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nixiebunny t1_iqrjv82 wrote

There's a lot of nothing in space, so not much scattering happens until the light reaches the Earth's atmosphere. The images we get from such telescopes as JWST are "diffraction limited", which means that the resolution is a function of the size of the telescope's mirror, in the case of JWST it's the mirror segments that cause the starburst pattern. A huge single-mirror telescope in space could make much higher resolution images.

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wswordsmen t1_iqrmmur wrote

It is also limited by the wavelength of the light that is collected. For most of the IR range the JWST actually has slightly lower resolution than the Hubble since while its mirror is several times bigger the visible light Hubble collected has a shorter wavelength than the IR of JWST and that more than makes up for the difference.

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mattjouff t1_iqsoich wrote

That’s usually not a limiting factor since you would lose the resolution of features smaller than IR wavelength so unless you are trying to resolve ants on Jupiter it won’t matter too much for astronomers!

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exoplanetaryscience t1_iqsxnyj wrote

That's not the same principle. The diffraction limit pertains to angular size, not physical size. You are correct that you wouldn't be able to resolve things smaller than a given wavelength, but the diffraction limit can apply to arbitrarily large objects as long as they appear small. A 100,000-light-year-across galaxy will simply appear lower resolution in an IR telescope than a visible-light telescope of the same aperture/focal length.

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Davidjb7 t1_iquic47 wrote

Exactly. The diffraction limit has to do with the limiting spatial frequency of the system, so for telescopes it's usually their apertures.

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Adrewmc t1_iqtm5ht wrote

While I agree most of the scatting is happening in our atmosphere, and that space is mostly nothing, it’s not completely nothing and when there is something there tends to be a massive amount of something there. There is a lot of dust, and there is a lot of space between us any any of there light source there is out there. And anything that we are interested is where a bunch of stuff is. This is why we want to look at the IR spectrum instead of the UV spectrum because IR light scatters much less in the presence of dust, and the UV spectrum of light can be scattered or blocked a lot easier.

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nixiebunny t1_iqtmx52 wrote

Yes, the interstellar medium (ISM) is rather opaque to visible light, but more transparent to infrared. My day job is in millimeter wave radio astronomy, which studies the makeup and behavior of the ISM.

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Ihavepurpleshoes t1_iqvbtqh wrote

What about dark matter? Can it block light or distort it?

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Skarr87 t1_iqvgy61 wrote

Whatever dark matter is, if it truly exists, appears to not interact with the electromagnetic field at all. This means that to light, dark matter doesn’t exist. So it would cause no change to any light passing through it. Dark matter does interact gravitationally so with enough of it one one place it can change the path of light causing a gravitationally lensing effect.

Fun fact, since it doesn’t interact with the EM field dark matter also can’t clump like normal matter does because you need those charge interactions to dissipate energy to slow down enough to clump. So dark matter just sort of oscillates back and forth through the center of gravity like a pendulum. This is why it always looks the same regardless of galaxy and why it’s always bigger than the galaxy.

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Krail t1_iqu4s8l wrote

If I recall correctly, this is why most of what we've seen beyond our galaxy is to galactic "north" or "south". If we aim our telescopes along the galactic plane, there's a ton of dust in the way (the "milky way" you can see with your eyes when in a dark enough location) that makes it hard to see anything past that.

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Old_comfy_shoes t1_iqtj74l wrote

What is the theoretical limit, if we had any size perfect mirror?

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nixiebunny t1_iqtnebo wrote

There's not much of a theoretical limit to the resolution. If you can make a telescope the size of the galaxy, it would have quite high resolution. But where would you put it?

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soulsnoober t1_iqtt47z wrote

"Put" is not the problem so much as collecting the data in one place. EHT, for instance, is a telescope the size of planet Earth. The practical limit on its ability to inform our awareness of the universe is assembling what it can see.

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andreasdagen t1_iqutey4 wrote

Does the inverse square law cause scattering?

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left_lane_camper t1_iqynboo wrote

Nope, scattering is a change in the direction of light due to an interaction. The inverse square law is just a geometric spreading of the light from a point source in the absence of an interaction.

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Shadow122791 t1_iqwjrgk wrote

Actually if you take a few light years at light speed without something to deflect or absorb energy from free floating hydrogen and dust your ship would be destroyed before you even reach the closest star outside our solar system. and they constantly say light from anything far away goes through alot of gases and stuff which is why they can see some of it in the first place.

Also at least 1 ok art of f hydrogen or dust poo er square meter. That's alot of stuff over several light years.

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