Scientific Questions

[TerranC]

I've always thought that Aaron got his ideas of Null space and Phased Polarons from Trek...

But Solar sails I think I can answer.

The Sun creates Solar winds; a path of ions (Methinks) that travel at high speed and keeps hitting our planet's magnetic sphear.

Solar sails are supposedley knit very closely that it catches the solar winds, and since the sail is made of a very thin substance, it can be propelled by the Solar winds.

A russian team funded by a company tried to launch a solar sail craft, but failed twice.

Edit: Mesons:

"All particles that participate in the forces that hold nucleons together in atomic nuclei."

Can't answer more than that; Wish I took physics.

[ June 09, 2002, 21:25: Message edited by: TerranC ]

[Taera]

Thanks for the sails.
Mesons? I also didnt take physics and now i dont know any much about that.

As for trek stuff it still should have semi-scientific explanation. so im curious (yes right, just a little too much)

[Batman]

Originally posted by Taera:


Ok.

*Solar Sail: i've met the thing in several other
places and curious how does it work

Photons have momentum (although no mass). So when photons hit something, they impart their momemtum to it and push it along. Of course, they don't have much momentum, so they don't push things very hard. Roughly, a solar sail would be about the size of a small country would be needed to propel a spaceship, and acceleration would be agonizingly slow. On the plus side, solar sails (in theory) could get ships up to a significant percentage of lightspeed (like, 50% say)

Meson BLaster: what *mesons* are?

Short answer: Mesons are sub-atomic particles (i.e. smaller than an atom, in fact, smaller than electrons, neutrons and protons). Long answer: study physics a lot, then study it a lot more.

*Phased Polaron and Phased Shields - no idea what these are
*Why null-space skips anything?

I think these are just made up. Polarons might be real, but as always google comes to the rescue. A google search for +meson +subatomic comes up with a whole bunch of useful results. A search for +polaron +subatomic comes up with (mostly) episode synopses for Star Trek Voyager.

I suppose, in theory, the idea is that regular shields have a natural polarization (i.e. they admit electromagnetic radiation which has its components oriented in a certain direction). Phased polaron beams would (presumably) oscillate in this direction, and pass right though. Phased shields would stop this.

The important thing to remember is that most of it is not scientifically accurate (like too much science fiction (See also: Star Trek Voyager)). If it inspires you to actually learn a little about science, then it has done its job. Just don't get discouraged when the actual science isn't so immediately fascinating

[Mephisto]

IIRC photons have a very small mass and a very high momentum. With a larger sail (not THAT big, several hundred meters) you can gain very high speed over time because of the constant pressure applied by the light. However, it would be very hard to navigate with such a sail as you can only sail with the photons (i.e. away from the nearby sun) and have no force (like friction) to "cruise" lake a real ship can in water.

[Ed Kolis]

Isn't it funny how you can use solar sails to fly INTO the sun in SE4?

[AeoN2]

Originally posted by [K126]Mephisto:
IIRC photons have a very small mass and a very high momentum. With a larger sail (not THAT big, several hundred meters) you can gain very high speed over time because of the constant pressure applied by the light. However, it would be very hard to navigate with such a sail as you can only sail with the photons (i.e. away from the nearby sun) and have no force (like friction) to "cruise" lake a real ship can in water.

If I remember my physics correctly light both has mass, and acts as it has no mass at the same time. For instance no mass can travel at the speed of light (according to E=MC2), but it still has mass in other calculations... i am tired and know i am rambling now though

I know I've learnt about Mesons, but I can't for the life of me remember anything about them... My favourite subatomics have always been Gravitons (though I still don't think they have proven they exist, am I wrong?)

The latest I think heard about solar sails is that there is a new deep space probe that NASA are developing that will use a solar sail, I think they have successfully tested the technology... but it could be sleep-deprivation combined with too many Star Trek episodes

DISCLAIMER: Star Trek used as an example because it was mentioned earlier, truth be told I prefer B5

--
AeoN2
--
Maugham's Thought:
Only a mediocre person is always at his best.

[Batman]

Photons *may* have an infinitesimally small mass, but it could also be zero (it's a topic of current physics research). The problem is that photons travel at the speed of light (by definition) and that as something approaches the speed of light its mass increases by a factor of

gamma = 1/(sqrt(1-v^2/c^2))
(where c is the speed of light and v is the object's speed)

which means that an object with mass should never be able to reach the speed of light, because it would have infinite mass and require infinite energy to accelerate further.

They have a momentum that is disproportionately high for their mass, but it isn't extremely high. If the photon momentum was too high, sunlight would knock you over

As far as the required size of the sail, you have to bear in mind that the further that you get from the star (or other source of light) the less dense the photons are.

If we take the output of photons to be constant, then the same amount of photons is spread over a spherical shell at a distance R from the sun. The area of this shell is A=4/3*Pi*R^3. A sail of area B captures B/A of the total photons emitted by the star. At double that distance from the star, the area of the shell is A2 = 4/3 * Pi * (2R)^3 = 8*4/3*Pi*R^3 = 8*A. So the same sized sail now captures only B/(8*A) of the total photons (because they are less dense). At double the distance, the sail is 1/8 as effective, and so on. So it should be big if it is to maintain effectiveness for the whole voyage.