From my dealings with David Jacobs it would appear an alien invasion of sorts is already happening even now. I won't attempt to explain the full spectrum of data but instead tell the story as I see it. Around the 1890's you have an alien species make contact with us (it may actually have been sooner but this date was arrived at through tracing family lines experiencing abductions). These beings appear insect-like, however because they are from an entirely different ecosphere Jacobs has concluded they most likely are very different, if not entirely different, than insects on this planet. Anyways these insect-like beings have interstellar travel, and they also have plans having been here for awhile as to the best method of using our resources. Instead of wasting time terraforming the planet or attacking us openly, instead, these rather smart creatures embark upon a generational program of biological integration. They begin abducting humans and slowly altering genes in order to mix their DNA with our own. The first attempts produce a species known as the Greys. These are beings that actually were the first joining of our species with their own. The final phase of their program is to fully integrate themselves into our society but keep their mental capacities intact. Because they are telepathic we see by merging their own species with ours they will then have the ability to control us without even really needing to. So you'll have telepathic humans that are basically linked to these EBE's. According to Jacobs this program is nearing it's end, whether or not it will openly become known is uncertain. From what we see though it's appearant the Insectoids never cared about hiding this forever, only the program leading to it. Once that is complete we will all be screwed. It is thought that because these beings have so little personality of their own they will eventually cycle out our cultures current systems of governing, etc and their own will replace it. Whether this is truly accurate I cannot say, however let me tell you that if Jacobs has actual done the research he claims to, and the data he's collected is somewhat true, then this is exactly what will happen. I actually thought up a theory that only a telepathic species would ever be capable of interstellar travel, and that's why we only see this single 1. Other cultures would long since have killed themselves off unless there were some mental link between the species causing them to work together for a common goal.
Assuming that this relativistic projectile was accelerated to 0.999c in another nearby star system, this projectile would be visible at a great distance using passive detection methods. The projectile's cross-section would intercept gas and dust at 0.99c and convert it into radiation; the object would effectively have a source of radiation on its front end which could be detected. Gravity waves would also be emitted for the whole of the interstellar voyage. If on the other hand the projectile accelerated near the target system that acceleration would emit radiation which would be detectable. Note that I am assuming an ultimate defence, here, as well; a solar system which can utilise the total energy of a star, and store that energy for an arbitrary period, and project that energy using (say) phased array lasers at any incoming target. Also I am assuming an ultimate passive detection system, including interferometry spanning the entire system. As a relativistic projectile approaches a planetary system it encounters more dust, and glows brighter. One way to reduce friction with the interstellar medium would be to make the projectile very long, and very thin; one imagines interstellar knitting needles with vast kinetic energy. But these would still be detectable by gravity wave detector (although I have not yet found an upper limit on the usefulness of these devices yet; it might be quite low).
Hitting the warhead with a phased array laser with the stored power of a sun would vapourise it; the vapour would continue to move towards the target while expanding, and could be a dangerous weapon in itself. In fact one strategy might be to fragment a way from the target and rely on multiple small impacts. The task of the defening technology is to vapourise the incoming weapon(s) at a distance where the vapour will be slowed down or stopped by the interplanetary (rather than interstellar) medium at the edge of the system. The radiation produced by the vapoursiation of the projectile would be considerable. but it would be isotropic- radiated in all directions, and subject to the inverse square law, so would be diminished by that. As I said, the energy in a projectile can not hope to match the energy available for defence. If a solar system puts (say) all the energy it can generate for a year into the launch of one kinetic missile, then it must achieve this without vapourising that missile. To avoid vapourising the missile it must be accelerated relatively slowly. This requires a long period of acceleration and the emission of a great deal of waste heat. Once that kinetic missile reaches the target, the defence systems can use the same amount of energy to vapourise it in a matter of seconds.
Ultimately the worst lind of warfare would be between planetary systems using beamed energy. So perhaps you are right; the ultimate offence would be to use the powerful beam weapons developed for defence as an interstellar offense. Here is an image I made a while ago of a 'killer star'; a star which is induced into a nova-like explosion, and the energy of that explosion is collimated and directed at another system. http://www.orionsarm.com/historical/killingstar.png Even without the technology to achieve this, a dyson swarm could store enough energy to power a phased array laser capable of vaopurising a planet in anpother system. One dystopian future I have imagined before is a standoff between a galaxy full of dyson swarms, each with the power to destroy one another. One day the firefight would start, and spread from star to star unstoppably...
Yes; there are ways of counteracting diffraction spreading, or so I am told. But one question is will it hit anything when it gets there? Planets are very small targets on interstellar scales, and the effect of the gravity of all the other stars in the galaxy effectively randomise the location of a planet over time. If you used a beam the width of the Earth to try to hit the Earth from Alpha Centari you would almost cetainly miss it because of this randomisation. So you have to use a much bigger beam, making the process inefficient. To entirely vapourise the Earth would take 22 days of the Sun's total solar output; if you have to make the beam much larger the beam might requre a whole year's worth of solar energy.
You’ve got to account for the fact that the emissions the projectile make only move at the speed of light. If the attacking ship fires from one light year away, then the defenders won’t know anything about it until those gravity waves come into contact with their detectors. By that time, the warhead has been moving towards the target for one entire year at near-light speed; if it’s humping along at .999c then it is only even detected at 1/1000th of the distance from which it was fired. All reasonable assumptions. But if so we are already talking an investment vastly exceeding the expense of the attacking missile, which was the basis of the original observation that offense is outstripping defense. On one side you’ve got cosmic losers hopping up a Pontiac interstellar road racer. On the other, a boggling expensive array of technology and networks sprawled over an entire solar system to try to stop it….a billion to one in relative expenses maybe? What if the attackers fire a million missiles at the same time? One problem is that the laser has to have a firing solution that is good enough that the vapour has a chance to expand far enough for most of it to miss the planet. If we assume this to be at, say, 1 million miles from target, and that the average speed of the missile has been .999c since it was fired, then the fire control computer has to shoot at the missile’s projected location using the targeting data of the missile’s position when it was about 999 million distant. This is because the emissions being made by the missile are moving only slightly faster than the missile itself. If the warhead is at .999c then the spectra that is at the defending base (upon which the firing solution is made) must have originated from a point 1000 times further away because any gravity waves emitted closer hasn't even reached the defenders yet. Simply put, the closer the attacker can get his missile to light speed, the more hopeless the defender’s position becomes. If the defenders build all the stuff you suggest, then all the attacker has to do to scupper it is make his missile go faster. Whether or not the missile takes one week or one month to accelerate to near light is irrelevent. The problem is that the emmissions of the missile that the defensive system must rely on to see it can't get from the missile to the radar fast enough to make a difference. What the defender "sees" at the moment of detection isn't where the missile actually is, so the defenders are firing almost blind on the basis of a projection. A possible defense might be to make planets more mobile, or shield them within an array of stellar bodies that have a statistically good chance of absorbing a blow. This might force the attackers to expend a number of shots vaporizing shields. Another method might be to create a spherical layer of matter at an appropriate distance from the star (say, near the orbit of Mars) with the intention of destroying the missile by kinetic impact.
Sending a relativistic projectile is still expensive, and requires a lot of energy, if you want it to hit really hard and fast you will need a large array of energy collectors in the offensive system. The only delay in passive detection at a distance caused by light speed would be the time it takes for signals to cross from one side of the interferometer to the other. If you start accelerating your incoming projectile at 1 light year away you will be visible for the entire acceleration period; if that takes a week then the defenders will have at least a week to prepare a laser defence. Starting acceleration in the middle of interstellar space might be tricky too; there are no sources of energy out there so you would have to take a lot of stored energy with you; that stored energy will have to be be somewhat more than the kinetic missile will be able to deliver. If you start accelerating in another nearby star system the warning time becomes rather longer; no doubt an alert defence would be monitoring any nearby systems for signs of unusual activity. This is all assuming that acceleration produces waste energy of course; a reactionless drive (if such a thing were possible) might not be detectable optically (but I bet it would show up like a beacon on a LIGO).
No force in the universe moves faster than light. If the system is using the gravitational effects caused by the acceleration of the projectile as it accelerates, it cannot see any danger until the generated energy crosses the distance to the detectors. That would take one year. Before that year is up, there would be no sign whatever in the target system that an attack was underway. Distance sentinels might see the attack, but their frenzied warnings home also move at the speed of light, so they will not arrive any earlier. During this period a .99c weapon will have covered 99% of the distance to the target. And once the missile is detected, the emissions that alert the defender would not be the ones coming from the missile's current location. They would be the ones made one year previously as it was launched. As the missile continued to bore in, what I suspect (not 100% certain) the defenders would see over the course of the final week to impact is the gravitational information generated by the missile over the course of the previous year all piling in at a greatly accelerated rate. The projectile will start out at the distant star and appear to be moving towards the defenders at a velocity far greater than that of light. As it nears, the apparent position of the warhead will begin to "catch up" to the real position of the warhead until the two merge together at ground zero. The defenders will be shooting on the basis of the apparent (not real) position well behind the warhead's actual location. No force in the universe will allow them to shoot at the missile's real position because information cannot travel faster than light. Thus, if the attacker is pulling evasive actions as it approaches, the defenders will have to saturate the entire area it could be in in order to secure a hit. If the defenders are capable of delivering that kind of firepower, the attackers can cancel their cleverness by the simple tactic of having a second or third missile (or however many it took to exceed the defender's energy reserves) approaching simultaneously on a different bearing. I don't think the attacking system goes "relativistic" until it is approaching light speed. Before that point it's acceleration probably won't be detectable, especially if the attacker uses tactics such as concealing his launch behind a star. Also, if detection is deemed a problem the attacker can elect to fire from further away. The planet will be just as dead when the bomb arrives.
I like the iea of accelerating behind a star; the emissions resulting from the acceleration of a relativistic kinetic projectile would be phenomenal, and difficult to hide any other way. If a relativistic missile were dispatched from behind our closest neighboring star, four light years away, it would become visible once it left the star system, and at 0.999c it would arrive a day and a half after it was first detectable. This would give the system time to prepare a laser defence, but the object would need to get a lot closer before it could be targeted reasonably accurately, because of light speed delay. Even when the projectile was a few light minutes away it could only be located approximately because of possible evasive manoevres. For this reason defence beam would need to cover all possible projected locations of the projectile, which would narrow down considerably as it approached. As there is a lot of energy available in the home system this is do-able; there is a limit on the amplitude of the evasive manoevres possible in any case as the fuel for such manoevres must be carried on board the projectile- and if the projectile jinks too much it will miss the target.
last time I talked to an alien he reminded me that "We are already here", haha. All time and all space are one time and one space to them and so they just jet-set around at will. Arghhhhhhhhhhhhhhhhhhh said Charlie Brown.
If the defending systems are passive, all that will be known is that a total mass is coming at them at a certain speed. This might be one or many attacking missiles. This in turn effects the total area that the beams will have to saturate. I doubt that effective targeting is possible. The momentum of an object moving at near light means that that it will be difficult to deflect from it's base course even with a beam weapon. The laser light might explode the warhead (causing a lateral movement of hundreds of meters per second), but the mass of the warhead will still be coming on at 184,500 miles per second, meaning that the actual angular drift introduced into the warhead fragments is a tiny fraction of the warhead's velocity. The warhead can deploy countermeasures (say, gases ahead of it) to absorb the energy of the laser blast. The hit then has to come far enough out that the drift introduced by the beam weapon disperses the remnants of the warhead, causing an acceptable fraction of it to miss the target (say 99.9% of it's mass misses). Another trick an attacker could use is to build the weapon system out of pure antimatter. This will allow them to disperse (detonate) the warhead into small chunks prior to the terminal phase of the attack.
Interestingly antimatter doesn't add much energy to the kinetic energy contained in a relativistic projectile; if you hit a planet with a kilogram of matter going at 0.999c the added energy of annihilation would be small in comparison. Since the beam weapon has an almost arbritary amount of energy behind it the goal is to vapourise the projectile, and then convert the vapour into radiation. A defence laser system might have the stored energy of several years worth of emission by the sun; this would decrease depending on the frequency of attacks. Meanwhile there is a real upper limit on the velocity and therefore the kinetic energy of the incoming projectile; if a projectile travelling 0.999c or above hits a single dust mote on its journey it will be very likely to be destroyed by the impact, which would be equivalent to many megatons of TNT. Once the projectile reaches the dusty outer reaches of a solar system this detonation becomes almost inevitable; as you suggested a shield of matter might be useful, but it would be a shield of dust. Perhaps a deliberately produced dust cloud.
A dust shield of sufficient thickness might prove very useful, yes. Both to blow up incoming projectiles and to conceal the exact location of the planet further in. The attacker could tell where the planets were on the basis of the wobble of the star itself, but I think a clever defender could cause uncertainty as to the location of the home world by cleverly manipulating the positions of planets within the dust shield. A near C projectile might come bursting through the layer (blown open by a series of projectiles) only to find that its velocity will carry it harmlessly past the target planet.
However, I assume that there are no passive detection methods in place right now. Hence we will not see it coming.
wouldn't it be more simple to fire a bomb into the opponents sun, because this would be the power source of the nation. Not that it would rip the star apart but it could make a enormous solar storm that damages the power collectors.
True. Thought anti-matter had more bang per buck for some reason. Still, even small amounts are enough to annihilate entire cities so if the attacker is using anti-matter munitions in the thousands or the millions (albeit at lower velocities) then defender would still have a bit of a problem. The USAF right now is working on an airborne laser system that will allow directed energy kills on incoming ICBM’s. Needless to say, the energy required to blow up a warhead or a missile is considerably more than needed to kill one of us. Also recall that we already have the technology, as the clique goes, to read license plates from space. Now, put these two fact bytes together and you’ve got a high-altitude system that patiently sits around scanning with eagle eyes and killing at the speed of light anything that moves on the surface of the planet. Not even a challenge, really. More like war by accounting. Battery B7624 you are 45.423% below quota. Anyone here supposing that a war with a technically advanced race would be nothing more than pure slaughter is deluding themselves…
