After a long, dark wait, NASA has finally confirmed that its Voyager 1 spacecraft has become the first human object to enter interstellar space.
Voyager 1, launched from Cape Canaveral, Fla., in 1977, is now almost completely beyond the reach of the Sun, some 12 billion miles away.
Scientists have long wondered whether the spacecraft and its twin, Voyager 2, had officially crossed the ethereal boundary that separates our cosmic neighborhood from what lies beyond. Voyager researchers finally answered that question Thursday in a report published in the journal Science.
"Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, a Voyager scientist at the California Institute of Technology, Pasadena. "We can now answer the question we've all been asking – 'Are we there yet?' Yes, we are."
By measuring the rattling effect a powerful solar eruption had on the Voyager and its instruments, NASA scientists were able to determine the density of the space surrounding the spacecraft. Interstellar space, in other words, sounds different.
From that data, Don Gurnett of the University of Iowa, the study's lead author, determined that Voyager was no longer in the heliosphere, the region of space still affected by solar wind coming from the hot surface of Sun. It is instead in an in-between zone – outside the main bubble of the Sun's influence, but not quite in the cosmic desert beyond our solar system and the Sun's rays.
Voyager 1 and Voyager 2 were originally designed to explore Jupiter and the solar system's outer planets. On its "grand tour' it tookfamous photos like the 'Pale Blue Dot' shot of Earth from 4 billion miles away in 1990.
The two probes, powered by nuclear radiation, have continued chugging long past their expected lifetimes despite outdated technology.
"The typical smartphone has more than 240,000 times more memory than Voyager," Suzanne Dodd, Voyager's project manager said at a press conference announcing the discovery. "Its 22-watt transmitter is about the size of a refrigerator light bulb, and a signal from it takes about 17 hours and 22 minutes to reach us here on Earth."
But Voyager 1 houses more than just outdated instruments. It also contains the golden record, an interstellar message in a bottle put together by author and astronomer Carl Sagan.
The record contains sound clips of music from artists including Beethoven, Chuck Berry, and Mozart, as well as spoken greetings in 56 languages and natural sounds like thunder, the ocean, and bird and whale songs.
Voyager 1 is expected to keep sending data back home until at least 2020. At some point, the transmissions will be too faint to detect, and the probe will continue alone on its journey, which could theoretically take it to a nearby star in 40,000 years.
"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and adding a new chapter in human scientific dreams and endeavors," said John Grunsfeld, NASA's associate administrator for science in Washington. "Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey."