Scientists have discovered six galaxies in the early universe that are so unfathomably massive that they challenge our basic understanding of the cosmos, reports Vice.

The primordial galaxies existed only 500-700 million years after the Big Bang, their mass was 100 billion times that of the Sun, making them almost as heavy as the modern Milky Way.

It is not clear how these galaxies were able to turn into such giant “behemoths” in such a short period of time. This suggests that our basic concept for understanding the universe, known as the ΛCDM model, may be “incomplete,” says research, published on Wednesday in the Nature journal.

Ivo Labbé, an astronomer at Swinburne University of Technology in Australia who led the new research, said the discovery of the galaxies was a huge surprise for his team.

“I think I spat out my coffee,” Labbé said. “Most of my colleagues were online all across the globe, glued to the screen, poring over the first images. I think I may have heard a jaw drop here and there. These objects are really extraordinary. One seems to have formed 100 billion solar masses in stars, similar to our present-day Milky Way, in only 5 percent of the time. This was most certainly not expected. We had expected to find 0. In addition, the shapes of these galaxies are really weird. Even though one has the same amount of mass as the Milky Way, it is 30 times smaller. Imagine the Milky Way as an average 160 pound 5’9″ adult: these galaxies are 1-year olds, that weigh just as much and stand just under 3″ inches tall. It’s truly bizarre.”

Labbé and his colleagues discovered the galaxies in observations captured by the James Webb Space Telescope (JWST), the most powerful observatory ever launched into space, which is a collaboration between NASA, the European Space Agency, and the Canadian Space Agency.

The Webb Telescope, which is the successor to the Hubble Space Telescope, has revolutionized our view of the universe since it began operating last year, discovering the oldest galaxies ever seen by humans and making other stunning observations. Now, a new, state-of-the-art observatory has made another cosmic discovery, seeing these six obscure galaxies that existed more than 13 billion years ago.

“Many of us knew that the Hubble Space Telescope was not providing us with the whole story,” Labbé explained. “It can’t. Ultraviolet and visible light from the first stars and galaxies that formed after the Big Bang is stretched out by the expansion of the universe as it travels towards us, so by the time the light reaches us we see it as infrared light. That’s why JWST was built. To see where Hubble was blind.”

Even before Webb opened his eyes to the universe, scientists were trying to explain the presence of massive galaxies that existed about a billion years after the Big Bang. Now, Labbé and his colleagues have deepened the mystery by identifying massive galaxies at even higher “redshifts,” a measurement that estimates distances using the expansion of light into longer, redder wavelengths as it travels across huge distances.

The team spotted the galaxies as part of Webb’s Cosmic Evolution in the Early Stages (CEERS) program, which observed a patch of sky near the Big Dipper. While it’s possible that future observations will show that the galaxies aren’t that massive or that far away, the new study is another hint that the ΛCDM model is missing something important about the formation of these early giants.

“ΛCDM ‘Big Bang’ cosmology is a really well tested theory,” Labbé said. “It makes detailed predictions about how much gas is available to form stars in the universe and when. To form the number of stars in these galaxies you need almost all available gas and convert it into stars at near 100 percent efficiency.”

“Cosmological theory is not going to cave any time soon,” he noted. “Extraordinary claims require extraordinary evidence. There are many steps to go to put these results on more solid footing. Alternative explanations might be that for some of the galaxies the light is not coming from billions of stars, but from gas falling into a supermassive black hole (a “quasar”). That’s exciting too, because the origin of supermassive black holes inside galaxies is yet another unsolved mystery. We’ll find out next year.”

Regardless of how they formed, it’s exciting to imagine what worlds might exist inside these compact massive galaxies at the edge of visible space and time — though Labbé warns that they would be extremely inhospitable to life as we know it.

“Aside from the fact that we probably don’t really know what shapes and forms life can take and survive, if we were inside of one of these galaxies we would be doomed,” he explained. “These galaxies are 30 times smaller, so at least 1000x more dense than our Milky Way. That means that nearby supernovas would have probably cooked off the atmosphere and fried us with radiation. There would be planets, and stars that live long enough to host them. But the environment would be downright hostile to life.”

In other words, these ancient galaxies are total death traps, although their mysterious origins may help scientists understand the evolution of modern galaxies, including the Milky Way, which is the only place where life is known to exist.

To do this, researchers will have to use spectroscopy to confirm that these galaxies are really as far away as they appear, and to assess whether their light is produced by stars or by something more exotic.

“Personally, I’m really excited about the potential of baby quasars in the galaxies,” Labbé concluded. “This is completely new and impossible to do before JWST. There are so many more discoveries to make. We have barely started!”