Updating gatherer database
It is a sphere which will grow at almost—but never quite—the speed of light.
five years to the triple system of Alpha Centauri, ten to that strangely matched doublet Sirius A and B, eleven to the tantalizing enigma of 61 Cygni, the first star suspected of possessing a planet.
At the worst, these will amount to eleven hours—the time it takes a radio signal to span the orbit of Pluto, the outermost planet.
Between the three inner worlds Earth, Mars, and Venus, it will never be more than twenty minutes—not enough to interfere seriously with commerce or administration, but more than sufficient to shatter those personal links of sound or vision that can give us a sense of direct contact with friends on Earth, wherever they may be.
These journeys are long, but they are not impossible.
Man has always accepted whatever price was necessary for his explorations and discoveries, and the price of space is time.
Bidirectional information transfer is called information exchange.
Suspended animation, an undoubted possibility, may be the key to interstellar travel.Communication within the orbit of Neptune will be at a maximum travel time of about 8 hours (though that can increase to up to two years if you decide to include the Oort cloud).No way around it: a galactic empire is going to need FTL starships and/or FTL communication.In this sense, information transfer is equivalent to data transmission which highlights more practical, technical aspects.The information transfer rate may or may not be equal to the transmission modulation rate.