At this very moment, Voyager 1 and 2, two spacecraft that left Earth in the 1970s, are exiting the solar system. They are passing through the magnetic bubbles at its edge approximately 9 billion miles from Earth.
Now, 9 billion miles is clearly far, far away, but it's also a pretty difficult distance to imagine. How about we put that into (somewhat) more practical terms.
Measured in cross-country flights, the distance to the edge of the solar system is great indeed. LAX and JFK airports are 2,475 miles (3,983 km) apart, so the Voyager probes have experienced the equivalent of three million to four million red-eyes.
One could also measure the distance they've gone in units of the Earth-moon separation. Our satellite orbits at an average distance of 238,857 miles (384,403 km). Line up 37,679 of those Earth-moon distances one after another, and you'll arrive at the edge of the solar system. [Video: Solar System's Border Lets Galactic Rays Through]
The Sun is close to 93 million miles (150 million km) away from us. The edge of the solar system and those intrepid Voyagers are almost 97 times farther afield.
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Follow Natalie Wolchover on Twitter @nattyover.
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Natalie Wolchover was a staff writer for Live Science from 2010 to 2012 and is currently a senior physics writer and editor for Quanta Magazine. She holds a bachelor's degree in physics from Tufts University and has studied physics at the University of California, Berkeley. Along with the staff of Quanta, Wolchover won the 2022 Pulitzer Prize for explanatory writing for her work on the building of the James Webb Space Telescope. Her work has also appeared in the The Best American Science and Nature Writing and The Best Writing on Mathematics, Nature, The New Yorker and Popular Science. She was the 2016 winner of the Evert Clark/Seth Payne Award, an annual prize for young science journalists, as well as the winner of the 2017 Science Communication Award for the American Institute of Physics.