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> “Cosmic Cliffs” in the Carina Nebula (NIRCam Image): > https://stsci-opo.org/STScI-01G7ETPF7DVBJAC42JR5N6EQRH.png https://stsci-opo.org/STScI-01G7ETPF7DVBJAC
by j0e1 4y ago
> “Cosmic Cliffs” in the Carina Nebula (NIRCam Image):
> https://stsci-opo.org/STScI-01G7ETPF7DVBJAC42JR5N6EQRH.png https://stsci-opo.org/STScI-01G7ETPF7DVBJAC42JR5N6EQRH.png
Is this for real?! It looks like it came right out of a Sci-Fi movie/book. Could anyone explain how much of this is post-editing magic?
- Retric 4y agoIt’s real light, just color shifted as the JWST is designed to look at severely very distant and thus red shifted objects. The nebula is however much closer than that. Anyway, that looks like science fiction because science fiction borrowed that look from astronomy. https://en.wikipedia.org/wiki/Nebula https://en.wikipedia.org/wiki/Nebula
- aaroninsf 4y agoI have been wondering, how does the scale of color shifting relate to the red-shift present in deep-field subject? Idly wondering: are the furtherest objects being captured, so red-shifted, that the translation for human viewing done in these images more or less balances that out, so what we see in the translated images for some thickness of distance-bubble, is what we would see from a much closer perspective with the naked eye, akin to "true color." (I.e. so close that the relative red-shift would be insignificant...)
- deleted 4y ago[deleted]
- Retric 4y agoIt’s not a 1:1 color mapping to correct for red shifting. Each color represents a wavelength, but the mapping is arbitrary and chosen to maximize contrast.
- dredmorbius 4y agoI'm suspecting that there's no hard rule for what colours are assigned to what frequencies, though "more red" in processed images probably corresponds to "longer wavelengths" in captured imaging data. There's no specific red-shift interpretation, though for viewing of distant objects (and galaxies particularly which have reasonably uniform emission spectra) "redder" -> "more distant, receding faster". What you'd want to see specifically are the emission spectra showing absorption lines for well-known spectral bands. This shows specifically how red-shifted the light is, and is how red-shift was initially detected. I doubt that there's an intentional mapping of red-shifted appearance + spectral sensitivity to near-and-unadjusted appearance. Though that might be possible. In practice, I suspect the bands JWST is receiving don't map well to the RGB sensitivity of the human eye, but insteat JWST's sensitivity is tuned to scientific interests and value.
- sbierwagen 4y agoImage stacking to remove noise and optical artifacts, careful use of color filters to enhance contrast and pull out detail. The press release says it used Red: F444W, Orange: F335M, Yellow: F470N, Green: F200W, Cyan: F187N, Blue: F090W. The N filters are narrowband. F470N is only 54 nanometers wide: https://jwst-docs.stsci.edu/jwst-near-infrared-camera/nircam-instrumentation/nircam-filters https://jwst-docs.stsci.edu/jwst-near-infrared-camera/nircam... Almost all the light in this image is way off the red end of the human visual spectrum, of course. The shortest wavelength filter is F090W which has a center wavelength of 902nm, about the same color as the light coming out of a TV remote infrared LED, which is barely visible in pure darkness. This is what it looks like through a film SLR, without the detail enhancing filters: http://www.phys.ttu.edu/~ozprof/3372f.htm http://www.phys.ttu.edu/~ozprof/3372f.htm Here's a 20 minute exposure through a telescope: http://www.phys.ttu.edu/~ozprof/3372fk.jpg http://www.phys.ttu.edu/~ozprof/3372fk.jpg Maybe what you would see with your own eyes through binoculars at a dark site well away from city lights. A dim red smudge, hints of finer detail.
- jvanderbot 4y agoHow does this "blueshift" compare to what we'd get if we just corrected for the relative-speed-induced redshift?
- sbierwagen 4y agoNGC3372 is inside our galaxy, just 8500 light years away. It's not redshifted by metric expansion to any appreciable degree, (A calculator I just checked gave me a z of 0.000000617) and radial velocity is a sedate ~34 km/s. (z = 0.000000115) The redshift on the other JWST images is because most of them are of objects that are much, much, much farther away. Infrared telescopes are great for observing those, but that's not the only thing they're used for.
- jvanderbot 4y agoMaybe my question would be better asked for other objects images then, but I can just google how far things are redshifted at extreme distances as well.
- The5thElephant 4y agoIt's all real, but you would not be able to see it with your bare eyes even if you were relatively close to the nebula. The world around us would look very different if our eyes could perceive more of the infrared and ultraviolet spectrum. The coloring is usually done to indicate different temperatures or wavelengths detected, so it can be a bit misleading.
- DougBTX 4y agoMaybe a similar but different question then, but what would a photo on Earth look like with this filter?
- vanattab 4y agoThe color mapping of these images is not the same as the what is used for JWST but this will probably give you some clue. https://images.app.goo.gl/9gqtdbcsBxY6RonY9 https://images.app.goo.gl/9gqtdbcsBxY6RonY9 https://images.app.goo.gl/pG7sfjLGU9nqmAvH7 https://images.app.goo.gl/pG7sfjLGU9nqmAvH7 https://images.app.goo.gl/JGebDZ7V5EamKoY89 https://images.app.goo.gl/JGebDZ7V5EamKoY89
- randyrand 4y agoDoes anyone have a simulated image of what it would look like in visible light without red shifting? i.e. If we were moving at the same velocity of the Nebula looking with our own eyes. i.e. What it would look like "in real life if I actually went there"
- yaakov34 4y agoThese objects are much too faint to see much of anything with human eyes. We can see them in astrophotography because the exposures are hours long (or weeks even, sometimes), and because telescopes gather more light than the eye per unit time, as well. This is why these nebulae look like billowing clouds - they are huge (light years across), so some light is absorbed as it crosses them, and some of the infrared light emitted by them adds up. And then we enhance the effect by taking very long exposures. If we actually went and stood near or even inside these nebulae, we would still be in pretty hard interstellar vacuum, and we wouldn't see anything.
- randyrand 4y agoVery nice description. Thanks for your time and effort.
- supernovae 4y agoVisible light looks like this: https://www.adamblockphotos.com/ngc-3372-carina-nebula.html https://www.adamblockphotos.com/ngc-3372-carina-nebula.html But that's with a telescope and long exposure & image stacking. But still in RGB as humans would see it. I guess there would be a point that if you were not so far away, but still far enough away - it would light up the sky. This is emission nebula after all. BUt if you were in it, it would be so diffuse that you wouldn't know it... perhaps a weird glow if you were near some of the forming stars.
- BurningFrog 4y agoMuch of it is in infrared light we can't see, so it's "transposed" to the visible spectrum. Not much weirder than looking at an X-ray image.
- est 4y agoI am wondering what size of the "cosmic dust" are. It looks like the size of stars but without emitting light?
- LargoLasskhyfv 4y agoI'm waiting for https://en.wikipedia.org/wiki/Pillars_of_Creation https://en.wikipedia.org/wiki/Pillars_of_Creation made by Webb. It's not the same object, but similarly awesome. Maybe the article gives you an useful overview of how different telescopes 'see', and how that is translated into pictures for us.