Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
Note: You can take 10% off all Slashdot Deals with coupon code "slashdot10off." ×

Comment Re:For me, it will always remain the mountain... (Score 4, Interesting) 318

I can't remember who it was... it might have been Halldór Laxnes... who said that a piece of nature isn't really a piece of nature unless it doesn't have a name. That is, the first thing people do once they start interacting with an object or place is to give it a name, and so once something is named it starts to become about the history of people rather than the history of the land itself. And that if you want to establish a real connection with nature, you don't go sit on top of that well-known named peak that people climb... you go to that little nameless stream or that remote nameless cliff or whatnot - places which tell only their own story.

Comment Re:Tradeoffs (Score 1) 42

More to the point, the James Webb telescope is supposed to be launched in late 2018; this flyby isn't until 2019. With seven times the light collecting area as Hubble, it could be a nice addition to the arsenal for finding bodies along Pluto's projected route (especially now that we know better what that route is going to be :) ) Though it operates in mid-IR to low-frequency visible, while Hubble operates primarily in visible/UV... I'm not sure how that would affect the ability to find solid objects. I know that far-IR is very good for it, but James Webb doesn't go down that far.

Comment Re:"clearing the neighborhood" (Score 1) 42

It's even worse than that. Compare Neptune's Stern-Levison parameter to Mars's. Neptune has at least two bodies that are each around 2-3% the mass of Mars in its "neighborhood" (quite possibly even larger ones), yet it has 290 times greater ability to "clear its neighborhood" than Mars. The concept that planets like Mars cleared their own neighborhood of bodies this size is not only unsupported by the research, but blatantly silly on the face of it. The IAU is attributing Jupiter's work at clearing the inner solar system to the inner planets in order to force their definition. And this isn't exactly news - pretty much all orbital dynamics simulations for a long time have been showing this.

Comment Re:While we're on the topic... (Score 1) 42

Mars is more than capable of clearing its neighborhood on its own, as seen by measures like the Stern-Levison parameter and others that have been derived from dynamics and simulation scalings. It isn't even close to being marginal.

Jupiter's Stern-Levison parameter is 1,38 million times larger than Mars's. No, Mars would not have "cleared its neighborhood"; it's well recognized in the literature that the majority of "neighborhood clearing" in our solar system was done by Jupiter and Saturn. There's lots of niggling over the exact details (here's one scenario), but there's no reputable peer-reviewed source involving orbital dynamics simulations arguing that Mars did the majority of work to clear its neighborhood. Heck, Neptune has a Stern-Levison parameter 290 times higher than Mars and it still has at least two bodies with around 1/50th the mass of Mars each in its neighborhood (and possibly even larger ones). If a 290 times greater ability to clear its neighborhood couldn't do it, why do you think Mars stands a chance on its own?

The whole "cleared the neighborhood" concept for planets is built on a bare falsehood: that the majority of them are actually responsible for clearing their own neighborhoods. The science says exactly the opposite: that the gas giants cleared the majority of bodies from our solar system.

Because some people care more about the dynamics of the planets and their orbits than what is on/in the planets. Even in geology on Earth, there are classifications for what makes up a mineral, and classifications for structures and locations they are found in.

Are you seriously trying to claim that, say, stilbite will be classified as a different mineral based on whether it occurs in Iceland or the United States? Minerals are what they are. The individual structures minerals are found in may have names (for example, the "Bakken Shale"), but those are just names. You know, like "Kuiper Belt".

Some geologists don't care where it came from as long as the make up is similar, others very much care if samples come from near the same location, even if they are very different minerals.

What on Earth are you talking about? If you're trying to say "Some scientists want to study the variety of objects in the Kuiper Belt and compare them to each other", then you already have a word for that: KBO.

You can go on and on about how dissimilar you think Jupiter and Earth are, but that doesn't change that there are metrics where they are much more similar than other rocky planets are to Earth.

You can't be serious.

Comment Re:A-10 for the Win (Score 2) 401

You realize that in that evaluation, the F-35 being tested was AF-2, a flight science model, right? It had:

  * No situational awareness software
  * No advanced weapons targeting software
  * No stealth coating

It was not designed to be a combat evaluation of the full system, rather just an attempt to stress the system with visual combat maneuvers.

That said, the F-35 is not designed to be a visual dogfighter. It has dogfighting capabilities, but its main design principle is high situational awareness enabling kills from far away - seeing the enemy from long before it itself is seen.

Comment Re:While we're on the topic... (Score 1) 42

1. Is just a nomenclature problem. The key issue was whether Pluto belongs in the same category as Mercury through Neptune.

First off, the problem category was called "nomenclature". Secondly, you act like mercury has bloody anything at all in common with Jupiter and Saturn. It's far, far more like Pluto. It's not an "edge case" issue, it's a fundamental misgrouping issue.

2. If a planet changes its orbit, one of two things will happen:

It clears its new neighborhood
It gets cleared out by a new neighbor or falls into a resonance with it

As was mentioned, this is not correct. Mars-sized planets don't clear their own neighborhoods. Mars did not clear its neighborhood - Jupiter did. Your "two things" are simply not accurate. It's a false supposition that's the entire foundation of this definition.

More to the point, extrasolar planets show how ridiculous this definition is even more. There are extrasolar planets larger than Earth which orbit their star closer to each other at times than the Earth is to the moon. They don't "clear" each other at all. It's just a ridiculous, completely false premise.

3. and 4. In geological terms yes, but I think the IAU was correct in preferring to define planets through orbital characteristics over geological ones.

Why? Why should we define what something is based on where it is rather than what it is? The answer is basically given in the question itself. When you say, "X is a planet", you're making a statement about what it is. That's the meaning of the word is. If you want single words to talk about orbits, we already have terms for that - that's what "asteroid", "KBO", etc are.

And really, you completely avoided these points. Pluto and Earth are far more like each other than either are like Jupiter. So grouping Earth with Jupiter and not Pluto is a complete absurdity. Hydrostatic equilibrium is a meaningful distinction - it has all sorts of consequences for the body. The nobody-can-agree-upon "neighborhood" definition has little to no bearing on what you're going to find there.

5. The neighborhood of a planet cannot be simply changed without significant consequences. If through some freak incident a formerly solitary planet ends up suddenly having a neighbor of significantly higher mass, that planet will not remain a planet for very long. Its "mutability" is then not even restricted to definition games, it will quite be literally destroyed or thrown away into deep space.

These are anything but the only two options. They can change orbits, migrate inward, migrate outward, get locked into new resonances, etc. A planet can be moved into for example a more out-of-plane orbit by an intruder and still receive the same insolation, and thus be exactly the same on the surface, but no longer be a planet. It's an absurdity.

6. An Earth-copy that hasn't cleared its neighborhood yet won't be an Earth-copy due to frequent crust destroying meteorite impacts

That's not true. For one example among many, the Earth copy and the other bodies in its neighborhood could both be in orbital resonance with a larger body.

. Such a child solar system will probably not be described well by our current terminology but these systems are also very rare because that phase of life only lasts for a very short time.

Yet another unsupported statement.

7. There will clearly eventually be edge cases, but Pluto isn't. There is an object with 10000 times its mass within its perihel and apohel. Its orbital period is not independantly "chosen" but defined by Neptune

And if Earth were located where Pluto is now, its orbital period would also not either be indepdently "chosen" but defined by Neptune.

Should I even bother mentioning that one of the leading theories to explain Sedna's orbit is that there is a roughly Earth-sized body out there? WISE isn't capable of spotting such small objects.

8. - 10. Those are all things that we are just now starting to discover.

No, they're not. We've known about exoplanets and binaries long before the IAU definition.

They might eventually change up the definition of the word planet again

They refuse to revisit the issue.

such as when we do find the first binary pair of planets with similar mass in the same orbit.

We already have one, Pluto-Charon. They refuse to acknowledge it. And binaries don't just affect planets - there are even binary asteroids.

11+ are mostly political points where you can have an opinion either way.

Dismissing points as "political" is a nice way to not have to actually address their substance.

But scientifically the question is: Are Pluto, Ceres, Eris and the 100+ other yet to be discovered KBOs really similar enough to the big eight to be in the same category.

Given that they're far more similar to Earth than Earth is to Jupiter? YES. Unambigulously yes. If you want to take them out of the category, you also need to say that either the terrestrial planets aren't planets, or the gas giants and ice giants aren't planets. And the ice giants really shouldn't be grouped with the gas giants anyway. Or we can just stop all of this nonsense and accept the practical definition that hydrostatic equilibrium is a really meaningful bound, and then subdivide "planet" into planet categories from there - dwarf, terrestrial, gas giant, ice giant, and all of the strange new types we're discovering in other star systems.

Comment While we're on the topic... (Score 5, Informative) 42

... here's 19 reasons why the IAU's Pluto decision was ridiculous. But first, the definition

The IAU...resolves that planets and other bodies in the Solar System be defined into three distinct categories in the following way:
(1) A planet [1] is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects [3] orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

[1] The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

[2] An IAU process will be established to assign borderline objects into either dwarf planet and other categories.

[3] These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

1. Nomenclature: An "adjective-noun" should always be considered a subset of "noun". A "dwarf planet" should be no less seen as a type of planet than a "dwarf star" is seen as a type of star.

2. Erroneous foundation: Current research suggests that individual planets do not necessarily cleared their own neighborhoods, and their neighborhoods may not always have where they are. Jupiter, and Saturn to a lesser extent, have cleared most neighborhoods.

3. Comparative inconsistency: Earth is far more like Ceres and Pluto than it is like Jupiter, yet these very dissimilar groups - gas giants and terrestrial planets - are lumped together as "planets" while dwarfs are excluded.

4. Poor choice of dividing line: While defining objects inherently requires drawing lines between groups, the chosen line has been poorly selected. Achieving a rough hydrostatic equilibrium is a very meaningful dividing line - it means differentiation, mineralization processes, alteration of primordial materials, and so forth. It's also often associated with internal heat and, increasingly as we're realizing, a common association with subsurface fluids. In short, a body in a category of "not having achieved hydrostatic equilibrium" describes a body which one would study to learn about the origins of our solar system, while a body in a category of "having achieved hydrostatic equilibrium" describes a body one would study, for example, to learn more about tectonics, geochemistry, (potentially) biology, etc. By contrast, a dividing line of "clearing its neighborhood" - which doesn't even meet standard #2 - says little about the body itself.

5. Mutability: What an object is declared at can be altered without any of the properties of the object changing simply by its "neighborhood" changing in any of countless ways.

6. Situational inconsistency: An exact copy of Earth (what the vast majority of people would consider the prototype for what a planet should be), identical down to all of the life on its surface, would not be considered a planet if orbiting in the habitable zone of a significantly larger star (harder to clear zone), or a young star (insufficient time to clear), a star without a Jupiter equivalent (no assistance in clearing), or so forth.

7. Ambiguous definition: There is still no consensus on what defines having "cleared the neighborhood" - in particular, what the "neighborhood" is.

8. Lack of terminology: Exoplanets - indeed, including any potential Earthlike planets - are arbitrarily declared to not be planets. This deprives those studying exoplanets of an IAU-acceptable term to refer to them by.

9. Inability to describe exoplanets even if not ruled out: There is no way that even if exoplanets hadn't been arbitrarily ruled out that one could ascertain whether a body has met a "cleared the neighborhood" via observations from Earth.

10. Failure to address binary objects. Self-explanatory.

11. Unscientific motivation: The primary reason cited by everyone interviewed thusfar for choosing an exclusive standard over an inclusive standard is along the lines of, "It would be too hard for schoolchildren to memorize the names of all of them". This is such a blatently unscientific standard that it doesn't even bear going into, and leads to absurd consequences when applied to other fields, such as the AMA declaring that there's only 8 bones in the human body and all others are "dwarf bones" that aren't real bones, or the USGS declaring that there's only 8 rivers in the world and all others are "dwarf rivers" that aren't real rivers, all for the purpose of making things easier for students to memorize.

12. Resistance to accept the diversity of reality: In every scientific field, the universe continually presents those making discoveries with a wide range of diversity. This is almost universally accepted in an inclusive manner, subdividing groups into subgroups, and subdividing those further. We will continue to find new types of planetary bodies in a wide range of diversity - large terrestrial planets, dwarf-scale planets, gas giants, ice giants, hot jupiters, super-earths, water worlds, supercomets, extremely large bodies orbiting as moons, planets without parent stars, and so forth. Rather than trying to hide diversity, science is supposed to embrace it.

13. Discouragement of exploration among the public: The term "planet" has a deep and meaningful place in the public mind, as a body worthy of exploration, perhaps even eventually colonization. "Small solar system body" does not. Public support for scientific exploration to these diverse and fascinating worlds should not be discouraged by poorly chosen names. Quite to the contrary, it would be worthwhile if fascinating worlds the diameter of Mercury like Ganymede and Titan were given the same level of attention with a label such as "planetary moons" (note again: an "adjective-noun" is a subcategory of "noun").

14. Distrust of the scientific population among the public: Images of discontent scientists sniping at each other and divisive voting on controversial "truths" have a profoundly negative consequence on the public's view of the scientific community. Anyone who spends any time looking at any of the internet commentary on the dwarf planet decision will find them full of comments along the lines of "Scientists can't even agree about whether Pluto is a planet, why should we trust them about global warming?" I wish this were hyperbole, but I've seen it far too often to ignore it.

15. Poor voting statistical representation: While 4% of the IAU would make up a statistically significant sample if chosen at random, the people involved were not "chosen at random". The people present were "those who could take a trip to Prague and didn't have to leave before the closing ceremony", which leads to numerous potential biases. As Owen Gingerich noted, "There were 2,700 astronomers in Prague during that 10-day period. But only 10% of them voted this afternoon. Those who disagreed and were determined to block the other resolution showed up in larger numbers than those who felt 'oh well, this is just one of those things the IAU is working on'." In this day in age where electronic balloting is simple to implement, that the IAU would be willing to make charged decisions on a 60% vote of a non-random 4% of the membership is highly inappropriate.

16. Wrong people making the decision: Only a small percentage of the IAU are planetary scientists, who are the actual people who should be the ones making decisions about what makes up a planet. Letting people who study stars decide what counts as a planet is akin to letting dermatologists decide how to treat a heart condition - hey, a doctor's a doctor, right? Just like when meteorologists or chemists make claims that global warming isn't real - a scientist is a scientist, right?

17. Making the decision before gathering the data: For most of the history of humankind's knowledge of Ceres and Pluto, we have not had any missions underway to explore them. They were just poorly resolved points of light. But at the time of the IAU vote, at long last, we had launched New Horizons to Pluto and were preparing Dawn for launch to Ceres. Yet it was at this narrow interval, between actually launching craft to gather data about the bodies, but not having them arrive, that the IAU decided to make their declaration. Making scientific declarations about objects that you know little about when vast amounts of data are coming in the pipeline - data that could influence members making the decision - is profoundly unscientific.

18. Not following through on its own declarations: The IAU decision declared that it would continue to name new dwarf planets as new data comes in. Yet there's not been a new declaration since 2006. We have far better data than we had to make declarations of dwarf planets in 2006, and there's a long list of them awaiting declaration - where's the IAU? For example, Quaoar's diameter is known is known to a mere ±5 km and is significantly larger than Ceres. Even the lower bound of 2007 OR10 is larger than Quaoar. Why aren't they and countless others on the list? It increasingly looks like the IAU just wanted to make its declaration purely for demotion purposes rather than for its stated purpose of categorization.

19. Disagreement with the IAU is so intense that those who disagree are simply ignoring it - a process that began in the literature almost immediately (example: http://arxiv.org/abs/0712.2198), let alone in conversations with the public (example: any press conference with the New Horizons team). This not only renders the definition meaningless but serves to undercut the IAU's authority in other issues (such as naming).

Comment Re:Still no word on if its discoverer gets to name (Score 4, Informative) 42

Such a program already exists. And guess what - shock of all shocks, the IAU is throwing a hissy fit about it. They're basically at war with NH's director Alan Stern and are planning to refuse a large portion of the NH team's feature names for Pluto.

Comment Re:Damned Revisionists (Score 3, Funny) 42

I think I'm going to take a cue from the IAU's attitude and go ahead and make my own definition for the IAU:

"The International Astronomical Union is defined as a member body of navel-gazing self-important wankers who use grant money to travel to exotic locales to get drunk and make shit up in the name of science."

All great discoveries are made by mistake. -- Young

Working...