NASA says Voyager 1 has left the solar system, for real this time
By Ryan Whitman, From Stumbleupon.com
It has taken 36 years, but Voyager 1 has finally left the solar system, according to NASA.
The past few years have been peppered with claims from various researchers that the space probe had finally left the solar system behind, but these claims never stood up to scrutiny. Having taken a more measured approach, NASA now says Voyager 1 passed into interstellar space in August 2012.
Voyager 1 is currently about 12 billion miles away from the sun, or about 0.002 light years. it sounds more impressive in miles, but this is an astounding feat nonetheless. Voyager 1 was launched in 1976 with a mission to get a close up look at Jupiter and Saturn before making a break for points unknown. The probe is also famous for carrying the golden record and inscribed greeting from Earth to any being that might encounter the probe. It also took the famous Pale Blue Dot image.
It has been hard to know when Voyager 1 left the solar system for a few reasons. Primarily, we’ve never been able to directly observe the very edge of the solar system before — this is all new. The original Voyager team also didn’t know exactly what the probe would need to measure to find the edge of the solar system, and everything it is equipped with is quite out of date now.
Researchers have been watching data on the density and direction of plasma (charged particles) flowing around the spacecraft. Voyager doesn’t have the necessary instruments to measure this directly, so the team uses magnetic field readings to work out the nature of the plasma environment.
In April, Voyager detected a clear increase in the density of plasma, indicating it had left the solar envelope behind and crossed into interstellar space. Using this template, the team combed over the recent data, finding a fainter, but matching signature. Based on this data, NASA estimated that Voyager 1 left the solar system in August of 2012. Now Voyager 1 will continue to go where no probe has gone before.
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