/sci/ - Science & Math

heres some of nasa's current jwst propaganda.
how is jwst 100x more powerful than hubble?

From the NGST meeting proceedings:
>This is an astonishing capability and is shown very explicitly in the paper by Jim Gunn
where he simulates images at a redshift z = 1 of a spiral galaxy with HST and with a 15
m telescope.
If you only build a 6.5 meter instead of a 15 meter there's going to be a notable difference. Nobody promised this, it was just simulation.

>>14702259
better mirror design, bigger collecting area, better positioning, more sensitive to infrared

>>14702239
>Why is JWST's actual performance so much worse than what scientists were dreaming up that it could do 30 years before it was launched
it ain't so bad.
https://www.webbcompare.com/
just take a look at the examples, keeping in mind that hubble had to spend days, if not weeks taking some of those pictures - meaning lost accuracy for it moving in orbit - compared to the stability of Webb.

>>14702444
oh yeah and webb takes them in hours instead of days and weeks. Imagine what we might get if we point webb at the same spot in the sky for like a month

>>14702444
>meaning lost accuracy for it moving in orbit - compared to the stability of Webb.
What???

>>14702239
>complaining about visual pictures and not all the trillion tiny bits of information also being collected that we don't see
and they collected far more data, far faster than ever.
and it only cost $10 billion, which frankly is a bargain for this awesome instrument.
and the technologies created to make this possible probably have use elsewhere in human society now.

$2 trillion for Afghanistan and a meager $10 billion for a tiny looking glass into the massive realm we inhabit. Or that God created if you take that view. Either way we should be trying to make sense of it, both near and far.

>>14702446
>Imagine what we might get if we point webb at the same spot in the sky for like a month
Probably a horribly overexposed image. Even the darkest regions of the sky are relatively bright to webb.

>>14702446
>Imagine what we might get if we point webb at the same spot in the sky for like a month

>>14702239
Forced diversity hires for NASA's CGI team

>>14702446
This is pure NASA PR stupidity.
The first image should have been taken in weeks of exposure and then compared to Hubble week photo.
Taking a similar photo in hours then having to explain to the public why it looks similar to Hubble's is just idiotic from a PR standpoint.

>>14703360
NASA is a low IQ organization with low IQ fanbois

>>14703360
>>14704939
>NASA doesn't waste weeks of valuable telescope hours on pandering to pop/sci/ faggots
based

>>14702239
why are you such a massive faggot

>>14705038
It's exactly what JWST was supposedly designed for!

>>14703014
>>14703360
That isn't done by exposing for a whole week at once, but take more shorter exposures, then add them up. There should be no problem taking more exposures to add them up with the first picture.

>>14706195
I'm sure you know better than the people who built it.

>>14706278
That's what THEY say.

>>14706321
You need to work on your reading comprehension.

>>14706195
And it will do it, on the best parts of the sky where there is deep ancillary data like the Ultra Deep Field or the Frontier Fields. If you're going invest weeks you better make sure you're observing the very best field to maximise the investment, in this case they were not. It would be a waste and the only argument for it is shear impatience.

>>14703011
no fuck you fuck spending money on shitty telescopes, I want more bombs for degenerates to be obliterated in countries I will never even know the locations of

>>14706458
>If you're going invest weeks you better make sure you're observing the very best field to maximise the investment, in this case they were not.
What's wrong with it?

>>14706517
It is at relatively low galactic latitude, meaning there is more milky way dust which makes everything appear fainter and so harder to observe.
There were many bright stars which cause problems with scattered light and saturation/persistence.
The Hubble imaging was very shallow, meaning that there is no deep visible or UV imaging. JWST doesn't cover these wavelength ranges so they're just missing If you want to do a range of galaxy studies you want many filters. There is also little deep data from other families like the VLT or ALMA.
It's also extremely far south, meaning northern hemisphere telescopes have no chance of observing it. Even for telescopes in Chile this field never rises that high in the sky. That means it can rarely be observed, and it's hard to observe it with high resolution adaptive optics.
Also the fact that it's a big galaxy cluster means you can't really do cross-studies with x-ray data, because the cluster itself will be so bright in x-rays that it cannot detect any distant x-ray sources behind it. The ultra deep field on the other hand is in the middle of the Chandra Deep Field South, with the deepest x-ray data in the sky.
Selecting areas for deep fields is not done randomly.

>>14703011
Are they able to calculate the distance to all these galaxies? It would be cool to construct a 3D map showing all their relative sizes and distances to each other.

>>14703002
Satellites are in constant motion. This matters for long exposures

>>14706714
It really doesn't when you're guiding off stars and the targets are so far that orbital parallel is irreverent.

>>14706729
lol, you actually believe that?

>>14706645
I think primarily by redshift. Also lots of galaxies contain pulsars that can be used for comparative reference.

>>14706744
How does it matter then? This will take a lot longer if you ask stupid questions instead of backing up your claim.

>>14706645
https://www.youtube.com/watch?v=2sUrauA0iq4

>>14706748
Pulsars have only been detected out to the very nearest galaxies to the Milky Way. They haven't even been detected in Andromeda, they're not useful for this.

>>14706714
That has absolutely nothing to do with why the exposures need to be so long.

>>14706470
I'm sure you vote for the party that went to Afghanistan.

>>14706756
That video was pretty amazing, thank you. But there's one thing I dont get. Those galaxies stretch back 10 billion years in time, which is a sizable fraction of the Universe's estimated age. They appear roughly equally distributed. Shouldn't we observe galaxies being clumped together more closely together the older they are, since the Universe was smaller then?

>>14706756
>Pulsars
My mistake, distance measure is done by measuring the brightness of a type of supernova where its absolute luminosity is known.

>>14703011
Where do those spinning lumps of matter acquire their angular momentum from? If the Universe began with an outward expansion of energy, which coalesced into matter, then the average vector of any clump of matter should be roughly parallel to its neighbors. Its like blasting a shotgun into space and somehow the pellets begin sticking together into one lump which then rotates. I just dont see where the rotational energy comes from.

>>14702239
when it got hit by that meteorite it did substantial damage and NASA is coping by pretending that it was supposed to make blurry images

>>14706847
The apparent angular size of objects changes in a non-trival way. The universe was less expanded back then but the fact that the universe expanded later blows up the apparent size of early objects. The apparent size of objects is basically flat over a lot of cosmic history.

>>14706899
When you have two blobs of matter flying at each other, if they contact off-centre they will start to rotate.

>>14706543
Wikipedia lists it as a deep field.
Why was it chosen so poorly?

>>14707097
You can call anything a deep field.
I don't know why they chose this particular cluster. Certainly popular appeal took precedence over scientific value. It would also have to be visible near the end of commissioning, which rules out fields like UDF.

WHEN THE FUCK

ARE WE GETTING MORE IMAGES AND DATA?

FUCK

>>14706905
JWST's optics were shit to begin with, the waffle pattern PSF makes the possibility of using the images for science extremely far fetched in most cases, rules it out completely in others

>>14708183
Could they rotate the telescope so that two images could be taken and the spikes removed? Or would the heat shield make it impossible?

>>14706973
>The apparent angular size of objects changes in a non-trival way. The universe was less expanded back then but the fact that the universe expanded later blows up the apparent size of early objects.
That's just the unintuitive effect of geometry. The longer the lens (the smaller area you look at) the more the distance seems squished.

>>14709976
>i have never used a telescope, but here is my expert opinion

>>14710004
It's commonly used in photography, for example to "fake" photos of a crowd where there are only some people randomly walking on the sidewalk, etc. A long lens "compresses" the distance, so near and distant people people look similarly sized and close together.

>>14710031
>i have never used a telescope, but here is my expert opinion

>>14707321
>I don't know why they chose this particular cluster
>bcoz I can't into Google

>>14712240
What is your point?

>>14712240
See pic. Same principle.

>>14712842
>i have never used a telescope, but here is my expert opinion

>>14712894
State your actual point faggot.

>>14712894
For comparison, your backyard telescope may have over 1m, JWST has 131.4m

>>14712842
Now repeat the experiment with an object 1 Megaparsec away. You will not see any effect.

>>14709976
Nope. It has nothing to do with the telescope, it is an intrinsic effect. Galaxies do not change their angular sizes if you change your focal length.

It took a better image than Hubble and with Hubble it took weeks compared to few hours of JWST. And you're complaining

>>14712954
Now I actually looked up the magnitude of the effect, that indeed can't be caused by long focal length.

But it does work regardless of distance, the apparent vompresdion comes from the fact that the image is made bigger but its perspective remains the same i.e. it isn't brought closer, only magnified.

>>14712954
Now I actually looked up the magnitude of the effect, that indeed can't be caused by a longer focal length.

But it does work regardless of distance, the apparent compression comes from the fact that the image is made bigger but its perspective remains the same i.e. it isn't brought closer, only magnified.

>>14706199
usually one long exposure is better

>>14712972
>But it does work regardless of distance, the apparent compression comes from the fact that the image is made bigger but its perspective remains the same
That's not how it works at all. There is no effect if you stand in the same position. "Lens Compression" is just the result of having to move further away to get the same objects in the field. Do you really think this was taken without moving backwards:
>>14712842

>>14712994
It really isn't. After even 30 minutes Hubble images are fucked by cosmic rays (pic related). You can also improve the resolution with dithering in multiple exposures.

what is with the right wing hate boner for the JWST
they keep on asserting how it's "so terrible" or "so much worse than hubble" when it's demonstrably head and shoulders above hubble

is it just more anti-science rhetoric to sow distrust in science?

>>14712996
Yes. But looking at farther galaxies is equal to moving backwards.

>>14713243
It's not. This is about the apparent size of nearer galaxies relative to farther ones. It has nothing to do with lens compression because the relative position of observe and galaxies is fixed.
And it literally makes no sense because telescopes don't "look at" galaxies of a particular distance. You observe everything in the field at the same time, including near and distant objects.

Yeah and the LHC was going to find gravitons and extra dimensions.

JWST is fake news

>>14713149
>muh persecution complex
>>>/pol/

>>14713365
you're not based and cool. sorry for that anon.

>>14713676
not what I asked not what I said
take your meds

>>14712994
https://ui.adsabs.harvard.edu/abs/1990ASPC....8....1T/abstract
t. 1990

>>14712958
>simulated images
anon...
>>14708219
>image all "star shaped".
>rotate camera 180 degrees.
>image now upside-down and "star shaped"
how was that supposed to work exactly?

>>14712926
>i have never used a telescope, but here is my expert opinion

>>14715550
Not 180 degrees. You'd need 30 degrees for the hexagon, and 60 degrees for the line.
>>14715783
>I have no point to make, but will repeatedly mock those who do.

>>14703360

If you want to complain about NASA go to >>>/pol/

Honestly, you're worse than people who complain about Amtrak on /n/. If you think NASA is bad at science then go make your own science agency and make your own telescope and prove them wrong. Otherwise, fuck off. This thread does not contribute anything except woman tier whinging, whining and complaining about things you clearly don't understand and refuse to consider when you are presented with contradictory information.

>>14715550
>>14715928
Or maybe those 30° could be enough with some clever calculation.

>>14715935
>If you think NASA is bad at science then go make your own science agency and make your own telescope and prove them wrong. Otherwise, fuck off.
Give me $10B and I will.

>>14713149

It's actually just an alt-right hateboner, my pet theory is that they're being used as pawns by Russians or Chinese. Probably both. I suppose these are the same people who live in Kentucky or Nebraska and can't imagine a world where the government could ever do anything good, or that liberal ideas like a space program could ever be useful. The sort of people who end up as Autozone managers and truck drivers because they could never learn enough trig to become a plumber.

btw, these are the same people that have consistently cucked us from an aggressive nuclear program because it'd cost money and do things with electricity that they can't easily comprehend. Most of these people are so stupid they can't even imagine electricity as a flow of elections, they can't imagine what an amp is let alone an amp-hour or it's conversion to electron-volts, so why should we expect them to understand physics that can only be defined in GeV? And same is the situation here but with macro physics aka astronomy.

>>14715940

You don't get something for nothing. Why don't you pull yourself up by your own boostraps like Jeff Bezos and Elon Musk did? It's not particularly hard to make a telescope, ffs Forrest Mimms (a known "right wing" -quotes mine- scientist) published a DIY gamma ray detector in Make magazine earlier this year. If some guy in his garage can study magnetars and similar nebulae, why not do it yourself?

>>14715947
>You don't get something for nothing
Which means you are eseentially banned from doing business, unless you are already wealthy. You won't get money to start one, unless you have started a business before to prove yourself, which you can't because you have no money to start one.

>>14715947
your reflexive defense of NASA is cringe, if they had competition in the space telescope industry then you'd get better space pictures than you currently are. all the private rocket companies proved that, Spacex is large multiples more cost effective than NASA ever was, a competitive private space telescope with JWST's budget would probably be in the 50 meter class, don't forget that JWST is only worth a half a billion dollars, NASA wasted a fortune producing it, but it was started with a smallish $500 million budget and none of the expenses above that number contributed to improving performance at all.
the lightweight mirror was why they thought it would be cheap and easy to make, they overestimated their abilities. after wasting a retarded fortune to do a small amount of work, they now have to build up JWST's PR to justify the costs

>>14715971
>all the private rocket companies proved that
By doing things which have already been done by the public sector decades ago. Very impressive.
>don't forget that JWST is only worth a half a billion dollars
Cost=/=worth. If you believe the conmen who made the inital low estimates then you're as delusional as they are. But it doesn't matter because the 500 million estimate was never a total cost, it only included phases C and D.
>a competitive private space telescope with JWST's budget would probably be in the 50 meter class
It's one thing to say NASA bureaucracy was deeply incompetent and allowed ambition to distort reality when planning, it's another to believe this fantasy.

>>14715947
So you want me to prove you wron, and pay for it?
NASA doesn't have to make profit. They just get money to spend. How did those people prove that they belong there?
The point is that $10B is a really big sum of money. It's nine times the cost of Boston Dynamics for comparison. Using all that for one telescope that might be a little bit better than the old one is just ridiculous.
Their approach is fundamentally wrong. It's all or nothing with ridiculous effort spent on testting and retesting so that nothing can fail. What I would do instead is that I would make let's say two or three telescopes in parallel, with 1-3years of development time, so that on average one is sent every year, which would allow gradual improvement and more experimentation without making an occasional failure a catastrophe.
Another thng is that I would probably focus more on short wavelength astronomy, as it has the potential for much higher resoutions. The resolution in areas like x-rays is limited by the technogy, rather than physics, while there is little that can be done for infrared, except for making the telescope bigger. (though there is the ability to see redshifted distaces of course)

i love how OP just comes along, shits out an unfounded assertion which is also clearly wrong, and then suggests other people are conspiring to be dishonest to him

>>14702433
>better mirror design
round glass mirror is optically superior to keck hex, jwst's mirror weights less than half of what hst's did, thats why they said they thought they could launch jwst for 25% of what hst costed, the weight argument was how they arrived at the proposed cost. turned out to have been badly underestimated. the same idiots are now spitting out numerical analysis of jwst data and their math is every bit as accurate and believable as their jwst cost and timeline estimates.

>>14702239
Global warming is ruining everything

>>14713365
>left-to-right Hebrew
lmao, brainlets