That headline is a little misleading. No galaxy walked into a bar. Instead, this is a story of two galaxies with bars and how scientists will have to rethink their ideas about galaxy formation.
It has nothing to do with that kind of bar. A barred spiral galaxy is a special kind of spiral galaxy with a “bar” at the centre. Think of it more like a candy bar shape. Astronomers estimate that about two-thirds of all spiral galaxies are barred. The Milky Way Galaxy, which is where we are, is a barred spiral galaxy.
For a long time, astronomers believed that it took several billion years for galaxies to become ordered enough to develop bars. But then came ceers-2112—a galaxy observed using the James Webb Space Telescope as it was billions of years ago. It was formed about a billion years after the Big Bang and it became a barred galaxy much earlier than our current understanding of science can explain.
#ICYMI: @ChandraXray and Webb recently teamed up to discover a record-breaking supermassive black hole. Webb’s infrared eye helped detect the black hole’s host galaxy, while Chandra’s X-ray detections helped confirm the existence of the black hole: https://t.co/xR39zKQwME pic.twitter.com/UBj5esA7nl
— NASA Webb Telescope (@NASAWebb) November 10, 2023
Galactic bars are believed to form in spiral galaxies where stars rotate in an ordered fashion, like the Milky Way. In such a galaxy, a bar can form almost spontaneously because of instabilities in the spiral structure or the effect of gravity from a nearby galaxy. But in the past, when the universe was very young, galaxies were quite unstable and chaotic. It was thought that bars could not form or last long in galaxies in the early universe. But ceers-2112 changes all that and the ramifications are massive.
First of all, this could mean that astronomers have to change theoretical models of galaxy formation and evolution to account for some galaxies becoming stable enough to host bars very early. Also, those models will need to adjust how much of the galaxies in the early universe were made of dark matter. You see, it is believed that dark matter is believed to affect the rate at which bars form. Further, there is a good chance that ceers-2112 is not the only galaxy in the early universe that was barred. So, its discovery might just open the floodgates.
Reading the word galaxy that many times is probably enough to put even the most hardcore stargazer to sleep so let’s turn our attention to smaller matters—the whimsically named Dinkinesh.
The asteroid Dinkinesh, named after the word for “marvellous” in Amharic, was selected as the first target for NASA’s Lucy mission to observe. Lucy is a mission launched in 2021 to observe the Jupiter Trojan asteroids, a group of asteroids going around the Sun in Jupiter’s path: One leading Jupiter and the other following.
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Before Lucy flew past Dinkinesh, it was believed that it was a single asteroid. Soon afterwards, teams at NASA discovered that it was actually two asteroids in a binary pair. This week, Dinkinesh gave another surprise—the smaller satellite in the binary pair turned out to be another pair itself. The smaller space rock turned out to be a “contact binary,” or two separate space rocks stuck together in contact.
If you put aside the small space rocks, scientists discovered something with more gravity. A lot more gravity. The oldest black hole ever discovered. The supermassive black hole they discovered was formed about 570 million years after the Big Bang, which happened about 14.8 billion years ago. To put that into context, our planet is about 4.5 billion years old.
Just like the barred galaxy that we spoke about earlier, the newly-discovered supermassive black hole is also important for scientific theory. It offers proof that the early universe is “seeded” with heavy black hole seeds. This confirms a whole new theory about how black holes can form.