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I'm trying to come up with a scenario involving a mining base built on a planet that may only be approached from the shadowed side; the star (or other body) allows only that narrow lane of approach. The base is in a fortified bunker to protect it when it faces the star.

The question is: What phenomenon would realistically limit approach without melting the planet or otherwise making the mining base impossible?

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  • $\begingroup$ Welcome to the site. Are you looking for natural, artificial, or "doesn't matter" phenomena? $\endgroup$ – Frostfyre Apr 20 '16 at 15:57
  • $\begingroup$ Primarily natural, but I'm not ruling anything out. $\endgroup$ – St0necr0w Apr 20 '16 at 17:56
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    $\begingroup$ Watch the movie Chronicles of Riddick. That exact scenario was in the movie, only the mine was a prison. $\endgroup$ – Chloe Apr 21 '16 at 3:19
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    $\begingroup$ Or read some of the Star Wars (now Legends) books - they had shieldships for getting to a (mobile) mining encampment. $\endgroup$ – Clockwork-Muse Apr 21 '16 at 8:43
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Have the planet orbit very close to a Pulsar or some other exotic star.

A neutron star is very small (few Km in diameter), for this reason your planet would have a very large shadow, thus making the planetary approach more feasible. The planetary mass would provide shielding from most of the star solar wind and radiation (at least in the shadowed area).

You can go more extreme and use another star like object to create a stronger justification for travelling in the shadow. Like a quark star, an antimatter star or a strangelet star. Your planet would be perfect for housing a scientific research station for studing the unusual star!

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    $\begingroup$ If it is a heavy mass star like a neutron star the planet will be tidal locked and will not rotate. Only one side will face the star, always. A neutron star is not realistic either because the gravity will be so large, even as far away as an orbiting planet. I think the gravity waves/tidal forces will even break up nearby planets. The neutron star will have burned off the rocky planets when it went supernova and collapsed (not sure about the supernova for neutron stars, but stars do grow and consume their planets as their fuel runs out. The sun will consume the earth.) $\endgroup$ – Chloe Apr 21 '16 at 3:27
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    $\begingroup$ being tidally locked is not necessarily a problem; but I'm not even sure about that since a neutron star is so small and radiative the planet can still be somewhat far from it. Your second point does not stand since we have found exoplanet around neutron stars (search Pulsar planet). Also the planet could be a captured rouge planet, I'm sure for wanting to put a mining station on such an though spot the OP will surely have something interesting on the planet that justifies the choice $\endgroup$ – SilverCookies Apr 21 '16 at 8:06
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    $\begingroup$ @Chloe "A neutron star is not realistic either because the gravity will be so large". Eh, no. There is a huge misconception about things like black holes, neutron stars and such, which is that gravity around them is suddenly multiplied. That is not the case. Gravity still works as normal. If our Sun at this moment was compressed to a black hole or a neutron star, its gravity here would not change one bit. The difference is that since these things are very dense, then you can get very close to their center of gravity. And only then do you begin to have some real problems from gravity. $\endgroup$ – MichaelK Apr 21 '16 at 10:39
  • $\begingroup$ @MichaelKarnerfors Never mind, I was thinking of our sun being replaced by a neutron star. Our sun won't turn into a neutron star, so I was thinking of a giant that turned into a neutron, as close as our sun. However, the other points need addressing Mt. Everest would only be 1cm tall on a neutron. Large irregularities may emit gravity waves that could destroy a rocky planet. Also, the star would have expanded and consumed close planets. I believe rocky planets exist in inner orbits. Perhaps it was captured after neutron formation? $\endgroup$ – Chloe Apr 21 '16 at 17:31
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If the planet was pretty close to the star that could do it, such that ships outside of the umbra/penumbra would be hit by the full force of the solar radiation and thermal energy.

That is kind of a problem though, because the umbra is kind of a small area. enter image description here

You would have to get pretty close to the planet before you could get into it's shadow.
Factors that determine how big the umbra is are the distance of the planet to the star, the size of the star, the size of the planet.

You might have to have another way to shield the ship until you get into the shadow, such as a solar parasol ship, like a giant umbrella that reflects the energy that it can, and with huge amounts of cooling to keep it from being consumed, that could ferry other ships to the planet.

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    $\begingroup$ Another approach would be some sort of wormhole navigation mechanism that drops you into the umbra. $\endgroup$ – Erik Apr 20 '16 at 16:07
  • $\begingroup$ SilverCookies has it right. Use a very small star, such as a pulsar (neutron star). If the star is no bigger than the planet -- and in theory, a neutron star might be about the same size as Earth -- then that works; the umbra would extend to infinity. As SilverCookies said, the extreme radiation from a pulsar would be an excellent reason for approaching the planet only within its shadow. $\endgroup$ – Lensman Apr 21 '16 at 3:09
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    $\begingroup$ 4th/last paragraph, like Sunshine! They didn't use cooling, just gold foil. $\endgroup$ – Chloe Apr 21 '16 at 3:46
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    $\begingroup$ Right, though I don't want to assume that Sunshine got it right that just a reflective surface would be enough to protect the ship. You could use a heat pipe system. Some heat pipes have demonstrated a heat flux of more than 23 kW/cm², about four times the heat flux through the surface of the sun. $\endgroup$ – AndyD273 Apr 21 '16 at 14:13
  • $\begingroup$ @Lensman Could be, though actually a neutron star would only have a radius of around 7 miles, much much smaller than the earth. I know neutron stars are the remnants of very large stars after a supernova event, and so I don't know what kind of planetary system would still exist naturally. A white dwarf on the other hand would be about the size of Earth, are still hot when they are new, and don't usually explode, though the expansion of the planetary nebula would probably kill any planet in orbit. $\endgroup$ – AndyD273 Apr 21 '16 at 14:26
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If you take Mercury as an example, the surface temperature of the planet is somewhere around 700 K, and its black body temperature is about 400 K. The planet is far more of a black body than your hypothetical spacecraft would probably be, but needless to say you would not want to expose your ship to those kinds of temperatures for long.

As AndyD273 was kind enough to demonstrate, there are several varieties of shadow behind a planet, only one of which is full enclosure, but all three would allow some protection from solar radiation.

What you could do is say that the mining base is on the dark side of the planet, and approaching ships try to approach from within the shadows to minimize heating problems. This might also make for interesting drama if the ship has to make a break for it straight into the direct sunlight for some reason!

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I was thinking about this, and it occurred to me that the only kind of substances one might be willing to mine in an extreme environment would be if they were extremely rare minerals made of stable transuranic elements or unlikely isotopes made stable by currently undiscovered supersymmetric particles. These kind of elements might only be made in highly energetic events, like the merging of two neutron stars, or possibly some kind of event with a black hole. The planet itself might be accreted from byproducts of the primary, making it not only necessary to approach the planet in its shadow, but to be very, very careful where you step.

I think it would be best to have a single primary, because you need the planet to be tidally locked.

It might be interesting to have a primary body that's almost, but not quite a black hole. It would be a condition that might make highly unlikely things be a little more likely.

It sounds like it might be a fun read. It also seems like you'll need to do some serious research to make it a serious science fiction story..

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    $\begingroup$ Unobtainium, of course! $\endgroup$ – Chloe Apr 21 '16 at 3:35
  • $\begingroup$ @Chlloe I was thinking of minerals that, if you come in contact with it, might make you turn into antimatter or zap you into another universe. Or something just as uninviting. $\endgroup$ – Howard Miller Apr 21 '16 at 15:05
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Having read these answers, consider a binary star system. One star's radiation is manageable, but two stars is overload. Therefore, you may only approach the planet when one star occludes the other. Of course, to get to the planet, you would have to travel in the plane of orbit when the stars and planet line up. This will necessarily be in the planet's shadow as you get close, but it won't be the planet itself which protects your ships.

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maybe its a pulsar and I would say the phenomena IS melting the planet. its just taking a while (planets are small compared to stars but they are still big). In the interim its worth picking up the 'rare mineral' being created. You are travelling to another star so have FTL. The only safe place to 'emerge' is in the planet's shadow (as deep in the umbra as possible) and you can only land / take off / mine while the underground base is in the shadow

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If the planet is near enough to its primary, it will get tidally locked and your base will either be always in the daylight or always in the shadow.

Also, if the planet is not locked and rotates, and the surface is so lethal, it's unclear how the base could get built in the first place.

You could try and solve these issues by positing that the planet is a recent addition to the solar system (it would need to have been captured by a very rare three-body interaction with one of the existing planets).

This yields some interesting consequences:

  • the planet can optionally be on a unstable or very elongated orbit, which implies long and harsh winters, impossibly hot summers, and even a limited life expectancy before it drops in the star or is further destabilized by another encounter with one of the planets and gets smashed, consumed by the star, or ejected from the solar system altogether. This can justify a time window of anywhere from a few days to several centuries before the planet is no longer mineable.

  • the planet's surface can have an interesting composition. Let's imagine a gaseous planet that got its atmosphere blown off by a nova (or supernova), becoming an ejected cinder covered by condensing volatiles from the outer rim of the planetary nebula.

You would get a very large snowball with a possibly very valuable core, which rotates not too rapidly around a star, melting on one side and resolidifying on the other. This means that the surface can be reached at any time, but landing is only possible during the night. The base would be some sort of submersible that resurfaces in the evening before night freeze, and resubmerges just before dawn, and has been simply "dropped" on the planet.

Whatever the planet's original star's death has deposited on the solid surface, under several hundred meters of ice, has better be worth the trouble.

Possibilities

Our cinder might have begun its existence as a loose aggregate of rocks inside the equivalent of a Kuiper Belt Object (KBO) around a massive star massing some 25 Sols. The star expansion during the carbon-neon burning stage would have stripped our KBO and left the core exposed. Then, in the last week of its life the star would have burned silicon, increasing its temperature to two billion Kelvin and irradiating the KBO with an enormous neutrino flux, pushing it outwards a little in its orbit and initiating all kinds of weird nuclear reactions. In the final explosion (core temperatures in excess of 100 billion K), the neutron and neutrino flux and the inflow of exotic materials could have allowed a runaway nucleosinthesys process to reach the fabled 'island of stability' creating a long-lived heavy transuranic (henceforth unobtainium), imbued with all sorts of useful properties. The synthesis of such a substance, while possible, would be ruinously expensive.

The particular radioactive spectrum of the cinder, revealing it to be a close witness of a supernova explosion, would then explain why someone went to the trouble of dropping an unrecoverable mining base on an almost-inaccessible planet.

If you have some kind of stellar drive involved in the plot, you could have it depend on unobtainium quantum flux capacitors. At that point, whoever owns Cinder and its (relatively) cheap unobtaiunium would automatically own galactic transportation and economy.

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  • $\begingroup$ There are theories that Jupiter's core is one large diamond. If the overlying gases were stripped away, the core might be worth mining for 100 pound diamonds, or diamonds with extremely useful properties. Sort of like dilithium. $\endgroup$ – Howard Miller Apr 21 '16 at 15:09
  • $\begingroup$ @HowardMiller By the time we are able to mine Jupiter's core, we can just as easily manufacture diamonds from the nano-scale up, á la Diamond Age. $\endgroup$ – Chloe Apr 21 '16 at 17:15
  • $\begingroup$ @Iserni In the scenario you describe, is the star/remnant a neutron star? Would an Electroweak star make sense? $\endgroup$ – St0necr0w Apr 21 '16 at 18:35
  • $\begingroup$ @Chloe Your argument applies to anything material. We won't be going to the stars for material goods. Spacetime makes certain things possible and all else impossible ... except maybe when spacetime is at the point of breaking down. $\endgroup$ – Howard Miller Apr 21 '16 at 21:15
  • $\begingroup$ @St0necr0w , the original supernova has been left behind. The planetoid now orbits a different sun, and any sun will do. The interesting things ought to have happened to the planetoid when its original primary collapsed into either a black hole or a neutron star, but they wouldn't be connected to that - rather, to the process of which the neutron star remnant is but one consequence. $\endgroup$ – LSerni Apr 21 '16 at 22:37
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Since radiation intensity falls off with the square of the distance, it's entirely possible that your story's spacecraft have heat/radiation management systems sufficient to deal with the star's radiation so long as they're at least a certain distance out, but not sufficient to deal with the influx at the planet's current orbit. Under those circumstances, building on AndyD273's answer, staying in the penumbra would be increasingly desirable as one approached the planet (and the star it was orbiting).

Eventually, per the premises of the question, the penumbra is no longer sufficient, and the approaching craft must stay within the umbra to avoid overheating - or, if you're feeling particularly dramatic, must get to the umbra before the heat buildup becomes lethal.

The base itself, meanwhile, may have access to nifty heat-management techniques unavailable to spacecraft (at least during its approach), such as "atmosphere" or "oceans". For all we know the planet itself might well be habitable, just a little close to its star for your spacecraft. Especially if your spacecraft were owned by stingy poor economical captains unwilling to pay for the considerable extra expense of cooling systems that are only really useful when approaching a certain handful of inhabited planets, anyway.

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  • $\begingroup$ @Stephn Voris Barring atmosphere and oceans (lets say they are in vacuum), what other ways to cool down would there be? $\endgroup$ – St0necr0w Apr 27 '16 at 19:05
  • $\begingroup$ @St0necr0w For the base, or the ship? The base's main advantage is that it doesn't have to move anything, so it can afford to be heavy - and, as a corollary, large. Insofar as I understand the current state/scientific understanding of physics, radiation is the only way to transfer heat across a vacuum; the other methods (conduction and convection) require contact. This still makes the base better at dissipating heat than your spacecraft - it just has to have more surface area to do the radiating; sort of the opposite of solar panels. $\endgroup$ – Stephen Voris Apr 27 '16 at 19:25
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The mining base is of questionable legality or must stay hidden for other reasons. The prevailing technology level in the system is sufficiently low that approaching in shadow is an effective means of keeping the powers that be from noticing.

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  • $\begingroup$ Welcome to the site, I think the question is intending that natural phenomena (heat or cold perhaps) make the scenario necessary rather than something like a hidden operation. Can you rework your answer to address that? $\endgroup$ – James Apr 21 '16 at 16:17

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