DAL59

Serious Scientific Answers to Absurd Hypothetical questions

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1 hour ago, ARS said:

No no no, this isn't about making something stealthed in space. It's about disguising an object to look like an orbital debris. Stealth is pretty much impossible in space, but a disguise COULD work, right? Making something invisible in space to avoid detection is not gonna work, but making something appear like stuff people won't take a second glance is still possible. The main question is, could we use a satellite with a passive sensor to monitor the surrounding area (no active usage at all) while it's disguised as a debris or defunct satellite?

Possibly, getting data from it undetected would be tricky though.  Apparently space data lasers work now so that could do the trick.

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3 hours ago, ARS said:

No no no, this isn't about making something stealthed in space. It's about disguising an object to look like an orbital debris. Stealth is pretty much impossible in space, but a disguise COULD work, right? Making something invisible in space to avoid detection is not gonna work, but making something appear like stuff people won't take a second glance is still possible. The main question is, could we use a satellite with a passive sensor to monitor the surrounding area (no active usage at all) while it's disguised as a debris or defunct satellite?

Disguises are precisely what is used when stealth is required in space today. Also chaff, active decoys, jamming etc.

I dont see any reason why you couldnt do what you suggest with some degree of success. Its not too far a stretch of the imagination to think that there might be some "communications satellites" up there right now that are in fact for something else.

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17 hours ago, Oiff said:

It would need to stay on the night side of the planet or the black silhouette would stand out to anything in a higher orbit or it could even end up between the Earth and the Sun and be picked up by any amateur with a solar telescope.

Staying in the Earth’s shadow would also help with the issue of solar heating.  Vantablack works by absorbing the vast majority of UV, visible and IR light that hits it, doing this in space would require you to be able to dissipate the heat produced by absorbing all those photons.  Heat is lost through radiation in space, if you cover your sat in a material that absorbs this you will have a problem.

I think a small patch would need to be exposed to radiate heat through, an exhaust if you will.  This could be directed to reduce likelihood of detection but would still prove to be a weak spot in the camouflage.

An alternative would be to store the heat chemically in batteries or fuel cells.  This would have the added bonus of providing a power supply (obviously the heat still needs to be dealt with if the power is used).

 

Vantablack reflects longer wavelengths so it would be susceptible to discovery by a search at these wavelengths. Since the Vantablack is on top of the RADAR absorbent material it will reflect the radio waves before they reach it.  This is probably the biggest weak point as there are already ground based RADAR installations that scour space for unknown targets.

 

 

Possibly the best camouflage would be to hide in plain sight, attach to a commercial satellite and it will be unlikely that anyone would give it a second glance.

Condense the heat with a focal point parabolic reflector at your enemies space craft or into space. You could use a heat pump to heat up into super heated water and then blast it into space.

You could place a big sign on your satellite saying 'out of order, please call again soon'
You could have the satellite tethered by several ropes, if a projectile approaches it starts spinning and then spreads out giving the projectile nothing to hit.
You could have a big red cape that is deployed and waves at the projectile while the satellite moves then as it passes the satellite will signal in morse code 'Ole'.
You could have the satellite suddenly start transmitting in russian or chinese as it was a case of mistaken identity.
You could make a cage of chain link fencing, as soon as a projectile is detect the satellites in the area scramble to get inside the nearest chain length cage while the music from Jaws is playing.
 

Finding really dumb ideas on how to protect your satellite is not easy.

 

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10 hours ago, ARS said:

No no no, this isn't about making something stealthed in space. It's about disguising an object to look like an orbital debris. Stealth is pretty much impossible in space, but a disguise COULD work, right? Making something invisible in space to avoid detection is not gonna work, but making something appear like stuff people won't take a second glance is still possible. The main question is, could we use a satellite with a passive sensor to monitor the surrounding area (no active usage at all) while it's disguised as a debris or defunct satellite?

No, this IS about stealth, because you’d still have to disguise the same thermal signature of an operational spacecraft as opposed to a dead chunk of metal.

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7 minutes ago, DDE said:

No, this IS about stealth, because you’d still have to disguise the same thermal signature of an operational spacecraft as opposed to a dead chunk of metal.

Space debris isn't always a dead chunk of metal., though. While satellites should be passivated, that doesn't always happen. Sometimes clubs try to reactivate them. Sometimes they contain an actual nuclear reactor, making a mess for anyone studying gamma rays in the vicinity. You're still disguising yourself as something wildly impractical, but it doesn't have to be completely inert. But yes, that's stealth, stealth isn't just fancy paint.

Now, exercise: disguise your projectiles as frozen droplets of coolant from a 30 year old spy satellite.

6 hours ago, PB666 said:

You could make a cage of chain link fencing, as soon as a projectile is detect the satellites in the area scramble to get inside the nearest chain length cage while the music from Jaws is playing.

There's no sound in space #helpful.

 

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5 hours ago, DDE said:

No, this IS about stealth, because you’d still have to disguise the same thermal signature of an operational spacecraft as opposed to a dead chunk of metal.

Why? Just register it as a civilian satellite and dont tell anyone. I wouldnt be surprised at all if this is done already.

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How long would it take for the oceans to freeze without the sun?

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7 hours ago, p1t1o said:

Why? Just register it as a civilian satellite and dont tell anyone. I wouldnt be surprised at all if this is done already.

That probably won't fly, pun intended. NORAD and RuVKS both have military units that independently verify the purpose of every object in orbit. "Space control" we call it.

sredstva_sprn_16.jpg

http://www.npk-spp.ru/deyatelnost/adaptivnaya-optika.html

Edited by DDE

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33 minutes ago, DAL59 said:

How long would it take for the oceans to freeze without the sun?

What will the conveyor belt do ? Interactions with the atmosphere ? No convection, no clouds any more, just radiation into space. It gets cold fast on a clear winter night. Faster over land and ice than open water. Surface temperature will drop pretty fast (months) to polar (-60°C) temperatures. Insulation of ice build-up will keep warmth inside and deep in the water bodies while surface freezes over quickly.

Pretty fast i guess, hundreds to max. a thousand years to build up a nice and shiny ice shield, longer to the deep sea floor. But that's just a guess without any math. What's your plan ? :cool:

 

But i can tell you that it takes a little more than a (1) thousand years for the Mediterranean to dry up when cut off from the Atlantic ocean. It took. Messinian salinity crisis. Salt anyone ?

Edited by Green Baron

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6 hours ago, DDE said:

That probably won't fly, pun intended. NORAD and RuVKS both have military units that independently verify the purpose of every object in orbit. "Space control" we call it.

Please, visually define the purpose of the object from my previous post.

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7 hours ago, DAL59 said:

How long would it take for the oceans to freeze without the sun?

According to wiki, the World Ocean mass is 1.4*1021 kg, average temperature 5°C.
Sea water melting point -2°C.

So, to freeze completely it has to cool by 7 K (heat capacity ~4 kJ/(kg*K)) and additionally release the heat of fusion (~334 kJ/kg).

Total heat energy ~= 1.4*1021 * (4000 * 7 + 334) = 4*1025 J.

Ocean luminosity ~= 4 * pi * 5.67*10-8 * (6.4*106)2 * 0.71 * 2754 ~= 1.2*1017 W.

Total time to completely freeze down to the bottom ~= 4*1025 / (1.2*1017 * 86400 * 365.2422) ~= 10.6 years.

***

Average depth = 3700 m.
Time to get a 1 m thick ice layer ~= 10.6 *365.2422 * 1 / 3700 = 1 day.

Edited by kerbiloid

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1 hour ago, kerbiloid said:

Total time to completely freeze down to the bottom ~= 4*1025 / (1.2*1017 * 86400 * 365.2422) ~= 10.6 years.

Which calculation fails to take into account the insulating effect of ice and leakage of heat from the Earth's core.

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53 minutes ago, DerekL1963 said:

Which calculation fails to take into account the insulating effect of ice and leakage of heat from the Earth's core.

Numbers, please.

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There is a heat transport through the upper crust as well as a layering and transport of heat differences and salinity. This will all stop, but how fast ? Ocean surface temp is much higher than 7° and once it drops below the natural gradients it will receive new warmth from below, only the internal factors count then.

I stay with the hundreds of years, without proof. But this thread is titled "absurd" anyway :-)

1 hour ago, kerbiloid said:

Numbers, please.

What to search: heat conductivity of earths crust, internal heat budget, and that of ice, the inertial mass and forces that propel the conveyor belt, salinity and density and its layering, atmospheric infrared permeability .... more ? :-)

Edited by Green Baron

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13 minutes ago, Green Baron said:

There is a heat transport through the upper crust as well as a layering and transport of heat differences and salinity. This will all stop, but how fast ? Ocean surface temp is much higher than 7° and once it drops below the natural gradients it will receive new warmth from below, only the internal factors count then.

The Earth heat balance mostly consists of the solar light income and infrared loss. The internal heat sources are, iirc, somewhat about 15% of total heat production (don't refer to this, it's just from memory).
Even if the Sun disappears, the Earth will keep radiating IR with the same luminosity, until it gets so cold that a liquid ocean could not exist at all.

Don't forget that the most part of the Earth is heated by Sun 365 days/year, and even in polar night the warm water and air flows still constantly come from equator.

So, I stay for:
* a fortnight to be fully covered by ice (just as a specific time of atmo-/hydro- flows)
* decades to freeze almost to the very bottom

Of course, the last hundred meters right above the oceanic bottom can stay liquid very-very long due to the volcanoes, etc. But this doesn't change the whole picture.

Edited by kerbiloid

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11 hours ago, DDE said:

That probably won't fly, pun intended. NORAD and RuVKS both have military units that independently verify the purpose of every object in orbit. "Space control" we call it.

sredstva_sprn_16.jpg

http://www.npk-spp.ru/deyatelnost/adaptivnaya-optika.html

Cool! But those wouldnt exist if someone didnt think it was worth checking out those identities... :wink:

If I wanted to put a surreptitious sensor in space, I'd put it on an actually functioning comsat and call it a "science experiment" or some jazz.

 

5 hours ago, kerbiloid said:

Please, visually define the purpose of the object from my previous post.

Err, well to be fair, yeah it looks like a kill vehicle, look at all those divert thrusters and that is definitely a warhead. But I do think it would at least be a challenge to spot that from the ground.

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7 hours ago, p1t1o said:

it looks like a kill vehicle, look at all those divert thrusters

Um?..

Killa.

Spoiler

poletdh2.jpg

Non-killa.

Spoiler

334px-Molniya_closeup.jpg

Does the peaceful commsat Molniya-1 look dangerous, too?

7 hours ago, p1t1o said:

and that is definitely a warhead

And if attach several solar panels around?

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1 hour ago, kerbiloid said:

Um?..

Killa.

  Reveal hidden contents

poletdh2.jpg

Non-killa.

  Hide contents

334px-Molniya_closeup.jpg

Does the peaceful commsat Molniya-1 look dangerous, too?

And if attach several solar panels around?

3 major things - size, lateral thrusters, solar panels.

Solar panels dont make any sense for a kill vehicle.

Molniya-1 is significantly larger and Im not seeing any lateral thrusters, or at least they are not very large, making it far less likely to have much in the way of high-divert capability.

You couldnt say that one was *definitely* this or that, but the smaller one looks nothing like a comsat and Molniyas does.

Its a bit moot though as the IS-A kill vehicle would maneuver directly towards its target, it would not loiter in orbit for a long time - it couldnt, without a long term power supply - so nobody is going to be staring at it with a telescope trying to figure out what it is.

Put one inside a Moniya though...

***

Better question, if you were not so familiar with the Hubble telescope, and were searching the sky for weapons...which one of these would stand out?

15460223454_86f0ac9b1e_b.jpg

2013-12-22-zenith-star-3-a1.jpg

 

 

 

 

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Would quantum communication (if it could be made to work) be detectable from a satellite in orbit?  My limited understanding is that the communication would be unreadable to an outside party but I am unsure if there are (or might be) methods of detection.

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13 minutes ago, James Kerman said:

Would quantum communication (if it could be made to work) be detectable from a satellite in orbit?  My limited understanding is that the communication would be unreadable to an outside party but I am unsure if there are (or might be) methods of detection.

Quantum communication still requires old-fashioned signals being sent back and forth via photons or smoke signals or whatever else. The trick is that the data itself is encrypted by quantum entanglement so only the intended recipient has the "key" to unlock the data.

On an unrelated note:

If the continents had moved from the original position (Rodinia supercontinent) to their intermediate position (Pangaea) and then to their current position in the span of a single year (as proposed by certain young-earth creationists), the heat release would be enough to boil the oceans and leave behind bare basins.

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Could a sufficiently powerful magnet attract the iron in your blood?  

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2 minutes ago, DAL59 said:

Could a sufficiently powerful magnet attract the iron in your blood?  

I don't believe so. The iron in your blood is bonded to oxygen; it is, essentially, rust. Rust is not ferromagnetic.

Even the un-rusted iron in the hemoglobin in your veins is, I believe, still bound to something and so the ferromagnetic metal-metal bond structure isn't there. 

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40 minutes ago, p1t1o said:

Molniya-1 is significantly larger

Absolutely the same. 1400 vs 1600 kg.

45 minutes ago, p1t1o said:

Solar panels dont make any sense for a kill vehicle.

They weight nearly nothing and can be jettisoned.

45 minutes ago, p1t1o said:

Molniya-1 is significantly larger and Im not seeing any lateral thrusters, or at least they are not very large, making it far less likely to have much in the way of high-divert capability.

Polyot vs Molniya's KDU-414.
Ok, let's add fake thrusters. Can you then see a difference?

Spoiler

polyot1.jpgRussian_thruster2.jpg

 

47 minutes ago, p1t1o said:

Put one inside a Moniya though

They are nearly of the same size.

50 minutes ago, p1t1o said:

if you were not so familiar with the Hubble telescope, and were searching the sky for weapons...which one of these would stand out?

(Though iirc the Hubble is in fact KH-10 or so.)
The upper one has the handrails and long side antennas. I would presume, it can be visited and probably is used for some measurements and/or for docking.
The second one has regular radial panels around the narrow side, looking as radiators. I would presume that a laser needs the radiators more than a telescope does.

12 minutes ago, DAL59 said:

Could a sufficiently powerful magnet attract the iron in your blood?  

As far as I have read, magnetic field 400 kOe would slow the blood flow twice, and 2 MOe would stop it completely.
Though not because of iron, but because of ions.

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