Colony : What were the aliens dropping out of the sky during the invasion?

Someone in another thread said that they were basically huge rocks, which kind of makes sense due to there being no actual explosion. However, we are talking about an alien race with vastly superior technology, so it could have been any kind of weapon they made that doesn't cause mass destruction, like a sort of "less-lethal" weapon. That scene when Eric Broussard left the meetup point was one the biggest holy sh!t moments in any TV show for me. I wasn't exactly expecting that to happen.

Maybe armed drones? I agree that scene was amazing.

cristalle1

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Maybe armed drones? I agree that scene was amazing.

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Yeah, they probably were armed drones seeing how much they loved using drones in season 1. Hopefully we get more scenes like that this season and we see more of the alien weaponry in action.

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Someone in another thread said that they were basically huge rocks, which kind of makes sense due to there being no actual explosion.

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The "rocks" wouldn't have been especially large, or even necessarily rocks. They could have been basketball sized metal spheres. The weapon I think they used is called a mass driver. It accelerates a projectile to very high velocity, much faster than any bullet. At sufficiently high speed one of these artificial meteors could create an explosion like a nuke (without the radiation) but at somewhat lower speeds it would have an effect like what we saw - the kinetic energy of the impact would cause the whole building to implode in on itself. The falling debris would come crashing down like a hammer, so there'd be no survivors alive under the rubble. It's an efficient way to target surgically in the middle of a city and totally destroy the desired structure without damaging much else. You could hear a bombardment going on in the distance before the house was flattened. Clearly the aliens were doing a bit of house cleaning that night.

chrisjdel

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The "rocks" wouldn't have been especially large, or even necessarily rocks. They could have been basketball sized metal spheres. The weapon I think they used is called a mass driver. It accelerates a projectile to very high velocity, much faster than any bullet. At sufficiently high speed one of these artificial meteors could create an explosion like a nuke (without the radiation) but at somewhat lower speeds it would have an effect like what we saw - the kinetic energy of the impact would cause the whole building to implode in on itself. The falling debris would come crashing down like a hammer, so there'd be no survivors alive under the rubble. It's an efficient way to target surgically in the middle of a city and totally destroy the desired structure without damaging much else. You could hear a bombardment going on in the distance before the house was flattened. Clearly the aliens were doing a bit of house cleaning that night.

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Yeah, it was a brilliant plan to get all of their key potential threats in one area so you can kill them all at once. They probably hit every FBI center, Homeland security, and others. The mass driver concept seems plausible at the very least considering its been in development by the military for a while.

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Yeah, it was a brilliant plan to get all of their key potential threats in one area so you can kill them all at once. They probably hit every FBI center, Homeland security, and others. The mass driver concept seems plausible at the very least considering its been in development by the military for a while.

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That had all the marks of a kinetic strike. No beam of energy, no exhaust trail, no explosion. Something just dropped out of the sky and crushed the building flat.

If they tried hunting those black ops guys down one at a time some of them would've escaped. But give them orders from SOCOM to gather at the local VFW and await further instructions, then hit the place from orbit? You get all of them in one shot. Except for the smart one who listened to his spidey sense and got the fck out while he still could.

I agree with the mass driver. Think of the space weapon in G.I Joe 2.

Rods of God. Supposedly it's already been theorized by the military. Tungsten rods launched at a high angle from orbit. Supposedly a 6 x .3 meter rod impacting at Mach 10 has a yield equivalent of 11.5 tons of TNT.

The impact in Colony, though, didn't look like the effects of a centralized force. I would expect even a kinetic projectile to produce a cratering blast effect since the energy is localized at impact. A projectile would penetrate the building until it hit the foundation and the released energy would blow outward. Like a meteor strike.

In S2E1, it looked like a *crushing* force from above, with the effects diffused over the footprint of the building. The building came down flat, as if a giant mass had been applied to it from above until it was crushed. I'm wondering if it wasn't some kind of gravitational weapon or something capable of creating a kind of directed high energy column of air downward onto the building.

A kinetic strike would produce an effect almost exactly like what they showed. Imagine a slow motion time lapse video of the event. The rock or metal projectile hits the building and bores through every floor, then the foundation, and into the bedrock in the blink of an eye. At that instant there's only a hole that looks like it was made by a drill bit. The rest of the building is completely intact. Then the area surrounding the hole starts moving downward.

In a delayed reaction, the rest of the building is being dragged along the same path as the projectile. Sure there's an outward force as well, but it's relatively insignificant - almost all of the momentum is directed along the slug's trajectory (i.e. down). The area of imploding building spreads outward radially and the debris crashes down like a giant sledgehammer. Well below the velocity of the projectile but still at very high speed. The frail human body doesn't stand a chance against this piston from hell slamming down from above. Everyone dies.

Seen at normal speed, the video looks like a small object (compared to the building) hitting the roof and then the whole thing crumples like an invisible giant just stepped on it. Some smoke and dust may spread out in all directions but almost all of the force has gone into driving the shattered pieces into the ground itself. Most of the rubble will end up compacted inside the crater. There won't be much left above ground level.

Watch a ballistic camera video of a bullet hitting a target like, say, an apple. Material blasted away from the apple sprays in a narrow cone along the bullet's trajectory, rather than exploding outward to the sides. Same basic idea.

The problem I have with this explanation is that meteor impacts always leave a crater and an ejecta field and they are the closest objects to a purpose-designed kinetic impactor, especially the iron ones.

A bullet hitting an apple is a good comparison to the impactor hitting the building structure, but in those videos the bullet passes through the apple. Most of its energy is retained after passing through. Plus the bullet velocity is less then a kinetic impactor by an order of magnitude.

In a kinetic strike on a building, only a tiny amount of its energy is lost passing through the structure, but the remaining kinetic energy will be transformed into heat as it hits the foundation and ground. It's this sudden release of impact energy that would blow the building outward, much as a meteor impact ejects material from its impact site and leaves a crater.

In the universe of Colony, perhaps the aliens are using much smaller impactors which have enough energy to deform the structure into collapse but not enough energy to overcome the material upon terminal impact. I think this has some physics problems (ie, some minimum mass and velocity numbers required to overcome atmospheric friction), but it's only science fiction after all.

Very high velocity kinetic strikes could produce something similar to a thermonuclear explosion. To have a projectile fall through the atmosphere without turning into a fiery streak it would have to be moving relatively slowly. A sufficiently "low" speed would be more like throwing a rock really hard; but is there a spread of velocities that collapses the structure like a house of cards, yet doesn't generate enough heat to cause an explosion? That I'm not sure of. Figuring it out is beyond the level of projectile problems in a college physics textbook. You'd need to run at least a moderately sophisticated computer model taking into account the building structure and materials in addition to the speed and composition of the impactor. Maybe the numbers would work, maybe they wouldn't. Hopefully a production like this does their homework and seeks expert advice but who knows?

One difference between the apple and the building: the building is a rigidly interconnected structure designed to distribute forces throughout in order to provide maximum stability. This same characteristic puts it in danger of total failure if the forces are too great. An apple is a soft, homogeneous target. There are no super-strong fibers running throughout the fruit and so part of it being punched out by a bullet doesn't rip the whole thing apart.

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A sufficiently "low" speed would be more like throwing a rock really hard; but is there a spread of velocities that collapses the structure like a house of cards, yet doesn't generate enough heat to cause an explosion?

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I think there may be, but lose velocity and you have to increase mass and volume a lot, I think. An low velocity object with a volume in the single digit cubic meters and with a cross-section in the single digit square meters I think would just punch a hole without trigger complete structural collapse. I think building collapse would require a large object with a cross-section a significant percentage of the building footprint.

Buildings are mostly held up by their walls, the trusses are mostly to bear the floor and ceiling loads, not keep the structure vertical. You would have to put a uniform force across a large cross-section of the footprint to bear enough load on the walls to bring the entire building down vertically.

Which is why to me what this looked like was either some kind of gravitational weapon that pushed down on the entire structure vertically to collapse it without a corresponding explosion from the sudden loss of kinetic energy of the impactor in the foundation.

For comparison purposes, look at buildings in WW II hit with unexploded 500 lb iron bombs they suffer significant damage, but don't come down. Even where the bombs explode, often significant portions of the structure are standing and only the internal structure is destroyed.

A chunk of metal the size of a small car traveling at ten times the speed of a rifle bullet could probably cause a building collapse. This is what "slow" means. Not particularly slow, just slower than the sort of planet killing bombardment weapons that show up in science fiction novels. At this speed air resistance would heat the projectile but not, I think, enough to make a meteor-like fireball. The World Trade Center Towers collapsed because the load bearing columns started to soften in the heat of the fire. A large hole being ripped through the center of a high rise would certainly compromise structural elements even if kinetic energy transfer alone wasn't enough to take the building down (which it likely would be).

Picture that video of the apple being hit by the bullet. If it was a hypervelocity bullet traveling much faster than normal the hole it made would enlarge after its passing as more and more adjacent material tore away. The apple would be largely or completely gutted and the debris blown downrange with little outward spread. Something very similar would happen to the building. To a person watching, it would look like the whole thing had been hammered into the ground by the impacting object even though it was quite a bit smaller than the building itself.

Just for reference, a 10x the speed of rifle bullet (2,000 fps) is 6 kilometers per second or Mach 17. Existing kinetic weapon development with .5 x 10 meter tungsten rods estimated terminal velocities launched from orbit of Mach 10 with impact yields around 11 tons of TNT.

Your two meter diameter chunk of metal traveling at almost twice the velocity is probably going to have impact yields closer to 30-40 tons of TNT. There's no way you're dumping those kinetic energies into the foundation without significant cratering and ejecta.

I think your "large, slow" impactor might work, but I think we're needing to up the cross-section to 100+ square meters but keeping the velocity very low, something on the order of a fraction of a kilometer per second. Basically you want a crushing load on the structure.

I still think some science fiction concept like a localized gravity field aimed at the building so that for some impulse you have 10x the gravity is a more appealing explanation for what happened in the show. If the gravitational field the building sat in was increased by an order of magnitude, the building would collapse downward in a manner like a planned explosive demolition.

Which if you think about it, is kind of what they accomplish in planned demolitions, only in reverse. They can't increase gravity, but they can weaken the structure enough that it can't hold the mass up against 1G and it collapses into itself.

Keep in mind that the blast would resemble that from a claymore, or a shaped explosive charge, much more so than the omnidirectional detonation of the average bomb (i.e it would explode primarily in the downward direction). Still, the Oklahoma City bomb had a yield of only 4 tons of TNT and we saw how badly that gutted the target. The portion of the blast that did expand outward might still be substantial even though most of it was directed into the earth.

An atmospheric shock wave in the form of a soliton, which is a localized disturbance that holds together like a giant particle, might work as an explanation too. If they do have some kind of graviton cannon that can project a distortion like you described, temporarily increasing the ambient gravity to, say, 10 or 20 Gs in the target area, that would certainly have a devastating effect on any human engineered structure. Nothing we build is designed to support 10-20 times its own weight even briefly. This would be especially bad news for the resistance. The technology required is quite a bit more advanced than mass drivers or sonic weapons, well out of reach for humans unless we somehow managed to steal it from them. You could pretty much forget about duplicating it or designing an effective shield against it.

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Which is why to me what this looked like was either some kind of gravitational weapon

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I was thinking the same thing, maybe something that causes the gravity to increase in a localized area.

If that is what they're using it's very bad news indeed. Gravitons pass through matter easily, the blast from such a weapon would literally go all the way through the Earth and out the other side. If it was set to produce 100 G's for only a few seconds and targeted a whole city every single fragile human body would be crushed. People who managed to find little hidey-holes in tunnels and basements deep under the city would be just as vulnerable as the ones on the surface.

Different thing.

Everyone else is referring to the "bombs" that aliens used in their "quasi-nuclear" tactical strikes.

J.

Ohh ok. I was wondering what that was. At first I thought it was going to be the walls until it showed them a few minutes later.

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I thought they were prebuilt walls that would eventually surround the city.

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At first I thought they were buildings but walls make more sense

Remember the wall in Season 1? Those big objects coming down on rocket thrusters were its component pieces. They didn't construct it over time, it was "built" by dropping prefabricated segments into place which linked together to form an instant wall.