Is Pluto really a planet or not?

Alain Brian
Mars 23, 2017

The change was a subject of much scientific debate and made no sense said Kirby Runyon, a scientist at the Johns Hopkins University in the US.

Last week on the The Late Show with Stephen Colbert, Science Superstar Neil deGrasse Tyson said those who are pro-planetary status for Pluto need to "get over it".

The year 2006 was a particularly eventful year in the astronomical and planetary science community as Pluto was relegated to the "non-planet" status thus bringing the total count of the number of planets in our solar system to 8. This specific wording allows the definition to include objects that are round but bulge at the equator due to outside forces, such as gravity from a nearby planet or star, again emphasizing a body's intrinsic properties as the basis for its classification.

Still, Pluto "as everything going on its surface that you associate with a planet".

Pluto and its newfound kin in the solar system's distant Kuiper Belt region were reclassified as dwarf planets, along with Ceres, the biggest object in the asteroid belt between Mars and Jupiter. Pluto's diameter is under three-quarters that of the moon and almost a fifth of Earth.

"There is nothing non-planet about it", Runyon said.

All the authors were scientists on the New Horizons mission to Pluto, which the Johns Hopkins Applied Physics Laboratory operated for NASA. They define a planet as "a sub-stellar mass body that has never undergone nuclear fusion" and that has enough gravitational heft to maintain a roughly round shape.

This definition differs from the IAU definition in that it makes no reference to the celestial body's surroundings. "In the decade following the supposed "demotion" of Pluto by the International Astronomical Union, many members of the public, in our experience, assume that alleged "non-planets" cease to be interesting enough to warrant scientific exploration". Alan Stern, the principal investigator of NASA's New Horizon's mission to Pluto, submitted a proposal in February to the IAU calling for a change in the definition of a planet as well.

"It really takes blinders to not look at the solar system and see the profound differences between the eight planets in their stately circular orbits and then the millions and millions of tiny bodies flitting in and out between the planets and being tossed around by them", he wrote in an email. "In the decade following the supposed "demotion" of Pluto by the [IAU], many members of the public, in our experience, assume that alleged "non-planets" cease to be interesting enough to warrant scientific exploration, though the IAU did not intend this outcome", wrote Stern. And that whopping increase is actually a good thing, Runyon says, as he thinks it will engage the public in space exploration.

D'autres rapports CampDesrEcrues

Discuter de cet article

SUIVRE NOTRE JOURNAL