Picture this. You pick up the phone to call a friend, say "hello," and then wait. And wait. A full day goes by before your hello even gets there. Then you wait another full day for them to say "hey" back.

That is about to be everyday life for the people who talk to Voyager 1. This week, a spacecraft that left Earth in 1977, built to last five years, crosses a line no human-made thing has ever crossed.

One light-day, explained

Fact: A light-day is a distance, not a stretch of time. It is how far light travels in 24 hours. Light covers about 186,000 miles every second, so in a day it goes 16,094,799,096 miles. That's the number NASA uses.

Fact: Voyager 1 hits that mark on Wednesday, Nov. 18, 2026, at 5:16:07 a.m. Eastern. It will have taken 49 years, two months and 11 days since launch on Sept. 5, 1977.

For a sense of scale: sunlight reaches us in about 8 minutes and 20 seconds. Voyager 1 is about to be a whole day out.

Fact: Radio waves travel at the speed of light, so once Voyager 1 hits the mark, every command NASA sends will take 24 hours to arrive, and every reply will take another 24 to come home. Voyager project manager Suzanne Dodd put it best: "If you want to say 'hello' to Voyager, you send your message and then you go home and you wait two days before you finally get a response."

Fact: Nothing actually happens on the spacecraft when it crosses the line. NASA says Voyager 1 won't notice any change at all. It's a mile marker. A really, really far one.

Wave hello on Tuesday night

Here's the fun part, and you can be in on it. Fact: NASA is inviting everybody on Earth to "Shine Bright for Voyager's Light-Day" after sunset on Tuesday, Nov. 17. NASA notes that any light from Earth would take 24 hours to reach the spacecraft.

Grab a flashlight, a lantern, a bike light or your phone, point it at the sky, and flash Voyager's call sign, V G R, in Morse code:

• V: three short flashes, then one long one
• G: two long flashes, then one short one
• R: one short, one long, one short

Pause a second between letters and repeat for about a minute, or until your arm gives out. Not a Morse code person? NASA built a flasher page that does it for your phone. NASA says to snap a photo or video and tag @NASA.

Fun bonus: Fact: Voyager already speaks Morse. The Golden Record, the interstellar greeting card both Voyagers carry, includes a Morse code message: "Ad astra per aspera," Latin for "through struggle to the stars."

BUSTED: "Voyager 1 left the solar system"

You have probably seen this one a hundred times. It's not quite right.

Fact: On Aug. 25, 2012, Voyager 1 crossed the heliopause, the edge of the giant bubble of solar wind the Sun blows around itself. Past that line is interstellar space, and Voyager 1 was the first spacecraft ever to get there. Voyager 2 followed in 2018. That is a huge deal.

But the bubble is not the solar system. Fact: NASA says the solar system's edge is out past the Oort Cloud, a collection of small objects still under the influence of the Sun's gravity. In NASA's own words, the Voyagers "have not yet left the solar system, and won't be leaving anytime soon." NASA figures it will take Voyager 1 about 300 years just to reach the inner edge of the Oort Cloud, and possibly about 30,000 years to get past it.

To be fair, the mix-up is easy to make. Even NASA's own light-day page slips and says Voyager 1 "left the solar system." Interstellar space? Yes. Out of the solar system? Not for a long, long time.

The little probe that refuses to quit

Fact: Voyager's computers handle about 8,000 instructions per second, with roughly 68 kilobytes of memory across six computers. Your phone laughs at that. And yet here it is, still sending data from interstellar space.

Fact: It runs on heat from decaying plutonium, and the power drops about 4 watts every year. In September 2026, engineers completed a swap they nicknamed the "Big Bang," trading three devices for lower-power versions so the remaining science instruments can keep running longer.

Fact: It gave the team a scare, too. On Oct. 18 and 19, NASA's giant dish antennas heard nothing from Voyager 1. On Oct. 20 the signal came back. A group of thrusters had gone offline and the backups switched on by themselves. As of late October, engineers were still investigating why. As mission manager Kareem Badaruddin said, at this point in the mission "we have to expect the unexpected."

Along the way, this same mission spotted the first active volcanoes ever seen on another world, on Jupiter's moon Io. And on Feb. 14, 1990, Voyager 1 turned around and took the "family portrait" of our solar system, including the famous Pale Blue Dot photo of Earth. Those were the last pictures it ever took.

Where it goes from here

Fact: Voyager 1 is cruising at about 38,000 miles per hour toward a dim star called Gliese 445. It will pass within about 1.7 light-years of it in roughly 40,000 years. Its twin, Voyager 2, should reach its own one light-day mark in November 2035.

NASA is holding a Voyager briefing at JPL on Thursday, Nov. 19, the same day the team gets Voyager 1's "reply" from the milestone, and is working on a Voyager documentary for the mission's 50th anniversary in 2027.

The verdict

SOLVED. Voyager 1 really is about to be one light-day from home, a first for anything humans have ever built. It's in interstellar space. It is not out of the solar system, and won't be for centuries. So on Tuesday night, go outside, flash V G R at the sky, and say hi. Just don't expect a quick answer. 🐇🕳️🚀

Sources

1. NASA Science, "What Is a Light-Day?" (Voyager 1). https://science.nasa.gov/mission/voyager/voyager-1/voyager-1-what-is-a-light-day/
2. NASA Science, "Shine Bright for Voyager's Light-Day." https://science.nasa.gov/mission/voyager/voyager-1/shine-bright-for-voyagers-light-day/
3. NASA, "NASA Invites Media, Public to Join Voyager 1 One-Light Day Activities," Nov. 10, 2026 (updated Nov. 13, 2026). https://www.nasa.gov/news-release/nasa-invites-media-public-to-join-voyager-1-one-light-day-activities/
4. NASA Jet Propulsion Laboratory, "NASA's Voyager 1 Conserves Power, Resolves Brief Communications Pause," Oct. 29, 2026. https://www.jpl.nasa.gov/news/nasas-voyager-1-conserves-power-resolves-brief-communications-pause/
5. NASA, "NASA's Voyager 2 Probe Enters Interstellar Space," Dec. 10, 2018. https://www.nasa.gov/news-release/nasas-voyager-2-probe-enters-interstellar-space/
6. NASA Science, Voyager Frequently Asked Questions. https://science.nasa.gov/mission/voyager/frequently-asked-questions/
7. NASA Scientific Visualization Studio, "NASA's Iconic Voyager Mission Reaches New Interstellar Milestone" (interview advisory). https://svs.gsfc.nasa.gov/15111