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

Starting point is 00:00:00 Hey everyone, this is Gary. I'm out of town this week, so instead of doing plain old encore episodes, I'm doing something a little different. This week, I am running full older episodes as they were originally released, but at the end, where I normally read a review, I'm going to be providing an update to the episode. So make sure to stay tuned all the way to the end. This episode was originally released on December 20th, 2021, and you might notice that the sound is a little bit different, as my recording setup at the time was different than it is today. With that, enjoy the incredible story of the James Webb Space Telescope. Sometime, within the next week of me recording this episode, hopefully, a rocket will be launched

Starting point is 00:00:41 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. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. If you're familiar with any space telescope, you're probably familiar with the Hubble Space Telescope.

Starting point is 00:01:44 The Hubble looks like a 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's 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 orbit, approximately 570 kilometers above the surface of the Earth, and it's zipping around the world

Starting point is 00:02:24 about once every 90 minutes. 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. Throughout the 1990s, astronomers debated about what the Hubble's successor should look like. At first, the plan was to create a $500 million 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.

Starting point is 00:03:05 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 adjoined. 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 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.

Starting point is 00:03:43 to change because the sound waves are compressed as it approaches and elongated as it goes away. 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 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 would, 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

Starting point is 00:04:23 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, once everything is 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

Starting point is 00:05:08 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. 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,

Starting point is 00:05:55 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. 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,

Starting point is 00:06:36 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. 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,

Starting point is 00:07:03 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. 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 goes wrong, the entire mission will fail.

Starting point is 00:07:44 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.2. 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, given the difficult orbital dynamics of getting to L2. While it's en 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,

Starting point is 00:08:29 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. 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,

Starting point is 00:09:07 sometime around May or June 2022, we should be getting our first glimpses of the most distant reaches of the universe. Obviously, there is a whole lot to update on this topic as I released it before the web was even launched. Suffice it to say, the launch and deployment were successful, and none of the 344 points of failure failed. It was launched just five days after the web. this episode aired and it went into service seven months later.

Starting point is 00:09:37 Since it began observations, it has basically upended much of what we know about the origin of the universe. It has observed the oldest galaxies in the universe and found that according to our current model of the universe, they shouldn't exist. It has made the first direct observations of an exoplanet and has been able to analyze the atmosphere of exoplanets. It's been able to make some of the best observations of Saturn's moon Titan. It has observed the most distant black hole ever seen. Just trying to put together a short list of accomplishments to put at the end of this episode was difficult because there are so many, because it seems like every few days a new discovery

Starting point is 00:10:13 is being announced. The observations have been so fast and furious that cosmologists will be trying to catch up to explain all of the observations for years. This is a topic I can guarantee you will be covered in a future episode. The only question is when I should do it, as the web is still scheduled to function for as many as 20 years.

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

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