...as a planet? I bet it is more acurate if we explore more Pluto first or wait for the New Horizon robot for the data, before judging it into a Dwarf planet. Cos we formally know that planets are Nine rather than Eight...
2006-09-06 04:22:20 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
The grounds on which they demoted Pluto don't involve any data on it that we don't already know. So provided we keep the same definition, there's nothing New Horizons can do that will change its planet status.
2006-09-06 04:24:42 · answer #1 · answered by Anonymous · 3⤊ 0⤋
The reason this decision was made now, rather than later, depends on two things: (1) such decisions can only be made at an International Astronomical Union General Assembly, and these happen only every four years and (2) lots of new planets are being discovered around other stars in the past few years [there are around 150 known planets now, and more every year], and so an accurate definition of the word "planet" is timely.
"Formally", there used to only be five planets, then six (when we realized Earth was a planet), then seven and eight (with the invention of the telescope), then nine (with the invention of the blink comparator). Now it's back to eight, with the improved understanding of Pluto that suggests it's not really a planet.
2006-09-06 11:43:41 · answer #2 · answered by cosmo 7 · 0⤊ 0⤋
The reason that Pluto was excluded is that it's just one Kuiper Belt Object (KBO) of many that we've now seen. Either there are eight planets or there are more (probably a lot more) than nine. Nine is not logical no matter what. It's not fair to favor Pluto over other KBOs, some of which are probably larger. And it's better to treat KBOs like asteroids, which are also not considered planets. That way we have eight well defined planets, thousands of asteroids, and thousands of KBOs, instead of trying to pick some special asteroids and some special KBOs out and call them planets. What could make them special, that people wold not argue endlessly about?
The data from New Horizons will not change that.
2006-09-06 13:36:22 · answer #3 · answered by Bob 7 · 0⤊ 0⤋
Nothing is set in stone. It can be changed back to a planet any time. Anyway, Pluto got demoted mostly because of the other objects recently discovered, like Sedna and Xena. It is similar to what happened to Ceres, the largest asteroid. It was in all the books as a planet from 1801 to 1850 but got demoted when they discovered so many other asteroids.
2006-09-06 11:31:01 · answer #4 · answered by campbelp2002 7 · 0⤊ 0⤋
People are so quick to jump to conclusions that are not based on fact - and I certainly hope this is one of them!@
2006-09-06 12:01:10 · answer #5 · answered by nswblue 6 · 0⤊ 0⤋