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Author: sykesix Big gold star, 5000 posts Top Recommended Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: of 63075  
Subject: Bad News for Pluto Fans Date: 3/28/2012 1:12 PM
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There could be many billions of planets not much bigger than Earth circling faint stars in our galaxy, says an international team of astronomers.

The estimate for the number of "super-Earths" is based on detections already made and then extrapolated to include the Milky Way's population of so-called red dwarf stars.

The team works with the high-precision Harps instrument.

This is fitted to the 3.6m telescope at the Silla Observatory in Chile.

Harps employs an indirect method of detection that infers the existence of orbiting planets from the way their gravity makes a parent star appear to twitch in its motion across the sky.

"Our new observations with Harps mean that about 40% of all red dwarf stars have a super-Earth orbiting in the habitable zone where liquid water can exist on the surface of the planet," said team leader Xavier Bonfils from the Observatoire des Sciences de l'Univers de Grenoble, France.

"Because red dwarfs are so common - there are about 160 billion of them in the Milky Way - this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone."




http://www.bbc.co.uk/news/science-environment-17532470
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Author: SeattlePioneer Big funky green star, 20000 posts Top Favorite Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41574 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/28/2012 1:29 PM
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Ummmmm... what does this have to do with Pluto?




This article DOES raise the prime issue I have with the Anti-Pluto people who have declared Pluto isn't a planet.

As I understand it (I have no technical knowledge) the reason for doing so is deciding that to be a planet, an orbiting body must clear its orbit of most other space debris.

This constructed definition was used to declare that Pluto is not a planet. BIG headlines generated as a result.

But look at this article, which talks about planets, and billions of 'em, detected based on highly limited observations and extrapolation of numbers. Nothing wrong with that, but with the limited observations available, there is obviously no way to determine if these observed planets have cleared their orbits of space debris.

All of a sudden, that criteria no longer seems to be important.

If these scientists are to be consistent, it seems to me that they can only declare that they have found billions of pieces of orbiting space junk which might or might not be planets.

But they obviously aren't doing that. They are using one definition of a planet to demote Pluto, and another to declare astronomical objects to be planets whether or not they have cleared their orbits of orbital debris.

That sounds like inconsistent, bad science to ME!



Seattle Pioneer
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Author: JamesBrown Big red star, 1000 posts Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41577 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/28/2012 2:50 PM
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As I understand it (I have no technical knowledge) the reason for doing so is deciding that to be a planet, an orbiting body must clear its orbit of most other space debris.

That was just one of the criteria. Using that criterion alone, not even Jupiter would be considered a planet, as it has Trojan asteroids sixty degrees ahead and behind of its orbit (part of gravitational weirdness).

As for extrasolar stuff, the term 'planet' has been used as a convenient public-friendly placeholder until future observations can clarify precisely what the object in question is, be it a planet, a dwarf planet, an asteroid, or even a brown dwarf.

That sounds like inconsistent, bad science to ME!

Okay, Mr. Conspiracies Everywhere, define 'planet.'

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Author: SeattlePioneer Big funky green star, 20000 posts Top Favorite Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41578 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/28/2012 3:22 PM
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<<As for extrasolar stuff, the term 'planet' has been used as a convenient public-friendly placeholder until future observations can clarify precisely what the object in question is, be it a planet, a dwarf planet, an asteroid, or even a brown dwarf.>>


Riiiiight. When scientists want to flog the public for more funding, use the most appealing term available. How principled!


<<That sounds like inconsistent, bad science to ME!

Okay, Mr. Conspiracies Everywhere, define 'planet.' >>



Heh, heh! I'm in favor for equal and traditional treatment for Pluto!


For thousands of years observers of the heavens identified planets as the "wanderers" of the sky. When far more scientific methods were developed, that tradition continued.

In a brief moment, a faction of observers decided to refine what a planet was, and demoted Pluto.

Then again with these recent studies of distant solar systems, the old definition of planet once again appears to reign among state of the art observers.

It seems to me that there is a lot of utility an life left in the traditional definition, which should include Pluto I claim.



Seattle Pioneer


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Author: JamesBrown Big red star, 1000 posts Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41581 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/28/2012 4:22 PM
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Riiiiight. When scientists want to flog the public for more funding, use the most appealing term available. How principled!

I'm not sure what this has to do with anything. Should scientists be charging an admission before powering up an instrument? Licensing term usage before anyone can write the word 'Pluto' or take a picture of it with their own backyard telescopes?

Your ability to criticize is impressive. But if you've got a better, more effective method to perform ground-breaking research, lay it out. If it works, then the scientists of the world will hail you as a genius and make you their king.

Heh, heh! I'm in favor for equal and traditional treatment for Pluto!

Why?

For thousands of years observers of the heavens identified planets as the "wanderers" of the sky.

Precisely. By that definition, both the sun and the moon qualified as 'planets.' Are you saying we should now stick with that old tried-and-true definition?

When far more scientific methods were developed, that tradition continued.

Your history of science is simplistic. When the true nature of the sun and the moon were discovered, they lost their planetary status, just like Pluto did. Oh, you should have heard the howls then.

Then, as observation methods improved, other objects were found to be orbiting the sun, like Uranus. Since the only objects ever named at that time were 'stars (including our sun),' 'moons,' and 'planets,' then Uranus was declared a planet.

But then more and more 'planets' were found. At one point, the number of planets was as high as 23. Except some of them were not that big, and appeared to be part of a group of junk, which were eventually called 'asteroids,' or 'little stars.' When the asteroids and non-asteroids were divided into their categories, the number of planets fell to a staggeringly low eight.

Now we have Pluto. Pluto was discovered because it's bright, but it's part of another group of junk called Trans-Neptunian bodies, among other names. But there's nothing special about Pluto that would not also be valid for many other objects out there. It's not the biggest object out there past Neptune, and if you moved it within the orbit of Jupiter, it would behave like a comet with a long tail and and a dwindling nucleus every year until it finally evaporated away.

If Pluto is a planet, then then number of planets would be in the hundreds, perhaps the thousands--far too many to name and force elementary school kids to memorize.

It seems to me that there is a lot of utility an life left in the traditional definition, which should include Pluto I claim.

Well, you would be wrong, which is why I asked you for a definition of planet, something that the world's astronomers have had difficulty doing for centuries. "Wanderer" is not going to cut it.

http://en.wikipedia.org/wiki/IAU_definition_of_planet

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Author: sykesix Big gold star, 5000 posts Top Recommended Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41582 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/28/2012 4:58 PM
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Now we have Pluto. Pluto was discovered because it's bright, but it's part of another group of junk called Trans-Neptunian bodies, among other names. But there's nothing special about Pluto that would not also be valid for many other objects out there. It's not the biggest object out there past Neptune, and if you moved it within the orbit of Jupiter, it would behave like a comet with a long tail and and a dwindling nucleus every year until it finally evaporated away.

Actually, I think the story of the discovery of Pluto is pretty interesting. Basically due to a mathematical error it was believed there was a fairly large planet outside the orbit of Uranus. Due to blind coincidence, Pluto happened to be right where they were looking for this new planet.

In later years the error was found and the physics was updated and it came to be known that not only was there no large planet beyond Uranus, Pluto was only much, much smaller than originally thought. On top of that it wasn't even the biggest object in its neighborhood (as you point out).

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Author: salaryguru Big gold star, 5000 posts Top Recommended Fools Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41590 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/29/2012 1:15 AM
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The history of Pluto is interesting. Ninety years ago, Pluto didn't exist. It became an official planet in 1930. And it was demoted to dwarf planet in 2006. Yet Pluto never changed. What changed was our knowledge of the properties of Pluto. As scientific knowledge about Pluto increased, our classification and description of Pluto changed to match the knowledge.

This is similar to our growing knowledge about global warming. Denialists point to the fact that our classifications and descriptions of global warming evolve as proof that it doesn't exist. Based on this, I think that most of these people would also want to believe that Pluto doesn't exist - not that it is a planet.

Or maybe I don't understand the denialist principle. Maybe it is not that growth in knowledge is proof for non-existence. Maybe they just want to believe whatever they were taught in 1950.

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Author: PSUEngineer Big funky green star, 20000 posts Top Favorite Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41600 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/29/2012 11:11 AM
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"Because red dwarfs are so common - there are about 160 billion of them in the Milky Way - this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone."

That's a good reason not to send "we are here" messages into space.

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Author: SeattlePioneer Big funky green star, 20000 posts Top Favorite Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41603 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/29/2012 11:48 AM
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<<"Because red dwarfs are so common - there are about 160 billion of them in the Milky Way - this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone."

That's a good reason not to send "we are here" messages into space. >>


Heh, heh! True, but I'm afraid that cat is out of the bag.



Seattle Pioneer

When will The Visitors arrive?

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Author: SeattlePioneer Big funky green star, 20000 posts Top Favorite Fools Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41610 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/29/2012 10:36 PM
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This is from the article you quoted from Wikipedia:


<<The definition of planet set in 2006 by the International Astronomical Union (IAU) states that, in the Solar System, a planet is a celestial body which:

is in orbit around the Sun,
has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and
has "cleared the neighbourhood" around its orbit.
>>


Note the words "in the Solar System."

So it appears that these scientists have two definitions for planets, one of which applies in the special case of our own solar system, and the other which applies to the rest of the universe.

Now, really! What's special about this measly solar system that justifies a special definition for planets? Seems rather arbitrary to me.

As a Plutocrat, I favor one, universal definition for planets!


<<For thousands of years observers of the heavens identified planets as the "wanderers" of the sky.

Precisely. By that definition, both the sun and the moon qualified as 'planets.' Are you saying we should now stick with that old tried-and-true definition?>>


Oh, I don't think ancient observers of the heavens mistook the sun and moon for planets.


Seattle Pioneer

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Author: JamesBrown Big red star, 1000 posts Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: 41643 of 63075
Subject: Re: Bad News for Pluto Fans Date: 3/30/2012 11:31 PM
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SeattlePioneer writes: So it appears that these scientists have two definitions for planets, one of which applies in the special case of our own solar system, and the other which applies to the rest of the universe.

Now, really! What's special about this measly solar system that justifies a special definition for planets? Seems rather arbitrary to me.


I don't know. Perhaps it's because we've written about one group of objects since the 2nd millennium B.C.E, and we've known about another group since only 1998, less than 0.3% comparatively. And when it comes to objects in our Solar System, the big bright ones have traditionally been called 'planets.' What we've discovered orbiting other stars are likewise big and bright--that's why we've been able to find them--and so they are rightly assumed to be planets. I'm quite sure that when observations of extrasolar systems find Pluto-sized objects, they'll be re-classified into a more logical category as well.

Sheesh--if you think this is arbitrary, you should watch biologists argue over how to classify newly-discovered species.


As a Plutocrat, I favor one, universal definition for planets!

Yes, you've established that, without explaining why you have such a seed in your dentures over what we happen to call a dirty snowball, nor without providing a definition of 'planet' that will satisfy everyone.


Oh, I don't think ancient observers of the heavens mistook the sun and moon for planets.

And there, too, you would be wrong:

https://en.wikipedia.org/wiki/Planet#Greco-Roman_astronomy
To the Greeks and Romans there were seven known planets, each presumed to be circling the Earth according to the complex laws laid out by Ptolemy. They were, in increasing order from Earth (in Ptolemy's order): the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn.

Remember, the original definition of 'planet' per the Greeks and Romans was anything that wandered across the background stars, which included the Sun and the Moon. When later observations demanded that these two objects be re-categorized, I'm quite sure old grumps howled at their cherished notions being re-named willy-nilly by elitists. But it was absolutely required then and it is required now. Funny how you agree with one change in nomenclature, but not another.

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