What tools did scientist use to discover that Pluto was no longer a planet?

Answer 1

No tools required... they merely solidified the definition of a planet, and Pluto no longer fit.

Answer 2

It is not true, that Pluto is no longer a planet!!!! Though the IAU demoted it, NASA, many countries, and even the Government of the State of New Mexico still consider it a planet. There is a worldwide petition going around the address this idiotic mistake, made only because the lazy IAU astronomers didn't want to catalog and remember more planets.

When Eris(the planet larger than Pluto) was discovered, it became apparent that no longer could Pluto be considered a planet if Eris was not. Instead of calling Eris a planet though, they took the easy way out and demoted Pluto. This is like many believe, nonsense, because pluto DOES fit the definition of what planets should be defined by.
1--It has it's own system, complete with 3 natural satellites.
2--It orbits the Sun and even if it hasn't "cleared" it's orbit, it hasn't collided with Neptune yet and they've been there for a long time. If Pluto isn't a planet, neptune shouldn't be either, because it hasn't cleared Pluto out of IT'S orbit.
3--Pluto has it's own atmosphere and seasons.
4--Pluto orbits the sun in an elliptical, yet constant pattern, and is held together by it's own gravity.

So there you go, it's the ninth planet...has been since 1930, and always will be...GO PLUTO

Answer 3

Over the last 20 years they have discovered many other "bodies" out beyond the orbit of Uranus. Pluto fits more in line with these new bodies than with the planets. Also, astronomers have not been happy about calling Pluto a planet from the time it was first discovered in 1930.

When all we knew were the planets and asteroid belt, it was the only categorisation one could apply to Pluto. In the light of new knowledge it was recategorised

It happens all the time in every branch of science, especially when classifying living species.

I am not sure why people seem to upset about Pluto. But the only people that do, are the ones who know very little about astronomy.

Answer 4

Telescopes, clocks and computers. A few years ago it passed in front of a background star. By timing how long the star was hidden behind the planet and using its known orbital speed, they were able to compute its true size. This had not been done before because it had not passed in front of any bright enough star. The result was that it is really smaller than the Moon. This, combined with recent discoveries of other small objects orbiting far from the Sun convinced astronomers they were wrong to call it a planet back in 1930 when it was discovered. Many astronomers had been uneasy with calling it a planet even as early as 1930, but the discovery of new objects, combined with the new size measurement, finally made them agree that it should not be a planet.

Answer 5

By calculating its orbital path using telescopic observations. Its orbit is outside the plane of the ecliptic and more like objects in the Oort cloud. In fact, there are objects in the Oort cloud that are larger than Pluto and more are being discovered every year. Some scientists still want to consider Pluto a planet just because it has been considered one for so long. I hope this helps you.

Answer 6

It wasn't a discovery. The definition of "planet" was formalized (though not unanimously agreed on) and then the IAU determined that Pluto no longer qualified as a planet under the new definition.
A new term - dwarf planet - was created to refer to orbiting objects that weren't planets but were still round due to their gravity. These were initially Ceres, Pluto, and Eris - more to come as additional objects are found and verified in the Kuiper Belt.

Answer 7

Base on the definition of planet, Pluto failed to comply with the definition, therefore Pluto failed itself to be define as a planet.

Answer 8

They just clearified the diffiniton of a planet and that new diffinetion made pluto not a planet.

Answer 9

It wasn't a matter of discovery, but of definition. The tools used were those of political maneuvering - build support for the proposal and schedule the vote at the end of the conference when only those who cared seriously about it bothered to stick around and vote.

Answer 10

A slide rule and a dictionary.