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[sneakey pete]

*some numbers*

Potential energy in space is an interesting topic, trust me on one thing though, its never going to be a case of just "dropping" something directly "down". there will always be orbits involved, if your in a stable orbit, it doesn't slowly decay and crash into the sun at a rate of less than billions of years. Remember the object is going sideways fast enough so that by the time it "falls", its already gone to the side and is still the same (for circular orbits) position. If you want to get something back to earth, you need to give it a big enough of a shove so that its going slow enough to be en an elliptical orbit around the sun* that has its closest point at the distance of the earth (and at the same time the earth goes past, etc), doable for Nasa's probes, yes, because they could launch when they liked so that the planets were in position. for trying to crash into a planet as soon as possible? harder. Not to  mention, that if your coming in from Neptune, the fastest you could really expect is a year or so's transfer, IIRC.

All I know is potential energy is not explosive force.  Sure, gravity will eventually pull an object from Neptune's orbit to Earth's orbit.  It would take millions of years due the incredibly low acceleration.  Nobody's doubting the physics, we're (or at least I'm) just saying that's it's silly to attribute the danger of a missile between planetary orbits to solar gravity.  A good shove would impart more energy in the same time, so just stick an engine on it and forget all that gobbledygook about gravity.

No, gravity won't eventually pull an object from neptunes orbit to earths orbit (well, if you simplify things). Neptune is still there afterall. To send something across, like i said, you need to slow your orbit enough so that you drop out of it, so to speak (yeah, the drop word ). Unfortunatly, however, your always going to have to not forget about gravity, everything in space always wants to be in an orbit. you'll never have though burn time for propultion of things like rockets, and for things like ion drives their propultion is so low, that you will always have to worry about orbits in your space crafts.

To everyone on here, i would reccomend taking a good orbital dynamics course, it really is quite interesting.

*well, its worth noting that the orbit only has to cross the path of the planet. if you, for instance, slowed your netpune distance orbit right down to it really was "stopped" and let it drop straight down, it would require a much, much greater change in velocity at the top, but a faster transfer time, but smaller boom at the end.

[Nikov]

I have been missing this conversation of theory for an exercise in practice; Baystation 12.

Nerdrods are ridiculous for reasons the crying baby on my lap prevents me from concentrating well enough to describe. Suffice to say I am in the nuclear camp, assuming we are destroying a surface area target.

[Azzuro]

Hey, if we're discussing space weaponry, what armaments do you think space ships would carry? Against large, slow moving(relatively) ships, I think the weapon of choice would be a mass driver. Battling against fast, agile fighters would be more difficult, as they might be able to dodge your shots easily. To protect against fighters, I think large ships would need to carry heat-seeking missiles, or fighters of their own. I admit I don't know much about lasers, but I think that heat energy would dissipate quickly in space, and as such, laser weapons wouldn't have much operational range.

In the case of stealth attacks from a planet, mass drivers would be much more effective than missiles, as they would not leave much identifiable foreign debris with which to trace an attacker, whereas a missile, with far more components, has a higher chance of producing traceable debris. Of course, the feasibility of building a mass driver on a planet with atmosphere would be far less than building a simple missile launch site. A missile also has the option of possibly confusing the enemy as to the location where the attack was launched, as it could travel far away from the launch site before escaping the atmosphere. A mass driver, assuming that the angle of collision was known, could be quickly found with simple Newtonian mechanics.

[Earthquake Damage]

Against large, slow moving(relatively) ships, I think the weapon of choice would be a mass driver.

Large, slow-moving ships would still be too fast for unguided ballistic weapons.  With the possible exception of high-powered lasers, the only viable weapons in space are missiles.

Also, ground-based anti-spacecraft weaponry would probably be limited to expensive missiles.  Orbital missile platforms are a better idea.  Atmosphere's a bitch.

[Azzuro]

Against large, slow moving(relatively) ships, I think the weapon of choice would be a mass driver.

Large, slow-moving ships would still be too fast for unguided ballistic weapons.  With the possible exception of high-powered lasers, the only viable weapons in space are missiles.

Also, ground-based anti-spacecraft weaponry would probably be limited to expensive missiles.  Orbital missile platforms are a better idea.  Atmosphere's a bitch.

To clarify my point on larger ships, this is assuming that the ship cannot change course fast enough to avoid a projectile. At this point, it doesn't matter whether the ship has detected it or not, it is still a guaranteed hit since the ship cannot move out of the way in time. In other words, I should have said "hard-to-maneuver" instead of "slow moving".

Also, with regards to orbital missile platforms, they would far easier to target than a ground installation. Don't forget that the atmosphere can also interfere with your targeting, due to cloud cover, etc. But yeah, ground-based anti-space weaponry would be pretty much impossible due to the gravity well.

Actually, I think that instead of anti-space weaponry, a planet could defend itself simply with an adequate air force. After all, for maybe the first twenty years or so of space travel, human ships would be essentially bound to Earth for needed supplies, such as food. Thus, instead of actively seeking out and destroying spacecraft, a nation could shoot up any inbound or outbound spacecraft in the atmosphere itself.

[MetalSlimeHunt]

You have to remember that speed is nowhere near as big an issue for spacecraft. If you're exerting force on the craft in the same direction it's traveling, it'll get faster untill you hit the speed of light or an opposing force of matter, energy, or gravity.

[Soadreqm]

Battling against fast, agile fighters would be more difficult, as they might be able to dodge your shots easily. To protect against fighters, I think large ships would need to carry heat-seeking missiles, or fighters of their own. I admit I don't know much about lasers, but I think that heat energy would dissipate quickly in space, and as such, laser weapons wouldn't have much operational range.

It's pretty much the opposite of that. Vacuum is pretty much the best insulator that exists, and thermal energy takes a long time to dissipate from objects. And there is nothing scattering the laser beam, so it would have intense range. And they would be just perfect for destroying space fighters. So perfect, in fact, that there wouldn't be much point in having space fighters. They're too tiny to have much armour, and they wouldn't really have much weapon capacity either.

To clarify my point on larger ships, this is assuming that the ship cannot change course fast enough to avoid a projectile. At this point, it doesn't matter whether the ship has detected it or not, it is still a guaranteed hit since the ship cannot move out of the way in time. In other words, I should have said "hard-to-maneuver" instead of "slow moving".

Not really. Space combat will most likely take place at ridiculous ranges. If you are in range of a laser beam, a mass driver will take days to hit. And since it has no warhead or anything, it has to hit perfectly. You just have to change your course a teeny tiny bit to make it miss you by thousands of kilometers. Missiles are much better, because they can be guided, and don't actually have to hit the target ship, just get close enough that the explosion hurts it.

Also, with regards to orbital missile platforms, they would far easier to target than a ground installation. Don't forget that the atmosphere can also interfere with your targeting, due to cloud cover, etc. But yeah, ground-based anti-space weaponry would be pretty much impossible due to the gravity well.

Actually, I think that instead of anti-space weaponry, a planet could defend itself simply with an adequate air force. After all, for maybe the first twenty years or so of space travel, human ships would be essentially bound to Earth for needed supplies, such as food. Thus, instead of actively seeking out and destroying spacecraft, a nation could shoot up any inbound or outbound spacecraft in the atmosphere itself.

Anti space weapons are certainly not impossible, just expensive. You just need bigger rockets to clear the gravity well. And the flaw with atmosphere-based air forces is that they're absolutely useless if someone wants to destroy your planet rather than invade it. Of course, if someone wants to do that, it will be very very hard to stop them, anyway. Planets are really easy targets.

[MetalSlimeHunt]

I would certainly hope future humans will never consider it acceptable to blow up inhabited planets, like we don't consider it acceptable to use nuclear weapons. Sure, countries wave them around a lot, but its all just an act to seem more of a threat than they really are.

[Soadreqm]

I would certainly hope future humans will never consider it acceptable to blow up inhabited planets, like we don't consider it acceptable to use nuclear weapons. Sure, countries wave them around a lot, but its all just an act to seem more of a threat than they really are.

Yeah, I hope so too. Indeed, if we don't keep our excellent record with not using nukes, there's a pretty decent chance we'll never get to the spaceship building age. And anyone being able to blow up your planets sounds like a pretty good deterrent to actually blowing up any planets.

[MetalSlimeHunt]

That said, techology that could crack open a planet like an egg would have excellent non-war uses, like blowing apart a dead rock in space to get at the absurdly mineral-rich mantle. Or course, one day that'll create space zombies.

Spoiler (click to show/hide)

Unless the government planted those space zombies in the first place! DUN DUN DUN!

[Azzuro]

Battling against fast, agile fighters would be more difficult, as they might be able to dodge your shots easily. To protect against fighters, I think large ships would need to carry heat-seeking missiles, or fighters of their own. I admit I don't know much about lasers, but I think that heat energy would dissipate quickly in space, and as such, laser weapons wouldn't have much operational range.

It's pretty much the opposite of that. Vacuum is pretty much the best insulator that exists, and thermal energy takes a long time to dissipate from objects. And there is nothing scattering the laser beam, so it would have intense range. And they would be just perfect for destroying space fighters. So perfect, in fact, that there wouldn't be much point in having space fighters. They're too tiny to have much armour, and they wouldn't really have much weapon capacity either.

To clarify my point on larger ships, this is assuming that the ship cannot change course fast enough to avoid a projectile. At this point, it doesn't matter whether the ship has detected it or not, it is still a guaranteed hit since the ship cannot move out of the way in time. In other words, I should have said "hard-to-maneuver" instead of "slow moving".

Not really. Space combat will most likely take place at ridiculous ranges. If you are in range of a laser beam, a mass driver will take days to hit. And since it has no warhead or anything, it has to hit perfectly. You just have to change your course a teeny tiny bit to make it miss you by thousands of kilometers. Missiles are much better, because they can be guided, and don't actually have to hit the target ship, just get close enough that the explosion hurts it.

Okay, thanks for correcting me on that one. I don't really know how lasers work. If lasers could work that well, then they'll be the sole weapon used in space, since they are near-impossible to dodge. The only drawback might be their large energy use.

Also, with regards to your second point, I had assumed that ships bigger than supertankers couldn't maneuver fast enough to avoid projectiles. After looking up some numbers, I think you're correct about it taking as much as a day to hit. In that aspect, lasers would probably excel, since they travel at the speed of light and are much more likely to hit.

That said, techology that could crack open a planet like an egg would have excellent non-war uses, like blowing apart a dead rock in space to get at the absurdly mineral-rich mantle. Or course, one day that'll create space zombies.

Spoiler (click to show/hide)

Unless the government planted those space zombies in the first place! DUN DUN DUN!

No matter how benign that technology might be, there would be some terrorist or extremist who wouldn't mind using it for evil. The chance of us having the technology to do so would also be quite high when we reach the space age, given current rates of technological progress.

As an aside, both the United States and Soviet Union once consider using nuclear explosions for earth-moving purposes, but the idea was dropped.

[Earthquake Damage]

That said, techology that could crack open a planet like an egg would have excellent non-war uses, like blowing apart a dead rock in space to get at the absurdly mineral-rich mantle. Or course, one day that'll create space zombies.

No matter how benign that technology might be, there would be some terrorist or extremist who wouldn't mind using it for evil. The chance of us having the technology to do so would also be quite high when we reach the space age, given current rates of technological progress.

Planet-destroying technology won't be here any time soon (that's not meant to be a hard scientific source, but you should get the idea).  We can certainly destroy most of human civilization.  We may, if not now then in the not too distant future, have the power to render it entirely unfit for human habitation.  Don't expect any Death Star shenanigans, though.

[Soadreqm]

Planet-destroying technology won't be here any time soon (that's not meant to be a hard scientific source, but you should get the idea).  We can certainly destroy most of human civilization.  We may, if not now then in the not too distant future, have the power to render it entirely unfit for human habitation.  Don't expect any Death Star shenanigans, though.

Ah, but this isn't something we expect to get within a reasonable timeframe. This is something we expect to get around the time travel between star systems becomes regular.

[Earthquake Damage]

Ah, but this isn't something we expect to get within a reasonable timeframe. This is something we expect to get around the time travel between star systems becomes regular.

Ah.  My mistake.  Carry on.

[x2yzh9]

Planet-destroying technology won't be here any time soon (that's not meant to be a hard scientific source, but you should get the idea).  We can certainly destroy most of human civilization.  We may, if not now then in the not too distant future, have the power to render it entirely unfit for human habitation.  Don't expect any Death Star shenanigans, though.

Ah, but this isn't something we expect to get within a reasonable timeframe. This is something we expect to get around the time travel between star systems becomes regular.

How true. Even by then, the earth will have been drained of most, if not all resources and will just be a population and maybe manufacturing center.