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Podcast Transcript
On December 25, 2021, NASA’s James Webb Space Telescope was launched from the European Space Agency launch center in French Guyana.
After six months of testing and configuring the telescope, in July of 2022, its first images were transmitted.
Since then, we have received a flood of images and data that have caused astronomers to rethink much of what we know about the universe.
Learn more about the discoveries made by the James Webb Space Telescope so far on this episode of Everything Everywhere Daily.
I should start by noting that this episode is a follow up to an episode I recorded back in December 2021.
That episode was recorded just before the James Web Space Telescope was launched and deployed.
Just to recap, the Webb is the largest space telescope ever built. Its mirror has a diameter of 6.5 meters or 21.3 feet. As a point of comparison, the Hubble Space Telescope has a diameter of 2.4 meters or 7.9 feet. The total light gathering area of the Webb is 6.25x that of Hubble.
Whereas the Hubble is designed to observe in the visible part of the spectrum the Webb is designed to observe in the infrared part of the spectrum.
The reason why it was built to observe the infrared part of the spectrum is because it is designed to observe some of the furthest objects possible in the universe.
The further away something is, the further back in time you are looking. As the universe is expanding, the light from these distant objects is stretched into longer wavelengths. This is known as the redshift, and it is the light equivalent of the Doppler effect that you can hear when vehicles approach you and drive away.
The launch and deployment of the Webb was a very risky and intricate affair. The telescope had 344 single-point failures. That means there were 344 things that, if they went wrong, would scuttle the entire mission.
Unlike other space telescopes, the Webb is not in Earth Orbit. Rather it is located at a gravitationally stable point known as L2 or Lagrange Point 2, which is located at a point in space on the other side of the Moon from Earth.
After years and years of planning, everything went perfect. NASA spent more than six months testing and tweaking the camera before it was ready to start making observations.
I should also note one other thing so that some of these observations make sense: Astronomy is a different type of science.
If you really want to apply the scientific method properly, you develop a hypothesis, and then you test it with an experiment.
You can’t really do that in astronomy. You can’t build a star to see how it works. Instead, astronomy relies on observations. You can make a prediction, but then you have to find something to verify it.
This was the case with gravitational lensing. Albert Einstein predicted that gravity could act like a lens to bend light in 1912. Decades after his prediction, in 1979, such an example was found.
Most of the time, astronomers will observe something, and then develop a theory to try and explain it. When they observe something that doesn’t jibe with the theory, then the theory needs to be adjusted or replaced altogether.
So, that being said, what have astronomers discovered?
Let’s start with the big stuff.
The Webb has peered back about as far as is possible and found something that…..shouldn’t exist.
According to existing cosmological theories, the universe is about ??13.787 billion years old. This is determined by the cosmic microwave background radiation and the universe’s expansion rate, the Hubble constant.
We also have a theory for how galaxies and stars form and how long the process of formation takes.
The galaxies that were observed were far larger and older than what we think should be possible. By analyzing the light emitted from these galaxies, it was determined that they were viewing light that was emitted 500 to 700 million years after the Big Bang.
Given how old they are and how much time had elapsed since the Big Bang, the galaxies shouldn’t be that big, and perhaps more importantly, the red stars in the galaxy shouldn’t be that old.
Previous observations by the Hubble have found blue stars in distant early galaxies. Blue stars are younger because they have more mass and burn hotter.
They expected galaxies with about a billion solar masses, but they found some with 50 billion solar masses.
As of now, there is no consensus explanation for these observations, but several theories have been put forward.
One is that the process of galactic formation in the early universe was either different than it is today or that some other variable, such as a large black hole in the center of the galaxy, accelerated the formation of galaxies.
Another theory is that we underestimated how quickly stars formed in the early universe. If stars formed in massive bursts shortly after the Big Bang, this could lead to the rapid evolution of galaxies, making them appear more mature at earlier times than our models predict.
Another theory is that perhaps physics just worked differently in the early universe.
Yet another theory is reviving an older idea known as tired light. This theory, which challenges the concept of cosmic expansion causing redshift, posits that photons lose energy over time due to interactions with other particles or space itself. If true, this could mean that the universe’s age has been underestimated because we’ve misinterpreted redshift.
Some estimates suggest the universe could be 26.7 billion years old, removing the need for dark matter by altering how we understand the expansion and light’s behavior.
Of course, we also can’t rule out the possibility of simple errors in measurement and observation.
We have no clue what the answer is at this moment, but resolving these discrepancies is going to be one of the hottest areas of cosmological research over the next several years.
Another area where the Webb has made exciting new discoveries is in the area of exoplanets.
If you remember back to my episode on exoplanets, the vast majority of the 5,765 known exoplanets, as of the time of this recording, have been discovered by their influence on the star they orbit.
Either the gravity of the planet causes the star to wobble, or it slightly dims the light coming from the star when it passes in front of it.
Given how powerful the Webb is, it is able to do something that has never been done before. It can directly analyze the atmospheres of some exoplanets.
Of particular interest was WASP-39b. The planet was first discovered in 2011, and it was a high priority for Webb. Webb analyzed the planet’s light spectrum and determined that it had water, carbon dioxide, sodium, and sulfur dioxide in its atmosphere.
WASP-96b is a planet about half the mass of Jupiter that orbits its star at one-ninth the distance that Mercury does from the Sun. The Webb found out that it had water in its atmosphere and that it probably had clouds and hazes in its atmosphere.
Water isn’t the only type of cloud that was found. Exoplanet VHS 1256b showed signs of silicate clouds and a variety of organic compounds, including carbon dioxide, water, methane, and carbon monoxide, suggesting a dynamic and potentially rich atmospheric chemistry.
VHS 1256b is actually closer to a brown dwarf than a planet. Its huge, but it isn’t big enough to start fusion and become a star. The silicate clouds in the atmosphere might actually be a type of sand.
One of the reasons VHS 1256b could be observed so well is that, unlike many exoplanets that orbit close to their star, this one is four times the distance from its star than Pluto is from our Sun, and it is 19 times as massive as Jupiter. Its distance means that it can be observed without the bright light from its start overwhelming the observation.
The very first exoplanet that Webb discovered was LHS 475b. What makes this planet so special is that its diameter is 99% that of Earth’s, and its mass is approximately 91%.
Unfortunately, it probably isn’t a good candidate for future colonization. It has a surface temperature of around 313 °C and it orbits its star every 2 days.
The Webb isn’t just observing fully formed stars and exoplanets. It has also made observations of stars that are in the process of forming.
By studying the disks around young stars where planets are believed to form, JWST has provided insights into the initial stages of planet formation.
Observations of these protoplanetary disks reveal the presence of chemicals that are necessary for life. The molecular cloud known as Chameleon I, about 500 light-years from Earth, has been found to contain carbon, oxygen, hydrogen, nitrogen and sulfur.
The infrared camera on the Webb has been able to see some things that other telescopes simply can’t. In the constellation Cetus there are two galaxies that are in the middle of colliding. Known as IC 1623, it has been obscured by the enormous amounts of dust.
Webb can peer through the dust in infrared wavelengths, and it has observed that the colliding galaxies are forming new stars at an accelerated pace. One particularly bright section is making stars at 20 times the rate of the Milky Way.
The Webb has also found an entirely new class of object which has been dubbed “JuMBOs,” which stands for Jupiter Mass Binary Objects.
Webb has found 40 pairs of JuMBOs so far, and they share one remarkable trait—none of them orbit a star. The fact that such large planet-type objects can exist outside the orbit of a star has challenged many ideas of planet formation.
While the major focus of the Webb has been making observations at the edge of the known universe, it has also made some observations in our solar system.
Titan, the largest Moon of Saturn, is one of the most intriguing moons in the solar system for one reason. Titan has an atmosphere. In fact, it has a relatively thick atmosphere. It is believed that Titan is the only place in the Solar System where you could walk around with a pressurized suit.
You’d certainly need protection from the incredibly low temperatures and toxic atmosphere, but you wouldn’t need pressure….or at least not much.
On November 4, 2022, Webb captured an image of Titan that showed clouds in its atmosphere. Two days later, the Keck Observatory in Hawaii captured an image of Titan that showed the clouds that were seen by Webb had moved.
On top of all of the discoveries I just mentioned, there are many many more observations that have been made the Webb Telescope so far. All of this has been done in close to two and a half years.
NASA traditionally has very conservative estimates for the duration of its unmanned missions, but they often surpass them by years. For example, the Opportunity rover on Mars was only scheduled for 90 days but ended up being operational for 14 years.
The Webb mission had an initial span of just 5 ½ years. However, because of the amount of propellent on board, it is entirely possible that the Web could be operational for another 20 years.
Assuming it continues to function, and based on previous NASA missions, this is highly likely, there should be a lot more discoveries made by the James Webb Space Telescope, some of which may require astronomers to reconsider what we know about the universe.