Are James Webb Space Telescope images really that colorful?

[Admin]

How do images taken by the James Webb Space Telescope (JWST) appear so colorful, and where do the colors come from?

Are James Webb Space Telescope images really that colorful? : Read more

 

[ChrisA]

"We don't know"? Of course we do. If you were to fly out in space and look close up with just you own eyes looking ut a window. All you would see is empty black space. The gas density is so close to a vacuum that there is so little "stuff' you would not see it.

Telescopes are dramatically larger then human eyes and can collect millions of times more light. It is not just their size but that Telescope can take very long exposures and add up the light that faal on them for hours.

So you would see blackness, but these high instruments can see the small amount of light in that darkness.

Then if you look through a small telescope from your backyard, almost everything looks white. Human color vision only works in daylight brightness, faith objects, look colorless.

It is even worse with JWST because it is looking in a range of "colors" that we can not see at all. So the data has to be translated up to what the eyes can see. Our eyes see infrared as "blackness".

"We don't know" is a very bad answer. We'd see nothing at all.

The better question is about Mars. It is red and orange but the eye adapts and after a few hours the color would fade and look more neutral. Just like our eyes adapt to light at sunset and we see it as less red than it really is.

 

[Spacelizard]

"We don't know"? Of course we do. If you were to fly out in space and look close up with just you own eyes looking ut a window. All you would see is empty black space. The gas density is so close to a vacuum that there is so little "stuff' you would not see it.

Telescopes are dramatically larger then human eyes and can collect millions of times more light. It is not just their size but that Telescope can take very long exposures and add up the light that faal on them for hours.

So you would see blackness, but these high instruments can see the small amount of light in that darkness.

Then if you look through a small telescope from your backyard, almost everything looks white. Human color vision only works in daylight brightness, faith objects, look colorless.

It is even worse with JWST because it is looking in a range of "colors" that we can not see at all. So the data has to be translated up to what the eyes can see. Our eyes see infrared as "blackness".

"We don't know" is a very bad answer. We'd see nothing at all.

The better question is about Mars. It is red and orange but the eye adapts and after a few hours the color would fade and look more neutral. Just like our eyes adapt to light at sunset and we see it as less red than it really is.

Off topic. But will JWST ever be capable of direct imaging of Earth size, rocky exoplanets ? Not just giant gas planets like Jupiter as it was done before. At the beginning they said it was possible, but now they are quiet about it. Was that all just hype ?

Same with (ESO) Extremely Large Telescope in Chile, planned for 2028 opening. They said that it will be theoretically possible, but what is an actual chance that we will actually see direct images of Earth size, rocky exoplanets during our lives ?

 

[motie]

Off topic. But will JWST ever be capable of direct imaging of Earth size, rocky exoplanets ? Not just giant gas planets like Jupiter as it was done before. At the beginning they said it was possible, but now they are quiet about it. Was that all just hype ?

Same with (ESO) Extremely Large Telescope in Chile, planned for 2028 opening. They said that it will be theoretically possible, but what is an actual chance that we will actually see direct images of Earth size, rocky exoplanets during our lives ?

I believe the angular resolution of JWST is roughly 0.05 arc-second. 0.05arc-sec = 1.3889e-5deg. Then tan(0.05arc-sec) = 2.424e-7. What if an object is X miles away from JWST? The smallest feature that JWST can see is X * 2.424e-7.

What if an object is one light-year away? That's 5.88e12 miles. JWST resolution is 2.424e-7 * 5.88e12mi = 1.4e6mi = 1.4 million miles. So even a star will be one pixel. Keep in mind that one lightyear is really close in astronomy.

What if an object is one million light-years away? JWST resolution is 1.4e12mi = 1.4 trillion miles.

If my math is wrong, please let me know. I am not an astronomy pro.

The other big problem is that planets are usually in orbit around suns, which are vastly brighter than the planets. So telescopes and cameras have a tough time seeing the planet, since it is so close to the sun. Most planets are within the same pixel as their sun. So you "see" the planet by observing the slight change in the sun's brightness as the planet traverses the sun's image.

 

[Spacelizard]

I believe the angular resolution of JWST is roughly 0.05 arc-second. 0.05arc-sec = 1.3889e-5deg. Then tan(0.05arc-sec) = 2.424e-7. What if an object is X miles away from JWST? The smallest feature that JWST can see is X * 2.424e-7.

What if an object is one light-year away? That's 5.88e12 miles. JWST resolution is 2.424e-7 * 5.88e12mi = 1.4e6mi = 1.4 million miles. So even a star will be one pixel. Keep in mind that one lightyear is really close in astronomy.

What if an object is one million light-years away? JWST resolution is 1.4e12mi = 1.4 trillion miles. So a galaxy will be one pixel.

If my math is wrong, please let me know. I am not an astronomy pro.

The other big problem is that planets are usually in orbit around suns, which are vastly brighter than the planets. So telescopes and cameras have a tough time seeing the planet, since it is so close to the sun. Most planets are within the same pixel as their sun. So you "see" the planet by observing the slight change in the sun's brightness as the planet traverses the sun's image.

How much better will be the angular resolution of the (ESO) Extremely Large Telescope in Chile, planned for 2028 opening, compared to JWST ? Will it be able to make direct images of Earth size, rocky exoplanets with better resolution than one pixel at least with closest exoplanets 4 light-years away ? They said it will be at least theoretically possible. But they said that also about JWST.

 

[contrarian]

Direct imaging of stars is the best we can hope for, unless it is a really large planet, and close by. We will require an enormous telescope to resolve planets.

Below is a link to resolved stars. Gives one the impression that it is not a cake walk even for stars. There are a number of interesting resolutions in this list. Spending some time on this list is worth the effort.

List of stars with resolved images - Wikipedia

en.wikipedia.org

 

[Spacelizard]

Direct imaging of stars is the best we can hope for, unless it is a really large planet, and close by. We will require an enormous telescope to resolve planets.

Below is a link to resolved stars. Gives one the impression that it is not a cake walk even for stars. There are a number of interesting resolutions in this list. Spending some time on this list is worth the effort.

List of stars with resolved images - Wikipedia

en.wikipedia.org

But I remember from the article about (ESO) Extremely Large Telescope in Chile (planned for 2028 opening), they claimed that direct images of closest Earth-sized, rocky exoplanets 4 light years away can be theoretically possible. And from these images (even if they will be just 1 pixel images) they could theoretically see changing seasons of the year and shapes of the continents. Are you saying that even with ESO 1 pixel images of closest Earth-sized, rocky exoplanets 4 light years away are beyond our reach ? How big Telescope would you need to achieve it ?

 

[motie]

But I remember from the article about (ESO) Extremely Large Telescope in Chile (planned for 2028 opening), they claimed that direct images of closest Earth-sized, rocky exoplanets 4 light years away can be theoretically possible. And from these images (even if they will be just 1 pixel images) they could theoretically see changing seasons of the year and shapes of the continents. Are you saying that even with ESO 1 pixel images of closest Earth-sized, rocky exoplanets 4 light years away are beyond our reach ? How big Telescope would you need to achieve it ?

Even with one pixel, you can do spectroscopic analysis of the light. Let's say water is blue and soil is gray. You can resolve those colors and figure out which color is dominant. What if soil is covered with snow in winter? The gray gets replaced by white.

Most astronomical images seen by the public are artist's representations. But that isn't often pointed out. So the average person thinks we can see fine details on distant planets. If you showed them the actual images, public support for space-related science would probably take a big hit.

 

[Classical Motion]

In my outside opinion, we are not trying to get a detailed image. Too far for it. We are trying to get high res molecular signals. Spots in the visible spectrum. We are searching for organic molecules, or good indicators of life. We need enough of collected light flux, to break and split apart, for these detections. Larger proportions. To fine thinner things.

Finding signs of life is the race today. But even if they find it, it will be like entanglement…...NO communication possible. No application. It won’t matter cept it’s there. But I’m sure many are willing to spend their careers on it. And that’s fine. Many fields in space.

The real cosmic questions will be answered, or at least teased, with distance/time detection. And that will take time. Time to collect, not just area to collect. Repeated intermittent directional integration. Of the dark spots.

Powerful long distance detectors. For fundamental research.

Just from what I have read. And self assemble.

 

[ChrisA]

Off topic. But will JWST ever be capable of direct imaging of Earth size, rocky exoplanets ? Not just giant gas planets like Jupiter as it was done before. At the beginning they said it was possible, but now they are quiet about it. Was that all just hype ?

Same with (ESO) Extremely Large Telescope in Chile, planned for 2028 opening. They said that it will be theoretically possible, but what is an actual chance that we will actually see direct images of Earth size, rocky exoplanets during our lives ?

No. Any earth-link planet would be so close to its star that it would be drowned out with glare. You need a "coronagraph". to block the star's light. But even then, JWST lacks the resolution to directly image a planet.

That said, Yes JWST could in theory observe an Earth-like planet using spectrometry. If the circles the star such that from our point of view it passes both in front and behind the star, JWST could see the spectrum change and deduct some of the gasses in the atmosphere.

Even with a more powerful telescope, we'd learn a lot more using spectrometry than direct imaging.

 

[ChrisA]

Even with one pixel, you can do spectroscopic analysis of the light. Let's say water is blue and soil is gray. You can resolve those colors and figure out which color is dominant. What if soil is covered with snow in winter? The gray gets replaced by white.

Most astronomical images seen by the public are artist's representations. But that isn't often pointed out. So the average person thinks we can see fine details on distant planets. If you showed them the actual images, public support for space-related science would probably take a big hit.

To detect life by directly imaging it, You need a telescope hundreds of thousands or perhaps hundreds of millions of miles wide. It would need to be larger than the Earth. and closer to the size of the Solar System. In theory, this is possible but in practice, it will be centuries before we do that.

Of course, it would not be a single telescope but a large number of telescopes in orbit and all of their light is combined coherently. In theory, there is no limit to the size but we must leave it for those living in the next millennia. (maybe in 3025?)

Here is an example of such a telescope that is smaller but uses the same idea: https://www.mtwilson.edu/chara/
Now imagine those six domes not on a single mountain but in orbit around the Sun. (At least they would not need to build vacuum tubes.). There are a million way-hard problems to solve to make that work, it will not be in our lifetime but someday we could be continents on an exoplanet.

That said, I can imagine a Chara-like array on Moon the someday. You would land the smaller domes around the perimeter of a large crater.