>OMG, are you for real? Did you even try to Google it?
Indeed. My original hypothesis that you were a broken google record was correct. Now that you provided me that valuable insight as to your _real_ "enlightenment", maybe I can illustrate my caution about drawing _conclusions_ this way:
Pluto's radius is not well known. JPL's value of 1137 is given with an error of +/-8, almost one percent - in large part because Pluto's own albedo varies from 0.49 to 0.66. Now extrapolate that estimate while estimating the albedo of said discovered planet, and drawing _conclusions_ that it is bigger. Unfortunately, you fail to see the mathematical difference between an "inference" and a "logical equivalence". You by no means are an Astronomer, and at best a 3rd rate mathematician. In time, if you spend less time gathering your intellect off the net and more so from study, you just might...
Yes. Everything you cited is well understood. However, you still (apparently) fail to understand the significance of what I was trying to illustrate by others drawing such a _conclusion_. Errors in reflectivity at such distances allow us only to conclude inferences (which is why we say estimates). But no conclusions may be drawn from them.
To illustrate, and hopefully this won't be lost on you, even pluto's albedo varies from 0.49 to 0.66. One object could be brighter than another because it is larger, more reflective, or some combination of both. To determine the size of a KBO requires astronomers to determine, or at least _estimate_, its albedo.
> If you just meassure the light recieved from the point, you have only albedo and radius left, which allows a minimum size estimate.
estimate? exactly.
In order to calculate the albedo of a planet, you NEED to know the surface area of that sphere. Do you? And do you know the radius?
Furthermore, in order to calculate the albedo, you must know something about it's atmosphere and temperature. Do we know that?
Mathematical conlusions based on mathematical inferences do not equate to logical equivalences. :. reflectivity != size
It doesn't get any simpler than that. You sound like a broken google record. How about you actually fill in all the blanks next time, and don't presume copy/pasting google snipets supercedes accredited study. Me thinks you presume too much. How so "enlightened" we are...
> Thus, the smallest the object can be is 97% the size of Pluto. Since the object cannot be a perfect mirror, it is bigger than Pluto.
97%? How did you reach that calculation?
> Likewise, the reflectivity of other substances can be tried. If the object is made of snow (90% reflectivity) it will be 2% larger Pluto, and if the object has the same composition as Pluto it will be 25% larger than Pluto.
Huh? Where'd you get those numbers? Actual calculations might help clarify your illustration. I'll try again by another (more practical) real life example...
Place a marble which is polished clear white, 1 inch in diameter, and 2 feet behind a brown marble 1.1 inches in diameter, and just stand 30 ft across a dark room and shine a light at it. Tell me which one reflects more light back. Brown marble 60%, polished white 90%. You already know the brown marble is bigger by.1 inch, yet you claim since the polished white marble is brighter it is bigger? You don't need any telescopes to perform this experiment. This _really_ isn't rocket science here. You can do it in your own house. Furthermore, if I move that polished white marble up next to the brown one, it gets brighter, right? So by your definition, that polished marble will GROW bigger in diameter. What I'm trying to convey to you is that there is NOT a 1:1 relation between reflectivity and size. I can move that polished clear white marble up to my feet as I shine the light on it. Has it gotten any bigger in diameter? And it's super bright now...
Unfortunately, and I guess you don't see it, you are making mathematical CONCLUSIONS based on mathematical INFERENCES.
I don't know how it can get any simpler than that. Maybe if you could provide a link to how these guys actually measure these distances and sizes WITHOUT actually being able to take a tape measure to them (or send a probe), I wouldn't be so inclined to believe it flys in the face of common sense (and practical real life examples), much less making a mathematically logical equivalence between reflectivity and size, when it's only an inference (especially when dealing in relative terms at vast spanses you cannot accurately measure)...
> In addition, we already know how far away the objects are due to measurements of it's position...
Indeed. That's a given (I suppose). I think you even mentioned "estimates" (by accident or not). What I meant to convey by my mirror analogy is a direct translation of what the article is stating. It makes the following logical equivalence (in mathematically discrete terms):
Reflectivity [is logically equivalent to] Size
...and I disagree (or fail to understand) that statement in the article.
I am saying:
Reflectivity [infers] Size
...quite possibly, yes. I don't dispute that.
The article could have suggested it as so. However, it concluded since it is brighter than it should be, it must be bigger than pluto. I am not nit-picking at the article here. I am just trying to understand the factual scientific means by which we draw such conclusions. How do we accurately measure the size of a planet without actually measuring it, especially when so far away? Other than inferring it's size, based on reflectivity, in association with those near it?
Ok. Well, then you are saying that the planet is a clean 10 (cm) mirror and pluto is a dirty 10 (cm) mirror. Right? You still cannot infer that a 10 (cm) mirror is bigger than a 10 (cm) mirror - since at that _vast_ relative distance they still appear to be the same size to us, only one's brighter than the other.
Reflectivity !-> Size
in other words, convince me a white dwarf star (the size of earth) 50 million light years away is bigger than a Gas Giant planet some 20 million light years away. Granted, I'm comparing a star to a planet here, but I'm using it to illustrate (my "apparent" lack of understanding) of associating reflectivity with size. It sounds like a leap of faith to me...
FTA: "In the case of the new planet, however, we know that even if it is extremely reflective (like fresh snow, for example) it still cannot be as bright as it is unless it is bigger than Pluto. Thus while we don't know for certain the precise size, we know for certain that it is bigger than Pluto."
How? I don't understand this logic here. What am I missing?
If one person holds a dirty 20 (cm) mirror in pitch darkness about a 100 meters away from me, another person holds a shiny 10 (cm) mirror about 200 meters away from me, and I shine a _powerful_ flashlight at them, I see the smaller mirror is brighter, yet it's NOT bigger, and both appear the same size relative to me...
To be historically acurate here: The 10th planet was formerly what we now call the "Asteroid Belt". All ancient civilizations from Egypt to South America to China along the Equator, constructed pyramids detailing that original astrolonomical layout...
Slashdot Mirror
Indeed. My original hypothesis that you were a broken google record was correct. Now that you provided me that valuable insight as to your _real_ "enlightenment", maybe I can illustrate my caution about drawing _conclusions_ this way:
Pluto's radius is not well known. JPL's value of 1137 is given with an error of +/-8, almost one percent - in large part because Pluto's own albedo varies from 0.49 to 0.66. Now extrapolate that estimate while estimating the albedo of said discovered planet, and drawing _conclusions_ that it is bigger. Unfortunately, you fail to see the mathematical difference between an "inference" and a "logical equivalence". You by no means are an Astronomer, and at best a 3rd rate mathematician. In time, if you spend less time gathering your intellect off the net and more so from study, you just might...To illustrate, and hopefully this won't be lost on you, even pluto's albedo varies from 0.49 to 0.66. One object could be brighter than another because it is larger, more reflective, or some combination of both. To determine the size of a KBO requires astronomers to determine, or at least _estimate_, its albedo.
Huh? The intensity DOES change, but the reflectivity does not. You need to go back and reread...
estimate? exactly.
In order to calculate the albedo of a planet, you NEED to know the surface area of that sphere. Do you? And do you know the radius?
Furthermore, in order to calculate the albedo, you must know something about it's atmosphere and temperature. Do we know that?
Mathematical conlusions based on mathematical inferences do not equate to logical equivalences.It doesn't get any simpler than that. You sound like a broken google record. How about you actually fill in all the blanks next time, and don't presume copy/pasting google snipets supercedes accredited study. Me thinks you presume too much. How so "enlightened" we are...
97%? How did you reach that calculation?
> Likewise, the reflectivity of other substances can be tried. If the object is made of snow (90% reflectivity) it will be 2% larger Pluto, and if the object has the same composition as Pluto it will be 25% larger than Pluto.Huh? Where'd you get those numbers? Actual calculations might help clarify your illustration. I'll try again by another (more practical) real life example...
Place a marble which is polished clear white, 1 inch in diameter, and 2 feet behind a brown marble 1.1 inches in diameter, and just stand 30 ft across a dark room and shine a light at it. Tell me which one reflects more light back. Brown marble 60%, polished white 90%. You already know the brown marble is bigger by .1 inch, yet you claim since the polished white marble is brighter it is bigger? You don't need any telescopes to perform this experiment. This _really_ isn't rocket science here. You can do it in your own house. Furthermore, if I move that polished white marble up next to the brown one, it gets brighter, right? So by your definition, that polished marble will GROW bigger in diameter. What I'm trying to convey to you is that there is NOT a 1:1 relation between reflectivity and size. I can move that polished clear white marble up to my feet as I shine the light on it. Has it gotten any bigger in diameter? And it's super bright now...
Unfortunately, and I guess you don't see it, you are making mathematical CONCLUSIONS based on mathematical INFERENCES.
I don't know how it can get any simpler than that. Maybe if you could provide a link to how these guys actually measure these distances and sizes WITHOUT actually being able to take a tape measure to them (or send a probe), I wouldn't be so inclined to believe it flys in the face of common sense (and practical real life examples), much less making a mathematically logical equivalence between reflectivity and size, when it's only an inference (especially when dealing in relative terms at vast spanses you cannot accurately measure)...Indeed. That's a given (I suppose). I think you even mentioned "estimates" (by accident or not). What I meant to convey by my mirror analogy is a direct translation of what the article is stating. It makes the following logical equivalence (in mathematically discrete terms):
Reflectivity [is logically equivalent to] Size ...and I disagree (or fail to understand) that statement in the article.
I am saying:Reflectivity [infers] Size
The article could have suggested it as so. However, it concluded since it is brighter than it should be, it must be bigger than pluto. I am not nit-picking at the article here. I am just trying to understand the factual scientific means by which we draw such conclusions. How do we accurately measure the size of a planet without actually measuring it, especially when so far away? Other than inferring it's size, based on reflectivity, in association with those near it?
Reflectivity !-> Size
in other words, convince me a white dwarf star (the size of earth) 50 million light years away is bigger than a Gas Giant planet some 20 million light years away. Granted, I'm comparing a star to a planet here, but I'm using it to illustrate (my "apparent" lack of understanding) of associating reflectivity with size. It sounds like a leap of faith to me...How? I don't understand this logic here. What am I missing?
If one person holds a dirty 20 (cm) mirror in pitch darkness about a 100 meters away from me, another person holds a shiny 10 (cm) mirror about 200 meters away from me, and I shine a _powerful_ flashlight at them, I see the smaller mirror is brighter, yet it's NOT bigger, and both appear the same size relative to me...
What I miss?
To be historically acurate here: The 10th planet was formerly what we now call the "Asteroid Belt". All ancient civilizations from Egypt to South America to China along the Equator, constructed pyramids detailing that original astrolonomical layout...