The James Webb Telescope

[Roger Wilco]

Sun shield thing is unfurling.

https://twitter.com/x/status/1475905004229779460

 

[Charmonium]

Sci stupid here, I get the concept of looking back in time but how do they know the specific time frame they're looking at? big bang + 150m seen like very specific in space's term.

A though, 10b sound like a large sum of $$$ in science's term but is pocket change in military/mega corp term. And this is just wrong, there should be a gofundme page for mega sci project like this. 50% of the world donate $3 will get it done.

By the red shift, which is a very specific and easy to measure thing to within a very, very tight margin.

To be fair, it’s not quite as straightforward to relate redshift back to distance or age. Redshift tells us precisely how fast something is moving away from us, but there is a lot of theoretical physics and modeling of the expansion of the universe that goes into correlating that back to an age and absolute distance. It’s pretty fascinating how it’s done and even more fascinating how recent a science all of that is. Less than a hundred years ago we thought the Milky Way galaxy was the entire universe.

I think the critical missing piece there are type 1A supernovae. These are used as a "standard candle" so to say in that they WERE believed to all have approximately the same brightness. So distance correlates with brightness or lack there of. Thing is, we now find that there are at least 2 or 3 different types of 1As and as of yet, I don't think that's been rigorously reconsidered by cosmologist. They're working on it though.

Sun shield thing is unfurling.

https://twitter.com/x/status/1475905004229779460

Woo-hoo. If you pray, now is the time.

 

[IronWing]

Sun shield thing is unfurling.

https://twitter.com/x/status/1475905004229779460

They should have used a big helium balloon instead. It would have avoided all the complications of unfurling the shield and it would float the telescope back to the L2 point w/o the need for fuel.

 

[[DHT]Osiris]

To be fair, it’s not quite as straightforward to relate redshift back to distance or age. Redshift tells us precisely how fast something is moving away from us, but there is a lot of theoretical physics and modeling of the expansion of the universe that goes into correlating that back to an age and absolute distance. It’s pretty fascinating how it’s done and even more fascinating how recent a science all of that is. Less than a hundred years ago we thought the Milky Way galaxy was the entire universe.

Yeah but the redshift is the axis of that wheel of mathematics and he needed the tldr . If he Google's redshift it'll lead him down the rabbit hole he needs.

 

[Red Squirrel]

What's kind of crazy to consider is that if there is parts of the universe moving fast enough, it's probably possible that there is no visible light at all coming from it because of how fast it's moving. Ex: if it's moving near or at speed of light, the light it emits never makes it out. I think? So this means there is actually a hard limit of how far we can see that are not bound by optics. Wonder if we will ever reach that limit or if optics will always be the real limit. The fact that we can see light that is many millions of years old is incredible though.

 

[[DHT]Osiris]

Ex: if it's moving near or at speed of light, the light it emits never makes it out. I think? So this means there is actually a hard limit of how far we can see that are not bound by optics

Yes, core tenant of the expansion of the universe and our eventual isolation from the rest of it.

Wonder if we will ever reach that limit or if optics will always be the real limit.

Only if we develop FTL travel, and even then only if we travel somewhere else to observe a given galaxy. Can't observe photons that never reach our observatory, after all.

The fact that we can see light that is many millions of years old is incredible though.

Billions, with a B.

 

[Roger Wilco]

"According to a NASA update, the James Webb Space Telescope may have enough fuel to more than double its minimum lifetime thanks to the precision of its launch and the two trajectory corrections the spacecraft has made to date."

"The Webb team has analyzed its initial trajectory and determined the observatory should have enough propellant to allow support of science operations in orbit for significantly more than a 10-year science lifetime. (The minimum baseline for the mission is five years.)" agency officials wrote in an update posted Dec. 29.

https://twitter.com/x/status/1476213599123169284

 

[deustroop]

The beginning of the universe. That's all.

Well I'm not interested in going THAT far back, maybe only a couple hundred years, just to see who killed Kennedy ? That Origin Light would be pretty dull in comparison .

 

[Charmonium]

Hmm. I might have to buy a serger - my tshirts are always too long. Can't have them covering my crotchables.

I'm warning you. I have feminine intuition. It's sort of like a spidey sense. Oh, and when you're raised by 2 women, you are legally permitted to have feminine intution. M'kay?

Anyway, I hope I'm wrong but I think that "thing" will probably try to kill you in your sleep.

Well I'm not interested in going THAT far back, maybe only a couple hundred years, just to see who killed Kennedy ? That Origin Light would be pretty dull in comparison .

OK, let me start with my standard caveat by saying I don't really get the connection yet, but there appear to be some issues with the inflationary version of the big bang and I think at the resolutions JWT will give astronomers, that supposed to give them more of the sort of data to iron this out.

For example (and I know what I'm saying is basically correct, I just don't understand), the inflation model says that the universe expanded at trillions of times faster than the speed of light.

Now apparently, on conclusion you can draw from that is that there should have been other universes that bubble out from our since once inflation startts, no one has a clue for how it could be shut down.

And Roger Penrose, for whom I have enormous respect, advocated not a bang but a bounce and believes he and his colleagues have evidence in this universe of black hole remnants from the previous univers.

 

[Red Squirrel]

Well I'm not interested in going THAT far back, maybe only a couple hundred years, just to see who killed Kennedy ? That Origin Light would be pretty dull in comparison .

If there is a puddle of water on a planet that's at just the right distance maybe we can try to get the Earth's reflection in it and then find out who killed Kennedy once and for all!

 

[Zorba]

What's kind of crazy to consider is that if there is parts of the universe moving fast enough, it's probably possible that there is no visible light at all coming from it because of how fast it's moving. Ex: if it's moving near or at speed of light, the light it emits never makes it out. I think? So this means there is actually a hard limit of how far we can see that are not bound by optics. Wonder if we will ever reach that limit or if optics will always be the real limit. The fact that we can see light that is many millions of years old is incredible though.

One thing to remember, too, the maximum relative speed is also the speed of light. So two objects moving away from each other at the speed of light still have a relative speed of C not 2C. Which is what causes the redshift.

 

[Spacehead]

APOD
JWST on the Road to L2

Where Is Webb?
Real time info about where it is, speed, temperatures, when things will be depolyed, what's been deployed, etc.
It's interesting, it's almost halfway to L2(48%) in 6 days but will take 29 days to get there. Cruising speed is currently .4565mi/s.

 

[SKORPI0]

IIRC, JWT still needs to cool down it's mirrors once it reaches LG2. This is for the infrared detectors to observe faint heat signals in the universe.
So we'll have to wait months until the first images are collected.

 

[Spacehead]

IIRC, JWT still needs to cool down it's mirrors once it reaches LG2. This is for the infrared detectors to observe faint heat signals in the universe.
So we'll have to wait months until the first images are collected.

After it reaches L2, there is a 6 month "commissioning phase". So no actual science till after July 2022 i guess.

 

[IronWing]

Live stream of heat shield unfolding. It isn't the most thrilling and the comments are inane but it does show progress. Note that the view of the craft is a live rendering based on telemetry data, not a camera feed.

 

[IronWing]

 

[Roger Wilco]

Sun shield deployed successfully.

"The James Webb Space Telescope has successfully deployed all five layers of its tennis-court-sized sunshield, a prerequisite for the telescope's science operations and the most nerve-wracking part of its risky deployment.

The challenging procedure, which required careful tensioning of each of the five hair-thin layers of the elaborate sunshield structure was a seamless success today (Jan. 4). Its completion brought huge relief to the thousands of engineers involved in the project over its three decades of development, as well as the countless scientists all over the world who eagerly await Webb's groundbreaking observations.

"Yesterday, we did not think we were going to get through the first three layers," Keith Parrish, the observatory manager for the James Webb Space Telescope, said in a live NASA webcast during today's deployment. "But the team just executed everything flawlessly. We were only planning to do one yesterday, but that went so well. They said hey, can we just keep going? And we almost had to hold them back a little bit."

https://twitter.com/x/status/1478439637291089923

 

[Red Squirrel]

That's great news! That's a pretty complex mechanism so lot of room for stuff to go wrong.

 

[Zorba]

That's awesome. I assume that the highest risk parts have now been accomplished.

 

[Ken g6]

I think the next step is the most important, deployment of the secondary mirror. If that doesn't work, the telescope can't see anything.

Once that's done I think it should be mostly adding mirrors and fine-tuning.

 

[Roger Wilco]

I think the next step is the most important, deployment of the secondary mirror. If that doesn't work, the telescope can't see anything.

Once that's done I think it should be mostly adding mirrors and fine-tuning.

Looks like it was successful!

https://twitter.com/x/status/1478771722769870851

 

[Red Squirrel]

Wow that's great news!

 

[Spacehead]

Cruising speed down to .2874mi/s
67.75% of the way there.

 

[Denly]

Just a thought, won't it be easier, safer, cheaper and faster(development time) to assembly in ISS with multi "shipments" then send off to L2?

 

[herm0016]

Just a thought, won't it be easier, safer, cheaper and faster(development time) to assembly in ISS with multi "shipments" then send off to L2?

the next one will have to be built in space as it will have a larger primary. also, probably not. and this thing is huge, it was designed to maximize the cargo area of the rocket it went up on. it would have to be totally assembled on space walks. its much larger than any single module on the space station.