On Christmas Day last year, the James Webb Space Telescope (JWST) began its journey to space when it launched from French Guiana. The launch was successful, and in July, NASA released the first mesmerizing, full-color James Webb images.
Like the Hubble Telescope, the JWST orbits the Sun, not the Earth, at a point that is 1.5 million kilometers away. This location, and the fact that it captures infrared light, will enable the James Webb Telescope to get better views than any other telescope in history.
Since Galileo first trained his telescope on the night sky, astronomy has come a long way. Even the cheapest telescopes on the market today are significantly better than what Galileo had access to when he found proof of heliocentrism. The James Webb Telescope is in a league of its own and has exceeded all expectations. It will indeed teach us many new things about the Universe. Here are five things you need to know about it:
1 – James Webb sees the past
What astronomers call “lookback time” is precisely what it sounds like: looking into the past. Light travels at a constant speed, which scientists describe as c = 3×108 m/s or 300,000 kilometers per second. While the speed of light is the fastest thing in the Universe, the vast distances still make it so that light can take billions of years to travel from a far-away object before it reaches the Earth.
When we look at the sky, we see approximately 8 minutes into the past because the light we see from the Sun spends 8 minutes traveling to the Earth. The more distant an object is from us, the further back in time we are looking. The James Webb Telescope will allow us to look almost as far back as when the Universe first got light.
2 – It will teach us about the early Universe
Astronomers hope the James Webb Telescope can tell us more about the Universe’s origins. By capturing light from extremely distant objects, the telescope can observe what the early Universe was like.
After the big bang, which happened 13.8 billion years ago, the Universe was too hot for any light to shine. When 380,000 years had passed, the Universe had cooled down enough that matter could begin to form. The first atoms appeared. But the dark ages did not end there. The first stars would not emerge for millions of years yet.
Cosmic dawn is the period that began about 100 million years after the big bang when the first stars materialized. It is thought that these stars formed smaller protogalaxies that merged and eventually became more giant galaxies like the ones we know today.
Scientists have estimated that this development period lasted 1 billion years. But initial observations from the James Webb Telescope might suggest otherwise. The telescope has already observed galaxies that could date back to just 180 million years after the big bang, and the findings are surprising.
Astronomers expected to see only relatively faint protogalaxies from this far back in time. But they have observed what could be bright, fully formed galaxies. There could be other explanations for the findings. For example, the brightness of the observations may have something to do with the amount of dust in the galaxies. Even so, these observations are baffling and surprising.
It is too early to say anything definitive, but it looks pretty likely that the James Webb Telescope will change our ideas about the early Universe. Established theories might change.
3 – The JWST is an infrared telescope
One way of understanding light is as a wave. The different wavelengths and frequencies distinguish the various forms of light on the electromagnetic spectrum. Infrared radiation has longer wavelengths than visible light, the portion of the electromagnetic spectrum visible to the human eye.
The James Webb Telescope can capture the light from cosmic dawn because it sees in infrared rather than visible light. Because of the Universe’s expansion, light stretches as it travels from far-away galaxies. The wavelengths become longer, which causes a redshift.
By the time visible light from distant galaxies reaches the Earth, it has been stretched into infrared light. The Hubble telescope was, therefore, only going to tell us so much about the early Universe. It saw in visible light and had minimal infrared capabilities, meaning that it would not get good views of distant galaxies and, in turn, the distant past.
4 – It can help us study other planets
A whole field of astronomy is dedicated to looking for other planets. These scientists look for exoplanets and study their chemical composition, atmosphere, weather, etc. One of their aspirations is to find ideal conditions for life elsewhere in the Universe.
The James Webb Telescope is set to explore 76 planets in its first year. It has already observed an exoplanet called WASP-39b with CO2 in its atmosphere. The presence of CO2 gas could be a sign of life. In all probability, WASP-39b is way too close to its stars for any life to exist. Yet, this is the first definitive evidence of CO2 in another world’s atmosphere.
This discovery is an essential step in detecting life on other planets. Scientists do not expect James Webb to find life. An even more advanced observatory might be necessary to do so. Still, detecting CO2 for the first time is a crucial step, far out of reach not long ago.
5 – Anyone can apply to use the James Webb space observatory
If you want to use the James Webb Space Telescope, you might be able to. You would probably need the help of a skilled astronomer, but the application is technically open to anyone. Applicants present a proposal that carefully details how they want to use the telescope, which is evaluated in a peer review process.
A pitch, however, is quite complicated. You could not simply email the Space Telescope Science Institute (STScl), which manages the James Webb and Hubble telescopes. It is necessary to use the Astronomer’s Proposal Tool (APT). APT is free software that helps astronomers organize everything from a project description to the exact settings on the telescope.
You would need to know not just a little bit about astronomy to use it, but if you can figure it out, you could apply for telescope time. In the meantime, you might want to start with one of our excellent telescopes.
The successful launch of the James Webb Telescope marks an exciting new epoch in understanding the cosmos. Astronomers worldwide are eager to use it, and there is no question that we have many baffling discoveries ahead of us.