Every time we stop to look at the night sky, we are amazed by the vast blue sky filled with thousands of stars. If we try to analyze it better, we will certainly come away with more questions than answers. And this is not only for us but also for many scientists. The night sky has always been a canvas of mystery for astronomers… when they stop to analyze constellations and distant galaxies, they come close to discovering new stories and unraveling mysteries. Now, with more powerful telescopes (like the James Webb) and smarter software, we are close to announcing a historic discovery in the Milky Way.
A mission possible only for James Webb
This historic discovery in the Milky Way is in the COSMOS field. The COSMOS is a remote region of the sky that has no nearby stars or interfering gases. It is like a small slice of the universe. Really small, because it is only 0.54 square degrees, which is about three times the size of the full Moon seen from Earth. Now, why was this region chosen by scientists? Well, it seemed like a great place to investigate the cosmic past in depth.
However, to do this investigation, they couldn’t use just any telescope, so they chose the James Webb Space Telescope (JWST). This is because it has a great capacity to detect infrared light even when it is extremely faint. To give a little more context, unlike the visible light captured by instruments like Hubble, the light that reaches us from ancient galaxies has already been stretched by the expansion of the universe, which makes it infrared, which is why the technology used has to be different. However, even with JWST, it took 255 continuous hours of observation to complete a full scan of the region. At least now we can say it was worth it.
We have over 800,000 galaxies to analyze now
Why can we say it was worth it? Well, the result of this scan was the creation of the largest and most detailed map of the universe ever produced. It already has a name: COSMOS-Web. What this project revealed was more than 800 thousand galaxies outside the Milky Way recorded in a single dataset. Just to give you an idea of the magnitude, this discovery covers almost 98% of the history of the universe, going back 13.5 billion years. It’s basically as if we were looking at the universe when it was still young, just 300 million years old.
And if you think it was just the number of galaxies (like this one that NASA has already warned is a mysterious and enormous galaxy) that surprised everyone, you’re wrong; it was their density that also shocked people. There were 10 times more galaxies than expected in the first 500 million years after the Big Bang. According to Professor Casey:
“We’re also seeing supermassive black holes that aren’t even visible with Hubble. And they’re not just seeing more, they’re seeing different types of galaxies and black holes.”
The discovery that will democratize the Milky Way
In addition to this discovery being historic, one of its most important aspects is the openness and democratization of data. This is because COSMOS-Web was not closed to a small group of experts. The entire database was processed over two years and is now available to anyone.
This means that with these images being processed and organized into catalogs, even undergraduate students and independent researchers can explore the early universe. This will make it even easier to understand how our Universe works and even where it ends, as NASA has already begun to observe 600 million light-years away.
