by This week’s Hubble Space Telescope image shows a small but intriguing galaxy called UGC 7983, which is thought to be similar to some of the earliest galaxies to exist in the universe. Located 30 million light-years away in the constellation Virgo, it looks like a nebulous fuzz and is small enough to be considered a dwarf galaxy. Its unusual shape also makes it a specific type called a dwarf irregular galaxy.
In addition to the galactic star in the show, the image frame is littered with galaxies of all kinds that are visible in the background, as well as many nearby stars that dot the image that are much closer than the background galaxies.
Astronomers are interested in studying dwarf galaxies like this one to learn about galaxy formation in the early universe. Researchers know that galaxies that formed when the universe was young, in the first few billion years after the Big Bang, were quite different from most galaxies we see today. And we know that dwarf irregular galaxies tend to have large amounts of dust and gas, making them hotbeds of star formation.
Dwarf galaxies were important during a period of the universe called the Epoch of Reionization, when the first stars began to spread the first light throughout the universe. That’s why the James Webb Space Telescope is studying dwarf galaxies like the nearby Small Magellanic Cloud to learn more about how the first stars and galaxies could have formed.
In addition to being important for learning about the early universe, this image also has another interesting feature. In the upper left you can see a beam of light created by a small asteroid passing by when the image was taken. If you look very closely, you can see that the streak is divided into four lines, which represent the four exposures that were combined to create the final image.
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