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geekmarine

The gravity of the situation...

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Has anyone ever stopped to think about Doom's gravity problems? Okay, it seems that Earth, Hell, Phobos, and Deimos all have the exact same amount of gravity, as demonstrated by when you fall off a ledge. Now, I guess the Earth and Hell thing are believable, but what about the two moons? I mean, they are basically little more than rocks in orbit around Mars. Our moon, which is gargantuan in comparison, has only 1/6 of Earth's gravity. The gravity on Mars' moons should be next to nothing. I mean, in reality, if the Doom Marine were running across a pool of sludge, he wouldn't need a radiation suit, as most likely by the time he got across, his feet would probably still be in the air. It's a good thing he can't rocket jump, because that would probably be more than enough to blast him into orbit, or even worse. Yes, I know it's stupid, but I was thinking about it last night and felt it had to be mentioned.

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Maybe some wise guy in UAC came up with the idea of artificial gravity on the moons.

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I noticed that too. Doom's gravity is certainly not believable, but..

Ichor said:

Maybe some wise guy in UAC came up with the idea of artificial gravity on the moons.

That's what I'm thinking too.

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Believable? Is that something like Jesus Christ?

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mmnpsrsoskl said:

Doom doesn't have gravity, you fall at a constant rate. I think.


nope, it has normal accelerative gravity.

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mmnpsrsoskl said:
Doom doesn't have gravity, you fall at a constant rate. I think.


Quite the opposite; in Doom things fall with constant acceleration(*), and there is no air resistance I think.

(*) Except in the first tic, where the acceleration is doubled - presumably in an effort to compensate for the player-overhanging-the-edge which makes the fall start later than might be expected in reality.

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Really. The Doomguy's suit has to have a mass of 300 kg or so (that would explain his ability to survive direct impact rockets and 10's of bullets).

Under those circumstances, I think his behaviour in response to the gravity is pretty realistic.

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geekmarine said:

Yes, I know it's stupid, but I was thinking about it last night and felt it had to be mentioned.


Naw, that's not stupid, it's fun! You can have various degrees of gravity with editing features available nowadays, even have different gravity in different parts of the map, and can also change it during the progress of the game.

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Oh, now I remember what the Archvile in that place which can be called "Last Resort" told me once. Fortunately it (he?) was in a little cage for some reason, so I could talk to it from behind a ledge.

You see, teleportation math really gets complicated if you have teleporters/landings in places with different gravity. So the Archviles sat down on their consoles and thought of a solution. The easiest one was to simply force the moons to have a earth-like gravity (though maybe they did some adjusting on Earth's too)...

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I always thought that the anomalies on Phobos and Deimos were the cause of Earth-like gravity. Wasn't that explained in some official source? Hm, maybe I'm thinking of some fanfic I read. Dunno.

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CyRaptor said:

I always thought that the anomalies on Phobos and Deimos were the cause of Earth-like gravity. Wasn't that explained in some official source?


I don't think so, no.

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Yeah, if the UAC were smart enough to put moon bases on Phobos and Deimos, and they were smart enough to terraform them, then you know that they added artifical, Earth-like gravity to the mix.

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Seeing as how these things (Phobos and Deimos) are basically just big rocks in space it bothers me that your main concern is that they have an Earth-like gravity and not the fact they have buildings, atmospheres, mountains... :-)

Whatever, maybe id decided that on phobos (and deimos - and even hell) the effect of low gravity was not to make you lighter, but to allow you to run at 90 mph, a trait that was transfered to Earth in the Doom2 invasions.

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DOOM was originally intended to be set on the planet Tei Tenga, which would have had an atmosphere, Earthlike gravity, etc., etc.

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CyRaptor said:

I always thought that the anomalies on Phobos and Deimos were the cause of Earth-like gravity. Wasn't that explained in some official source? Hm, maybe I'm thinking of some fanfic I read. Dunno.


If so, then what about Hell? (the hell that Deimos floats above)





(200th post!)

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Fredrik said:

Really. The Doomguy's suit has to have a mass of 300 kg or so (that would explain his ability to survive direct impact rockets and 10's of bullets).

Under those circumstances, I think his behaviour in response to the gravity is pretty realistic.

Long time no physics huh?
Whether you are 300kg or 30kg you are affected by gravity the same. You fall at exactly the same rate of acceleration (ignoring air friction).

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A little science, why not?

Phobos is 22.2 km in diameter, as opposed to Deimos' 12.6. I suppose it's probable that buildings can be built on Phobos. As for the mountains, there is a (in relation to the size of the moon) massive crater called Stickney that takes up something like 1/7 of the moon's face. Judging by the map of the Phobos installation in the game, which is in a crater, it could be Stickney. Either way there'd be a ridge around the crater's perimeter that would rise a couple thousand feet above the center of the crater and look like mountains. Thre's really no explanation for the high gravity though, unless it is in fact caused by the anomaly.

Deimos can still be large enough to build an installation on, but there aren't any significant mountains or anything. However, since Deimos was floating above Hell it's likely that the gravity from Hell could also affect Deimos' (Deimos is probably being suspended above Hell with evil magic or something, not anything scientific).

Hell pretty much explains itself.

As for atmospheres on both moons: neither Phobos nor Deimos can be terraformed. There's no way. Deimos' red sky can be easily be explained away as the planet Mars in the sky, or Hell's own sky (which is also red). There's really no reasoning behind the white Phobos sky though, although I've heard a theory that the Phobos base is encased in a glass dome that refelcts sunlight, making the sky white. I'm not particularly fond of that one.

Maybe I'm overanalyzing just a bit? :)

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Note in Doom if you drop off a ledge from higher your knees bend more :)

We have to assume gravity has been implemented somehow, we've discussed many problems like this before, Doom ain't perfect sadly. Use your imaginations, whee...

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That dome theory might work if Mars and the moons were a little closer to the sun. That, and both moons have no atmospheres of their own. Even when the sun is up, the sky would be black on Phobos.

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You people remind me of those nerds arguing with Homer about Itchy & Scratchy at the comic store from that one episode of The Simpsons.

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According to the DVD-ROM "Mars: The Red Planet", astronauts would be able to reach escape velocity from Deimos simply by jumping (and could put themselves into orbit if they got it just right).

I always assumed that the Doom Space Marine therefore had special boots that prevented him from jumping upwards - and presumably he didn't have time to change into normal boots for his trip through hell or when he got back to Earth. Perhaps all the shoe shops had been destroyed by the hellspawn.

I'm sure that's how they'll explain it in Doom III.

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....unless they found a way to generate gravity artificially. It is set in the future, after all. If they can create plasma weapons (which would be very difficult, as if a plasma touches any surface whatsoever, it cools instantly) then I'm sure they can create gravity generators.

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Holy shit I just realised! Doom is just a game! The physics are totally arbitrary!

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Ultimate DooMer said:

....unless they found a way to generate gravity artificially. It is set in the future, after all. If they can create plasma weapons (which would be very difficult, as if a plasma touches any surface whatsoever, it cools instantly) then I'm sure they can create gravity generators.

I'd suspect artificial gravity is probably further in the future than things like terraforming (attempts could be started this century, albeit at a hideous cost) and teleporting (a laser beam was "teleported" recently, which is a start at least). Artificial gravity would presumably involve the creation of gravitons, but any working theory of quantum gravity was still a long way off the last I heard. I'm a few years out of date on such matters though.
Regarding "plasma", I'd imagined that some artistic license would have been used in naming the weapons, and that "plasma" may or may not be involved in the workings of them, and is not necessarily what gets spewed out.

Also, artificial gravity wouldn't account for the fact that a marine who can run at c. 90 mph can't jump upwards.

fraggle said:

Holy shit I just realised! Doom is just a game! The physics are totally arbitrary!

Heresy! Doom is real.

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fraggle said:

Holy shit I just realised! Doom is just a game! The physics are totally arbitrary!

Liar.

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