Planets Found by Math
Ancient
peoples have always known about Mercury, Venus, Mars, Jupiter and
Saturn because you can easily see them with you eyes. The discovery
of Uranus was the first time a planet was found that needed the aid
of a telescope to be see. William Herschel discovered this planet in
1781.
In
the next century, another planet was discovered, and this one was
discovered in a very interesting way. The
credit
for
finding planets is usually thought to go to the first person to point
their telescope at it, but this case is a little different.
In
the 1845, Urbain Le Verrier looked
very closely at the orbit of Uranus, and discovered it to be slightly
off from what was known from Kepler about planetary motion. Soon
after,
he had a hypothesis that another planet beyond the orbit of Uranus
could account for the perturbations in the orbit he observed. Le
Verrier
contacted
Johann Gottfried Galle at the Berlin Observatory and
told him to point his telescope at a particular location at a
particular time to look for this eighth planet.
Johann Gottfried Galle |
This,
however, was not the only planet found by math. Later on, small
perturbations were noticed in the orbit of the planet Mercury, again
by Le Verrier.
A
small
planet was hypothesized, this
time inside the orbit of mercury, too close to the sun to see. This
theorized planet was given a name – Vulcan.
Yes, the one and same,
though the hypothesized planet came before the Star Trek series by
more than a century (and was the Roman god of fire, volcanoes, and
metalworking well before that).
This planet does not actually exist. We have since sent spacecraft
close
enough to the sun to see any potential Vulcanoids, and to date have
found none.
So what of the perturbations of the Mercurial orbit? The answer is
relativity. Because Mercury is so deep in the sun's gravity well, it
experiences relativistic affects, and this accounts perfectly for the
precession observed in its orbit.
Image: Terry Virts
LLAP
|
Cheers,
- Scott
LINKSTORM:
Videos of space physics. Things behave differently in freefall.
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