For the past few weeks, we have been exploring different aspects of the James Webb Space Telescope in anticipation for its upcoming launch. This is the final part of our series on this incredible mission.
This Christmas Eve, astronomers around the world are feeling a combination of nervousness, excitement, and hope. That’s because if all goes well tomorrow morning, they will receive an incredibly powerful $10 billion space telescope to keep them occupied for decades to come: the James Webb Space Telescope. Only this time, the Christmas gift for astronomers will not be coming down the chimney. Instead, it’ll be riding up into space onboard towards its new home which lies about a million miles away from Earth.
All rocket launches have an inherent degree of risk associated with them, but the James Webb Space Telescope takes this degree up to an entirely new level with over 300 potential points of failure. Not only is the telescope itself irreplaceable, but the sheer willpower and effort that went into getting this project off the ground is also priceless. Over 30 years of work has gone into the JWST, and that’s before it has even become operational! To put that into perspective, it only took 12 years from the launch of the first artificial satellite for the first human landing on the moon. So, not only will an Ariane 5 rocket take off tomorrow with a precious passenger, but it will also be carrying the hopes and dreams of an entire generation of scientists who have poured their lives into this one project.
This Christmas Eve, astronomers around the world are feeling a combination of nervousness, excitement, and hope. That’s because if all goes well tomorrow morning, they will receive an incredibly powerful $10 billion space telescope to keep them occupied for decades to come: the James Webb Space Telescope. Only this time, the Christmas gift for astronomers will not be coming down the chimney. Instead, it’ll be riding up into space onboard towards its new home which lies about a million miles away from Earth.
All rocket launches have an inherent degree of risk associated with them, but the James Webb Space Telescope takes this degree up to an entirely new level with over 300 potential points of failure. Not only is the telescope itself irreplaceable, but the sheer willpower and effort that went into getting this project off the ground is also priceless. Over 30 years of work has gone into the JWST, and that’s before it has even become operational! To put that into perspective, it only took 12 years from the launch of the first artificial satellite for the first human landing on the moon. So, not only will an Ariane 5 rocket take off tomorrow with a precious passenger, but it will also be carrying the hopes and dreams of an entire generation of scientists who have poured their lives into this one project.
To understand JWST’s value, we must understand the importance of the electromagnetic spectrum in the context of astronomy. Every single section of the spectrum, from radio waves to gamma rays, contains valuable information that can reveal a new perspective on the objects that make up the universe. However, arguably more important to astronomy than the electromagnetic spectrum is the incredible speed of light itself (299,792,458 m/s to be exact). For instance, light from the sun takes about eight minutes to arrive at Earth, which means that every time we look at it, we are seeing it as it was eight minutes ago.
The same applies to objects further away from Earth. Radio signals from spacecraft orbiting Mars can take from five to twenty minutes to arrive, and the transmissions from Voyager 1, the furthest spacecraft ever launched, take 21 hours 35 minutes to arrive as of the time of this writing. As we get further from Earth, light itself becomes our measuring unit; when measuring astronomical distances we use the light-year, or the distance light travels in one year. For example, the light we see from the Andromeda galaxy today left the galaxy 2.5 million years ago when our ancestors Homo Habilis walked the Earth, so we can say the Andromeda Galaxy is 2.5 million light years away from Earth. So the farther away we travel from Earth, we see objects as they were millions and even billions of years ago. This can allow us to learn about astronomical events that happened way before we even existed!
Much of the JWST’s scientific value revolves around what we currently understand about the history of the universe and its founding event: the Big Bang. According to this theory, the universe was born out of a single point of infinite temperature and density that suddenly exploded outwards in a gaseous cloud around 14 billion years ago. Many hundreds of millions of years passed before stars began to form, and it took even longer for them to group together in the galaxies we can see in the sky today. While the aforementioned Andromeda galaxy is an excellent example of a galaxy that we can see with the naked eye, there are millions more, potentially billions, that are much further away and have been around for much longer.
For instance, the farthest object observed to date by Webb’s predecessor, the Hubble Space Telescope, was a galaxy named GN-z11. The light from this irregular galaxy that we see today first began its journey about 13.4 billion years ago, during the period of time when galaxies first began to form. Webb, with its massive 6.5 meter-wide mirror, will be able to collect light that was emitted even further back, allowing astronomers to see the birth of stars and galaxies in greater clarity. Observing such processes can shed light on the evolution of galaxies and help us understand more about dark matter, dark energy, and the origins of our home, the Milky Way. With the JWST, we will be one step closer to answering these questions while revealing entirely new ones.
The JWST will also conduct some other intriguing observations aside from studying stars. For instance, it will be able to find and observe planets orbiting around distant stars, called exoplanets. Like other telescopes that observe exoplanets, Webb will use the transit method to find exoplanets when they pass between Earth and their parent star. This will allow Webb to determine the atmospheric composition of these planets, making it easier to identify ones that are potentially habitable. Additionally, it’s possible that the JWST will even be able to directly image nearby exoplanets, which as you might expect is an exciting prospect for the search for extraterrestrial life. Webb will also use its capabilities to observe the planets in our own solar system, further advancing our knowledge of our local celestial neighborhood. Unlike Hubble, which makes observations in the visible light part of the spectrum, Webb will also be able to see in the infrared spectrum, giving it the ability to see deep inside clouds of gas which are just beginning to form new stars.
However, scientists are already dreaming of ways to expand the scope of space-based astronomy even further in the future. For instance, the Nancy Grace Roman Space Telescope which is scheduled to launch in 2027 will have a mirror as wide as the one inside Hubble, but it will have a field of view that is 100 times larger! Yet, there are proposals which are even more ambitious. One of these proposed projects, the Large UV Optical Infrared Surveyor (LUVOIR), will be a mammoth telescope capable of observing in infrared, visible, and ultraviolet wavelengths. Essentially, you could think of LUVOIR as an oversized, overpowered version of the JWST. In its largest configuration, LUVOIR could have a mirror that is over 15 meters wide! There are also numerous other proposed telescopes focused on everything from exoplanet research to the more violent realm of x-ray astronomy. With so many missions planned in the next decade, the future of space-based astronomy is looking bright!
For now, however, scientists are focused on tomorrow. It’s been a long and winded road to launch for Webb, but its mission is only about to begin. If successful, this telescope has the potential to completely revolutionize our understanding of astronomy by illuminating the furthest reaches of the observable universe. You could even say that the capabilities of the James Webb Space Telescope are astronomical…
Sources & Further Reading
JWST science themes