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View Full Version : Observatory Trip (Anrab, You gotta read this!!!)


Hasib
March 13, 2004, 06:40 AM
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.

Arnab
March 13, 2004, 01:33 PM
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:

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

Hasib
March 13, 2004, 03:52 PM
Lets put it this way, Jupiter and Saturn also appear black and white...

Arnab
March 13, 2004, 04:07 PM
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.

Hasib
March 13, 2004, 04:20 PM
OK... 1st explain WHY then does Jupiter and Saturn appear black and white, when we know they have colour.

Arnab
March 13, 2004, 05:32 PM
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]

Hasib
March 13, 2004, 05:49 PM
They had probes fly past them. In fact jupiter's moons appear white as well.

Arnab
March 13, 2004, 06:02 PM
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?

Hasib
March 13, 2004, 06:05 PM
I have only one point... Nabulas have colour. The other stuff are just back up evidence.

Arnab
March 13, 2004, 06:17 PM
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.

http://acept.la.asu.edu/PiN/rdg/color/visible.gif

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]

Hasib
March 13, 2004, 06:21 PM
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]

Arnab
March 13, 2004, 06:25 PM
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.

Hasib
March 13, 2004, 06:27 PM
They already know the actual colours coz they have flown probes past them... yet from Earth they appear black and white.

Arnab
March 13, 2004, 06:31 PM
So?

Hasib
March 13, 2004, 06:33 PM
If this is the case with these planets... i.e. the colurs not appearing from Earth, than why not with the Nabulas?

Arnab
March 13, 2004, 06:36 PM
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.

Hasib
March 13, 2004, 06:37 PM
Nice way to avoid my point.

Arnab
March 13, 2004, 06:43 PM
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]

Hasib
March 13, 2004, 06:46 PM
Pay you when you to fill me with nonsense? I have already talked to an expert on this feild, unlike you.

Arnab
March 13, 2004, 07:09 PM
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.

Hasib
March 13, 2004, 07:14 PM
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!

Carte Blanche
March 13, 2004, 07:19 PM
"will have to"

Hmm... Boy!! Arnab you are so patient!!

Arnab
March 13, 2004, 07:24 PM
Arggh!!!

Here, take this free online course about "Color in Astronomy".

http://www.valdosta.edu/phy/astro/pl_shows/color_2000/first_page.htm

Arnab
March 13, 2004, 07:31 PM
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.

http://www.valdosta.edu/phy/astro/pl_shows/color_2000/mwop2.gif

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.

http://www.valdosta.edu/phy/astro/pl_shows/color_2000/mwir2.jpg

Here it is in infrared light at a wavelength of 2, as a snake might see it. Infrared light at this wavelength is radiated mostly by warm dust.

http://www.valdosta.edu/phy/astro/pl_shows/color_2000/mwmm2.gif

And in radio light at a wavelength of a few millimeters, you can see the bulge of old stars around the Galactic center.

http://www.valdosta.edu/phy/astro/pl_shows/color_2000/mwrad.jpg

This radio image shows the distribution of atomic hydrogen in the Milky Way, the material from which the next generation of stars will form.

http://www.valdosta.edu/phy/astro/pl_shows/color_2000/mwx2.jpg

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]

Hasib
March 13, 2004, 07:35 PM
According to them, the method shows Jupiter's colour like this-


http://www.valdosta.edu/phy/astro/pl_shows/color_2000/juprad4.jpg

Hasib
March 13, 2004, 07:37 PM
Also they r talking about infared.

Arnab
March 13, 2004, 07:38 PM
How old are you, Hasib?

Hasib
March 13, 2004, 07:39 PM
You want to attack me for my age don't you?

Arnab
March 13, 2004, 07:42 PM
No, I actually want to pick your rotten brain out of your skull and throw it in a garbage can. But that's beside the point. :)

Hasib
March 13, 2004, 07:43 PM
hmmm... rotten brain... look whos talking.:P

[Edited on 14-3-2004 by Hasib]

Arnab
March 13, 2004, 07:45 PM
I know. :)

Hey, let's make a race. Let's use this thread to see who gets to 2000 posts first. Deal?

Hasib
March 13, 2004, 07:47 PM
A race...? Good thing it's not running... (ok... I'm not that bad at running... I'm in the Div 1 for running events in school athletics carnivals... but I always come last :( But once I did come third :lol:)

Arnab
March 13, 2004, 08:19 PM
That's so cool! What school do you go to again?

Hasib
March 13, 2004, 11:44 PM
ummm... how is that cool...? You wouldn't know my school its in Australia...

Arnab
March 13, 2004, 11:56 PM
Ok, I admit it's not that cool. But it was interesting. Do yo go to a big school or a small school?

Hasib
March 14, 2004, 12:02 AM
It's a small school... but its the best one I've been to. Bigger school are suppose to be better than us, but we sometimes out class them. The percentage of students who donate blood ("the blood run" organized by a friend of mine) is higher than the other school. We currently hold the Teams math challenge Sheild (i'm the only member of that team that won who is still a student at the school). And last year 13 of the 14 sports teams entered the finals.

Shubho
March 14, 2004, 12:02 AM
arnab, i think the games you play are hilarious. you're a really funny guy.

do you go to school or do you work?

Arnab
March 14, 2004, 12:41 AM
shubho, playing games is essential. We are all chatty children inside who will talk for hours about our own selves when we are sufficiently wound up.

hasib, do you guys have any regional math quiz championship that you participate in? do you plan to study anything math-related in the future?

Hasib
March 14, 2004, 01:15 AM
We have a Math teams Challange once a year. We also have a individual math comp. No I don't want to do anything Math realted... more into the other sciences.

Carte Blanche
March 14, 2004, 01:23 AM
Originally posted by Arnab
I know. :)

Hey, let's make a race. Let's use this thread to see who gets to 2000 posts first. Deal?

Arnab you'll lose for sure. Hasib's saga of "one-liners" is unmatched on Banglacricket. The 2nd most useless poster. I hold the first place :)

Hasib
March 14, 2004, 01:24 AM
http://www.freewebs.com/banglateststats/4.jpg

Orpheus
March 14, 2004, 02:39 AM
I think Hasib goes to eigth grade! If he doesn't, he is a p**** ... What is he doing with eights graders!

[Edited on 3-15-2004 by chinaman : Watch your language]

Sami
March 14, 2004, 01:12 PM
why didnt u guys just have this conversation over MSN or yahoo or something...? wudnt that me so much easier?

Hasib
March 14, 2004, 03:44 PM
Originally posted by Orpheus
I think Hasib goes to eigth grade! If he doesn't, he is a p*** ... What is he doing with eights graders!

Orpheus... I'm surrounded by Australians... and they are taller then Bangladeshis so...

[Edited on 3-15-2004 by chinaman]

Orpheus
March 14, 2004, 05:36 PM
so you are a short eighth grader....

Short and cant run! You are future mahmud!

Hasib
March 15, 2004, 03:48 AM
No, I'm not an eighth grader... why else would I be doing Biology? I'm in grade 12. (this is a pic from last yr... i was in yr 11... the others in yr12.)

Orpheus
March 15, 2004, 02:03 PM
what pic?

I think you mentioned sometime ago that our maturity level was that of an eight grader in your school! Thus I assumed you are an eight grader.

You definitely don't sound like a 12th grader! That's not a compliment.

By the way they also teach you Biology in 7th grade. I had it.

[Edited on 15-3-2004 by Orpheus]

Nasif
March 15, 2004, 02:11 PM
Originally posted by Hasib
No, I'm not an eighth grader... why else would I be doing Biology? I'm in grade 12. (this is a pic from last yr... i was in yr 11... the others in yr12.)

The link for the picture that you posted few posts above does not work.

Hasib
March 15, 2004, 03:58 PM
Originally posted by Orpheus
what pic?

I think you mentioned sometime ago that our maturity level was that of an eight grader in your school! Thus I assumed you are an eight grader.

You definitely don't sound like a 12th grader! That's not a compliment.

By the way they also teach you Biology in 7th grade. I had it.

[Edited on 15-3-2004 by Orpheus]

You misinterperated me... what I meant in that thread was that I was being more mature then some ppl in there (a lot more).

When u did biology in 7... was it just unit in the subject "Science"?

[Edited on 15-3-2004 by Hasib]

Zunaid
March 15, 2004, 07:04 PM
Ok, kids. Let's put a stop to this.

Colors are nothing more than how our brain interprets photons of certain wavelengths. As Arnab mentioned in this thread somewhere, our eyes can only register a certain range of wavelengths - the visible spectrum.

Now, the retina of our eyes has photoreceptors. There are two kinds: rods and cones. Rods are not sensitive to color and the brain interprets light hitting the rods in black and white. Cones ARE sensitive to light. Current understanding is that cones can be differentiated into three types: blue, red and green in terms of their sensitiveness to light of certain wavelengths. A blue cone's sensitivity peaks for wavelength of light that we call blue and so on.

Interestingly, there are lot more rods than cones which explains why in low light situations we see things mostly in black and white. The rods are also denser in the periphery of the retina while the cones are concentrated near the center. This is called the Fovea Centralis and is located just above where the optic nerve transmits the messages to the brain. This is actually completely rod free.

Because the rods are distributed more in the periphery, you might actually notice that you can see peripheral objects more sharply at night.

The amount of red, green and blue cones are not equal: 64%, 32% and 2% respectively. The blue cones are most sensitive but not enough to compensate for the paucity in numbers. However, tests have shown that our final visual perception of blue is comparable to that of the other colors leading to theories of the existence of a "blue" amplifier in the brain.

Now, lets get back to Jupiter and colors. From basic physics, white light is white because the distribution of wavelengths/frequencies of the light is equal and our brain interprets that as white light. That is why sunlight is "white". Now Jupiter does have color - because it does reflect sunlight in the visible spectrum. The big red spot IS red. I am not sure why Hasib saw the image in black and white. But, he did mention something about a camera - usually the optical cameras associated with observatory telescopes take B/W pictures. With a powerful direct telescope you should be able to see the colors of Jupiter.

In fact even nebula radiate some electromagnetic frequencies in the visible range. What astronomers usually do is to use radio telescopes to measure ALL electromagnetic frequencies being emitted by a stellar object. Now they can artificially render a visual image by mapping a certain range to some human visible color. That is what is known as "false imagery" and is the source for all the spectacular pictures of galaxies and what not. There usually is not a one-to-one mapping of the colors they render to the actual colors if we actually had the opportunity to do a fly-by.

Here is an example of a "true color" picture of the dumbbell nebula:


http://www.noao.edu/image_gallery/images/d3/02674a.jpg

And here it is with false color imagery:


http://www.not.iac.es/general/photos/astronomical/n6853a.jpg

- Z

Arnab
March 15, 2004, 08:38 PM
Thank you. Thread dismissed.

Nasif
March 15, 2004, 08:40 PM
Zunaid bhai all of these will fall on deaf ears. I have posted the detailed info on color formation of cats eye but that was of no use. Fell on deaf ears. I was asked the same question over and over again in circular loop (which implies that I didn't get the question first time or I am lacking the intellect to grasp the material { The thread (http://www.banglacricket.com/alochona/viewthread.php?tid=3381&page=1) }).

If someone refuses to accept that H will emit mostly red spectra (and thus the term red giant, if it had sodium it would have glowed pale yellow like our good old sodium vapor street lamps) what can you say? How can you argue with someone when they don't accept that as this outer layer of H on red giant explodes in supernova it still emits red spectra giving the supernova a TRUE RED COLOR?

Thats why I gave up posting in these threads. Curious minds can study the life of star at http://aether.lbl.gov/www/tour/elements/stellar/stellar_a.html

But I bet there will be a post next to this directing me to study why cats eye will be green. Oh! I wish I had little more intellect.

fab
March 15, 2004, 09:44 PM
That was a very nicely written Dr Z. Thank you!

(btw, is it just me or did the first picture look like a rose? ;))

Hasib
March 16, 2004, 03:05 AM
So Nabulas CAN have colour! From what he said Anrab, u were wrong, I said Nabulas can have colour... and they do... as I said just before u asked me my age ur articles were about infared... so Anrab just coz ur older doesn't mean u r beta.

[Edited on 16-3-2004 by Hasib]

Orpheus
March 16, 2004, 05:40 AM
Good job Nasif. But do you still believe Cat's Eye Nebula is mentioned by those ayats forgetting about its color for a moment?

I always liked your Quran analysis though. A bit surprised.

Nasif
March 16, 2004, 05:57 AM
Originally posted by Orpheus
Good job Nasif. But do you still believe Cat's Eye Nebula is mentioned by those ayats forgetting about its color for a moment?

I always liked your Quran analysis though. A bit surprised.

I don't think the verse is pointing to Cat's Eye in particular. The verse is just a general description of an exploding star (could be our sun or any other star).

Here is the translation again:
Verse 55:37-38
Literal:
So if the sky/space split/cut open, so it was a red/a rose as/like the paint/painted with oil. So with which (of) your Lord's blessings (do) you (B) deny/falsify ?

When the sky disintegrates, and turns rose colored like paint. Which of your Lord's marvels can you deny?

Note that the verse points to the visuals as painting in sky. Its not saying its just red stuff or red blob, but rather it gives a vivid imagery of painting. And, most certainly supernovas look like painting of a masterful artist.

[Edited on 16-3-2004 by nasif]

Orpheus
March 16, 2004, 06:10 AM
Van Gough's Starry Night was associated with one of those recently!

Orpheus
March 16, 2004, 06:29 AM
I don't think the verse is pointing to Cat's Eye in particular. The verse is just a general description of an exploding star (could be our sun or any other star).


I will probably agree with you somewhere here. It might just be the marvel of an exploding star that we can't deny.

Most ppl connected the verse and the nebula with the death of our sun. This is where I disagree. Cat's Eye is waay different than our sun.

I also do not like the idea of connecting Quran with things in science that are still in their embryonic stage.