The Perfect Spacecraft

[the_big_m_in_ok]

onthecuttingedge2005 said:

...there used to be some Physics literature on the mass of light which was so small that by physics standards was to infinitesimal to categorize as a mass unit. so I think it was never employed as a unit of mass and hence was given as a massless particle or wave.

Hey, Jerry,

Well, the laser does actually move, so light must be something massive enough to do the job.

But, I do know this:

e=mc^2

So, the energy in 'e' is measured in ergs.  An erg equals one gram moved one centimeter in one second.  An expression of power.
So then, a laser, emitting light isn't changing mass, unless electrons expended in the creation of the laser beam are equal to the mass, 'm', of the equation?  Electrons do have mass.  Not much, but they do.

--Lee   

[triffid]

I watched some videos on u-tube about solar sailing.It said that sunlight always exerts a pressure on any object it touches.There are scales that will weigh to a thousandth of an oz.
And it has to be kept out of sunlight or it affects the readings when they weigh GOLD in london.In connection with the gold markets.The u-tube video said it was a very slight pressure (as much pressure as a piece of paper in your hand).But its always there and can be used to send man to other planets and even on to other star systems.Triffid

[triffid]

Think of the pressure that sunlight exerts on the earth.Oh, it balanced out a long time ago, I guess.
But an object the size of the earth would have a lot of sunlight pressure pushing down on it.Food for thought here?Triffid

[the_big_m_in_ok]

triffid said:

Think of the pressure that sunlight exerts on the earth.Oh, it balanced out a long time ago, I guess. But an object the size of the earth would have a lot of sunlight pressure pushing down on it.Food for thought here?Triffid

@triffid
Yes, light pressure---according to scientists---exerts several thousand of tons of 'thrust' pressure on the sunlit side of the earth.  However, nothing happens in outward orbital movement because the earth has a mass of 5.94 *10^24 metric tonnes.  This figure, I remember, is from the CRC Handbook of Chemistry & Physics, a yearly published American reference.

--Lee

[triffid]

Like I said,it balanced out a long time ago(orbital movement of the earth).So maybe someone can figure out how to use some of that several thousand tons of sunlight pressure to shoot payloads into space?Like a ram pump in a stream of water.Which uses the pressure of the water in the the stream to pump water upstream up a certain distance.Even molecule sized payloads(water comes to mind)would have value.triffid