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As to 1: It would take years for the light to get there, it would also take several MORE years for the ship to actually get there. The important take away is di

As to 1: It would take years for the light to get there, it would also take several MORE years for the ship to actually get there. The important take away is distance can't be used to hide, there is no "Oh they won't notice us we're still outside the orbit of Pluto."

talmand 15y ago
How can that be? Space is big, we cannot even properly comprehend how big it is. I'm talking just in our immediate vicinity. If I took, say, three of the world's largest ships, put them together to form one ship and then placed it in a random spot somewhere within the orbit of Pluto; how long would it take you to find it? Keep in mind I'm not talking within the orbital plane, I'm saying within the sphere of the solar system. Unless someone is watching 100% of the sky for even the slightest miniscule changes, I imagine you could get mighty close (granted, close is Pluto) without being detected. Isn't most of the information we have about newly discovered far away objects is how they interacted with other known far away objects? But, of course, there's the given that if we've advanced far enough to engage in space combat then we've likely created technology to help in detection.
- sp332 15y ago
  Well yes, there are quite a few telescopes that constantly scan the sky for tiny changes. And it's not just the size of the ship, but the burning fuel from its engines as it navigates near our solar system.
  - talmand 15y ago
    Good replies, but I'll combine my thoughts here. Ships CAN be bright, we have the tech now to make them dark. True, burning fuel is a big problem. Especially if they were traveling rather fast towards us and they flipped over to reverse thrust to slow down. But what if you don't burn fuel as a means of propulsion? I'm going with the assumption if that if someone wished to do something bad, say invading a neighboring solar system, they would take precautions in being detected.
    - Locke1689 15y ago
      The point was never that the ships themselves can be bright, it was that the radiation is easily visible. The article was also operating within the realm of theoretically available technology. There are very few propulsion systems that don't emit hot matter out the back (like solar sails) and the article addressed them suitably.
- Avshalom 15y ago
  It's two things basically: -You can do a full survey in about 5 hours with one telescope these days. -Ships are very bright, don't look anything like stars and CCDs are very sensitive. http://www.projectrho.com/rocket/spacewardetect.php http://www.projectrho.com/rocket/spacewardetect.php has a good break down.
  - dalke 15y ago
    I've been trying to get a sense of how effective these scans are. Asteroid 2005 YU55 was discovered 28 December 2005. It's about 400m in width, which is the length of the biggest vessel we have. When it was discovered, it was 0.8AU from the Earth, and its orbit is inside that of Mars. This tells me that 6 years ago we did not know all of the +300m asteroids within the orbit of Mars. How much better are we now? I read the page you linked to, but that didn't list actual numbers based on asteroid searches. There's an estimated 4,000,000 asteroids in the solar system of size 300m or larger. I sincerely doubt that a telescope survey of 5 hours finds 1 million+ asteroids each night, otherwise that number would be pinned down a lot better. (It can't find all 4 million because at 5 hours there's still substantial portions of the sky unseen.)
    - cschneid 15y ago
      Asteroids don't pump out waste heat. Things get a lot more obvious when heat differentials are big.
      - dalke 15y ago
        I was commenting on Talmand's scenario; take "three of the world's largest ships, put them together to form one ship and then placed it in a random spot somewhere within the orbit of Pluto; how long would it take you to find it?" Using the formula in the "Refrigeration" section of the page linked to by Avshalom, the "maximum range a ship running silent with engines shut down" (assuming diameter = 500 m and temperature = 290K is about 500 million km, or about 3.3 AU. That's well within the orbital radius of Jupiter. That's assuming the entire asteroid is at 290K. Pluto averages about 40 AU out, given a 0.056% chance that a room-temperature asteroid would be detectable. I'm also uncertain about the reasoning in the page linked to by Avshalom. I think that assumes a 3K background, and I think you also think there's a big heat differential. However, the average temperature of the moon is something like -25C, and if an asteroid were closer to the sun, then the difference in surface temperature between an internally heated vs. sun heated asteroid is well within the errors in measuring the physical properties of the asteroid. You can even work it out for yourself, using the equation at http://en.wikipedia.org/wiki/Standard_asteroid_physical_characteristics#Temperature_measurements_and_regular_temperature_variations http://en.wikipedia.org/wiki/Standard_asteroid_physical_char... . I worked it out to: 166C at Mercury orbit: http://www.google.com/search?&q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(0.3+*+150000000+km)**2)))+**+(1%2F4) 90C at Venus orbit: http://www.google.com/search?q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(0.6+*+150000000+km)**2)))+**+(1%2F4) 5C at Earth orbit: http://www.google.com/search?q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(1.0+*+150000000+km)**2)))+**+(1%2F4) (The values for albedo and emissivity are not well known, so there is a wide error range in this calculation.) Still, that's enough to show that the heat differentials inside of the Earth's orbit are not that big.
j_baker 15y ago
Well, now we're getting into the theoretical issues. For instance, if we develop wormhole technology, the ship could very well be there before the enemy can see it. Otherwise, I just don't see interstellar space warfare as being that practical if it takes years to launch an attack.
- rbanffy 15y ago
  If I could create wormholes at will, I wouldn't traverse the wormhole with the whole ship - just the bombs would suffice.
  - _Y_ 15y ago
    Why waste bombs. If you can create wormholes at arbitrary locations just teleport piece of a star into a planet.
    - rbanffy 15y ago
      If I could position both ends arbitrarily, a better approach would be to connect the planetary core with a black hole.
  - Locke1689 15y ago
    If you can create wormholes at will, you don't need bombs. Put one end of the wormhole in the target and the other in the center of the sun.
    - scarmig 15y ago
      Any guesstimates on how large the wormhole would need to be for it to be a doomsday device? Two estimates, one for a wormhole on the surface of our sun, and the other for its core. I'll try to post my results sometime later. What about a neutron star? It's probably too exotic to consider how a wormhole would interact with a black hole.
      - dalke 15y ago

talmand 15y ago

How can that be? Space is big, we cannot even properly comprehend how big it is. I'm talking just in our immediate vicinity. If I took, say, three of the world's largest ships, put them together to form one ship and then placed it in a random spot somewhere within the orbit of Pluto; how long would it take you to find it? Keep in mind I'm not talking within the orbital plane, I'm saying within the sphere of the solar system. Unless someone is watching 100% of the sky for even the slightest miniscule changes, I imagine you could get mighty close (granted, close is Pluto) without being detected. Isn't most of the information we have about newly discovered far away objects is how they interacted with other known far away objects? But, of course, there's the given that if we've advanced far enough to engage in space combat then we've likely created technology to help in detection.

sp332 15y ago
Well yes, there are quite a few telescopes that constantly scan the sky for tiny changes. And it's not just the size of the ship, but the burning fuel from its engines as it navigates near our solar system.
- talmand 15y ago
  Good replies, but I'll combine my thoughts here. Ships CAN be bright, we have the tech now to make them dark. True, burning fuel is a big problem. Especially if they were traveling rather fast towards us and they flipped over to reverse thrust to slow down. But what if you don't burn fuel as a means of propulsion? I'm going with the assumption if that if someone wished to do something bad, say invading a neighboring solar system, they would take precautions in being detected.
  - Locke1689 15y ago
    The point was never that the ships themselves can be bright, it was that the radiation is easily visible. The article was also operating within the realm of theoretically available technology. There are very few propulsion systems that don't emit hot matter out the back (like solar sails) and the article addressed them suitably.
Avshalom 15y ago
It's two things basically: -You can do a full survey in about 5 hours with one telescope these days. -Ships are very bright, don't look anything like stars and CCDs are very sensitive. http://www.projectrho.com/rocket/spacewardetect.php http://www.projectrho.com/rocket/spacewardetect.php has a good break down.
- dalke 15y ago
  I've been trying to get a sense of how effective these scans are. Asteroid 2005 YU55 was discovered 28 December 2005. It's about 400m in width, which is the length of the biggest vessel we have. When it was discovered, it was 0.8AU from the Earth, and its orbit is inside that of Mars. This tells me that 6 years ago we did not know all of the +300m asteroids within the orbit of Mars. How much better are we now? I read the page you linked to, but that didn't list actual numbers based on asteroid searches. There's an estimated 4,000,000 asteroids in the solar system of size 300m or larger. I sincerely doubt that a telescope survey of 5 hours finds 1 million+ asteroids each night, otherwise that number would be pinned down a lot better. (It can't find all 4 million because at 5 hours there's still substantial portions of the sky unseen.)
  - cschneid 15y ago
    Asteroids don't pump out waste heat. Things get a lot more obvious when heat differentials are big.
    - dalke 15y ago
      I was commenting on Talmand's scenario; take "three of the world's largest ships, put them together to form one ship and then placed it in a random spot somewhere within the orbit of Pluto; how long would it take you to find it?" Using the formula in the "Refrigeration" section of the page linked to by Avshalom, the "maximum range a ship running silent with engines shut down" (assuming diameter = 500 m and temperature = 290K is about 500 million km, or about 3.3 AU. That's well within the orbital radius of Jupiter. That's assuming the entire asteroid is at 290K. Pluto averages about 40 AU out, given a 0.056% chance that a room-temperature asteroid would be detectable. I'm also uncertain about the reasoning in the page linked to by Avshalom. I think that assumes a 3K background, and I think you also think there's a big heat differential. However, the average temperature of the moon is something like -25C, and if an asteroid were closer to the sun, then the difference in surface temperature between an internally heated vs. sun heated asteroid is well within the errors in measuring the physical properties of the asteroid. You can even work it out for yourself, using the equation at http://en.wikipedia.org/wiki/Standard_asteroid_physical_characteristics#Temperature_measurements_and_regular_temperature_variations http://en.wikipedia.org/wiki/Standard_asteroid_physical_char... . I worked it out to: 166C at Mercury orbit: http://www.google.com/search?&q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(0.3+*+150000000+km)**2)))+**+(1%2F4) 90C at Venus orbit: http://www.google.com/search?q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(0.6+*+150000000+km)**2)))+**+(1%2F4) 5C at Earth orbit: http://www.google.com/search?q=(((1-0.1)+*+(3.827E26+watts)+%2F+(0.9+*+Stefan-Boltzmann+constant+*+16+*+pi+*+(1.0+*+150000000+km)**2)))+**+(1%2F4) (The values for albedo and emissivity are not well known, so there is a wide error range in this calculation.) Still, that's enough to show that the heat differentials inside of the Earth's orbit are not that big.

j_baker 15y ago

Well, now we're getting into the theoretical issues. For instance, if we develop wormhole technology, the ship could very well be there before the enemy can see it. Otherwise, I just don't see interstellar space warfare as being that practical if it takes years to launch an attack.

rbanffy 15y ago
If I could create wormholes at will, I wouldn't traverse the wormhole with the whole ship - just the bombs would suffice.
- _Y_ 15y ago
  Why waste bombs. If you can create wormholes at arbitrary locations just teleport piece of a star into a planet.
  - rbanffy 15y ago
    If I could position both ends arbitrarily, a better approach would be to connect the planetary core with a black hole.
- Locke1689 15y ago
  If you can create wormholes at will, you don't need bombs. Put one end of the wormhole in the target and the other in the center of the sun.
  - scarmig 15y ago
    Any guesstimates on how large the wormhole would need to be for it to be a doomsday device? Two estimates, one for a wormhole on the surface of our sun, and the other for its core. I'll try to post my results sometime later. What about a neutron star? It's probably too exotic to consider how a wormhole would interact with a black hole.
    - dalke 15y ago