Where No Man (-Made Object) Has Gone Before

Ever since the invention of exploration, we have always wanted to know what is "out there"--whether that means what's on the other side of the mountains, ocean, or world--curiosity keeps us moving. Well, we--or, at least something we made--has made it past the first step of the ultimate "out there".

After over a year of analyzing data, on September 12, 2013, NASA announced that Voyager 1 has left the solar system and is now in interstellar space.

Voyager 1 and twin craft Voyager 2 started their journeys back in 1977. (Voyager 2 was actually launched first, with Voyager 1 launching 16 days later. ) In the 36 years since, Voyager 2 has moved to a distance of 9.5 billion miles from the Sun, while Voyager 1 is an astonishing 12 billion miles from the Sun.

How do we know that the craft is in interstellar space? First, we have to define what's meant by "interstellar". The common definition of interstellar is that it's the area outside the solar bubble, which is the area around the planets where the affects of the Sun are still felt. Once outside that bubble, there is just plasma (ionized gas) in between stars. That is where the craft is now.

But determining that was not easy because Voyager 1 does not have a plasma detector. So, other methods had to be used. As explained in the press release:

A coronal mass ejection, or a massive burst of solar wind and magnetic fields, that erupted from the sun in March 2012 provided scientists the data they needed. When this unexpected gift from the sun eventually arrived at Voyager 1's location 13 months later, in April 2013, the plasma around the spacecraft began to vibrate like a violin string. On April 9, Voyager 1's plasma wave instrument detected the movement. The pitch of the oscillations helped scientists determine the density of the plasma. The particular oscillations meant the spacecraft was bathed in plasma more than 40 times denser than what they had encountered in the outer layer of the heliosphere. Density of this sort is to be expected in interstellar space.

The plasma wave science team reviewed its data and found an earlier, fainter set of oscillations in October and November 2012. Through extrapolation of measured plasma densities from both events, the team determined Voyager 1 first entered interstellar space in August 2012.

Simply put, and to continue the analogy, this means that  although the craft could not see the violin (no plasma detector), it could still hear it (because it has a wave instrument). Because the plasma wave got denser over time (the violin got louder), eventually the craft got to a point that it reached interstellar space.

This is very exciting news. As Ed Stone, Voyager Project scientist at the California Institute of Technology, Pasadena says: "Now that we have new, key data, we believe this is mankind's historic leap into interstellar space. The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are."

NASA expects that Voyager 1 will continue to send signals, which currently takes 17 hours to reach Earth, until 2020. I expect they--and we--will learn a lot in the next 7 years. There is so much more "out there" to be explored; so many more questions to be asked. Not the least of which is this: Was Star Trek right? Have we witnessed the birth of V'GER?