One of the most amazing discoveries by James Webb Space Telescope (JWST) could soon get its answer. Astronomers studying data from recently launched mission of Webb said the new line of evidence is giving the insightful clues about the mysterious “Little Red Dots” that have been puzzling the scientists ever since Webb started the exploration of the far universe.
Amazingly small yet very bright red objects are what astronomers called Little Red Dots. They were found soon after the Webb started making extraordinary images of the early cosmos like never before. Little Red Dots were quite different from anything known until now. They were surprisingly numerous, amazingly tiny and far brighter than astronomers expected in the earliest times of the universe.
Actually, their sudden arrival was a big surprise and it turned upside down the existing ideas for the formation of galaxies and supermassive black holes after the Big Bang. Initially, scientists had a hard time figuring out what these bright red objects were. For example, whether they were very small and compact galaxies full of stars, rapidly growing black holes or something else they did not know. Though, their unexpected brightness and distinct red color made them the talking point of modern astronomy.
Because of new data from JWST, the researchers understand the genuine nature of these little red objects. Even very small galaxies had to be packed with stars and some of these objects might have growing black holes. Yet, it was the spectroscopic analysis with the help of JWST that showed many of such red dots have signatures of supermassive black holes actively growing inside.
Supermassive black holes are some of the most extreme objects in the universe. Most galaxies, including our own Milky Way, have their centers occupied by black holes that are millions or even billions of times more massive than the Sun. When gas moves towards these black holes and is compressed very tightly, it is heated to very high temperatures and produces huge amounts of energy that can be even greater than the luminosity of the entire galaxies.
The current interpretations of the given evidence show that this same mechanism may be used to explain the extreme brightness of the Little Red Dots even though they are relatively small. Astronomers are realizing that these are not normal galaxies with millions of stars, but rather galaxies that have their central black holes at work rapidly devouring the material during the early stages of the universe.
The reason why these black holes are red is now also almost clear. Cosmic dust clouds that are thick and surround these growing black holes are believed by scientists to be responsible for absorbing the light of short wavelengths and letting the longer red wavelengths go through. Besides that, the light is also stretched to the red end of the spectrum due to the expansion of the universe. This combination creates the characteristic look that is seen by the James Webb Space Telescope.
This finding is very significant in understanding the early universe. One of the biggest mysteries in astronomy is how supermassive black holes were able to grow so huge in such a very short time periods after the Big Bang. The current models predicted that these gigantic black holes would have needed a lot more time to grow to the sizes that are being seen by JWST.
If it turns out that the Little Red Dots are exactly the rapidly growing black holes at the time of the infant universe, they could be the evidence that these supermassive black holes grew up much faster than what the scientists had thought. That means, the astronomers would have to rethink their current view of how galaxies and black holes evolved in the first billion years of cosmic history.