Silly question

[Polynomial]

[quote]Thanks for the info Craig and PolyN. I've never really paid any attention to the clocks and radios and beams etc. I don't have a manual, the FS was given to me so I don't have instructions about the lessons etc.

As far as the Astronauts are concerned, I don't think it matters what time it is when you leave Earth. It would be more for the benefit of 'Mission Control' and schedules etc. So whatever is convenient would work well enough.

Hey Polyn. I think you're going to win next years Competition with that Signature. I think it's GGRREEAATT.

I'm not into modern aircraft much at all, but I do recognise and love my F16.

[Oso]

But light exerts no force so it doesnt have a mass??

Read up on solar (light) sails for interplanatery travel. It does have a force, albeit small. A few kilometer diameter sail could have a spacecraft going the biggest part of the speed of light in a few years.

[Professor Brensec]

Read up on solar (light) sails for interplanatery travel. It does have a force, albeit small. A few kilometer diameter sail could have a spacecraft going the biggest part of the speed of light in a few years.

Very true. I'm aware of these devices. I don't know if there has ever been one used or not, probably not.

But being an avid Trekkie, it's something that has featured in a couple of the later series. It is apparently a proven phenomena that light does exert a force, not unlike a light breeze, in the vaccuum of space. After all light consists of 'particles' that are moving. That being the case, they could cause movement if harnessed.  ;D

[BFMF]

So your saying my flashlight does nothing but shoot out particles???

[stormy]

lol Andrew..  ;D

[Professor Brensec]

So your saying my flashlight does nothing but shoot out particles???

Apparently so mate. I'm not really that well up on light and the composition of same, but I'm led to believe it is a combination of rays or waves and particles.
I'm not sure, other than to say that it dose have 'mass' of some sort.

I'll have a read up on it and let you know. I'm interested myself anyway.  ;D

[Rifleman]

It makes sense that UTC time is used on antarctica, but why wasn't it used by astronauts on the moon......

The time used on Lunar exploration was "MET", if my memory serves me well...... ....it was much more convenient for them to start the mission clock on launch and stop it at splashdown.....

Mission Elapsed Time              e.g.    T+ 49 Hrs 32 Secs

[Polynomial]

The way to look at light though is this:

Some ways it can be explained as a wave and others as a particle and even sometimes as a wave and a particle at the same time.

Solar sails sound expensive and very impracticle.

I still struggle to understand the particle theory of light, if it is a particle - why doesnt the glass in front of lights, or as Andrew says in your flashlight stop the particles escaping?  But then the French scientist De Broglie introduced the revolutionary theory of Matter Waves, because it was observed that while light obeyed both wave and particle theory, matter (i.e. stuff u can see down to electrons and particles) obey wave laws.  Believe it or not, when you throw a tennis ball it moves with wave motion.  This is called wave-particle duality and it is a very complecated branch of physics but it nonetheless is very fascinating.

Don't you just lover pondering the questions of the universe?!?!

[Professor Brensec]

Here you go - a quick explaination about the difference between Solar light and Solar wind. Also the difference between Solar Sails and Solar cells.
Plus a mention of 'photons' which are 'light particles'.

Solar sailing is a method of converting light energy from the sun into a source of propulsion for spacecraft. In essence, a solar sail is a giant mirror that reflects sunlight in order to transfer the momentum from light particles (photons) to the object one is interested in propelling. Since the phrase "solar sails" is often confused with "solar cells", which is a technology for converting solar light into electrical energy, we will use the term "light sail" for the purpose of this discussion.

[Polynomial]

Nice clear explanation Professor!

[Travis]

Just FYI--to date, no solar (okay, LIGHT) sail has been built, nor is there any forseeable time that one will be built.  Someone would first have to figure out some way to keep the other particles of space matter (atoms, flying at ~160 mps, or 1/1000th light speed) from blasting holes in the sail.  One marble-sized piece of rock travelling at that speed could completely destroy a light sail.  And the chances of something like that hitting a sail so big (many square kilometers) is very high.

I don't know how this conversation went from time at the poles to space travel, but there are many other, better ways to get from star to star.

[Scottler]

I agree Ender Baron.  In fact, in Hollywood, they sell maps, and will even take you on tours!

[Travis]

LMAO!!  Your wit continues to catch me offguard, Scott!

[Scottler]

Glad to be of some use.  ;)

[Rifleman]

And here I was going to offer up the writings of Zephram Cochrane...........as a means of getting from star to star.........