I have a crazy idea. The round trip travel time of light to the moon and back is about 3 seconds, and we did leave a mirror up there. At modern modulation rates and with multiple frequencies of light in use at the same time (aka different color lasers), a lot of data can fit into that 3 second window.
A memory made of the vacuum of space. The lightest hard drive ever.
Sure. You can also do radio moonbounce, which radio hams routinely do.[1]
About 2.5 secs of lag. It takes a sizable antenna. You could probably use that as a delay line. Noisy, so error correction will be necessary.
Laser moonbounce is harder to do than radio.[2] Early systems used so much laser power that they had to be equipped with radars to turn the system off if aircraft were in the area. Later systems with safer lasers could detect single photons with a 40cm telescope and transmit a 2KHz signal.
Here are some SLR2000 papers that are more easily accessible.[1][2]
Doing this with low-power lasers requires rather good receiving optics.
There has been a major breakthrough in laser data transmission - the first cat video has been sent by laser to and from a spacecraft. "At the time, Psyche was traveling 19 million miles (31 kilometers) from Earth, about 80 times the distance between Earth and the Moon. Traveling at the speed of light, the video signal took 101 seconds to reach Earth, sent at the system’s maximum bit rate of 267 megabits per second."[3]
I think this is a candidate for best two sentence combo ever written:
So we have 1 million chainsaws per second, for 335.36 hours, which is 1.215 × 10^12, a configuration known as tera-wield. This requires expert juggling skills.
Not a 2 sentence combo. Also, for the confused, there are 19 characters if you consider non-trivial rotation to be switching between different characters.
The straightfaced and unhinged nature of the chainsaw section reminds me of Hitchhiker's Guide to the Galaxy, and probably some Kurt Vonnegut stuff. I love this style of writing.
Figure 1 is somehow beautiful in it's chaotic dis/organised structure, a representation of the whole internet, something which us humans now so heavily rely on
It's a rabbit hole that had be fascinated for quite a while.