Voyager 1 is almost one light-day from Earth
Voyager 1 is one of humanity’s most poignant and remarkable technological achievements. During its nearly half-century odyssey, the probe has sighted the gas giant Saturn, crossed the threshold of interstellar space and continually sets the bar for our most distant man-made object. But according to NASA projections, Voyager 1 is less than a year away from reaching a new milestone. On November 15, 2026, the spacecraft will officially be one light day from Earth.
Astronomers frequently measure distances across the universe in light years given the incomprehensible size of the cosmos. As far as physicists can tell, nothing moves faster than the speed of light in a vacuum, which travels at 186,000 miles per second. That’s about 5.88 trillion miles each Julian calendar year (365.25 days). For reference, the closest star to our sun, Proxima Centauri, is 4.2 light years away. This means that it would still take just over four full years of traveling at the speed of light to reach the red dwarf – but you wouldn’t necessarily survive such an experience.
Although Voyager 1 is not traveling at the speed of light, it is still moving at an impressive speed. The spacecraft traveled about 11 miles per second for decades, adding another 3.5 AU (the distance between Earth and the sun) to its total mileage each year. This also means that radio communications to and from NASA mission engineers continually take longer. For example, it took weeks to sort out Voyager 1’s technical difficulties last year since each command relay required just over 23 hours to travel the billions of miles at the speed of light from Voyager 1 to NASA and back.
In just under a year, Voyager 1 will finally be 26.1 billion kilometers from Earth, which is equivalent to the same distance light travels in 24 hours. If all goes according to plan, NASA will still communicate with the spacecraft at the time of the celebration. However, mission engineers know that light days are numbered. Even if it no longer experiences technical problems, Voyager 1’s three radioisotope thermoelectric generators will eventually run out of power in the 2030s.
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