The controversy regarding planet X is an
interesting one that goes way back.
Basically, one studies the motions in detail of
the known planets to see if the predictions match
the realities. In fact, this is exactly how
Neptune was found.
The motion of URANUS could not be explained by
accounting for the gravitational effects of the
sun and the other known planets. In 1845-1846, two
astronomers independently estimated by some
laborious calculations that, to explain the motion
of Uranus, another planet should exist at about 30
AU from the sun and have a mass of such and such.
On the evening of Sept 23, 1846 a German
astronomer in Berlin was able to first see
Now, there are some who have looked at the
orbit of Neptune and Pluto who have argued that
there must be still another massive planet that
explains what some believe to be irregularities
in the orbit. This is very
controversial, because in order to
compute a reliable orbit one need to have watched
the planet for at least one orbital period.
The problem with the outer planets is that their
periods exceed a few hundred years---we simply do
not have enough data to reliably claim that their
orbit really are different that what we predict..
.because the predictions have inherent
Nevertheless some have taken the older data
that may not be very good and have determined that
if a planet X was in a high inclination orbit then
it would be hard to find and could be the source
of a gravitational perturbation that could affect
the orbit of Neptune, that some say has
"RESIDUAL anomalies" in its orbit.
So, the JURY is still out on the presence of
a planet X large enough to perturb the orbit of
As far as the dinosaur thing... the idea is
that IF such a planet does exist, then when it
passes through the plane of the ecliptic it could
shake rattle and roll some big asteroids and send
them onto Earth crossing orbits. But this is
speculative to say the least!!!! The search
goes on for planet X although most astronomers
think that it does not exist.
Your question indicates that you understand
this issue... what books have you been
reading? There are many around on basic
astronomy; if interested I can give you some
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