Design a research probe to enter the sun.

[Astro Pen]

A design challenge, which may be impossible but let's have a go as a team challenge
How could you construct a probe to enter the surface of the sun? To either simply scoop and exit (easier) or to be able to transmit data out to a receiver (much harder).
(Also we can, more realistically, try to probe the surface of the somewhat cooler Betelgeuse)
A couple of thermal facts.

Surface temperatures:
The sun 5772 k
Betelgeuse 3500k

Melting points
Diamond 4700k
Tantalum hafnium carbide 4100k

Obviously we will have to do a bit of 'outside the box' thinking but as sf writers we have have certainly had some practice at that.

 

[BAYLOR]

Tough indeed . . Perhaps some kind of electro magnetic shield force bubble that could deflect the heat off of the probe?

 

[BAYLOR]

Betelgeuse is unstable and could go nova at any time so, there is the issue of turbulences within that star which the craft would have to be able to withstand and navigate. This also bring up the problem of maintaining communication with the probe . Inside of the star ,would that even be possible? Info , how would you direct and control the probe?

 

[BAYLOR]

A break though in communication would probably be required? Perhaps a Neutrino transmitter ?

 

[Wayne Mack]

Considering that heat is the vibration of atoms, then perhaps the probe could be built of extremely dense material and thus return this vibration. Perhaps a material only slightly less densely packed than a black hole? Given such a material, it would be then possible to build a bucket and chain to scoop solar material. Telemetry would be more of a challenge, because, if the dense material has minimal reaction with the internals of the sun, then it would pose a challenge in building sensors.

I'll leave to those with a better understanding of physics debate and probably shoot down this idea.

 

[Dave]

Can't you just send it at night?

 

[hitmouse]

Can't you just send it at night?

Yeah. Or head for the polar icecaps.

 

[AllanR]

To either simply scoop and exit (easier) or to be able to transmit data out to a receiver (much harder).

My take is that it would be the opposite. The gravity well of the sun would require too much energy to escape and would pull the probe in so fast that it would 'land' at an rather fast velocity. The 'surface' (photosphere) gravity is 28x earth. Maybe some parachute to use the solar wind for breaking? and a sail to launch off?

What I would expect rather would be a controlled crash landing that has some measurement devices and a transmitter. Or in absense of a transmitter, a crash designed to yield specific information that is observed from distant vantages .

 

[StilLearning]

If we're ok with it being a one-way probe then we could just layer it in something designed to ablate away as it heats, taking the heat with it as it does so. I don't know how long it could be made to last, but some amount of speed might be a plus, especially if the heat from friction with solar plasma is the same kind of magnitude as the heat received from the solar irradiance. And the probe will have speed a plenty, having fallen through most of the solar gravity well.

If we can get the speed down then, at least until you enter the photosphere, you'd basically need a shield that is a really good mirror surrounding the probe in a sort of cone, pointy end down. It's worth looking at the breakthrough starshot project and other laser-sail ideas, as these would also need materials (for the sails) that reflected damn near 100% of the radiation that fell on them, as they would subjected to a laser beam more intense than an industrial cutting laser, and would need to kast at least tens of minutes in that environment.

As for data transmission... There are wavelengths at which the Sun is relatively dark, and energy is not an issue in that environment, so perhaps a transmission could be sent back out, at least as long as it was transmitted before the solar plasma surrounding the probe became opaque. Or you could have a courier probe, shielded in the same way, that launched from the main probe and had enough in it's engines to at least clear the limb of the Sun enough for a signal it sent to be discerned, before it fell back, so it could rely the data the main probe had collected.

 

[Astro Pen]

Good point about the dark frequencies @StilLearning . We can certainly use that.

 

[StilLearning]

Happy to be of any help [Edit]: Just off the top of my head the Sun is pretty dim in shorter wavelength x-rays, and almost 'black' in gamma ray wavelengths [end edit].

I found an article that mentions some details of the materials science proposed for interstellar laser driven light-sails, which would need to survive temperatures getting on for the range we're talking about: Innovative Reflective Materials to Accelerate Space Probes Light Years Away

 

[Venusian Broon]

Sorry, this temperature given for survival for any sort of probe (~6000K) to get close is not correct. The temperature routinely stated for the 'surface' of the sun is the blackbody temperature, i.e. a theoretical number that describes the photon distribution of the sun's light as blackbody radiation when the mass density of the sun becomes diffuse enough for it to become transparent to light.

However to get to this level you would have to cross the corona which can have temperatures in the range 1-3 million Kelvin, although I believe temperatures up as high as 20 million Kelvin have been recorded, as well as deeper 'atmospheric' levels that are much denser that the corona and up to 1 million K, just above the photosphere surface level. You have to build a probe that can survive that first.

But the issue is how to build something that can survive the plasma at these temperatures, even the relatively cool 6,000K, as getting closer to the sun will see any object getting evaporated by being bombarded by bits of broken atoms that make up the plasma. I'd suggest a massive and very heavy shield to give you enough time before completely evaporating to actually do something. Hence ruling out small probes. (But not too big either, as a very big object will shatter in the sun's gravitational gradient - in the same way that the Sun chews up and destroys comets that come too close...)

Plus given the fundamental EM nature of plasma, it's hard to see anything electrical, especially our modern computers, surviving at close distances in relatively dense plasma clouds near the sun, without science fiction levels of unobtanium shielding. One might say 'use magnetic fields' as a start, however I think it likely that all you'll end up doing is piling up a much denser wad of plasma in front of you, that will eventually overwhelm you very quickly and cause you to evaporate your probe even faster!

However, we don't need to send probes that close to the sun to get a sample. Luckily the Sun spews it's plasma all the time, giving us Coronal Mass Ejections and Solar Winds, and we have been measuring what sort of particles and radiation come from them using experiments such as WIND for decades now.

Yes, this has not stopped me doing some very "high-tech, high-unobtanium malarkey" in my novel regarding 'sun-diving' because I want to use all this built-up plasma mass of the star for something else... but it's SF, not science. To paraphrase the marvellous Ursula K. Le Guin, in her own introduction to The Left Hand of Darkness, which I recommend all SF writers read: "science is the business of scientists, it is not the business of (SF) novelists. A novelist's business is lying."

 

[StilLearning]

Sorry, this temperature given for survival for any sort of probe (~6000K) to get close is not correct.... ... A novelist's business is lying."

The electrical hazard (and that this is all fiction, so go ahead and apply that handwaveology and unobtanium!) of flying through such a plasma environment is well pointed out. But I'm gonna point outbthat the solar corona has only 0.000000000001 the density of the photosphere so, although it is indeed at over a million degrees K (about 200 - 300 times hotter than the photosphere) it contains far less energy per cubic metre, and so will contribute far, far less heat. Hence why the photosphere is blindingly bright, and the corona only visible under special circumstances (pardon my nerdiness).

 

[Venusian Broon]

The electrical hazard (and that this is all fiction, so go ahead and apply that handwaveology and unobtanium!) of flying through such a plasma environment is well pointed out. But I'm gonna point outbthat the solar corona has only 0.000000000001 the density of the photosphere so, although it is indeed at over a million degrees K (about 200 - 300 times hotter than the photosphere) it contains far less energy per cubic metre, and so will contribute far, far less heat. Hence why the photosphere is blindingly bright, and the corona only visible under special circumstances (pardon my nerdiness).

Just really pointing out that the 6K figure is not what you should be designing your probe for and is largely meaningless - yes the corona is thin, but the transitory atmosphere between that and photosphere thickens up considerably and remains very hot.

The other thing to remember is the intensity of the radiation. (Just the radiation, I ain't talking about the plasma matter.) Off the top of my head a square metre of material facing the sun at the orbit of the Earth, if it absorbs everything recieves approx 1300 Watts. Needless to say translating to an orbit a couple of hundreds of km above the photosphere would mean a power transfer of about 10 to the 18 watts every square metre. (I'm doing the sums in my head inbetween exercises at the gym, so that is likely to be wrong! But that sort of order of magnitude feels rightish.)

If mirrors aren't perfect in all relevant wavelengths and then your ability to remove excess heat from your craft is not quite literally astronomic, one can see how quickly excess heat will render one's probe a plasma of heavy elements re: the specifications of original probe's mission

 

[StilLearning]

Just really pointing out that the 6K figure is not what you should be designing your probe for and is largely meaningless - yes the corona is thin, but the transitory atmosphere between that and photosphere thickens up considerably and remains very hot.

They could probably use that, writing-wise - the transitional layer between corona and photosphere (EDIT: the chromosphere, seE below END EDIT) is, IIRC, pretty poorly understood (it's dimmer than the photosphere and just a hair's breadth, astronomically speaking, from it so very hard to examine well). As well as being a worthy target of such a probe, in it's own right, that sounds like a good spot to apply some handwaveology - just as an example: Perhaps the transition layer has properties or features that allow a view or sensor reading of the deeper interior (something like pores or windows that tunnel deeper into the Sun) or material from much deeper in than could otherwise be reached to flow out.

EDIT: Ahem, as i should have remembered, the 'transitional layer' is called the chromosphere - it's also home to a host of poorly understood phenomena with names like fibrils, chromosphere loops, the chromospheric network, plages and so on. The wiki article has plenty of links at the bottom ( Chromosphere - Wikipedia) but basically I would suggest the probe might attempt to do a fast skim of the top of the chromosphere, about 5000 km off the solar photosphere (which feat will still need all the reflective and ablative shielding engineering can muster to be survivable), and access a made-up phenomena there that allows material or sensor reading from much deeper in to be made - if that's in line with plot needs. And, yes, I am starting to construct my onw sun-diving adventure mission in my head here, so I'll take a step back and let @Astro Pen work on their project END EDIT

It depends on what the plot needs, but it sounds like the mysterious transition layer could make a good 'solar mcguffin' to solve any problems that @Astro Pen has a bit more surmountable? I don't know exactly what their plot needs are, but it sounds like an opportunity...

 

[Cthulhu.Science]

I'll make my probe out of pure plasma.

But I can't help you with the technical requirements. That is the Engineers' job.

 

[AllanR]

There is a fun short story called The Weather Man by Theodore L Thomas. (not sure where it was first published, Its in an anthology and the attribute only says permission by author)
Humans operate vehicles within the sun in order to alter its specific outputs as to alter the weather on earth. A massive and power Weather Bureau becomes the defacto world government.

 

[Wayne Mack]

Ignoring the radiation aspect for the moment, perhaps a series of explosions could push the sun's plasma out of the way and allow the probe to tunnel below the surface of the sun. With a shallow enough flight path (and an absurd amount of explosives), the probe might be able to return out of the sun.

 

[mosaix]

There is a fun short story called The Weather Man by Theodore L Thomas. (not sure where it was first published, Its in an anthology and the attribute only says permission by author)
Humans operate vehicles within the sun in order to alter its specific outputs as to alter the weather on earth. A massive and power Weather Bureau becomes the defacto world government.

I seem to remember it was first published in Analog, @AllanR. Not sure of the date though.

 

[THX1138]

We need to also think about the electromagnetic fields too. That alone could destroy any electronic equipment used and could even alter the probes path as well as the path of any transmission outside of the fore mentioned Neutrino transmitter possibly.

Perhaps a smart material can be made that repels the EM fields could be the outer covering of the probe?

Plus, the moment the probe passes through the surface, it would reach the point of no return due to the gravitational pull on it. If it went down 1km, a photon of light at the same depth would break the surface long before the probe. And the energy needed for the probe to do so at that depth would be enormous I would think. The amount of light that is emitted from the Sun is just a small percent of the actual amount of light trapped below its surface. Gives an idea of the strength of the gravity and electromagnetic forces at play at 1km down given that the light that is reaching us today was generated in the Suns core about 2000 years ago.

Perhaps an anti-gravity repulsion drive could be used?