https://d2r55xnwy6nx47.cloudfront.net/uploads/2022/07/NGC749...
About false color... Real things in the universe have real color -- they emit light in a variety of wavelengths -- even when that color is outside of the perceptual range of your eyes. The colorized photos like the ones released by NASA or Nebula Photos just expose the real relative color differences present in the original data, just shifted into a range that is you are able to perceive. "false color" images are definitely not someone taking a colored pencil to a black and white photo of a nebula and "coloring it in" to look nice, the colors are actually meaningful and give you more information about everything that the telescope actually detected than what a black and white photo could show alone.
It's amazing to see the structure in such colorized images or even the picture of our Milky Way. I wonder, without the colorization, say, to a human eye, would such images appear mostly black (black-and-white)?
The JWST sees in infrared. Our eyes don’t. This makes it not representative of what we would see with our eyes.
Your wall would look very different depending on whether the sun or your lamp shines on it. Or maybe you're in complete darkness?
What does the sun look like up close? Your eyes would malfunction.
A picture could look very different depending on lens and camera settings.
Your perception could be very different from that of someone who has just woke up in a dark room, walked in from the sun, or peaking on acid.
I guess "convey information" would be an important principle to both brains and astronomists.
What if you were to be a species distinct from whatever you are now? With different eyes, perception and cognition?
What if you're looking out the window of a spaceship at relativistic speed? Is is it fake?
Webb and Hubble have different filters so what does this mean? Did they just take some Webb filters and pretended they where Hubble filters and ran their old code?
Not all the wavelengths these telescopes capture can be seen by the human eye so some post processing is necessary for the "publicity shots"
A lot of the real science is not done visually but by analysing the data
Still, would be interesting I think.
The JWST literally cannot take colour images, the colours are entirely a post processing choice.
And there really isn't any obvious choice either, I suspect they chose colour values so the end result looks like a Hubble image.
Though most things probably look pretty similar in visible light.
Both Hubble and Webb also take observations with fairly narrow filters. In a PR image these essentially grayscale images are mapped to a color channel, red, green, or blue. The wavelength mapped to the "red" channel might be a mix of 650nm and 600nm filters. This blend will not look like what your eye would see but makes for a pretty desktop wallpaper.
Webb in particular only sees in the IR bands which your eye can't see. Making a PR images from Webb images arbitrarily maps IR wavelengths to RGB channels.
That's not to say a researcher won't filter and process the raw data. But their goal is to extract useful scientific information and not just produce an attractive image. They'll spend more time looking at graphs from the raw data than the actual 2D array of pixels.
For instance, if you know the composition for an object you know what it's spectra should look like. If you compare that spectra to what's received you can calculate the red shift of every pixel. Doing this for the whole image can then let you tell the red shift of an entire object giving an idea of its proper motion relative to us. For say a nebula this can show how it's moving and give an understanding of its 3D structure even though the images are all 2D.
I don't mean to disparage the PR images. They can often be used to explain phenomena to non-experts (not that I'm an expert). But they're never really going to show what the human eye might see, most stellar objects would look like mostly diffuse white blobs even "up close". Most things emit a number of wavelengths which just mix and look white to us. It's only with narrow band filters that telescopes can actually pick out fine details of most objects.
Webb can do "imaging spectroscopy", where it can take an image, but it will take a spectrum and every pixel of the image as well. In imaging spectroscopy, there is information on the spectrum of wavelengths present in each tiny piece of the image. This can help clue scientists in as to what elements or chemicals might have created that spectrum.
https://www.space.com/james-webb-space-telescope-hubble-imag...
The wikipedia article does note that pseudo-color is an alternative, and that carries less generally negative connotation.
This is all nitpicking anyway, but thanks for the bit of education!
[added - although now I can pick at the definition of "true color", since it is based on the idea of how a color would appaer to a human viewer. We know pretty well that there's quite a variance of perception of color amongst humans, so there arguably is no "true color". There's just X% of people see this color. :) ]
Perhaps it's like most other things in life. In hindsight, we might have done it differently.
In this case, there are probably better, more descriptive (and less confusing) adjectives than "fictitious" which would succinctly describe a non-existent but perceived (or imagined) force.
Even so, I never visualized something pushing me back into the seat. I always visualized the seat pressing against me. After all, I didn't feel sensations on the front of my body when accelerating. The sensations are the same as if someone has come from behind and starting pushing you.
I’ve been unable to find any technical reports on the technique, but the gist of it is here: https://www.axios.com/2022/07/17/james-webb-space-telescope-...
No. There are basically two things influencing the colors of galaxies, their age (young ones have bright, blue stars, old ones are more red) and their distance. In the first "unveil" image of the gravitational lens, you can find several extremely red objects (that are completely absent in the HST images if you do a side by side comparison). These are likely extremely distant galaxies where the "blue"/"green" bands in the JWST image (and all the HST bands) are very faint because it falls in the extreme UV in the galaxy's rest wavelengths.
Think of it this way: If you take a picture from a mountain, things in the distance will look bluer than they are when you are close, but does this mean that all the pictures taken from mountaintops have "fake" colours that need to be corrected?
In this sense redshift is just another thing that makes things change colour as the distance increases.
Most stellar objects emit a whole bunch of wavelengths of light, some emit more IR than visible. Interstellar dust doesn't red shift light due to velocity but because the molecules absorb higher energy photons and re-emit lower energy photons.
https://www.science.org/content/blog-post/chemistry-colors-i...
Equating the two is possible, but lazy.
But if it seems to you too vague, then I can come to a point from a different angle: did you hear about tetrachromacy? "A study from 2010 actually suggests that a rare condition known as tetrachromacy exists in up to 12% of women in the world."[1] Don't you think that these women see colors in a "more true" way than other people? I personally think they are. It means, at least, that a more common way of a trichromacy is not the true way to see colors. It gives us not true colors, but some approximation which is very far from reality.
You mentioned "most humans" as a reference point, so probably you believe that the truth can be established by a voting. I do not. I know that the objective truth is an unattainable ideal, but I do not believe that the majority of votes would be enough to establish an acceptable approximation to the ideal. It needs something more than that.