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James Webb Space Telescope

Started by Alberon, December 24, 2021, 12:17:20 AM

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Replies From View

Quote from: Endicott on December 24, 2021, 01:15:33 PMBasically, yes. Although there are different theories. Google inflation in the early universe.

I didn't even know Google existed back then.

Replies From View

Quote from: Endicott on December 24, 2021, 01:20:49 PMAnother thing to bear in mind is that although matter can't travel faster than light, space-time can. Which is why light can't escape from a black hole, because space-time is travelling into the black hole faster than light. Add to that that the universe is expanding because space-time is expanding, and it all gets quite hard to visualise.

Yeah just the last bit really tips it over into being difficult

touchingcloth

Quote from: ZoyzaSorris on December 24, 2021, 01:02:55 PMThat's interesting - I thought the expansion of space was accelerating (hence why the existential nightmare end point of head death) - so did it expand faster for a bit then slow down (before starting to accelerate again)?

Yeah, like @Endicott says there are plausible (but definitely contested) hypotheses that the very early universe expanded very quickly, to the point of being one with tens of zeroes after it larger within the first 0. tens of zeroes 01 seconds of its existence. To my understanding one of the reasons for that hypothesis is that the microwave background we can see doesn't look entirely like that we'd expect from the very early universe, so I also understand that some cosmologists see the idea as a bit of a fudge that doesn't necessarily explain what actually happened.

I get @Replies From View's point, though - I'm not sure how to explain that the very earliest photons haven't run out, so to speak. In some ways it would stand to reason like the observable edge of the universe should be ever-decreasing because of that.

ZoyzaSorris

I was vaguely aware of the theory of inflation but I thought that purportedly happened in the first few fractions of a second after the Big Bang. That's when the universe expanded faster than the speed of light for a little bit (like fractions of a second) isn't it?

imitationleather

I might start getting really into space stuff. I do need a hobby.

touchingcloth

Quote from: ZoyzaSorris on December 24, 2021, 02:22:24 PMI was vaguely aware of the theory of inflation but I thought that purportedly happened in the first few fractions of a second after the Big Bang. That's when the universe expanded faster than the speed of light for a little bit (like fractions of a second) isn't it?

Yeah, that's my understanding as well. I explained it pretty shoddily with

Quotethe first 0. tens of zeroes 01 seconds of its existence

Fractions of fractions of a second.

Alberon

We can see the earliest moments of stars in the universe because, as said above, inflation rapidly expanded the universe immediately after the Big Bang for a very brief time. That light has then had to travel right across the visible universe over billions of years to reach us.

As spacetime continues to expand that light gets stretched over the years meaning its wavelengths increase in size. Light that was in the visible spectrum when it left the star is now deep in the infrared zone. The James Webb will see further into the infrared range than Hubble can so should be able to look further back in time.

Many many billions of years from now the redshift effect will completely hide the origins of the universe. Any civilisation arising then would be unable to directly detect the earliest light of the universe.

seepage

I like it now that rockets look like proper science fiction ones instead of a couple of toilet rolls with a cone on top.

touchingcloth

Quote from: Alberon on December 24, 2021, 02:33:57 PMWe can see the earliest moments of stars in the universe because, as said above, inflation rapidly expanded the universe immediately after the Big Bang for a very brief time. That light has then had to travel right across the visible universe over billions of years to reach us.

As spacetime continues to expand that light gets stretched over the years meaning its wavelengths increase in size. Light that was in the visible spectrum when it left the star is now deep in the infrared zone. The James Webb will see further into the infrared range than Hubble can so should be able to look further back in time.

Many many billions of years from now the redshift effect will completely hide the origins of the universe. Any civilisation arising then would be unable to directly detect the earliest light of the universe.

Yeah, that's a good point, and also makes me how, say, WMAP isn't better for looking back to the earliest eras of the universe than James Webb, as it would detect things which had been shifted even further than the infrared spectrum. Did it detect microwaves, or what were microwaves before they had been shifted en route to us?

Replies From View

Ok so what can I passively sit and watch so that all of this makes sense?  Has Brian Cox mentioned it in passing?

beanheadmcginty

With a design like that, I'm baffled that they've named it after this James Webb guy and not Bob Holness.

Endicott

Quote from: Replies From View on December 24, 2021, 03:31:00 PMOk so what can I passively sit and watch so that all of this makes sense?  Has Brian Cox mentioned it in passing?

Cox's programmes don't have enough meat on them.

Jim Al-Khalili is a good bet. I think Atom was his best one but it doesn't cover cosmology, so try these. I haven't actually watched them in a long time though, so I'm afraid I can't remember how well they cover this stuff.

The Beginning and End of the Universe

Light and Dark - 1 of 2 - Light

Light and Dark - Dark (2 of 2)

Replies From View


TrenterPercenter

Quote from: Replies From View on December 24, 2021, 03:31:00 PMOk so what can I passively sit and watch so that all of this makes sense?  Has Brian Cox mentioned it in passing?

How far away is it - David Butler

Give this a whirl it's amateur but absolutely fantastically comprehensive and talks through things from the perspective of how far away things are starting in the narrators back garden and eventually leading to the edge of the observable universe.  It also covers the lagrange points along the way.

Replies From View


Goldentony

been to space, fuck all there, said this over and over but they still persist every year

Sonny_Jim


Uncle TechTip


Butchers Blind

Proper funny when they realise they put it in the wrong way round and everything looks even further away.

Replies From View


Replies From View

Quote from: Butchers Blind on December 25, 2021, 11:15:19 AMProper funny when they realise they put it in the wrong way round and everything looks even further away.

Or it's an endoscope instead, like a bird's endoscope

Replies From View

I wonder where this telescope will fit into the MCU spider-verse

Replies From View

when anyone says "Greg" they mean Greg Ronson

GMTV

Look forward to the next space telescope in about 50 years time that'll tell us the origin of space and that, just like all the other things were meant to tell us.

Replies From View

Quote from: GMTV on December 25, 2021, 12:02:00 PMLook forward to the next space telescope in about 50 years time that'll tell us the origin of space and that, just like all the other things were meant to tell us.

lol so triggered by telescopes

Rich Uncle Skeleton

Loving the director of operations shiny head. Reckon he had it glossed specially for the big day?

Rich Uncle Skeleton

Also why is Gambacini commentating on the nasa stream?

Goldentony

Quote from: Rich Uncle Skeleton on December 25, 2021, 12:19:39 PMAlso why is Gambacini commentating on the nasa stream?

jeff lynne is inside the telescope

Replies From View

For something so fast it sure is taking ages to get incredibly far away from the Earth

Replies From View

Just over 2000 km in 10 minutes.  Come on slow coach.  I could have pinched and zoomed back and forth numerous times on Google Earth within this time span.