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wrycoder

Maybe Hubble could take a snapshot or two?

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With Hubbles's highest resolution optics, the JWST will be about one-tenth the size of a pixel.

Scale. We are just a bit of noise in an impossible to understand large, complex system.

It is crazy to think about.

How can it make out galaxies at billions of light years away, but not a truck sized craft at a few million miles?

I haven't done the math myself, so I'm certain one side of that equation is wrong, but that seems hard to believe!

It’s interesting that you are expressing an opinion about something that you could calculate in the same amount of time it took to write down that opinion.

It seems like they are going for the "the easiest way to get a right answer is give the wrong answer on the internet" approach.

Cunningham's Law

https://en.wikipedia.org/wiki/Ward_Cunningham#%22Cunningham'...

To be fair, for someone who is not well-versed in either optics or space physics, calculating the answer is not that straight-forward.

You can do pretty well just comparing the ratios of the size to the distance, right? Or is it more than that?

That's a start, for sure, but to do a super accurate calculation (the kind I feel unqualified to carry out), you need to take into account apparent size, redshift, whether or not there's gravitational lensing, interstellar dust in the way, etc etc.

But I want to reiterate that what's meaningful about this discussion is in part how unintuitive things at the far edges of our scales of perception really are. It's a muscle that, left untrained, will lead you to make incorrect characterizations like the one I made.

It's been over a decade since my last astrophysics class, but I appreciate you being charitable about my assumed knowledge! I think if anything this thread shows:

1) how absolutely mindblowingly big space is

2) how bad humans really are at intuiting things at the scale of space

>a truck sized craft at a few million light years?

JWST is three light seconds from earth

Awful typo on my part! Definitely face palmed when I caught it.

Well galaxies at billions of light years distance are also 100000s light years wide. Rest of the math you can do about resolution now!

Here's the math[1]. Seems believable to me. The Web telescope is miniscule conpared to faraway galaxies, and it doesn't emit much light.

[1]: https://mobile.twitter.com/gfish/status/1479339620785524736

I did a little math of my own, and found that while the ratio of these distances is on the order of 10^15, the ratio of the sizes of these objects is on the order of 10^19.

In other words, Webb is only one TEN THOUSANDTH the apparent size of a galaxy that's a _billion light years away_

That's just mind numbing to consider!

galaxy_width / truck_width = 3 × 10^20

That is staggering. Just, wow.

Hubble can't see the Apollo descent stage on the moon either, and that is a LOT closer than L2.

TLDR: Not really. At the distance of the JWST, a single pixel on the hubble's camera is about 700m across, or roughly 30 times the size of the JWST.

The L2 point is about 1.5 million km from earth [0]. The smallest size Hubble can resolve is about 1/20 arcsecond [1]. It's in a pretty low orbit, so is effectively "on earth" relative to the distance to the L2 point where JWST is. Calculating the size of an angular measure at a given distance [2], you get about 727m [3].

[0] https://en.wikipedia.org/wiki/Lagrange_point#L2_point

[1] https://illuminateduniverse.org/2019/04/11/angular-resolutio...

[2] https://astronomy.stackexchange.com/a/20728

[3] https://www.wolframalpha.com/input/?i=tan%28%281+arcsec%29%2...

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