spacecraft · beyond the heliosphere, interstellar space
Voyager 2
Only spacecraft to fly past all four giant planets; entered interstellar space in 2018.
What it is
Spacecraft: Ours. The only things on this list we made. Every kind of thing there is →
Can you see it?
No. No telescope on Earth will show you this one; it is here to be understood, not seen. It is here because it is worth knowing about — and because leaving it out would make the sky look emptier than it is.
Worth knowing about Voyager 2
Voyager 2 is about as wide as a bus is long, once its booms are unfolded. In weight, about as much as a small car. Sunlight takes 19.8 hours to reach Voyager 2 — and a little longer every day, because it is still heading outwards.
- How it moves
- About 21.4 billion km from Earth as of 2026.
- The machines we sent
- Launched August 20, 1977 -- a couple weeks before Voyager 1, but on a longer looping path. The only spacecraft ever to fly past all four giant planets -- Jupiter, Saturn, Uranus (1986), and Neptune (1989) -- discovering Neptune's rings and geysers erupting on its moon Triton along the way.
- What makes it worth knowing
- Entered interstellar space on November 5, 2018. Also losing about 4 watts a year of power; engineers found a clever way to tap backup power so it could keep an extra instrument running through 2026 rather than switching it off early. Both Voyagers are expected to keep sending back at least a trickle of data into the early 2030s -- after their power runs out, they'll keep drifting silently through the galaxy for billions of years.
Seen next to things you know
The numbers
| Across | 0 km |
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| Distance from the Sun, on average | 21 400 000 000 km (21.4 billion) · sunlight takes 19.8 hours |
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How anyone knows this
Nobody flew a tape measure out there. Every number on this page was worked out from the ground:
What it belongs to
Then go outside
Not this one. But the sky over your head is full of ones you can see, and the Planetarium knows which.
