The Conversation contributed the article to Space.com's expert voices.
Michael J. I. Brown is an associate professor of astronomy at the university.
We have seen the first data from the space telescope. It has seen clouds of gas and dust in stellar nurseries, as well as the atmosphere of distant planets.
We've seen headlines saying that the James Webb Space Telescope has found the oldest galaxies we've ever seen, but what does that mean?
I'm an astronomer and I find this a little puzzling.
The James Webb Space Telescope has its first photos in the gallery.
Peering back in time and observing the early universe is one of the key science goals of the project. This is possible because it is a time machine.
When we look at the moon we see it as it was two years ago. Our solar system's planets are millions or billions of kilometers away, but we still see them as they were a long time ago.
Light that has taken millions or billions of years to reach us is what we see when we look at distant galaxies with telescopes. We are seeing the same things we did millions of years ago.
The Hubble Space Telescope can only see a small portion of the universe.
It is above the Earth's atmosphere. Hubble has a 2.3 meter mirror for focusing light, while Webb has a massive 6.5 meter mirror. The expansion of the universe has stretched the visible and invisible light into theIR, which is what we see from the most distant galaxies.
Among the first data obtained was a picture of a cluster of galaxies.
The light took 4.5 billion years to reach us, so we are seeing it as it was in the past. The Earth was formed 4.56 billion years ago.
In the last few weeks, there have been more attention given to the distant galaxies. There are a number of galaxies that are so far away that their light has taken over 13 billion years to reach us.
My excellent summer students @sophmjewell and @claraluciep have made this beautiful colour image of our redshift 16.7 galaxy from @cdonnanastro's new paper. This galaxy is 35 billion light years away, observed as it was just 235 million years after the Big Bang @NASAWebb @BBCAmos pic.twitter.com/JD1DCkLgUSJuly 26, 2022
You can see more.
More data will need to be gathered to confirm their distances, but some of the candidates are very compelling.
The light has taken more than 13 billion years to reach us, so we are seeing the same things as they were when the light first hit the Earth. The universe is just a few hundred million years old, so it's possible to see the stars.
These distant galaxies have been advertised as the oldest of them all. We are seeing the stars when they were very young.
Our own Milky Way galaxy is also very old now. Our sun is 4.56 billion years old, but there are many stars in our universe that are 10 billion years old.
It will look different today than it did yesterday. Galaxies grow when they acquire gas and dark matter.
A small galaxy that was forming stars soon after the Big bang may have ended up being the seed of a giant galaxy that is still forming stars today. The small galaxy and its old stars might have ended up being part of a larger galaxy formed recently.
The most distant galaxies should be called young or old. Maybe it isn't.
James is looking at some of the first galaxies that formed after the Bigbang.
"yet observed" is the final caveat I have thrown in. Current analyses are based on data collected over hours after the mission began.
With days' worth of data, Webb will be able to see more objects, and even more distant ones. A few times before the year ends, the record for the most distant and earliest observed galaxy will likely tumble.
Under a Creative Commons license, this article is re-posted. The article is open in a new tab.
Become a part of the discussion and follow all of the Expert Voices issues and debates on social media. The author's views do not represent those of the publisher.
All Rights Reserved © 2024
