To: WSFA members <WSFAlist at KeithLynch.net>
From: "Keith F. Lynch" <kfl at KeithLynch.net>
Subject: [WSFA] Voyager 1 anniversary
Date: Tue,  5 Sep 2017 22:16:39 -0400 (EDT)

Today is the 40th anniversary of the launch of Voyager 1.

For the past 19 years it has been the furthest manmade object from
Earth, and nothing else that has been launched so far will ever
overtake it.  Not Voyager 2 (which had been launched two weeks
earlier), not Pioneers 10 or 11 (which had been launched about
five years earlier), and not New Horizons (which flew by Pluto
two years ago).

It is 139.6 AU away from both Earth and the sun.  That's about 13
billion miles, 20.9 billion kilometers, 19.3 light hours, or 0.0022
light years.  This distance increases by 10 miles (17 km) every second.

Its transmitter and some of its scientific instruments are still
active.  It of course takes 19.3 hours for a signal from it to reach
Earth or vice versa.  Amateurs can pick up its signal and confirm its
trajectory, so there's no chance that it's fake.

It is expected to remain active for about 10 more years.
Unfortunately it will take about 300 years to reach the Oort cloud,
and tens of thousands of years before it is closer to another star
than to the sun.  By some standards it's already in interstellar
space, as it's apparently beyond the reach of the solar wind.  But
it's not in darkness; it's still bright enough to comfortably read
there, and it will remain so for centuries.

It's very unlikely to ever run into anything, since space is so large
in comparison with the sizes and quantities of the things in it.  It
should remain intact and recognizable for tens of billions of years.
Possibly much longer if the collision between our galaxy and Andromeda
in four billion years tosses it into intergalactic space.  However,
it's very unlikely to ever be found even if the universe is teeming
with intelligent life.

For more information, see
https://voyager.jpl.nasa.gov/mission/status/
and
https://en.wikipedia.org/wiki/Voyager_1