The James Webb Space Telescope: Hubble’s Mind-Blowing Successor | Answers With Joe

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The Hubble Telescope opened our perspective of the cosmos and our place in it. But the James Webb Space Telescope may show us the very origins of our universe.

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Animation of the JWST launch and deployment:

JWST focusing procedure:

JWST Documentary:


So let’s talk about what we’re getting for our $8 billion dollars shall we?

The first thing everybody talks about with the JWST is the mirror. Or I should say mirrors.

The collecting surface is a massive 6.5 meters, or 21.3 feet, as tall as a two story building. The only way to get a mirror that size into space is to fold it up, so the mirror is made out of 18 hexagonal gold-coated beryllium units that fold together to make one surface.

By the way, the mirror on the Hubble – the mirror that gave us an entirely new perspective on our universe by showing us things we didn’t know were there – is 2.4 meters. This DWARFS Hubble.

And unlike Hubble, which could see in the infrared, visible, and ultraviolet wavelengths, JWST’s will focus on the infrared spectrum

The reason is because JWST’s primary mission is to find the furthest and earliest stars and galaxies in the universe. Think of the Hubble deep field on steroids and meth.

And because of the expansion of the universe, the further a star or galaxy is from us, the more redshifted their light will be.

So the furthest galaxies will be redshifted way down into the deep infrared.

The trick with infrared telescopes is in order to see the smallest frequencies, you have to be really cold. Most Infrared telescopes have very short life spans for this reason because they’re cooled with liquid nitrogen or helium. These things are so sensitive that even the heat from the computer on the telescope can mess with the results.

But James Webb cools passively as much as possible through the solar shields. These shields are the size of a tennis court but are thinner than a human hair.

They have to be insanely thin to keep from weighing too much.

One specific star JWST plans to check out is KIC 8462852 – Tabby’s Star, which I just covered about a month ago in a video that will likely be obsolete once JWST takes a look at it.

LUVOIR is a 12-meter telescope that can see in multiple wavelengths, including the visible spectrum, which James Webb can’t do.

It would be used to study galaxy formation and examine the early universe even further than James Webb, but maybe the coolest part is it will have an onboard chronograph that blocks starlight, meaning it’ll be able to find exoplanets visibly without the planet’s star getting in the way.

Perched atop Mauna Kea, the Thirty Meter Telescope’s mirror has a diameter of – you guessed it – 30 meters, with a collection area of 655 square meters, made up of 492 individual segments.

This will have capabilities from ultraviolet, through the visible spectrum and into the mid-infrared field, giving it a wide range of wavelengths to cover.

There are a couple more extremely large telescopes in the works worth mentioning, including the European Extremely Large Telescope with a diameter of nearly 40 meters and the Magellan Telescope, both of which are set to be built in Chile.

But all of this is dwarfed by the Chinese five hundred meter Aperture Spherical Telescope – or FAST.

This is a radio telescope that is twice as large as the Arecibo telescope in Puerto Rico. It got its first light in 2016 and has already discovered a pair of pulsars, though it’s still a ways away from being fully operational.


Locut0s says:

The complexity of this thing terrifies me. I’ve been looking forward to its launch for years but knowing all the things that can go wrong, its cost, and the insane ambition of it I’m more than a little freaked out about the whole thing. I can only imagine what those building it must feel. Projects like these are amazing and necessary but they also pose huge risks if they end up being failures.

Remi Caron says:

Very awesome I just hope we have a few decades left.

Shadow Heart says:

10:06 If they think the mountain tops are sacred, then what is more fitting than constructing the pinnacle of observation on them?

PatricK WithaKay says:

Hi Joe.
Would just like to say that I really enjoyed this video and I have also subscribed.
Greetings from the UK.

DM Bara says:

Hey Joe. Can you find out if Space X has any monitoring for the suit and critical equipment? Is there any crucial research happening and what else is in the glove box?

Guillaume Lemaigre says:

Maybe you should do a video on the Lagrange points, so you can get your fact straight about it, you didn't seemed to know much about it, but it's plenty intresting.
And about Hubble, it was not the focusing mechanism that was wrong, it was the mirror itself that was flawed, Curious Droid has a very good video about that.

NonGamer live 247 says:

What about Cankerboy t-shirts

Marco Polo says:

How about the TFT

Jon Calderwood says:

Keep up the great work. The more we can see out there, the more it will help us to grow and understand our place in the cosmos.

Cade Silvers says:

When we launch it in 2013 err 2014 15 18 19 !?!?!?!

panks103 says:

Great days ahead for Astronomy!!! It will be super exciting to see what all we discover!! Great video as always Joe, your level of research shows in the content !!

Chad Severi says:

FOCAL (Fast Outgoing Cyclopean Astronomical Lens)Telescope! Using the SUN's gravitational lens for a telescope… and it would work with existing technologies! Sure there's plenty of caveats but it would have the power to view the surface of exoplanets in detail.

Conway79 says:

If these telescopes are so foldable and flat, why aren't they sold at Ikea?

skin-job retiree says:

Is the universe we see from 13.8 billion years ago moving away from us the fastest (due to the expansion of the universe) because it has the lowest entropy?

56un dsdu says:

Why wouldn’t they try to fly astronauts to refuel the telescope in like 10 years or so when it runs out to double its lifespan?

Adam Borton says:

I think you are doing a great job. I really enjoy your videos.

BillyCBoxingFan says:

I can't wait to see the James Webb ultra deep field. I wonder if we'll get to see what was before the Big Bang. 😉

Anna B says:

hey there! I have a question concerning the stability of the material, the solar shields are made of. If they are so thin and light, aren't they extremely sensible to dust particles / space junk flying around with high speed in space? I mean, at that pace, a pinpointball- big thing could rip the solar shields through or scratch the mirror, I would assume. How do you manage to keep that from happening? Or is the probability of the telescope encounterng a potentially harmful piece so low that its not actually made "dust proof"? Thank you, great video!

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