On my way home from work, I noticed a large cloud that looked remarkably like one of those spaceships from Independance day entering the atmosphere. It got me thinking…
What effet would those three-mile-wide ships have on the Earth’s atmosphere? Is the massive fireball depicted a realistic visualization of the type of friction that would be generated?
I don’t recall the exact numbers from the movie so let’s say 100 ships 3 miles in diameter and 600 feet high.
Don’t know the answer to the question, but I do know the ships were 15 miles across, not 3.
For a really really cool comparison of fictional ship sizes checkout The Starship Dimensions page. They have practically everything: Star Trek, Star Wars, ID4 etc. The site is bandwidth heavy as its just a ton of graphics.
And according to them, yes the city destroyers were 15 miles long. The orbiting mothership was about 340 miles long.
As far as the science of Independance Day goes, ahem, to paraphrase Lex Luther, “All the accumulated knowledge of the universe, you’d think these dummies would’ve had Norton Antivirus installed…” 
Since you’re asking, I’d like to tag a question on from the same movie:
At the end, when the ship over Area 51 crashes, wouldn’t there have been some tremendous ground shaking when it hit?
The short answer is, “Who the hell knows?”
The long answer would explain why I’d need a lot more information regarding mass, exact geometry of the hull, hull material (assuming ablation on entry), means of propulsion, any aerodynamic deceleration aids, and a host of other things. It’s just unanswerable.
Nobody watched Independence Day to get a primer in aerodynamics, anyway.
One effect of the ships entering the atmosphere would be for them to displace a huge amount of air, flattening anything that was under them with hurricane force winds. The mother ship would have raised huge tides that would have wiped out all coastal cities. The aliens were stupid for even entering the atmosphere in the first place if they had plasma cannons that could destroy cities, and a single nuke isn’t going to do much more than make a minor hole in something 1/4 the size of the moon. There’s lots wrong with the movie.
While this won’t answer your question precisely, it will give you an idea of the kind of havoc and destruction which would have occured.
For that matter…why not nuke the alien ships in the atmosphere after taking the shields down? It’d be a hell of a lot more efficient that shooting sidewinders at 'em.
You underestimate the weapons humans have created.
A thermonuclear bomb is capable of having quite a lot of power. The one in Independence Day could have realistically been 500 megatons or more. That’s a big fucking bomb.
Not hardly. The largest bomb we know of is ostensibly a 100 MT monster the Soviets built. The never tested it at full power, though. The design was tested to 50 MT in 1961.
Not if they were using current weapons. B2-As either carry 200 kiloton nuclear cruise missiles (which is what they actually fired in the movie), or upwards of 9 megaton gravity bombs. The largest nuke in the US inventory right now is only about 25 megatons. The largest bomb ever detonated to date was 50 megatons.
I think you over estimate the weapons humans have created.
The largest nuclear weapon ever tested was the Tsar Bomba, which had a yield of fifty-seven megatons, was eight meters long, and weighed twenty-seven tons.
This weapon was so large and cumbersome as to be militarily useless. Kruschev claimed that the Russians had developed a 100-MT design, but it is highly doubtful that it was ever put into a stockpile.
The weapon used in ID4 was physically much smaller than the Tsar Bomba, and was (probably) an American-designed bomb—which usually had a lower yield than their Russian counterparts, anyway. In any case, the largest (yield) nuclear weapon still in the American stockpile is the Nine megaton Mk-53. Most current warheads have yields much smaller than that, usually topping off in the kiloton range.
That’s not to say that one nuke couldn’t cripple a 300-mile spacecraft…it all depends on where it goes off. If it went off, say, inside the ship, and in or around the main control room, or near the engines, it might cause quite a bit of damage. Maybe the mothership used antimatter for it’s engines, and the nuke blast caused a catastrophic containment failure. Who knows.
It still doesn’t excuse the computer virus working.
Getting back to the original question, the alien spaceships were clearly capable of hovering in the air. So they must also be capable of entering the atmosphere slowly, without causing any disturbance.
Of course they could also choose to enter the atmosphere at high speed and cause a sonic boom, or even a shock wave that reaches the ground, similar to a bomb blast. But even then, I don’t think it would look like a fireball. Red flame and black smoke are results of combustion, not just heating. There’s nothing in the air or on the surface of those ships that can burn.
Not to be a total party pooper, but this is a complete waste of time.
Emmerich & Devlin are the two biggest hacks in Hollywood. Short of not showing Jeff Goldblum & Will Smith walking around unprotected in a vacuum they base everything, and I mean everything, on how cool it will look.
This short thread here contains more scientific discussion on this movie than these two bozos ever had before & during making it!
Let us not forget that they made Godzilla, where they wouldn’t even keep the monster’s size consistant in order to get the shots that they wanted! One minute he’s as big as a building, the next he’s crawling thru a subway tunnel?!
B-B-But… in Superman, Lex got his hands on two 500-megaton bombs! Movies wouldn’t lie to us, would they?
Moreover, isn’t it remarkable that a a 15-mile-wide (not three, apparantly) spaceship with no aerodynamic properties positioned directly over Area 51 ended up crashing about 10 miles down the road?
Lawrence Krauss’ book, Beyond Star Trek, talks in depth about the effects those ships would have. It also talks about the “science” in several other movies/shows.
All in all, it’s a pretty fun read.
Fifteen miles across, eh? And they had those nifty green forcefields, which made them impervious to physical impact, and obvious antigravity drives…
Screw the funky plasma cannons. This is how the movie should’ve turned out…
Goldblum’s character warns the president that time has run out, that the alien’s countdown has expired. Unseen to us, an alien captain on each ship reaches over and flips a toggle…
And, all across the world…
The alien ships begin bouncing up and down, flattening entire metropolises with each impact.
The White House? Completely flattened.
Those people, throwing the parties underneath the ships? Nothing left but a red smear and a few party paper-thin party favors.
That damn dog, who could miraculously jump out of the way of the plasma explosion? Dead, dead, dead.
Heh heh… this is my favorite nit of the movie. “Yay! We know how to defeat their ships! Now let’s make several dozen fifteen-mile hunks of foreign metal hovering a few hundred yards above our largest, most important cites fall.”
Well, to be fair, if it were a choice between destroying a few cities and total extermination, I say toast Rome, Paris, Moscow, NYC, et al.