What's new
Off Topix

Off Topix is a well established general discussion forum that originally opened to the public way back in 2009! We provide a laid back atmosphere and our members are down to earth. We have a ton of content and fresh stuff is constantly being added. We cover all sorts of topics, so there's bound to be something inside to pique your interest. We welcome anyone and everyone to register & become a member of our awesome community.

Do you think Pluto is a planet?

Randy

Aw, awww!
Thread Creator
Posts
3,671
Likes
118
Points
1,845
 
Do you think Pluto is a planet?

Why or why not?

new horizons space GIF by Disney
 
Yes.
It just is. :p
 
Yes.
It just is. :p

According to NASA and the IAU, it is not a planet. It's a Dwarf Planet. They are not the same thing.

In August 2006 the International Astronomical Union (IAU) downgraded the status of Pluto to that of “dwarf planet.” This means that from now on only the rocky worlds of the inner Solar System and the gas giants of the outer system will be designated as planets. The “inner Solar System” is the region of space that is smaller than the radius of Jupiter’s orbit around the sun. It contains the asteroid belt as well as the terrestrial planets, Mercury, Venus, Earth, and Mars. The “gas giants” of course are Jupiter, Saturn, Neptune, and Uranus. So now we have eight planets instead of the nine we used to have.

What is a Dwarf Planet?​

A “dwarf planet,” as defined by the IAU, is a celestial body in direct orbit of the Sun that is massive enough that its shape is controlled by gravitational forces rather than mechanical forces (and is thus ellipsoid in shape), but has not cleared its neighboring region of other objects.

So, the three criteria of the IAU for a full-sized planet are:

  1. It is in orbit around the Sun.
  2. It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
  3. It has “cleared the neighborhood” around its orbit.
Pluto meets only two of these criteria, losing out on the third. In all the billions of years it has lived there, it has not managed to clear its neighborhood. You may wonder what that means, “not clearing its neighboring region of other objects?” Sounds like a minesweeper in space! This means that the planet has become gravitationally dominant — there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence, in its vicinity in space.

So any large body that does not meet these criteria is now classed as a “dwarf planet,” and that includes Pluto, which shares its orbital neighborhood with Kuiper belt objects such as the plutinos
 
Yes. It was when I was a kid, damnit! Bring Pluto back into the mix!
 
I feel like it's an honorary planet :p .

Though, if anyone's interested in why Pluto's no longer considered a planet... CGP Grey did a good video explaining why:

 

Create an account or login to post a reply

You must be a member in order to post a reply

Create an account

Create an account here on Off Topix. It's quick & easy!

Log in

Already have an account? Log in here.

Back
Top Bottom