Date: Prior to 1993
My students came into class yesterday claiming that they had
heard that a new planet beyond Pluto was discovered. They said that the new
planet was named Karla. I have seen nothing about this in the papers.
Another teacher said she heard it on the news. Do you have any information
about this supposed discovery?
Yes, I have heard something about a new planet beyond Pluto ...
but not that it was named "Karla". I have a hunch, though, that the name will
not stick, if indeed it was the name, simply because all the other planets are
named after mythological figures and some consistency in naming is always in
order. I also have the impression that this planet (called planet X when I
read about it) had a retrograde orbit ... that is, it revolves around the sun
in the opposite direction as all the other planets.
This seems to be a popular question! Careful searches, including
an infrared sky survey by the IRAS satellite, have produced no evidence of the
hypothetical Planet X. Some astronomers believe that the observed orbital
irregularities which prompted the search for X were due simply to
observational error in the "old" (say, pre-1900) data. Others object on
theoretical grounds, claiming that a planet as massive as the hypothetical
Planet X (4 or more Earth masses) just could not have developed so far out in
the solar system. In order to explain the absence of evidence (including the
lack of any "tug" on either of the Pioneer or Voyager probes due to an unseen
planet) some proponents say that Planet X has an eccentric and/or highly
inclined (relative to the ecliptic) orbit, so that it was close enough to the
outer planets to produce the perturbations observed up until ~1930, but has
since moved out in its orbit, away from the rest of the solar system, so that
it cannot now be detected. If so, it will not come back to the "detectable"
range for several thousand years. Given such a situation (we cannot observe
it, and the reason for its proposal is in doubt), it is likely that most
astronomers discount the existence of Planet X. Update -- the October issue
of Astronomy magazine refers to a recent study by Myles Standish of the Jet
Propulsion Lab. The study shows that"the irregularities in the orbits of
Uranus and Neptune result from the slightly incorrect values for the masses of
the giant planets used in previous studies. When Standish used more accurate
values determined from data obtained by the Voyager spacecraft, the
There could be a planet beyond Pluto, but there is currently no
evidence for one. A small planet well beyond Pluto's orbit would be EXTREMELY
difficult to detect.
Update - March 2011
In 2005, there was a new dwarf planet discovered past Pluto. As of August 2006, the dwarf planet was confirmed and named Eris. Eris is listed as a dwarf planet, as is Pluto.
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Update: June 2012