New Horizons Gets Closer to Pluto, But Mystery Spots Now Out of Sight

The L.A. Times reports that the strange spots spotted on the surface of Pluto by the New Horizons mission will be on the wrong side of the planet for the approaching fly-by that the craft will make of the smallest planet (or dwarf planet, depending) of our solar system. (The BBC makes a similar observation.) That doesn't mean that New Horizons' approach is anything short of "a spectacular event."

Comments

im not saying aliens.....

[ganjadude]

but aliens!

Scientific explanation

[Tablizer]

Pluto's embarrassed by its age spots, and so is showing its good side to the probe.

Meanwhile....

[Rei]

A fraction of a percent of the AMA has, out of concern of students having to learn so many bones, voted to declare that there are only 8 bones in the human body, and all of the others are dwarf bones, and that those don't really count as bones. And to tell the difference between a bone and a dwarf bone you have to do a detailed study using a definition that nobody can agree on. But, if you move a bone from one part of the body to the other, it can change between being a bone and not being a bone. Also, other mammals don't have bones at all - their bodies are held together by "something" that isn't defined at all.

Only a tiny fraction of those present at the AMA vote were in a field doing anything with anatomy; the rests were bacteriologists. But nonetheless, despite the criticism by anatomists, the AMA has adamantly refused to revisit their decision.

Re:Meanwhile....

[queazocotal]

Pluto as a planet doesn't really make much sense, without including others.
Eris, for example. While currently three times the distance of pluto from the sun, at times (next ~2800AD) it is actually closer than pluto to the sun, as well as more massive.
There is no real inarguable set.

Re:Meanwhile....

[Rei]

... without including others

Exactly. They should be included, obviously.

The concept of a planet is pretty intuitive - it orbits a star and its big enough that its gravity has pulled it into a sphere. That's what pretty much everyone on Earth outside of the IAU understands a planet to be. The concept that you have to try to pretend that diversity doesn't exist in order to shrink down the list to a number whose names schoolchildren can memorize is a horribly unscientific approach.

We need to accept the universe that nature has created for us. There are terrestrial planets. There are gas giants. Ice giants. Eccentric giants. Hot jupiters. Super-earths. Water worlds. And yes, dwarf planets. They're all planets by pretty much any reasonable definition. In fact, they're a lot more similar to terrestrial planets than gas giants are.

We should be thrilled by the number of worlds in our solar system instead of intimidated by it and trying to write them out by a ridiculous definition that leads to absurd consequences. And uses nomenclature ("dwarf") that even the IAU itself doesn't use elsewhere (do they plan to declare "dwarf stars" to not be stars?). An "adjective-noun" is also a member of the group "noun" in any realistic nomenclature.

Extrasolar planets aren't planets according to the IAU either. You could have an exact replica of Earth orbiting an exact replica of the sun with an exact replica of Earth's "neighborhood" and it'd still not be called a planet. And even if they didn't arbitrary exclude them, we'd have no way to be able to determine if any of them had "cleared their neighborhood" without sending a probe there - aka, effectively impossible at this point in time. Not that "cleared the neighborhood" makes any sense, there's lots of objects in Earth's neighborhood, and new ones keep entering our neighborhood. And many of the planets don't appear to have formed in their current neighborhood anyway. Plus, Neptune has freaking Pluto in its neighborhood. And since when does what something "is" have anything to do with where it happens to be currently located? Would it make any sense for a cow be declared a "dwarf cow" and not really a cow if it was exactly the same but in a location that had several cowlike animal species near it? Would it make sense to make a definition of a "dwarf river", with the only rationale being to limit the total number of rivers in the world to 8?

I can just imagine an IAU-inspired Star Trek:

Kirk: "What is that planet on the viewscreen? Prepare a team to beam down to the surface."

Spock: "Actually, captain, we cannot be certain that it is a planet."

Kirk: "Spock, I can see it right there, it's a planet - it's a huge round thing orbiting its star."

Spock: "Yes, captain, but I have not yet completed my scan to see whether it has 'cleared its neighborhood'; I need to first find out if any asteroids that cross its orbit. The survey will take a few hours to complete."

Kirk: "But Spock... it's right there, it's a planet! It's even got oceans, an atmosphere, clouds - it's a veritable second Earth!"

Spock: "It could be a dwarf planet, which isn't really a planet, despite being having 'planet' in the title." (beat) "Captain, I have been reviewing the IAU's definition; because it's not orbiting the sun, it's not only not a planet, it's not anything at all."

Kirk: "Okay, okay - somebody prepare a team to beam down to the nothing-at-all that looks like a damned planet!"

Re:A rose by any other name

[Rei]

Why do you feel that you have to memorize them all? Do you feel compelled to memorize all of Earth's rivers or all of the named stars in our galaxy? The concept that "what I can remember all the names of" is grounds for a scientific classification is an absurdity.

And New Horizons' Alan Stern recommends - and I agree - that indeed moons that would otherwise meet the definition of being a planet except that they are moons of a planet should be seen as planetary moons. So our solar system could be said have several "planetary moons" and "dwarf planetary moons" - Earth's, the Galilean moons, Titan, Triton, maybe others. "Planet" being the general category for non-stars in hydrostatic equilibrium, "planetary" being the adjective form, "moon" being a body in orbit around something that's not a star, "dwarf planet" just being a category of planet, etc. They're all just different categorizations that you can apply where they're needed. Other systems might have other types of planetary moons, even gas giant moons.

Likewise, you should be able to have planetary bodies that aren't in orbit around anything and drift freely through space. We don't have the technology to spot them yet, but I wouldn't be surprised if the galaxy was chock full of them - why shouldn't it be? What an object orbits around doesn't define what it is. So you could have roaming terrestrial planets, roaming gas giants, roaming dwarf planets, and on and on.

Nature always likes giving us diversity. In almost every field of science, this diversity is embraced. Except apparently when it comes to the IAU and planets, on the grounds that "I couldn't memorize them all". Well, tough luck, we're going to keep finding more and more planets under any definition, and more and more diversity, with time, you can't hold out on your "I can't memorize them all" nonsense forever.

And really, why not embrace the fact that these aren't just undifferentiated hunks of rocks? Something being large enough to reaching hydrostatic equilibrium says a lot about the object. It means you start getting all sorts of geological differentiation processes, uneven heating, localized mineralization, long timeperiods to cool down, etc. It makes them very interesting places for exploration - and for the search of for life.