James Webb capturing distant galaxies

There's been a lot happening up in the skies recently. Matt Bothwell from the University of Cambridge brings Juia Ravey some insights on these exciting extra-terrestrial endeavours...

Julia - There's been some brilliant images circulated online of James Webb capturing loads of really bright objects. What have the images from the scope shown us so far? And when are we hoping to see those first proper images come through?

Matt - I think the most exciting thing about the incredible James Webb images we've seen so far is that we haven't actually seen any real science data yet. So far, all we've seen are the engineering calibration images. Because the mirror is 6.5 meters wide, it was too big to be sent up as a single mirror, so there's actually 18 different hexagons that all function as one big mirror. It's a marvel of engineering; this thing was launched and then unfolded in this origami-like way in space. A few months ago, the telescope focused on a bright nearby star and took the first image and it didn't look particularly great. It was 18 different, strange blurry images of the same star. Over the last few months, those mirrors have had these micro adjustments to bring them all into unanimous harmony, and so they produced one single image of one star for the first time. The most striking thing I think for me, particularly as a galaxy astronomer, is that in the background you can see just an absolute field of galaxies behind this star. James Webb is so sensitive, it can't help but pick up a swarm of galaxies every time it looks, because it's so sensitive. It can't help but see back to the start of the universe, every time it opens its eyes. The first science images should be arriving this summer.

Julia - James Webb to me sounds like that kid who doesn't even try and gets top marks in class. Just getting all those galaxies in the background and not even trying. Obviously we're gonna see the universe like never before with James Webb. Are there any problems in cosmology at the minute, which we hope that this can help us to solve?

Matt - Yeah. James Webb has a few sort of major science goals. One of them is 'what do the atmospheres of exoplanets look like?' It's going to be very good at looking for the signatures of molecules. James Webb is gonna be very good at looking very, very far away in the universe and seeing basically the first galaxies ever to form. I think the most exciting thing is almost not so much which questions will it answer, but which questions will it reveal. James Webb will look for new exciting problems that we can go and solve in the future. It's like a double whammy. It's going to be great.

Julia - All those unknown unknowns, definitely coming our way soon. Now that we're heading into the warmer months, many of us might be sitting outside on a warm night, looking up at the sky. How can we get the best stargazing experience at home? What are your top tips?

Matt - First of all, as much as you can try to go away from lights, such as lights in your house and street lights and stuff. All of that's going to be pretty bad. Get the darkest sky you can. If you are in the middle of a city, then maybe go out to a park or a field or something. It's also good to remember that your eyes take about 20 minutes or half an hour to properly adapt to the dark and looking at a phone screen will ruin your dark adoption, so make sure you spend time in the dark and let your eyes adjust, and then you'll be able to see fainter and fainter things. There are some really cool things to look out for in the summer sky. I think my favorite thing to look for is the summer triangle. It's this very striking constellation. You can't really miss it. If you look up in the summer months, you'll see this huge triangle in the sky made of these three stars. What I like about these three stars is that it hides a really remarkable secret. One of the stars is Vega, that's about 25 light years away. One of the stars is Altair and that's about 16 light years away. But one of the stars is Deneb and that is nearly 4,000 light years away and it's in fact, one of the brightest stars in the entire galaxy. It's 200,000 times more powerful than our sun. It's the most distant thing we can see with our naked eye, and it's just hiding there completely innocuously. I like pointing out that triangle to people and saying that that star there is the most distant thing you can see with your eyes.

Julia - Well, I'm definitely going to look out for that. I've moved recently from London to Cambridge and my goodness, there's a difference in looking up and seeing the stars. We're just going to move a little bit closer to home now. There have been reports over the past few months of problems with space junk. What needs to be done to keep our skies clear?

Matt - There is a lot of junk out there and space, particularly orbiting around the earth and it's getting worse and worse. There are tens of thousands of things in earth orbit. We do a few things to try and mitigate this. First of all, when we do human space flight, we make sure that we stay in orbits that are relatively clear of space junk. But long term, we are going to have to think about clearing it up. There are all kinds of solutions that are being proposed from big nets in space catching it all, to shooting it down with a laser. The issue is it's only going to get worse because when two pieces of space junk crash into each other, they often fragment and you end up with a hundred pieces of space junk and so you get this cascade. Unless we do something about it, leaving earth orbits within a few decades could be quite difficult. Clean-up efforts are needed.

Julia - Yeah, we need a space recycling centre, for sure. We need one of them up there.