Question: When Tom Cruise is battling to get free of the tentacle pulling him into the ship from the cage, there is alien (presumably) writing visible on the underside of the tripod just beyond his arm and above the lights. Can someone shed light on what this may say (theories, previously suggested writer/director thoughts)?
Question: Before Tom Cruise is ushered into the tunnel in Boston, he tells the army man, "______ is the key." What does he say; what is the key?
Answer: It is actually the army guy who says this, not Tom Cruise. Cruise notices the birds are able to land on the tripod and realizes the shields are down. He points this out to the army guy who yells to his men "The Javelin is the key." The Javelin is the anti-tank weapon they use to take the tripod down.
Question: What happened to Ogilvy?
Answer: Ray couldn't trust Ogilvy to be quiet when the aliens arrived. So Ray had to kill Oglivy in order to save him and his daughter.
Question: When all of the people are trying to get on the boat, how does a tripod just randomly come out of the water like that?
Answer: While it's never explained, there are several possibilities: as all the tripods were buried deep underground, this one may have been lodged below the lake and was just emerging. Also, a tripod could have "walked" from somewhere else, then went underwater to explore, and, attracted by the ferry's noise and movement, surfaced to investigate. It's also conceivable that, observing how ferries worked, it slipped underwater from further away and ambushed the boat, or the tripod was simply making a crossing from one shore to the other (traveling underwater if it was deep enough) and just happened upon the ferry when it did.
Question: Is there any indication as to where the aliens come from and what exactly they want?
Answer: In the original George Pal version they were Martians and the reasoning for what they were doing was never explained. In this version, its never explained where they come from, but their mission is simple, to eradicate human life from Earth, and use our bodies to fertilise the planet, probably so that they can colonise the planet for themselves.
Question: Several other answers and corrections state that the reddish liquid sprayed by the tripods was what essentially grew the red vines. However I thought I heard someone in the film say something along the lines of "using us (i.e. blood) as fertiliser". Can someone please clarify?
Answer: Since the tripods tended to spray the red fluid shortly after pulling a human into themselves, it seems a good assumption that the red fluid is essentially blood. Given this, it seems likely that the "spore" of the vines is spread in the red fluid.
Question: Near the beginning of the movie during the lightning storm Ray says "wheres the thunder?", Isn't thunder just the sound lightning makes and if you were close enough to the lightning wouldn't the sound occur at the same time as the flash?
Answer: Precisely - Ray is seeing the lightning but there is no sound of thunder at all - there is also no sound of the thunder as the lightning is getting closer too, it's just the lightning itself and that 'whooshing' sound, but the sound doesn't sound like thunder.
Question: In the scene at the ruined house, what is Ray doing in the closed room while his daughter is closing her eyes and singing?
Answer: Tim Robbins was shouting quite loud (and losing his mind) and Ray did not want the aliens to discover their hiding place. He therefor had no choice but to kill (or possibly beat unconscious) Robbins in order to keep his daughter safe. Rachel was told to sing so she would not hear what her father was doing.
Question: Why did the aliens need the human blood, and why did they spread it around? Also, when Ray and Rachel are in Boston, he breaks a white thing off a statue. What was it? And why was it dying?
Answer: They didn't spread blood around. That was a red fluid seeding the planet with the red vine. The red vine was the first stage in making the Earth suitable for Martians. At the statue, Ferrier broke off a piece of the red vine - dead and brittle. It was the first clue that Martian life wouldn't survive on Earth.
Question: Why didn't the aliens take over earth for their own means millions of years earlier? And why send machines millions of years before any humans or life that could be considered a threat?
Answer: It's not known when the aliens sent the machines--the 'millions of years' comment was just one bystander's speculation. The machines could have been sent well after humans evolved and for whatever reason, the aliens did not journey to Earth until much later. Obviously, humans were never considered a threat--just an incovenience to be eradicated. Because we don't know who the aliens are or how their society and technology works, many questions will remain unanswered.