8 December 2012
Voyager One was launched the Fall I started the undergraduate Meteorology program at the Univ. of Oklahoma (September 1977), and the fact that it is still working is pretty amazing. As the video above shows, it is reaching the edge of the Sun’s influence and within a few years it will enter interstellar space where it will remain for the eons. Project scientists this week announced that they are now seeing strong signs that Voyager is nearing the heliopause.
The stream of particles in the solar wind is changing directions and speed as it meets the stream of particles that flow between the stars. We can still hold Voyagers hand but those days are coming to an end now. It’s plutonium power supply will give out by 2025, and contact with Earth will be lost. It will then sail on alone in the cold dark emptiness between the stars.
I tend to think of Voyager as Carl Sagan’s parting gift to our imagination. Just trying to imagine how far away Voyager is already is difficult, but not impossible. No object made by humans is farther away from its origin. Forget about miles or kilometers, because expressing it that way is meaningless (Newspapers and TV newscasts do that all the time, and I tend to throw things at the screen when they do!) but here are a couple of ways to think about it. Below are my two favourite ways to ponder where Voyager is and how immensely distant it now is.
1. It takes 1.5 seconds for a radio signal, to reach the Moon, and about 8.3 minutes to reach the Sun. A radio signal to Pluto will take around 6 hours. To send a signal to Voyager 1 now takes 17 hours and 7 minutes!
2. A better way to visualize it is to go to a park or the beach with a tape measure, a toy ball, a ping pong ball, and some grape nuts cereal . Put the ball down and let it be the sun. Go out 1 meter and put down a grain of Grape Nuts cereal. That’s the Earth. A ping-pong ball at 5 meters is Jupiter. Now go to 40 meters and put a fragment of a grape nut down. That is Pluto (no it is NOT a planet). The scale I am using here is AU or Astronomical Units. The distance from the Earth to the Sun is DEFINED as ONE AU.
Finally, walk to 122.6 meters away from the ball. This is Voyager. As you can see from the picture on this page, Voyager is not in the same plane as the planets but is climbing well above it, so imagine your standing on a 40 meter tower out at the location of Voyager. The nearest star to our own Sun on this scale is 271 kilometers further on.
That’s 271 THOUSAND meters.