Everything Everywhere Daily: History, Science, Geography & More - The James Webb Space Telescope

Starting point is 00:00:00 Sometime, within the next week of me recording this episode, hopefully, a rocket will be launched from the European Space Agency's facility in French Ghana. On it will be NASA's latest and greatest space telescope. It's unlike anything which has ever been launched in a space before, and if successful, it will allow us to see further than we ever have. Learn more about the James Webb Space Telescope and how it will radically advance astronomy on this episode of Everything Everywhere daily. Do you ever climb into bed ready to sleep, only to have your mind start racing the moment your head hits the pillow? Thoughts bouncing around, replaying the day, or jumping ahead to tomorrow? That is exactly why Catherine Nikolai created Nothing Much Happens. Each episode is a gentle,

Starting point is 00:00:52 cozy bedtime story where, well, nothing much happens. No drama, no tension, nothing you need to follow closely. Just soft narration, calming repetition, and soothing sensory details designed to help your mind slow down and your body relax. It's not about entertainment, it's about rest. And millions of listeners around the world use it every night to quiet the thoughts and finally fall asleep. If you've ever struggled to shut your brain off at night, this might be exactly what you've been missing. You can listen to Nothing Much Happens wherever you get your podcasts. Episodes are every Monday and Thursday. If you're familiar with any space telescope, you're probably familiar with the Hubble Space Telescope. The Hubble looks like a

Starting point is 00:01:35 telescope. There's a mirror at the bottom of a very long tube, it has some solar panels on the side, and it zips around the Earth orbit. The Hubble mirror is 2.4 meters, or 7 feet 10 inches, in diameter. Since it was launched into orbit on the space shuttle 31 years ago, it has revolutionized astronomy. Putting a telescope into space has tons of advantages over ground-based telescopes. Space telescopes operate in the vacuum of space and never have to worry about atmospheric interference. There's no dust that will ever collect on the mirror, and you never have to worry about cloud cover. The Hubble is located in low Earth, approximately 570 kilometers above the surface of the Earth, and it's zipping around the world about once every 90 minutes.

Starting point is 00:02:15 If you've ever seen an image with hundreds of galaxies in it, it was probably taken by the Hubble. The Hubble hasn't been the only space telescope. There's actually been dozens of space telescopes of many different varieties which have been launched that observe everything from gamma rays to radio waves. Before the Hubble was even launched back in 1990, there were already plans for a successor space telescope.

Starting point is 00:02:37 Throughout the 1990s, astronomers debated about what the Hubble's successor should look like. At first, the plan was to create a $500 million, dollar low-cost telescope. However, as these things tend to do, the scope and budget of the project increased. What they ended up proposing was something incredibly audacious. The proposed telescope was called the James Webb, which was named after NASA's second administrator who led the space program through the Apollo era. The telescope is a joint project of the Canadian space program, the European Space Agency, and NASA, who is the lead organization. The telescope would be designed to observe the infrared spectrum of light. Here I should explain why they wanted to

Starting point is 00:03:15 observe infrared light as opposed to visible light. If you've ever heard an automobile or train approach you and then move away, you've probably experienced the Doppler effect. As the vehicle approaches you, the pitch gets higher and as it goes away, the pitch gets lower. The sound isn't actually changing, but the sound is perceived to change because the sound waves are compressed as it approaches and elongated as it goes away. Light like sound is also a way. Light like sound is also a wave, and when a light-emitting object moves away from something, its wavelength will also elongate in the same way that a sound wave does. This is called a red shift. The light waves are elongating and moving to the red or infrared parts of the spectrum. The light sources from the most

Starting point is 00:03:55 distant parts of the universe are moving away from us the fastest, and it's the light that is the most red-shifted. So if we want to observe things that are extremely far away, we have to create a telescope designed for infrared light, because that's what all the visible light has turned into. The next thing about the James Webb is that the mirror is really large. Light from the farthest reaches of the universe is extremely faint, and you need a large mirror to gather that much light. The James Webb's mirror is 6.5 meters in diameter, which means it will have a light-gathering area over six times larger than the Hubble mirror, and the total power of the telescope,

Starting point is 00:04:32 once everything is considered, will be about a hundred times that of the Hubble. The problem is, how do you get a mirror that large into space? The Hubble mirror is one solid, circular piece of honeycomb glass coated in aluminum. A 6.5 meter diameter mirror can't fit on a rocket. The solution was to create a collection of hexagonal mirrors, 18 in total, made of beryllium and plated in gold. The reason why the mirror is segmented like a honeycomb is so it can be folded for the launch. Because the mirror is folded, it can't be put into a tube like the Hubble Space Telescope. is. It's exposed to outer space. And because it isn't in a tube, that creates another problem.

Starting point is 00:05:12 Infrared light is also what we call heat. If you put a mirror in space, it's going to be exposed to the extraneous infrared light from the sun, the earth, and even reflected light from the moon. In order for the instruments to work and not be overwhelmed by heat coming off the spacecraft itself, it has to be kept cool. Very cool. To be specific, it has to be kept under 50 Kelvin, or minus 223 degrees Celsius or minus 369 degrees Fahrenheit. So how do you keep everything cool? Even though space is pretty cold, for something like this, you need to block the heat coming from the Earth and most importantly from the sun. That's why the James Webb is equipped with a large sun shield.

Starting point is 00:05:52 The shield is about the size of a tennis court, and it's made of five layers of a lightweight material called Capton E, which is thinner than a human hair. As with the mirror, a sun-sized shield, the size of a tennis court, can't be put into a rocket. And just like with the mirror, the solution was to fold it. There's one other thing that the James Webb is doing that's rather unique. It isn't going to be put in Earth orbit. It's going to be located at Lagrange Point 2. Now, you might be asking, what are Lagrange points? Lagrange points are areas in a system of two gravitationally massive bodies where the attraction of the bodies and the centripetal force of the object balance out. There are five Lagrange points for any two-body system.

Starting point is 00:06:33 There are five for the Earth Sun and there are five for the Earth Moon, and they are known as L1 through L5. The James Webb will be located at L2 in the Earth Sun system. This is located well beyond the Moon, approximately 1.5 million kilometers from the Earth. Once it's parked there, it will basically sit there, gravitationally bound. It'll be far enough away that, together with the Sun Shield, it shouldn't have too much exposure from the heat from the Earth or the Moon. If folding mirrors in a tennis court-sized sun shield sounds really complicated, that's because it is. There are a whole bunch of things going on, many of which have never been done before. And that's why the James Webb has been chronically late with constant delays.

Starting point is 00:07:14 To give you an idea, the original launch date was supposed to be in 2011. One internal study of the program found that there were 344 single-point failures with the telescope. That meant that there are 344 things, which, if any one of them, them goes wrong, the entire mission will fail. The big reason for the delays is that $10 billion and 20 years of astronomy are all riding on this one mission. The first obstacle is that the whole thing has to be launched into space, which is never a risk-free endeavor. If it blows up on the launch pad, everything's done. Then it has to go to Lagrange Point two. To put this in a perspective, the moon is 385,000 kilometers away, and L2 is 1.5 million. The entire transit time will take a month,

Starting point is 00:08:00 the difficult orbital dynamics of getting to L2. While it's in route, it will begin to deploy. This is basically unfolding everything in a version of space origami. It will take most of the month traveling to L2 for the telescope to unfold. First, the delicate sun shield will slowly unfold, and then finally the mirrors itself. Assuming everything does go right, it'll be another six months of testing and calibrating everything before the first real observations can take place. Unlike the Hubble, which is in low Earth orbit, we can't really send astronauts up to fix it if something goes wrong.

Starting point is 00:08:34 There were five different space shuttle missions sent to service the Hubble, and that is impossible for something which is over four times the distance to the moon. So, if you're listening to this around the time when the episode is released, hopefully on Christmas Eve 2021, the James Webb Telescope will be launched into space. And if everything goes according to plan, which I hope it does, sometime around May or June, 2026. we should be getting our first glimpses of the most distant reaches of the universe. Everything Everywhere Daily is an airwave media podcast. The associate producers are Thor Thompson and Peter Bennett. If you'd like to support the show, you can do so over at patreon.com. And remember, if you leave a review or send in a question, you two can have it read on the show.

Everything Everywhere Daily: History, Science, Geography & More - The James Webb Space Telescope

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