4 ms·
The error correction on the signal must be great for 15 billion miles+ distance
by ge96 2y ago
The error correction on the signal must be great for 15 billion miles+ distance
- ForOldHack 2y agoVoyager 1 is more than 15 billion miles (25 billion kilometers) away. Voyager 2 is over 13 billion miles (21 billion kilometers) from Earth. In fact, due to this distance, it takes over 23 hours to get a radio signal from Earth to Voyager 1, and 19½ hours to Voyager 2.
- ahazred8ta 2y agoThe signal we receive is about one RF photon per second per square meter.
- mmooss 2y agoThat's too incredible to be true. I'd love to quote it though - where does it come from?
- ahazred8ta 2y agoAh. This writeup https://gigazine.net/gsc_news/en/20240604-voyager-1-photons-per-bit https://gigazine.net/gsc_news/en/20240604-voyager-1-photons-... says that the 70m dish collects 240,000 photons per second, which is about 60 per second per square meter. The 1/sec figure was from the recent outage when Voyager's transmitter glitched and fell back to S-band. Received energy per bit is 4.5e-21 Joule across the whole dish, or 1e-24J per square meter.
- mmooss 2y agoToo bad; it was a great story. Still, they managed to communicate, in an emergency, using 1 photon/sec/m^2 !?