveling tens of kilometers per second relative to Earth.

The extinction of the dinosaurs may have been caused by the Chicxulub impact of a body 10 to 15 kilometers (6.2-9.3 miles) in diameter traveling at tens of kilometers per second and releasing energy equivalent to 10 billion Hiroshima atomic bombs.

So a method of handling the velocity differences between the departure point and the destination point is necessary when teleporting between different objects in the same solar system.

Our Sun also orbits around the center of the galaxy with a speed of about 300 kilometers per second. A solar system orbiting at the same distance on the far side of the galaxy would have about the same speed in the opposite direction, and thus there would be a velocity difference of about 600 kilometers per second to allow for when teleporting objects from such a solar system to our solar system.

In E.E. Smith's Lensman series starships can become inertialess to travel much faster than light, but when a starship turns off the inertialess drive and become inert again its original velocity - and its difference from that of the destination - returns. Thus careful maneuvering is required to prevent the starship from slamming into the destination planet at great speed and devastating the planet.

This makes it very difficult to transfer even a single person or a much smaller object between two different space ships with different inert velocities, and it is used as a weapon by moving planets with inertialess drive, turning off the inertialess drive once they are in position, and letting their intrinsic velocities smash them into target planets. The Lensman series has some very big explosions.

There is also the difference in gravitational potential energy between different objects at different distances from the center of gravity of an astronomical object.

For example, objects that are higher on Earth have more potential energy than objects that are lower, because they could potentially fall farther toward the center of the Earth. An object that fell from an infinite distance to Earth would be accelerated to a velocity of 11.186 kilometers per second. And that is also the velocity needed for an object to escape from Earth's gravity - the escape velocity.

The escape velocity from the surface of the Sun is 617.5 kilometers per second. But at Earth's distance from the Sun, the escape velocity from the solar system is only 42.1 kilometers per second.

Wikipedia Article

Space.SE question

From the table, you can see that each body in the solar system has a different escape velocity, and each body with a different distance from the sun also has a different solar system escape velocity.

Thus the total escape velocity from Earth and the solar system is 53.286 km/sec, and the total escape velocity from Pluto and the solar system is about 7.83 km/sec, etc.

At the Sun's distance from the center of the galaxy, the escape velocity from the galaxy is about 492 to 594 km/sec. Thus the total escape velocity from Earth, the solar system, and the galaxy should be about 545.286 to 647.286 km.sec. And the potential energy of an object at a particular position should be proportional to the total of all the escape velocities at that position.

So teleporting an object from one astronomical body to another should cause a significant change in the object's potential energy.

So you should read Larry Niven's story "By Mind Alone" (1966).

And his article "The Theory and Practice of Teleportation".

Once you decide how your teleportation system will handle the differences in velocity and potential energy, you can then calculate those differences for various known and imaginary astronomical bodies and decide whether planets or asteroids would be better for teleportation based mining.

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    $\begingroup$ The quetion specifies that travel costs are the same for every destination - this should include devices to attenuate velocity. Furthermore the OP specifies in the comments his teleportation works like Portals in Star Gate: All transported mass changes it's velocity to the velocity of the target frame of reference. $\endgroup$ – Falco Jul 17 '18 at 8:03
  • $\begingroup$ Golding - that's an excellent and detailed treatment of the problems with teleportation - I love the way Larry Nivan addressed the momentum delta problem in his short stories. However, this question just conveniently ignores these issues (same as the original question which led to this one) - I think that any hard science setting with such a device opens up a lot of (ab)uses to break energy conservation and other basic laws of physics. Making the device much more than just a teleporter. $\endgroup$ – G0BLiN Jul 17 '18 at 9:01
  • $\begingroup$ What about framing the device as a portal that connects the two sides as if they were cospatial? Angular momentum is usually felt by the agent as gravity/centripetal force so there I would expect a sudden change in "gravity" but otherwise it seems like a relatively simple framing. I agree you'd need weird physics to cover what happens when two portals get too close together but we should be able to discount that in this scenario. $\endgroup$ – Mark McKenna Jul 17 '18 at 12:59
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Both and neither, under those circumstances, all else being equal, you mine the richest sources of the target material that you can find regardless of source.

All else may not be equal though, in particular planets may be worse targets because they:

A. are more likely to have certain, dangerous, conditions like poisonous atmospheres or extreme gravitational conditions that make them harder to extract material from

B. are worth more as is than as a strip mine, a world that is an Earthly paradise is worth more ecologically intact than it is to the mineral extraction industry.

The only other note I would make is that multiple asteroids are better than a single planet of the same mass when it comes to the rate at which you can extract material because of the cubed-squared law. But with the gravity of a world being a non-issue any rich source of a given element is an equally valid target economically.

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If instant teleportation technology exists, such that travel between any two locations in the universe is equal cost, then planets are much easier to mine.

Their atmosphere makes heat management much easier to work with, whereas asteroids require you to build large radiators to dissipate heat.

Their surface gravity makes manufacturing significantly easier (note that somewhere around the gravity of our Moon or Mars is the optimal for manufacturing, but Earth-like is still much better than almost none. Most asteroids, on the other hand, have surface gravity measured in micro-gees, making manufacturing completely different.

Planets have a lot more resources to mine than asteroids. Mars has 190 times as much mass to mine as an asteroid does, while the Earth has 1800 times as much.

Earth-like planets can also give you free life support through plants replenishing your oxygen and making food. Obviously, this only applies to planets which already have life on them, so not all planets have this perk, but it's still worth thinking about.

It is also much easier on people in a world which has significant gravity. Your asteroid miners will have their muscles atrophy and will have difficulty standing when they return home, unless the teleportation is cheap enough to use it for daily commutes. Even with only the Moon's gravity, it becomes much easier to maintain enough muscle mass to continue standing when you return to the Earth.

While people have commented that planets are more likely to have dangerous weather etc., asteroids are perpetually dangerous. You have to lug along your own life support, always be careful that things don't go flying off into space, and watch out for several ton rocks moving on the order of millimeters per second crushing you. I'd argue that planets are safer.

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    $\begingroup$ Outside of the rare exceptions that are earth-like planets, chances are that a mining colony is still going to have to bring extensive life support, food, water, and oxygen. Unrelated, what are your sources for Mars's 190x and Earth's 1800x mineable mass? I'm interested to learn what research has been done on the topic. $\endgroup$ – MindS1 Jul 16 '18 at 19:27

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