Hiding inside a star

[Darth Hoth]

Much soft sci-fi will not give hard numbers, therefore other means of scaling powers are required. One thing that I have run across in several series is ships hiding inside stars; if I recall correctly, a Culture ship did it once, the Rebels did in an old Marvel SW comic, and I am sure that there are several other examples.

What I was wondering was, can such incidents be used to calculate shielding power/dissipation for ships? Assuming that a star has known properties for its type, is there any easy way of converting the forces affecting a ship in the star's core (pressure should be the most important, at first glance) into energy measurable in watts on a given surface area?

[Samuel]

What I was wondering was, can such incidents be used to calculate shielding power/dissipation for ships?

I don't see how this can be used for dissipation. There is nowhere to dump all the excess energy.

[Imperial Overlord]

There's a couple stories with ships hanging out in the corona or photosphere and having radiating mechanisms that allow them to dump heat outside of the star.

[Junghalli]

I suppose one could try taking the intensity of sunlight at Earth (around 1300 watts/m^2) and using it to figure out what the intensity of sunlight would be very close to the core of the star (intensity will increase 4X each time you half the distance). It's undoubtedly an overly simplistic analyses but it might give you something to go on.

As I remember from one of the stories in Stephen Baxter's Vacuum Diagrams the outer layers of a supergiant star might actually be relatively "cool", so being able to hide inside of one might not actually require hugely impressive technology.

I don't see how this can be used for dissipation. There is nowhere to dump all the excess energy.

There is whatever magic allows approximately 99.999% of all soft sci fi ships to fly around without huge radiators. I don't know how they get rid of their waste heat, but it seems to involve horrible Lovecraftian violations of physics somewhere.

Well, I guess their engines and weapons could also just be ridiculously efficient.

[Starglider]

I don't see how this can be used for dissipation. There is nowhere to dump all the excess energy.

Actually there is. In SW, ships have magic 'neutrino radiators' (it would not surprise me if Culture ships could do something equivalent involving infraspace/ultraspace). Even in hard sci-fi, lasers can actually be used to dump energy faster than it is generated, cooling the ship in the process (as used in David Brin's 'Sundiver').

[Atlan]

It's a tactic sometimes used in the Perry Rhodan series of novellas. However their shields act as hyperspace shunts, simply making the energy go somewhere else, rather than actually deflecting it.

[Luzifer's right hand]

It's a tactic sometimes used in the Perry Rhodan series of novellas. However their shields act as hyperspace shunts, simply making the energy go somewhere else, rather than actually deflecting it.

It was used before the hyperspace shunting shields were introduced.
Pretty much a standard tactic as the hyperspace-energy emissions of stars can overshadow those of ships.

[FaxModem1]

Spoilers for War Planets/Shadow Raiders
Spoiler

The Beast planet was hiding from the allied fleet until the season 1 finale where it emerged from the sun and then decided to do some proper eating of the planets.

[Nyrath]

Even in hard sci-fi, lasers can actually be used to dump energy faster than it is generated, cooling the ship in the process (as used in David Brin's 'Sundiver').

Well, actually, everybody has been yelling at Brin for violating the second law of thermodynamics.
http://groups.google.com/group/rec.arts ... 710bfee99f
http://groups.google.com/group/rec.arts ... 67351631d1

[Starglider]

Would this actually work? It seems like it would run into the second law of thermodynamics.

No, it doesn't. Imagine a refrigerated trailer (for a semi-truck). It maintains a temperature much lower than ambient. Now imagine powering that trailer from a fuel cell located inside the refrigerated compartment. The fuel cell produces some waste heat, but the temperature will only rise slightly, because the heat transfer capability of the heat pump (the refrigeration system) is considerably higher than its own power consumption. Energy is being expended to maintain a temperature gradient, just like energy is being expended to maintain a concentration gradient across your cell membranes. The total order of the system is still decreasing, because the fuel is being consumed to maintain the static temperature gradient. AFAIK real world laser cooling systems are nowhere near that efficient, in fact they consume orders of magnitude more power than their heat transfer capability, but they are possible in principle.

[Connor MacLeod]

It seems like alot of the time the idea of cooling or refridgeration, the problem is due to confusion of terminology (for example I think they think of heat simply as energy, which isn't neccesarily the case.

[Shroom Man 777]

I don't understand this tactic. If you hide in a star, with the logic that they can't see you in the star, then you can't see them out of the star either. What if the bad guys just wait for you to come out, and when you do, they end up popping your sun-blinded sunburt ass dead?

[Lord of the Abyss]

I don't understand this tactic. If you hide in a star, with the logic that they can't see you in the star, then you can't see them out of the star either. What if the bad guys just wait for you to come out, and when you do, they end up popping your sun-blinded sunburt ass dead?

They may not be sure you are there and leave. Or you may need the time to make repairs. Or you may be expecting reinforcements to show up. Or like in Sundiver, the point may be to go investigate what's inside the star in question.

[GrandMasterTerwynn]

I don't understand this tactic. If you hide in a star, with the logic that they can't see you in the star, then you can't see them out of the star either. What if the bad guys just wait for you to come out, and when you do, they end up popping your sun-blinded sunburt ass dead?

As long as you're not talking about a white dwarf, neutron star, or red dwarf, a star is a huge place. A garden-variety yellow dwarf like Sol is 1.39 million kilometers across. A red giant like Arcturus is 40 million kilometers across. A red supergiant like Antares is 600 million kilometers across. If you've got the fuel to overcome the drag induced by the hot gas in the star's photosphere (the Sun's photosphere has a density of 1% that of the atmosphere at sea-level on Earth,) you can travel quite a distance while using all that hot glowing gas to cover your movements.

[Starglider]

I don't understand this tactic. If you hide in a star, with the logic that they can't see you in the star, then you can't see them out of the star either.

True for EM sensors, but not necessarily for all sensors. For example Trek-style A/M power plants throw out a lot of neutrinos; stars also emit a lot of neutrinos, but only from the core, not the outer layers. If the ships are equipped with sensitive neutrino detectors the one hiding in the star's photosphere would be able to track operating A/M reactors and drives just fine (across the hemisphere not washed out by the star)*, but other ships in the system would not be able to detect the hiding ship's emissions amidst the solar neutrino glare. Gravitic and exotic (subspace, hyperspace etc) sensors may experience similar effects, depending on the technology.

* Building a neutrino detector with the required sensitivity and directionality is left as an exercise for the reader.

[18-Till-I-Die]

I recall this was used in...one of the Hyperion books, been like a lifetime since i read it so i can't recall which.

But they did use some hella big radiators, so yeah. If memory serves they were like a million miles long and trailing out of the ship, and i think it worked too. I have to re-read that series some day.

Hyperion had some crazy shit in it man...

[Ford Prefect]

That actually happens in Endymion or Rise of Endymion, during a Pax exercise. It's noted to be against regulations for a simulated battle, and they did use extremely long filaments to act as radiators; the implication is that sundiving is actually taught in the academy.

[18-Till-I-Die]

Yeah I knew it was one of the books in that series, I couldn't remember which. It's been so long, I could have sworn it was done to hide in an actual battle, but yeah that's what I meant.

Filaments. I couldn't think of that word for anything, thanks dude.

They prolly do teach it in that universe, that's the one with the Pax battleships that can snipe at people millions of miles away with jump-capable drones and mind-scrabling "Death Beams", and interstellar nomads live in giant trees in space. The whole series is based on Rule of Cool, tactical use or practicality doesn't factor into the equation. It's like WH40K if they were less GRIMDARK.

[Memnon]

I recall this was used in...one of the Hyperion books, been like a lifetime since i read it so i can't recall which.

But they did use some hella big radiators, so yeah. If memory serves they were like a million miles long and trailing out of the ship, and i think it worked too. I have to re-read that series some day.

Hyperion had some crazy shit in it man... :P

Interesting...
The material in the radiators must be some crazy stuff, if the radiators are actually long enough to be trailing - has to withstand both structural forces and the intense heat. The heat has to travel pretty fast too - such a heatsink would probably have a relatively small surface to dissipate heat from.

[rhoenix]

Here's a random layman's question concerning the heatsinks necessary to do this - would it be possible to simply shunt the most of the heat into a small fusion chamber?

[TheLostVikings]

Here's a random layman's question concerning the heatsinks necessary to do this - would it be possible to simply shunt the most of the heat into a small fusion chamber?

The "fusion chamber" that you speak of would generate more heat that you would have to get rid of, not less.

[Samuel]

Here's a random layman's question concerning the heatsinks necessary to do this - would it be possible to simply shunt the most of the heat into a small fusion chamber?

Only by generating waste heat in the process.

[Starglider]

Here's a random layman's question concerning the heatsinks necessary to do this - would it be possible to simply shunt the most of the heat into a small fusion chamber?

It is theoretically possible to use a hot plasma as a heat sink, if that's what you mean. That would be hopelessly inefficient with any remotely realistic technology, since it radiates very strongly and magnetic confinement technology can only cope with very low pressure plasmas. If you could contain plasma at stellar core temperatures and pressures in some kind of perfectly reflective force-field-thermos-bottle, and come up with a magic heat pump system that can cope with the incredible temperature gradient, then sure. Even given this magic pump and containment technology, there would be absolutely no point having the plasma fuse, as that would just make it heat up on its own and waste heatsink capacity.

[rhoenix]

It is theoretically possible to use a hot plasma as a heat sink, if that's what you mean. That would be hopelessly inefficient with any remotely realistic technology, since it radiates very strongly and magnetic confinement technology can only cope with very low pressure plasmas. If you could contain plasma at stellar core temperatures and pressures in some kind of perfectly reflective force-field-thermos-bottle, and come up with a magic heat pump system that can cope with the incredible temperature gradient, then sure. Even given this magic pump and containment technology, there would be absolutely no point having the plasma fuse, as that would just make it heat up on its own and waste heatsink capacity.

An excellent explanation - thank you. So, what would be the requirements for any heatsink system to hang out near or within the surface of a star, and what would be some possible ways of accomplishing those requirements?

[Teleros]

The three main requirements are capacity, efficiency and of course how quickly you can dump unwanted heat into your heatsink. That's why David Brin used a laser - having the rest of the universe act as a heatsink means you have for all intents and purposes unlimited capacity.

Problems
- I'm not sure how important the position of your starship is though - as I recall, the deeper into a star you go, the longer it'll take for any one photon to escape (due to the increased chance of collisions), which will affect how well your laser works. That energy will also heat up the environment you're in as well, but to what extent I don't know - I don't know anywhere near enough about the physics involved. Position will also mean various other problems, even if you're using an internal heatsink (eg pressure).
- You're going to need ridiculously efficient machinery to minimise the waste heat produced, whatever type of heatsink you use. Obviously the less hard sci-fi the setting is the easier this becomes, but bear in mind the knock-on effects too.
- There will always be some waste heat, so you can't expect to stay in there forever: even if the machinery can survive inside a star for years, if your ship's reaches boiling point in just a month then you're in trouble.
- As Starglider pointed out, dumping the excess heat into hot plasma can lead to fusion, which in most lighter elements creates more energy. Fusing heavier elements results in a net energy loss, but I've no idea how practical this is, or what the limit is even if you can.