Despite being in orbit for more than three decades and recently being joined by the most powerful space telescope, the Hubble Space Telescope has just made a stunning discovery. WAMC’s Jim Levulis spoke with Jennifer Wiseman, a Hubble Project Scientist with NASA.
Wiseman: Well, we're very excited because the Hubble Space Telescope has detected the farthest individual star that we've ever seen before. So this is a star that's almost 13 billion light years away, that means that its light began its trek to us across the universe almost 13 billion years ago. The whole universe is only 13.8 billion years old. So we're seeing this star shining to us from the very early epics of the universe. So this is quite exciting.
Levulis: And I understand that star has an interesting name, what's the name of it and the story behind it?
Wiseman: Well, the discovery team, led by Brian Welch of Johns Hopkins University and Dan Coe of the Space Telescope Science Institute, and their collaborators named it Earendel, which is an old English word for “morning star.” And the reason they named it the morning star is because it sits in a galaxy, that's actually been magnified through a process I'll explain in a few minutes. But this magnification made that galaxy into a stretched out arc that they call the sunrise arc. So since the star is within the sunrise arc, they call it the morning star, which I think is quite appropriate.
Levulis: And as you mentioned, one reason that Hubble was able to see this star was because of natural magnification of a galaxy cluster. Can you explain what that is?
Wiseman: Sure. So it turns out that math itself can distort space. Einstein predicted this, that if you have any kind of mass, it would actually distort space time around it. Sounds pretty freaky, but we actually see this, when we look out in space with the Hubble telescope, especially in regions where there's a lot of math like a cluster of galaxies, we can see that it's distorting space a little bit, because light from behind that cluster coming through that distorted space gets magnified, and gets stretched out, kind of like a funhouse mirror would do. And so we call this gravitational lensing, like nature's magnifying glasses. And we use this a lot as a tool to help us see very distant galaxies that we otherwise wouldn't be able to see, they're just too faint and too distant. But if they happen to be behind a cluster of galaxies in the foreground, that's creating this kind of magnification lens, then we can see these very distant galaxies. We're already doing this with Hubble a lot. We're seeing these lens distant galaxies. What's different this time is that the team, again, trying to study these very distant galaxies, by looking at regions where they might be magnified, found one galaxy that was so perfectly aligned along our line of sight with this gravitational lens, this foreground cluster of galaxies, that they could pick out one individual star in that distant galaxy. Now, most of the time, when we see distant galaxies, we see them as smudges, the starlight from the billions of stars within them, is all kind of blended together. But in this case, because the alignment with that magnification lens was so perfect, the background galaxy was not only magnified, and kind of stretched out into this funny looking arc shape, but it was stretched out in such a way that they could see an individual star. And this is quite profound. It's the first time we've ever seen an individual star this far away.
Levulis: So I'm sure you've heard this, it's not just the stars aligning, it's the galaxies aligning in a sense.
Wiseman: Exactly right. That's exactly right.
Levulis: And then so there's the thought that this discovery could shed some light, again pun intended there, on the results of the Big Bang. Is that right?
Wiseman: Well, what's great about this, like all astronomy, we're looking back in time, everything we see in space, we're seeing as it was when the light began its trek to us. And so for nearby stars, you know, this could be maybe hundreds or even a few thousand light years away. When you look up in the night sky these stars are in our own Milky Way galaxy. But this star Earendel we're seeing from a very distant galaxy. Its light began its trek to us almost 13 billion years ago. So we're seeing it as it was in its galaxy, very close to the beginning of the universe. And by studying this very distant galaxy and this very distant star within it, we can learn something about what the universe was like not too long after the universe began. The epoch when the first atoms and molecules were forming, the epoch when the first generations of stars were forming out of this, this very primitive gas. And we're studying what those first stars might have been like, we know the star is not like our Sun, it's much more massive, at least 50 times more massive than our Sun, a lot brighter, it's probably at least a thousand times brighter than our Sun. And we know it must have been rather primitive in its composition, because it was made out of the material available to it in the early universe, which was mostly just hydrogen, and a little helium and not too much else. And we know that these early stars as they shine, they actually are fusing elements in their core, and that creates heavier elements. Those elements are then dispersed when the star finishes its star life into the interstellar gas and then are caught up in subsequent generations of stars. So we know that our Sun is not a first generation star, it's drawing upon material that was actually created in fusion processes made in earlier generations of stars like Earendel, like this star. So by studying these very early galaxies and very early stars, we can see what the universe was like in the early ages, and how the actions going on there created material that we need for stars like our Sun and solar system in our epoch.
Levulis: And finally, what does this discovery mean for the future work of Hubble, which has spent more than three decades in orbit, considering that NASA launched the James Webb, which is considered the most powerful telescope in space just late last year?
Wiseman: Yeah, we're very excited about the Webb Space Telescope. It was launched last year, in December, and it has now gone to where it's going to be doing its observations, which is over a million miles away from the Earth. The Hubble Telescope is continuing to operate, it's in orbit around the Earth to get it above the Earth's atmosphere. And these two observatories are going to be really powerful and complement with each other because the Webb Telescope sees infrared light. It’s designed to be very sensitive to infrared emission that we would see from very distant galaxies, as well as from star-forming regions in our own nearby galaxy. But the Hubble Telescope will complement this because Hubble can see visible light and ultraviolet light that the Webb Telescope cannot see. And you need all these different kinds of wavelengths of light, in order to fully understand whatever we're studying in the universe, whether it's galaxies, or stars, or even our own solar system. So we have a lot of science lined up for the coming years for the Webb Telescope and also for the Hubble Telescope. And this science will be very complementary. It's going to be a powerful season of astronomy throughout this decade to have both of these observatories working together.
