Voyager 1 leaving solar system matches feats of great human explorers
It's official. Voyager 1 has left the
solar system. While there will be little
immediate benefit from this feat, it
does represent a historic milestone of
exploration.
Voyager 1's achievement is every bit
as important as Roald Amundsen's
party reaching the South Pole on 14
December 1911, or Edmund Hillary
and Tenzing Norgay conquering
Everest on 29 May 1953. The
difference is that there is no human
inside Voyager.
With no obvious human, there is no
obvious hero to venerate for the
achievement. And the army of
scientists and engineers who built and
shepherded the mission seem too
diffuse a collective for adoration.
We must therefore celebrate Voyager
1 itself, as being a robotic extension
of our senses, carrying our
experiments to places that we simply
cannot go. The duration of its mission
alone is worthy of celebration.
Launched in 1977, the same year that
Elvis finally left the building, Voyager
1's primary mission was to visit the
giant planets Jupiter and Saturn. Its
orbit was designed to make a close
pass of Saturn's mysterious moon,
Titan, but that left the spacecraft
coasting through space with no other
planets to encounter.
In the subsequent decade, sister ship
Voyager 2 stole the limelight because
of its flyby of Jupiter, Saturn, Uranus
and Neptune. Voyager 1 was
travelling faster, however, and that
extra speed now means it is around
120 times the distance of the Earth
from the sun, whereas Voyager 2 is
lagging behind at about 100 times.
Powered by radioactivity, both are
still communicating with Earth. It
was realised that sunlight would be
far too weak in the outer solar
system to drive solar panels. The
power is gradually running down,
however, as the radioactive fuel
decays.
The craft are expected to last until
around 2020, and that gives plenty of
time to collect data about this newly
reached realm of nature.
The boundary of the solar system is
defined by the magnetic field created
inside the sun. This bubble of
magnetism traps particles and when
Voyager passes the boundary, the
density of particles will change
abruptly. A recent review of the
spacecraft data shows that this
happened on 25 August 2012, over a
year ago.
So, according to Nasa Voyager 1 has
officially left the solar system.
It is difficult to say at the moment
what benefit this knowledge will
bring to us – just as it was difficult to
say what benefit Amundsen's and
Hillary's achievement would have on
society.
But just as certainly, achievements
inspire us and drive us on to our own
personal goals and therefore cannot
be underestimated.
