[QUOTE=damnatus;50123858]20% of light speed is relativistic? I thought it's like, 95%[/QUOTE]
95% is where you start to really feel time dilation
shit starts getting funky pretty quick, less than 10% makes things start to get trippy
[QUOTE=paul simon;50124036]
How would sapphires help, exactly?
[/QUOTE]
Tried to find out exactly why
[url]http://www.niac.usra.edu/files/studies/final_report/4Landis.pdf[/url]
[quote]Silicon dioxide is particularly well characterized, and has a
high emissivity. Aluminum trioxide (alumina, or "sapphire") is also well characterized, and has a somewhat
higher refractive index and a considerably higher melting point, resulting in higher performance as a sail
material.[/quote]
I don't claim to be any kind of expert btw
[QUOTE=_Axel;50124096]The astronomers who pointed lasers at a mirror on the moon didn't seem to have problems with that. I think you overestimate the diffusing effect of the atmosphere.[/QUOTE]
The moon is very close, and the margin of error was probably quite big as their laser beam was probably pretty wide.
From my experiences with telescopic equipment, atmospheric distortion is a pretty noticeable thing even on cold nights, and if you require perfect optics to pull something like this off.. well, the atmosphere of the earth will be the bottleneck of your optical system.
how the fuck does it brake?
[QUOTE=kimr120;50124570]how the fuck does it brake?[/QUOTE]
Maybe travel close to a star and use gravity to slow it down? Nukes exploded in space are also a feasible idea to accelerate/deccelerate but I have no idea how you could make sure the nuke is in front of the space craft.
[QUOTE=mdeceiver79;50124612]Maybe travel close to a star and use gravity to slow it down? Nukes exploded in space are also a feasible idea to accelerate/deccelerate but I have no idea how you could make sure the nuke is in front of the space craft.[/QUOTE]
potato chip sized nukes
[QUOTE=Empty_Shadow;50124110]95% is where you start to really feel time dilation
shit starts getting funky pretty quick, less than 10% makes things start to get trippy[/QUOTE]
10% makes no big differences, aka a 0.005% time dilation vs. when you're not moving
y axis is gamma, the lorentz factor, you divide your ''proper'' time by it to get your dilation.
x axis is your % of your speed compared to light speed
[IMG]http://newt.phys.unsw.edu.au/einsteinlight/jw/images/gamma.GIF[/IMG]
[QUOTE=kimr120;50124570]how the fuck does it brake?[/QUOTE]
It Doesn't.
[editline]13th April 2016[/editline]
Just to clarify, they plan on sending hundreds of the little buggers at once, this way it wont need to stop to scan the system they can just use the data by all of the nano-ships and piece it together during a flyby.
[QUOTE=Morgen;50123595]I was under the impression that the laser would be firing at the sail for a relatively short period of time.[/QUOTE]
Assuming all of the laser power is concentrated on the sail, and assuming the craft weighs 10 grams, my (possibly incorrect) calculations put the length of acceleration at 3 weeks. So much shorter than the "many years" I originally mentioned, but still a sizeable length of time.
[editline]14th April 2016[/editline]
Alright, I forgot to account for the fact that the sail would be reflecting the light, so you can halve that value to 1.5 weeks.
[QUOTE=Headhumpy;50125377]Assuming all of the laser power is concentrated on the sail, and assuming the craft weighs 10 grams, my (possibly incorrect) calculations put the length of acceleration at 3 weeks. So much shorter than the "many years" I originally mentioned, but still a sizeable length of time.
[editline]14th April 2016[/editline]
Alright, I forgot to account for the fact that the sail would be reflecting the light, so you can halve that value to 1.5 weeks.[/QUOTE]
It'll probably take longer they cant fire the laser 24/7 because of the earths rotation.
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