- Galaxies come in many different shapes and sizes. Our own Milky Way galaxy is a flattened disk.
- “UFO galaxies” are a type we only discovered recently. They are disk-shaped, bright red and really dusty.
- Astronomers found them using the Webb Space Telescope. They are only visible in infrared light, so remained undiscovered until Webb saw them.
Mysterious ‘UFO galaxies’
Scientists are investigating UFOs in deep space. But these aren’t the kind of unidentified flying objects you probably think of when you hear that term. Instead, these are galaxies that are big, red and really dusty. They’re only visible in infrared light, and NASA’s James Webb Space Telescope (JWST) was the first to find them. Scientists call them Ultra-red Flattened Objects (UFOs). On November 19, 2024, a team of researchers led by the University of Colorado Boulder (CU Boulder) said it’s starting to find answers about these enigmatic galaxies, such as their common shape.
They published their peer-reviewed findings in The Astrophysical Journal on October 3, 2024.
Invisible … until now
Justus Gibson in the Department of Astrophysical and Planetary Sciences at CU Boulder is the lead author of the study. He and his fellow researchers wanted to know more about these unusual galaxies. They seemed similar in size and shape to other galaxies like our own Milky Way. But why were they so red and dusty? Why hadn’t astronomers seen them before Webb? Gibson said:
JWST allows us to see this type of galaxy that we never would have been able to see before. It tells us that maybe we didn’t understand the universe as well as we thought.
Co-author Erica Nelson at CU Boulder added:
They’re so visually striking. They’re enormous red disks that pop up in these images, and they were totally unexpected. They make you say: ‘What? How?’
Galaxies that only Webb can see
The galaxies’ redness and the fact that telescopes like Hubble hadn’t seen them before have a common explanation. They give off very little visible light. Therefore, human eyes and Hubble can’t see them. But Webb is an infrared telescope. The galaxies do emit infrared radiation, so in Webb images, they appear bright red in color.
The galaxies are closer to us than some that Webb has previously found. Those galaxies are incredibly distant, both physically and in time, much closer to the Big Bang itself. Astronomers thought they had a good idea of what the closer galaxies to us were like, so the UFO galaxies were a surprise. Gibson said:
Prior to the launch of James Webb, we thought we would find really, really far away galaxies. But we thought that closer to us, we already had a pretty good understanding of all the types of galaxies there are.
Why are they so dusty?
The researchers still aren’t sure why these galaxies have so much dust in them. They contain about 50 times more dust than the Milky Way. As Nelson noted:
Why on Earth do these galaxies have so much more dust than all the other galaxies? Got me.
The research team also ran simulations to find out just what shapes the UFO galaxies are. As it turned out, they are likely disk-shaped, just like our own Milky Way. Nelson said:
You have these big bad disks – like our home, the Milky Way – flying around space, completely invisible to us.
Overall, galaxies come in many different shapes (and sizes), including disks, footballs and spheres.
Other red galaxies
Earlier this month, an international team of astronomers also reported on other red monster galaxies. These galaxies formed earlier, within the first billion years after the Big Bang, which occurred about 13.8 billion years ago. They were also red, dusty and almost as large as the Milky Way. Astronomers are trying to learn how they became so massive so soon after the Big Bang. Is there a connection to the other UFO galaxies?
Bottom line: Astronomers using NASA’s Webb space telescope have discovered “UFO galaxies.” They are disk-shaped, bright red and unusually dusty.
Via University of Colorado Boulder
Read more: UFOs – Ultra-red Flattened Objects – revealed by Webb
Read more: Red monsters were massive galaxies in the early universe