You used the correct (but obscure and arcane) spelling of lede. Well done!
Are we sure that’s Jupiter? And not, say, some giant space station that’s pointing a super laser at Earth through that concentrated glowing spot off to the right?
It’s not just what’s collected. It’s what the sensors are able to detect. You can’t, for example, take the camera on the back of your phone and tell it to start looking at infrared. The sesnor just isn’t physically built to do that.
JWST has several sensors, but they’re all built to detect portions of the infrared part of the spectrum.
Which I believe means that the images we’re seeing are (basically) heat maps rather than true color. It’s just not built to detect light in the part of the spectrum visible to to the human eye.
No professional astronomical telescope has RGB filters like a normal camera has. So even though the big scopes in observatories around the world are almost all made to work in the visible spectrum the pictures they publish are not the same as what you would see with your eyes out of a the window of a space ship. Starting about 80 years ago the U,B,V,R,I filter set became standard so researchers could compare data knowing they were all looking at the same wavelengths in their images. Picking the R V and B filters to build a color image gives you something similar to RGB but the bandwidth of the filters don’t match up so it’s still a false color image.
Of course books can be written about what is “true color”, everyone’s eyes are a little different, the RGB standard isn’t exactly what the average eye sees, add in some talk about CMYK, it could go on and on…
This still amazes me that, even in the frigid vacuum of space, you have to take extra steps to keep hardware cold. I totally get it, it just seems so counterintuitive at a glance. But solar radiation is so much harsher outside an atmosphere, and once you get beyond the magnetosphere you are subject to the particulate bombardment of the solar winds.
Screens can be calibrated, there are standards and tools to do it, so people that work with color can be sure what they are seeing on their screen is the same as someone else’s screen.
Yes, if by “heat map” you mean the data visualization term and not temperature heat. Similar to how rainfall radar output shows different colors based on intensity.
The JWST detects and images a range of wavelengths of light mostly outside human vision. To us, a “raw” image might appear mostly if not fully black. (Everything outside the “visible” range in the chart above looks like nothing or blackness to humans.) So scientists map that range to a human-visual range of wavelengths. This not only has the effect of getting us pretty pictures, but also engages the parts of the brain that can analyze patterns in visual data: swirls, boundaries, brighness, shadow, etc.
CMOS sensors are actually quite good at picking up near infrared! Too good, in fact. One wants to maximize the sensor’s sensitivity in the optical band, so there’s typically an IR blocking filter in the camera’s lens stack somewhere, either as a discrete element or as a lens coating.
The IR block isn’t perfect, though — point a TV IR remote control at your smartphone camera sometime, hit some buttons on it, and watch its IR LED blink in the camera viewfinder.
What’s a Dewar flask or Thermos bottle, after all, but a vacuum insulating whatever is inside the container, preventing it from cooling or warming by convection or conduction? When you think about it that way, you suddenly realize that one of the world’s largest, if not the largest Thermos bottle in the world is the International Space Station — which has equipment and people inside of it generating heat.
Wow, thanks for the incredibly informative answers @RRRob (and @RocketJForklift, and everyone else)! The process is much more complicated than I thought; really brings home what an accomplishment it is that we’ve created these devices.
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