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Forget Cricket Talk about anything [within Board Rules, of course :) ] |
March 13, 2004, 06:40 AM
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Cricket Legend
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Observatory Trip (Anrab, You gotta read this!!!)
On Friday Night, our Physics class went to the Alloway Observatory (During the 5th ODI). Ower main purpose was to look at the lenses in the telescope, but we did get to talk about stars and stuff. We got to see Venus, Saturn, Jupiter and 2 nebulas.
Now Anrab, you once said that they just add colour to the pics to make them look nice. But I had a little chat to one of the Astronomers over there. He said that the colours ARE added to the pics... BUT not to make them look nice... BUT because their camara can only take the photo in black and white. They figure out the actual colour through the wave lenght of light. In fact if you look at Jupiter and Saturn through a telescope, they will appear Black and White, only way to know the actual colour is being close through it, or figure it out through the wave length of the colours.
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March 13, 2004, 01:33 PM
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Hasib, A LOT of these "wavelengths" are invisible to human eyes, ok?
You, a human, can't "see" ultraviolet or infrared wavelength waves. Only the waves whose wavelengths fall under the VIBGYOR spectrum will be visible to you. Can you SEE an x-ray? Can you see the intensity of a light souce in different shades of color? No.
So when they added color to the cat's eye nebula picture, they couldn't possibly relate any color to the ultraviolet or x-ray waves. But they did.
For example:
Quote:
The quintessential Hubble photograph is a 1995 image of the popular Eagle Nebula, also known as M16 or the Pillars of Creation. The soaring structures had one of their red emissions converted to green -- by the astronomers who took the picture -- in order to highlight scientific detail. In "reality," no green was detected coming from the Pillars.
In some cases, the colors are as true to reality as anyone could imagine. Other times, as with the Eagle Nebula, colors are changed for effect. Hydrogen and sulfur were each detected in red tones, so the hydrogen, which involved a shorter wavelength, was made green
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March 13, 2004, 03:52 PM
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Lets put it this way, Jupiter and Saturn also appear black and white...
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March 13, 2004, 04:07 PM
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Ok. This will be a good exercise for you. Try to form a clear, step by step statement of what your trying to say to me here. I will answer after you do that.
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March 13, 2004, 04:20 PM
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OK... 1st explain WHY then does Jupiter and Saturn appear black and white, when we know they have colour.
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March 13, 2004, 05:32 PM
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How do you know that Jupiter and Saturn have certain colors? Have you ever seen them with your naked eyes? Have you flown near Jupiter itself and observed its color?
[Edited on 13-3-2004 by Arnab]
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March 13, 2004, 05:49 PM
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They had probes fly past them. In fact jupiter's moons appear white as well.
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March 13, 2004, 06:02 PM
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What is your point? Look, instead of wasting my time by forcing me to respond to your one line posts, think for half an hour (or take whatever amount of time you want), write down ALL your points and questions in a clear, step by step logical fashion. Can you do that?
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March 13, 2004, 06:05 PM
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I have only one point... Nabulas have colour. The other stuff are just back up evidence.
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March 13, 2004, 06:17 PM
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OK, here is what I think might address whatever point you have:
Any nebulae in the universe will radiate electromagnetic waves of various wavelengths. If some of these waves contain wavelengths between 400 and 700 nanometers, they will be visible to the human eye and you will experience various "colors", ranging from red to violet.
The photos of the nebulas that you saw in the religion thread did not take into account the actual visible wavelength of the waves when they applied colors to those photos. The colors were based upon wavelengths that are not visible by humans.
Let's say I apply a certain shade of blue to represent a wavelength of 20 nanometer. Now, 20 nanometer has no real "color". But to make things more descriptive to the human eye, I just chose blue as the color. The real thing has no color. Get it?
[Edited on 13-3-2004 by Arnab]
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March 13, 2004, 06:21 PM
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From what you are saying, Jupiter and Saturn are black and white. From a distance they seem like that. But from close up (probes) they have colour
[Edited on 13-3-2004 by Hasib]
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March 13, 2004, 06:25 PM
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Whatever. I don't know for sure what the actual colors of Jupiter or Saturn are. If you want to know what colors they have, ask your Astronomy teacher whether they radiate any waves that have wavelengths between 400 and 700 nm. If they do radiate those waves, then then they have some color. If they don't radiate those waves, then they will appear black and white to the human eye. Because human eye cannot detect any color outside that range. The capability of our eyes is limited.
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March 13, 2004, 06:27 PM
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They already know the actual colours coz they have flown probes past them... yet from Earth they appear black and white.
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March 13, 2004, 06:31 PM
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So?
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March 13, 2004, 06:33 PM
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If this is the case with these planets... i.e. the colurs not appearing from Earth, than why not with the Nabulas?
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March 13, 2004, 06:36 PM
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Do you want me to give you a ten day lecture on how these things are done? You will have to pay me a couple of thousand bucks then.
Why don't you do a google search on it and read some online articles from a good science source, say astronomy magazines or astronomy department webpages from different colleges to rad about how it is really done.
Come back after doing that and we will discuss more about it, ok? I promise.
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March 13, 2004, 06:37 PM
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Nice way to avoid my point.
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March 13, 2004, 06:43 PM
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I am not avoiding your point. I am trying to evade the responsibility of babysitting you through the whole thing. It's tedious. Send me cash (paypal will do) and I will show you how it all works.
[Edited on 13-3-2004 by Arnab]
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March 13, 2004, 06:46 PM
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Pay you when you to fill me with nonsense? I have already talked to an expert on this feild, unlike you.
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March 13, 2004, 07:09 PM
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OK, show your expert whatever discussion we had in this thread and ask for his comment. Also ask him also whether he can figure out any substantial point made by you in this thread.
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March 13, 2004, 07:14 PM
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The only problem is, our class isn't going back to the observatory... so you will ust have to explain WHY than do the planets appear black and white when they are not... why don't you answer this one question? If you have a proper answer the debate will end!
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March 13, 2004, 07:19 PM
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"will have to"
Hmm... Boy!! Arnab you are so patient!!
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March 13, 2004, 07:31 PM
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Alright, let me quote from that link to answer your question:
Source: The Astronomy Webpage of Valdosta State University, Virginia, USA.
Since our eyes are not sensitive to wavelengths longer or shorter than visible light, we build instruments to translate the x-ray, uv, infrared and radio light into wavelengths which we CAN see. We stick these instruments on telescopes and hook them up to computers. Arbitrary colors are then chosen to display the images.
This is a visible light, whole-sky image of our galaxy, the Milky Way. This is how we see it, but at shorter and longer wavelengths it looks quite different.
Here it is in infrared light at a wavelength of 2µ, as a snake might see it. Infrared light at this wavelength is radiated mostly by warm dust.
And in radio light at a wavelength of a few millimeters, you can see the bulge of old stars around the Galactic center.
This radio image shows the distribution of atomic hydrogen in the Milky Way, the material from which the next generation of stars will form.
Many stars in our Galaxy shine at very short wavelengths, in ultraviolet and x-ray light, as seen here. Actually, honey bees see the Milky Way much like this because their eyes are sensitive to ultraviolet. Some flowers direct bees to pollen and nectar by marking their petals with landing strips and taxiing directions that reflect only ultraviolet light which only bees can see.
[Edited on 14-3-2004 by Arnab]
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March 13, 2004, 07:35 PM
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According to them, the method shows Jupiter's colour like this-
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