Yahoo's Time Capsule Project

eldavojohn writes, "Yahoo is compiling a time capsule (Flash required). This massive project, which accepts donations from anyone, is no ordinary time capsule, though. This time capsule will be digitized and beamed into space from the ancient pyramid of Teotihuacan in Mexico. From the article: 'Starting on Tuesday, enthusiasts from around the world will have a chance to submit text, images, video and sounds that reflect human nature to be included in the message.' I highly doubt this 'time capsule' will reach anyone, but it is a neat idea. After browsing through some of the pictures posted, I would hope extraterrestrial life would be more hesitant to exterminate us — if not for anything else than curiosity. We constantly strive to have our legacy live on in the galaxy." Yahoo worked with Internet artist Jonathan Harris on this project.

Send It To Ourselves

[cybrpnk2]

Something like this was proposed in the David Gerrold novels of his Dingilliad [gerrold.com] series. The sum total of human knowledge was constantly being shot around the solar system on a laser beam that bounced off of various retroreflectors on the different planets. If you waited some finite amount of time (an hour or so) for the next pass of Item X, anything you wanted could be siphoned off of the stream by setting up a telescope receiver and picking up part of the "spillover" laser beam that hit your colony location but missed the retroreflector. This dynamic "storage medium" was used at the time of the story instead of a "static medium" like physically immobile hard drives or memory chips.

As I recall, Gerrold presented some mumbo-jumbo that said the storage capacity of such an arrangement - a billions-of-miles-long laser beam - was truly enormous. Sounded like a pretty good idea. Anybody think it would really work - and better yet, be practical?

Re:Send It To Ourselves

[AeroIllini]

As I recall, Gerrold presented some mumbo-jumbo that said the storage capacity of such an arrangement - a billions-of-miles-long laser beam - was truly enormous. Sounded like a pretty good idea. Anybody think it would really work - and better yet, be practical?

It does sound like an intriguing idea. Some of my thoughts on the subject:

In order to maintain a constant signal strength, each receiver/transmitter would need to "boost" the light signal, presumably by adding a beam of light of its own. The spillover light you mention is a result of the focus angle, and if some of it is not reflected, then the light signal degrades with each station. Also, reflection itself is lossy; some light is always absorbed by the mirror. The whole system would dim over time unless you boosted it back up periodically.

In order to boost the signal, you would probably need to have the signal not be reflected, but rather collected, processed, and retransmitted. Since nothing travels faster than light (according to Einstein, and I hear he was pretty good at math), it would be impossible to collect a signal, interpret it, and send an identical signal in the time it takes to reflect. So the boost signals would be slightly behind the source signals, resulting in some phasing of the signal over time. The whole thing would "blur." That means we're left not with reflection, but with collection and retransmission. There would be a slight delay, but it would work like the 7-second delay built into radio stations: if it's constant, no one notices. The other alternative would be to place enough mirrors between the reception mirror/signal collector and the transmission mirror/signal booster to keep the timing of the signals lined up. But the signal would still need to be collected and retransmitted, perhaps through a partially-silvered mirror at the outgoing end. All this would require that each station be powered. Even if you used the incoming light to power the system (and did no reflection at all, simply collect light -> generate power -> read signal during generation using generated power -> retransmit using generated power), the act of collection/retransmission, and the spillover, will result in a negative net power generation, and power would need to be supplied. This could probably be taken care of with solar cells or something, but that brings us to the question of...

Maintenance. The system you're talking about, with one giant ring of retransmission stations, allows for a single point of failure, which would result in loss of data. This is unacceptable. Instead, I would propose building each station so that redundancy is built in; there would actually be several rings transmitting identical data in parallel. With proper "junction" stations, one could even build a striping system that would ensure that even if several receivers/transmitters went down, no data would be lost.

However, if this were being accomplished in a solar system, it would have to be bounced off satellites in a polar orbit around the sun, to avoid the situations where the signal would need to travel close to the sun and receive interference. A better system than bouncing just between planets would be to have the planets be just stops on the loop, with the majority of stations as satellites in very eccentric orbits around the sun (all the solar systems we know of so far have all the planets basically in a single plane of orbits). The planet stations themselves, of course, would be satellites in orbit around those planets to avoid all the nastiness with transmitting through atmosphere.

Additionally, the stations themselves would need to be self-correcting for perturbations in orbits and pointing angles. This can't be accomplished by a central server or even by communication between the satellites, since that communication would take place at the speed of light, and misalignment would result in loss of data. Each station would have to be semi-intelligent about orbit perturbations and alignments.