Plate Nº 15 · recorded November 15, 2026
Space & AstronomyReported finding
Voyager 1 Reaches One Light-Day From Earth, 46 Years After Rewriting Jupiter
On Nov. 18, Voyager 1 reaches 25.89 billion km from Earth — one light-day. We look back at how it revealed Jupiter's rings, storms and the first alien volcano.
By Marcus Bennett4 min read710 words
In brief
- Voyager 1 reaches 16.09 billion miles (25.89 billion km) from Earth on Nov. 18 — one light-day.
- In March 1979 Voyager flew within 174,000 miles (280,000 km) of Jupiter, photographing it every 96 seconds.
- Voyager discovered Jupiter's faint dust rings and the first volcanic eruption seen beyond Earth, on Io.
- Only 2 of Voyager's 10 science instruments still receive power; the probe is expected to die in the 2030s.
On Wednesday, November 18, NASA's Voyager 1 spacecraft will sit 16.09 billion miles (25.89 billion kilometers) from Earth — so far that light itself needs a full 24 hours to cross the gap. No human-made object has ever traveled farther, and the probe that holds the record earned it by first transforming what we know about Jupiter.
Voyager 1 launched in 1977 and has pushed into ever more remote reaches of the solar system ever since. This week's milestone marks its crossing of one "light-day" — the distance light travels in 24 hours. The spacecraft will mark the occasion in darkness: mission scientists switched off its camera in 1990, right after it captured the famous "Pale Blue Dot" image and the "Solar System Family Portrait" from beyond Neptune's orbit.
Before the camera went dark, Voyager 1 sent home tens of thousands of images, and several of them rewrote planetary science.
What did Voyager 1 see at Jupiter?
From January to April 1979, the probe observed the solar system's largest planet and several of its giant moons up close. It swept within 174,000 miles (280,000 km) of the cloud tops in March 1979, according to NASA. As it closed in, Voyager snapped one photo of the gas giant every 96 seconds, stitching them into a time-lapse film of Jupiter's churning atmosphere.
The footage revealed distinct bands of atmosphere spinning at different speeds and in opposite directions — clouds racing past as if on conveyor belts while planet-size storms swirled alongside them. The film covered roughly 60 Jupiter days, equivalent to about a month on Earth, because one Jupiter day lasts only about 10 Earth hours. It remains the most comprehensive, high-resolution look at the planet of its era.
The observations built sharply on data from NASA's Pioneer 10 and 11 probes, launched half a decade earlier. Where Pioneer sketched the outline, Voyager showed the atmosphere was far more dynamic than astronomers had assumed.
Takeaway: Voyager turned Jupiter from a striped blur in telescopes into a restless, measurable weather system.
How did it find Jupiter's rings?
Just before its closest approach, Voyager 1 spotted something no telescope had ever seen: Jupiter has a thin, faint ring system. The rings, made mostly of dust, appeared only when the spacecraft viewed the planet backlit by the sun. Ground-based observatories confirmed them soon after, and Voyager 2 captured clearer images when it reached Jupiter in July 1979.
Scientists now know all four outer planets — Jupiter, Saturn, Uranus and Neptune — carry rings. Today they suspect Jupiter's dusty rings are replenished in part by volcanic eruptions on the moon Io.
Takeaway: A lucky viewing angle in March 1979 added an entire structure to Jupiter's inventory.
Why does Io's volcano matter?
The ring discovery traces back to Voyager in another way. During a close pass of Io, the spacecraft witnessed the first volcanic eruption ever observed on a world beyond Earth. That single observation proved that moons, not only planets, can be geologically active.
One image from the mission shows Loki Patera, the largest volcano on Io, erupting material into space. Loki Patera spans an estimated 125 miles (200 km) — wider than many countries.
Together, the Jupiter observations revealed the giant planet and its moons as a far more dynamic, complicated and chaotic system than anyone had realized. The close-up views also did something subtler: they turned distant points of light into real places — worlds to map, explore and eventually visit. Just this week, China's space agency announced plans to land a probe on Jupiter's moon Callisto, which would be the first landing mission to the Jovian system.
Takeaway: Voyager's images converted the outer solar system from astronomical data into destinations.
What is Voyager 1 doing now?
Voyager 1 officially entered interstellar space in 2012. With its camera off, it studies the radiation environment of space using magnetic field and plasma detectors — the last two of its 10 science instruments still receiving power. Scientists expect the probe to run out of power entirely sometime in the 2030s.
Until then, the most distant human-made object keeps measuring the space between the stars, one light-day from home.
via livescience.com/feeds/news (Source)
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News editor covering regulation, policy and their impact on general science news at SciBeat.
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