A Question of Scale

Space and the universe are on my mind tonight. This was prompted by the confirmation that Voyager 1 has reached the termination shock.

The termination shock is the point in space where the stream of solar particles from our sun meet with the slower interstellar particle stream. Many researchers believe this to be a good definition of the "edge" of our solar system. Check out the science section this weekend of the New York Times online. Ken Chang has an excellent article on it.

Voyager by the way is an 815 kilogram space craft, launched in the Summer of 1977. Before personal computers and long before the internet. It's the one with that famous record on it with greetings from planet Earth to whoever finds it!

Little Voyager is now the most distant man made object from the Earth. It is an incredible 14 Billion km from home now. Looking through a window on Voyager the Sun is just a very bright star among many in the black sky.

There is a real problem with throwing a number like 14 Billion km out. It really doesn't mean anything. No one cam imagine how far that distance is.

LET'S DO BETTER

Voyager is almost 3 times further from the sun than Pluto now. But how far way is Pluto?? I can give you the true figure of 5,913 million km but that makes as much sense as 14 billion km.

LET'S DO BETTER

The Sun is 150 million km from Earth on average. We are a bit further away from the sun in Summer and closer to it in Winter. This distance is called an Astronomical Unit by Astronomers (AU). 1 AU is the distance from the Earth to the sun.


So how far away is Voyager??
93.3 Astronomical Units away from the Sun!

Pluto is at about 39 AU!

THAT MAKES MORE SENSE

If we could travel at light speed, we could circle the earth 8 times in one second. We would pass the Moon in 1.5 secs! The sun is 8.3 minutes away. We would pass Jupiter in about 40 minutes. Half an hour later would be Saturn. Finally 2.5 hours later we would pass Neptune.

It would take us a total of 5 hours and 30 minutes to pass Pluto.

Then nothing for another 7 hours until we arrived at tiny Voyager 1.

It takes over 12 hours for a radio signal from Voyager to reach earth. It is so weak that only the largest and most sensitive radio telescopes can pick it up.

Still, the nuclear reactor on Voyager will last another 15 years and if NASA budget cuts do not close up shop, we will still be able to pick it up as it sends it's last good bye home across an immense empty void.


The thing to note here, is that great distances can be put into perspective. Next time you read an article where some reporter has put some big number out. Do some calculations like I did above and send them an email....Tell them that
WE CAN DO BETTER!

Have a good weekend,
Later,
Dan