NASA Laser Communication System Sets Record with Transmissions to and from Moon • Hacker News Board

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#21

Post by throwaway9101 » Wed, Oct 23, 2013, 2:45 PM UTC

milliams wrote: post #7

2close4comfort wrote: post #2

That is better than the connect at my house. I am moving there!

The latency would probably kill you though.

Or the cold.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#22

Post by drakeandrews » Wed, Oct 23, 2013, 2:46 PM UTC

toomuchtodo wrote: post #14

gprasanth wrote: post #9

Earlier quoted context omitted.

Unless, our technology advances to always do stuff a couple of seconds in advance by knowing our intents.

Or we figure out how to use quantum entanglement or gravity as information transfer mechanisms.

Unless we discover gravity is bound to the speed of light too.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#23

Post by agashka » Wed, Oct 23, 2013, 2:47 PM UTC

erid wrote: post #4

The latency must be huge though.

wouldn't it be less then RF? Radio Frequencies travel at the speed of sound, while lasers would be light-speed, from my understanding. I'd really love some insights on this!

EDIT: I still need to learn a lot on signals!

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#24

Post by danbruc » Wed, Oct 23, 2013, 2:49 PM UTC

toomuchtodo wrote: post #14

gprasanth wrote: post #9

Earlier quoted context omitted.

Unless, our technology advances to always do stuff a couple of seconds in advance by knowing our intents.

Or we figure out how to use quantum entanglement or gravity as information transfer mechanisms.

Gravity propagates at the speed of light, too.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#25

Post by robin_reala » Wed, Oct 23, 2013, 2:50 PM UTC

agashka wrote: post #23

erid wrote: post #4

The latency must be huge though.

wouldn't it be less then RF? Radio Frequencies travel at the speed of sound, while lasers would be light-speed, from my understanding. I'd really love some insights on this! EDIT: I still need to learn a lot on signals!

Radio waves are EM waves, same as light. They all travel at c.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#26

Post by zargon » Wed, Oct 23, 2013, 2:51 PM UTC

agashka wrote: post #23

erid wrote: post #4

The latency must be huge though.

wouldn't it be less then RF? Radio Frequencies travel at the speed of sound, while lasers would be light-speed, from my understanding. I'd really love some insights on this! EDIT: I still need to learn a lot on signals!

Radio is not sound, it is an electromagnetic wave that travels at the speed of light.

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#27

Post by sslayer » Wed, Oct 23, 2013, 2:54 PM UTC

toomuchtodo wrote: post #14

gprasanth wrote: post #9

Earlier quoted context omitted.

Unless, our technology advances to always do stuff a couple of seconds in advance by knowing our intents.

Or we figure out how to use quantum entanglement or gravity as information transfer mechanisms.

Spooky TCP

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#28

Post by Aardwolf » Wed, Oct 23, 2013, 2:54 PM UTC

nraynaud wrote: post #6

paulgerr wrote: post #5

Earlier quoted context omitted.

2.6 second round trip for light, so pretty huge ping times.

That's why I always found moon people to be lame at quake!

One day technology will really have to do something about lightspeed to allow interplanetary quake!

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#29

Post by femto » Wed, Oct 23, 2013, 2:55 PM UTC

ck2 wrote: post #8

How huge is a 1mm beam when it hits the moon (and visa-versa) ? I wonder if wolframalpha can tell me... Actually, I don't even know how to ask it the proper question. Can anyone make this formula work in wolfram? http://laserpointerforums.com/attachments/f51/17952-calculat... update: I think I figured this out as ((λ * L) / d)* 2 (((630nm in meters)*(380000km in meters)) / (1mm in meters)) * 2 Which would be a nearly…

The width of the beam is determined by diffraction, caused by the finite aperture of the laser:

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/cirapp.htm...

Re: NASA Laser Communication System Sets Record with Transmissions to and from Moon

#30

Post by robodale » Wed, Oct 23, 2013, 3:02 PM UTC

agashka wrote: post #23

erid wrote: post #4

The latency must be huge though.

wouldn't it be less then RF? Radio Frequencies travel at the speed of sound, while lasers would be light-speed, from my understanding. I'd really love some insights on this! EDIT: I still need to learn a lot on signals!

oh boy.