Astronomy Picture of the Day -- Pluto: From Mountains to Plains

NASA ^ | December 14, 2015 | (see photo credit)

[SunkenCiv]

[Credit: NASA, Johns Hopkins U. APL, SwRI]

[SunkenCiv]

http://www.freerepublic.com/perl/post?id=3372825%2C0

http://129.164.179.22/apod/image/1512/PlutoCloseUp_NewHorizons_1080.jpg

http://129.164.179.22/apod/image/1512/PlutoCloseUp_NewHorizons_3600.jpg

[Crazieman]

In before morons that will go “Looks like a planet” without realizing they’re conferring the same status on nearly a dozen other objects.

[SunkenCiv]

Pluto’s a planet, nyah nyah. ;’)

[Crazieman]

I know you know better.

Now repeat after me. Mercury, Venus, Earth, Mars, Ceres, Jupiter...

[SunkenCiv]

"To Pluto And Far Beyond" By David H. Levy, Parade, January 15, 2006 -- We don't have a dictionary definition yet that includes all the contingencies. In the wake of the new discovery, however, the International Astronomical Union has set up a group to develop a workable definition of planet. For our part, in consultation with several experienced planetary astronomers, Parade offers this definition: A planet is a body large enough that, when it formed, it condensed under its own gravity to be shaped like a sphere. It orbits a star directly and is not a moon of another planet.

[dr_lew]

I see Pluto as a hypermoon of Neptune. It is not in orbit around it, per se, but it is held in place by Neptune, in a resonance with its solar orbital period. So I believe it really is “the ninth planet” in dynamical terms.

[SunkenCiv]

Pluto’s a planet. Ceres, not.

[onyx]

Wonders never cease!
BTW, you’re WONDERful!

[Crazieman]

So... what about MakeMake? Eris? Quaoar? 2007 OR10?

Do we have 30 planets?

[Osage Orange]

I have 30 plants...

[raybbr]

You won! You’re post beat the other morons.

[Moonman62]

I think most planetary scientists still consider Pluto to be a planet.

The IAU which demoted Pluto in an underhanded way, isn’t dominated by planetary scientists.

[eastforker]

I have a question for all you brainiacs on here. If the earths moon has a gravitational effect on our oceans tides, how come the earths gravitational pull, being about 50 times greater have no effect on the moon. I am sure that’s an elementary question but I still do not understand it.

[Vaquero]

Bodies that form a sphere...Ceres and Vesta comes close. Kinda lumpy though. Ganymede and Titan are bigger than Mercury, but they are still planetary moons.

I suppose a sentient civilization that possibly exists on some of the ‘super earths’, might have a different definition of ‘planet’.

Pluto is not on the ecliptic kind of tilted.

It’s not a given what sun orbiting bodies are to be called. It’s a determination we give to a group to make. A group that studies such things. I am not unhappy with the current status of Pluto. Neither was I before it changed

[Izzy Dunne]

What makes you think Earth’s gravity has no effect on the moon?

I’d be willing to bet that if Earth turned off our gravity, the moon would fly off somewhere else.

That’s quite an effect.

[from occupied ga]

Earth’s gravity has an effect on the moon. The moon is tidally locked to the earth so that one side of the moon always faces the earth. This is caused by earth’s gravity.

[eastforker]

Yeah I have heard all that before, sort of like gravity itself. We know it exist, we feel it yet we can’t see it.We say it does have an effect on the moon yet our astronauts are totally weightless in the ISS and they are a lot closer.I just don’t have the analytical mind to grasp it even though I accept it.

[o_1_2_3__]

Is it me, or...

[Campion]

Astronauts are weightless in orbit because they, and their ship, are both in continuous free-fall. They aren’t outside earth’s gravitational field; earth’s gravitational field is what keeps them in orbit instead of flying away into space.