Nitpicking on Doom 3's astronomy.

[Maes]

Maybe it's a massive blooper, may it's not:

according to wikipedia's article on Mars as well as common sense and simple maths, the surface gravity on Mars should be roughly 1/3rd of that of the Earth, yet the Doomguy doesn't seem able to jump any farther and higher or walk/run any faster than he would on Earth.

The situation with Phobos is even more paradoxical, since it has a surface gravity that's literally 1/1000th that of the Earth, so little in fact that everything could be flung in space with little effort!

Artifical gravity inside artificial stuctures and buildings could help explain that, but there are outdoors areas to account for...

Also, the sky on the few outdoors areas on Phobos don't appear all that different from those on Mars, even if there's no atmosphere to speak of (let alone that exiting a building would leave you practically exposed to outer space, not just a thin atmosphere...).

[Creaphis]

The Doomguy sticks to the surface of Phobos because the UAC accelerated its spin. You forgot about centrifugal force, silly!

[Maes]

Creaphis said:

The Doomguy sticks to the surface of Phobos because the UAC accelerated its spin. You forgot about centrifugal force, silly!

That, if anything, would work even more against gravity. Centrifugal force is directed...well...away from the center of rotation, so it actually adds a small (in the case of the earth) acceleration against the force of gravity. Unless Phobos is actually hollow and all of UAC structures are build on the inside...

[Creaphis]

No no no, they accelerated the spin the other way.



(My first post was intentionally ridiculous.)



This is something I have actually considered, and, as there's no canonical man-made gravity well implanted in the cores of Deimos and Phobos, I think we have to assume that at some point the extremely low gravity of those moons was deemed less important than the wicked awesome fact that their names mean "fear" and "panic" respectively.

Aside from just accepting this glitch as another part of Doom's campy appeal, I can think of two ways to resolve this.

1. There ARE massive man-made gravity sources in Phobos, Deimos, and Mars too, while we're at it. This allows the moons to be easily traversable and to hold an atmosphere thick enough to provide oxygen and trap solar energy. This huge increase in gravity in the region massively increases the tidal effects between Mars and its moons, which means that the moons could break apart or crash into Mars at any moment, making the artificial gravity sources not really worth the investment, but UAC isn't known for its foresight.

2. The gravity actually is really low. The more you think about it, the more it makes sense. Imps and demons stay stuck to the ground due to their spines and claws. Zombies remain on the ground because of their natural affinity to dirt. Cacodemons and lost souls don't really have flight powers, they're just falling with style. AND, here's the most convincing evidence: this explains why the Doomguy never jumps; he knows that, if he did, he might never come back.

[Coopersville]

Doomguy makes up for it with two hundred pounds of ammo and equipment.

[kristus]

I don't want to play through an entire game of low gravity maps.

[Creaphis]

kristus said:

I don't want to play through an entire game of low gravity maps.

Right, that's something else I was going to say. Low gravity in games is an awkward device in general, and really isn't ever modeled anywhere close to accurately. In real life, lower gravity would cripple your acceleration. You need high gravity to give your feet more friction, and so that you can quickly redistribute your weight into a running stance. But, I can't think of any games where this is implemented. For game developers, low grav = high jumps. For gameplay value, that's probably the best way to implement the concept, but that means that whenever I'm playing a new map for ZDoom, or UT2k4, or something else, I'll be running around minding my own business with no visible signs that gravity is low until I jump - and then wait, very, very patiently, to return to earth, which is where I would prefer to be.

[Enjay]

I *think* "Red Faction" (also set on Mars) may have had a nod to the low gravity. It felt slightly lower gravity that most Earth-bound games (IMO) but it wasn't so low as to be annoying.

Oh, and seeing as how it was mentioned, centrifugal force (as most people think of it) doesn't really exist:

http://en.wikipedia.org/wiki/Centrifugal_force_(rotating_reference_frame)

[Gez]

Heh.

[Tetzlaff]

Maes said:

Also, the sky on the few outdoors areas on Phobos don't appear all that different from those on Mars, even if there's no atmosphere to speak of.

You don´t visit Phobos in the official Doom 3 game. If you mean "Phobos Labs" in Resurrection of Evil: they are as well located on Mars itself, not on the moon Phobos.

Enjay said:

I *think* "Red Faction" (also set on Mars) may have had a nod to the low gravity. It felt slightly lower gravity that most Earth-bound games (IMO) but it wasn't so low as to be annoying.

Yes indeed, Red Faction made jumping a bit floaty to simulate the low gravity on Mars. I also think it was done fairly well, but I didn´t miss it in Doom3.