Originally posted by karajorma
I don't think the penetration of the ray is linked to the fact that it is ionising or non-ionising. Gamma rays are non ionising radiation
Uh, gamma rays are
very ionizing. As far as I know, gamma rays are the highest frequency on the EM spectrum, and also have very high penetration. They are not appreciably deflected by electric or magnetic fields (and, hence, electromagnetic fields), either. Earth's atmosphere does provide good protection from them, though -- I think it's the ozone layer.
Alpha particles on the other hand are most ionising of the three common types (alpha, beta and gamma).
Alpha and beta particles are not EM. An alpha particle is the nucleus of a helium atom (2 protons + 2 neutrons), and beta particles are electrons or positrons (antielectrons).
yet they can be stopped by a piece of paper! 
Alpha particles are stopped by paper. Beta particles go right through it as if it weren't there. Gamma rays do too.
Cosmic rays aren't actually EM despite the name. They are actually particles travelling at a fair proportion of the speed of light.
Some of them are, some of them aren't. The term 'cosmic ray' refers to all sorts of radiation of extraterrestrial origin (usually from outside the system). This includes gamma rays, protons, alpha particles, and so on. Collision with Earth's atmosphere has interesting effects on cosmic rays, such as transforming them into some other sort of ray or particle.
As long as the ray is charged you could deflect it with a EM field but if the particle is a neutron then the field won't do much about it.
Right, EM fields only affect charged particles (and, hence, all atoms, and the nuclei and electrons in plasma). The strength of the field versus the velocity and mass of some incoming object (particle, atom, spider, ...) determines how much of an effect there is on that incoming object. This means that gamma rays
are affected by EM fields, though you'd need a pretty strong field to deflect them (like Shivan shields
).
Originally posted by Carl
well, how did they do it when they went to the moon? no van allen belt there, right? i don't know about using lots of lead, though.
Speaking of Shivans...
Anyway, the moon's orbit is very close to the Earth, and well within its Van Allen belt, so orbital and lunar craft and personnel are protected by it.
that's really heavy stuff, and when you're going to mars, you've gotta be really stingy with your fuel.
Not if your fuel is deuterium or antimatter.
...i seem to remember something about 256 colors for some reason.
Probably the old software rendering engine in FreeSpace 1. Software renderers generally do 256 colors only, presumably because higher bit depths would slow them down. The software renderer is still in FS2, but it's disabled, presumably because of new graphics stuff like the full nebula.
Originally posted by Fry_Day
There are two 'why's that I can see. First one is, "Why are images converted to 16-bit internally", to which the answer is, they just are. I'm guessing Volition never considered storing the textures at 32-bit internally since that would be a total waste of on-board RAM when you're using an 8MB Matrox G200 or 16MB Riva TNT. That could probably be changed, but there are lots of places in which it needs to be changed.
Storing the textures at 32-bit internally means storing them as 32-bit on
main memory, not the video hardware's texture memory. Converting to 16 bpp could be done when the textures are transferred to the video card, or it could be done when the textures are loaded off the disk, as necessary.
The other question is "Why is there quality loss?"
Well, a 256-color image can choose out of 16777216 different colors (2^24), giving you 8-bits per channel. If the image is say, greyscale, it would have 256 different shades of grey (including white and black, of course), yet, a 16-bit image, stored in the 565 format, would have only 64 (2^6) shades of grey, and even then, they wouldn't be exactly grey. A lot of images with smooth gradients can suffer such problems even if they managed to be converted fine (Look at nebulae backgrounds).
I didn't ask why there is quality loss. I know why there is loss of quality in 8 and 16 bpp -- the only way to retain the quality of a 32 bpp texture is to not convert it.
And, beyond that, I just love it when this forum becomes a discussion of theoretical physics
Since this is a forum about a space combat simulation, I would imagine that happens reasonably frequently. By the way, most of this physics stuff isn't theoretical -- it's well known physics, much of which is taught in school / college.
