- A focused beam of electrons would have the effect presented in the film, violently vaporizing water which could destroy people and vehicles while leaving stuff like clothes intact (if ragged).
- Or he is one of the more "Heroic" versions of Godzilla.
- I was thinking along these lines too - 26 strikes.. I doubt these things had a crew of 26. And why wouldn't anyone have found the tripod when they were building the street in the first place? Nanotech machines implanted into the ground to assemble the tripod, then the crew came down.
Unicellular life forms evolve quickly, though. If they left their Tripods on Earth deep in the past (maybe a few hundred thousand years ago), then it would be entirely possible for some ubiquitous bacteria or archaea to emerge in that time frame that could cause them trouble. It might not even be something that attacks them directly. Instead, it could produce something toxic that threatens their survival, but not ours.
That's not so surprising, since we've already seen that the Invaders harvest people as Human Resources for use in spreading the Red Weed. They appear to do that, though, by drawing the victim's blood through a specialized tentacle while they're outside of the Tripod. With the people unlucky enough to wind up in this cage, the Tripod instead latches onto them with a separate mechanical appendage and pulls them into an obviously biological orifice that sits overhead.
It looks a lot like the "machine" is eating them.
In scenes where a Tripod is taken down, too, we often see gallons of orange fluid pour out of it on top of witnessing several enormous explosions from its mechanical parts. That could be some kind of hydraulic liquid or maybe even an "atmosphere" for the Tripod pilots. Considering that these things appear to need feeding, though, it's probably blood (or something similar).
If a species had domestic animals as large, powerful, and deadly as the Tripods, then they might decide to just roll with the idea of "mounted cavalry" well past the period when armies on Earth were giving up those tactics. By equipping the Tripods with weapons and dense metal plate armor, they'd be able to turn them into something both deadlier and more cost-effective than any purely mechanical weapon they could come up with.
For one thing, she has panic attacks, which aren't the same as a child's normal reaction to stress or fear. The most obvious occurs fairly early in the movie, when the family are fleeing Bayonne but notably after they're out of immediate danger. Robbie and Rachel start asking Ray questions, but Rachel's questions become increasingly frantic, especially when her father responds poorly. Eventually, she loses control completely and starts yelling for her mother, then wordlessly screaming until Robbie comforts her.
The way that he does so, too, is significant. He tells Ray that what he's doing "isn't helping", which kind of implies that he's seen this happen before (although it's...well, also just obvious, since literally telling a screaming child to shut up is never going to make any progress). Then, he says that Rachel is claustrophobic and goes through a routine of delineating a space around her that is safe, where she's in control. It seems pretty doubtful that this is something her family has come up with on their own. Rather, it's more likely that they're aware she has problems with circumstances that feel totally outside of her control, and have sought help.
Later, when she's just upset (after discovering that her mother and stepfather aren't home), Ray attempts to use the same technique. Both Rachel and Robbie make it clear that "that's not how it works", because it's something that helps her feel more safe and protected in that particular situation and isn't useful when she's troubled but otherwise has control over her emotions.
There are a few other times when this happens, although the circumstances are more extreme. In general, though, her issues seem to center around feeling as though those around her cannot (or will not) protect her. Notably, the idea of Robbie leaving her with her biological dad drives her to lash out physically and ask who will take care of her if he's gone. She generally seems to love Ray, but not to believe that he'll keep her safe if no one else is there. She even flees away from Ray when she notices that a Tripod has located her in Ogilvy's basement, and then continues to hide once he comes outside looking for her even though he asks repeatedly for her to let him know her location.
Although obviously the events of the film wouldn't improve things in general (forcing someone who feels unsafe and out of control into a situation where they're genuinely in danger and really have no control doesn't do that), her arc seems to center around recognizing that Ray is a person she can trust to guard her with his life. This starts when he protects her by killing Ogilvy, after which she both turns to him for comfort and offers the same. Really, though, it seems like the destruction of the Tripod marks the final turning point. By the end, she's much more comfortable around him than she is at the beginning.
We see a Tripod moving through the Hudson River, in water that clearly isn't as deep as it is tall (once it stands up, the majority of its bulk is above the surface). The sort of crab-walk that the Tripod goes into when capturing Rachel, far from looking difficult for such a Humongous Mecha to accomplish, actually seems like a more comfortable form of locomotion, and was probably what its sibling was doing underwater. Given that the Tripods seem to have a significant organic component, there's a good chance that's how they behave in the wild, standing up with all three legs fully extended only to survey their surroundings. This also matches with the gait taken by their operators.
On top of the Tripods and their operators, the only other organism we see from their planet also looks like a recent colonizer of the land. The Red Weed forms enormous patches, but grows out like a creeping vine rather than growing up. It's capable of covering trees and buildings, but otherwise sticks near the ground's surface. While it's apparently a vascular plant, it doesn't have any of the rigid structures that would be necessary for vertical growth. There are still plants like that on Earth, but their greatest biodiversity came deep in the geological past, before competition for sunlight led plants in an upwards-moving arms race.
The fact that the Red Weed appears to turn water into something like blood may also explain why the Tripods harvest humans (and probably animals). If the plant changes its environment to something similar to the color and chemistry of mammalian blood, and if it grows naturally in a moist environment, it may have evolved to require liquid like that as a chemical cue to germinate. With the Earth having a decent biomass that produces a suitable liquid, this could even be the reason why the aliens opted to come to our planet in the first place, and to wait until there were enough humans and livestock to supply their needs. Transporting any quantity of water from their oceans would be much more difficult than just gathering it in situ, and might even be completely outside their capabilities. Once the Red Weed started growing, it would be able to produce the circumstances that it (and likely several other parts of the food web, given how ubiquitous it seems) needed to survive, effectively reverse terraforming the planet. Of course, with the exception of a few unicellular organisms that could survive and adapt, a hydrosphere effectively converted to gore would not be one that could sustain Earth-based life, so a war of extermination against anything that might resist extinction would be necessary at the outset.
The aliens coming from a planet with a delayed move onto land might also suggest the reason for their attempted invasion. Continents are a tempting niche for life, and will usually be taken over as quickly as possible by multicellular organisms. If that occurred so late that their home world already had large, intelligent animals populating it, there's probably a good reason. Being close to a star late in its life cycle, like a red giant, would make surviving above the ocean's surface even more of a challenge than it was here thanks to high heat and solar radiation. If their star's that old, then they're likely trying to avoid extinction when it inevitably either swallows up their world or collapses in on itself. The invasion, then, would have been a battle for survival between two ecosystems rather than just two species. One that really played out in favor of the Earth's biosphere rather than mankind in particular.
