BLOG: Voyager Leaves the Solar System

As I in the evenings around Laguna Niguel and look up at the clear night sky, I think about the stars and how far away they are. And I think about how Voyager 1 and Voyager 2 after 35 years of travel are just now leaving our

Our is immense. The Voyager space program was two unmanned probes launched in 1977. I remember 1977. I was in the 11^th grade, wearing bell-bottom jeans and listening to Earth, Wind and Fire on my 8 track player.

Voyager 1 and 2 have been zipping along at 38,000 miles per hour and so they're covering about 900,000 miles a day. And in our big Solar System it took Voyager 2 a full 12 years just to reach Neptune.

So how big is the Solar System? Currently, Voyager 1 is 11 billion miles from the Earth and Voyager 2 is about 9 billion. We think (and by “we” I mean scientists who are a lot smarter than me) that Voyager 1 is about to cross the Heliopause and leave the Solar System.

We say the “edge” of our solar system is where the velocity of the solar winds are counteracted by the hydrogen and helium in the interstellar space. Solar winds are the super charged particles (the electrons and protons) emitted at high velocity by the Sun.

The point where the solar winds is stopped by interstellar space is called the heliopause. And scientists believe that Voyager 1 and 2 are pretty close to crossing that point. For more information and to see really cool videos on this check out Khan Academy, a source for thousands of free videos on math, science and economics. 

Voyager 1 and 2 are going to keep going until they run out of power, sometime between 2020 and 2025. They won't be able to reach another star system. But who knows, maybe someone out there will see them and know we're here.