Peterborough Linux User Group (Canada) Forum

General (non-Linux) => Politics & Society => Topic started by: Jason on July 08, 2022, 01:50:09 PM

Title: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: Jason on July 08, 2022, 01:50:09 PM
The James Web telescope is ready to go and will be snapping pics in just under 4 days. NASA has picked its targets for the first batch of images (https://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images) and you can watch as they come in live at the NASA channel on YouTube (https://www.youtube.com/watch?v=21X5lGlDOfg). I plan on

You can also just view the images (https://www.nasa.gov/webbfirstimages) as they come in or later. But how boring. There's nothing like seeing a room full of scientists jumping up and clapping as the pictures roll in. Seriously, it'll put a smile on your face with all the bad news going on in the world.

Scientists who have already seen some images have said that they brought tears to their eyes (https://arstechnica.com/science/2022/06/nasa-teases-extraordinary-images-captured-by-its-webb-telescope/).

There's more information about the JWT here (https://webb.nasa.gov/index.html).

The attached countdown screen is from that website.
Title: Re: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: ssfc72 on July 09, 2022, 06:39:52 AM
Thanks for the info, Jason.
Title: Re: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: Jason on July 12, 2022, 07:32:07 PM
The first images that Webb took were released this morning. CNN does a short video showing you the images and what they mean. One "image" actually isn't an image but a spectrograph of the atmosphere of a planet over 1 000 light years away. That's still pretty neat. It circles its sun every 3 1/2 days, is 1000 C0 at its hottest and is 1.2 x the size of Jupiter but much lighter. And it has water vapour in the atmosphere. If there's life there, though, it'd be very different from anything we'd be used to since it's a gas giant. It'd have to live high up in the clouds or be crushed to death on the solid core (at least I think it is).

And we have a picture of our early universe as it was over 13 billion years ago because that's how long it took to get here. Hard to get your mind around how long ago that is but JWST is a universe unfolding time machine. We will be able to early galaxies in various states of formation which is as good as watching them form. And we get to see them dance with each other on the long engagement to the union.

Amazing stuff. One of the guys that worked on the project finally got to see it working 16 years later. Imagine having a job that takes 16 years to pay off. It'd be like going through school again but no idea if, in the end, you'll actually graduate.

Go to the NASA website to download better-quality images. Hint: They make great desktop wallpaper.
Title: Re: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: fox on July 13, 2022, 07:30:41 AM
That nebula in your wallpaper looks like mountains.
Title: Re: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: Jason on July 15, 2022, 02:59:26 PM
I think it was an anchor (presenter) on CNN that said exactly that. Nature imitating nature!

What's also interesting is that some of the stars over the nebula are actually behind it and would be invisible to human eyes. But because Webb can see in the Infrared, too, it can look right through some things like gases that block visible light. This telescope will be able to see in ways never seen before, not just because it's far enough away to see even dark objects and due to its magnification but because of seeing into the infrared. It will be able to possibly discover the first advanced civilization on another world because of its heat signature and because of its ability to see through some atmospheres like those with water vapour.
Title: Re: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: ssfc72 on July 16, 2022, 01:50:53 AM
The JWST photo sensors are only detecting infrared wavelengths of radiation (invisible light, so to speak).
The images captured and transmitted back to earth, then have to be converted into a visible light (human eye visible) image.
This article seems to explain this a bit.
https://slate.com/technology/2022/07/james-webb-space-telescope-photos-colors-infrared.html
Title: Re: James Webb Telescope First Images on Tuesday, July 12 at 10:30 am EDT
Post by: Jason on July 17, 2022, 02:07:05 AM
It's pretty neat, huh? That's a great explanation of how they do it. But I take except to the idea that NASA is colouring the images just to show off their new toy. It's not a toy and they're not doing it for that reason. We can't see into the infrared so anything they show isn't going to be exactly what it looks like. The various degrees of infrared *has* to be converted into different colours. And the colours bring out the detail. They aren't a PR exercise.

Webb can see visible light as well but it's optimized to see infrared light which Hubble could only see a bit of.

"Hubble can see light that ranges from about 200 nm to 2.4 microns. Webb will see about 600 nm to 28 microns. (Visible light ranges about 700 - 400 nm; Webb will be able to see in the red/orange part of the visible light spectrum.)" (Source: https://webb.nasa.gov/content/about/faqs/faq.html#sharp )

I didn't realize this picture used infrared only. But as the article and you pointed out, we wouldn't be able to see it at all if the various degrees of infrared frequencies weren't brought out into colours we *can* see. This article (https://www.planetary.org/articles/1208-colors-in-planetary-imaging) points out that every telescope sees things our eyes aren't capable of picking out even if they could see as far as the telescopes do (i.e. the magnification). It's aimed at younger people but still explains it well.

Even photographic images on Earth have to have their colours touched up so they look like what *we" saw. I've taken pictures, and I bet you have too, where the blue in the photograph wasn't as impressive as what we actually saw *even* with the backlight on the phone. So, I will use a filter to bring out the blue better.

I haven't take it yet, but the Planetary Society has a short course (more like a few lectures) on how to enhance pictures yourself.

https://courses.planetary.org/p/imageclass