- The James Webb Space Telescope has revealed new galaxy candidates that are perplexing scientists.
- These dense galaxies date back to a time when other parts of space were very primitive.
- If they’re really galaxies, they challenge everything we know about the young universe.
NASA’s James Webb Space Telescope (JWST) has already made a huge impact on scientific research about space, as well as the public imagination about far-out space objects. In a recent paper published in Nature, astronomers found and classified a group of galaxies that date back to 500–700 million years after the Big Bang, but retain an astonishing density that we identify more with the very beginning of the universe. They’re so strange that scientists aren’t even sure whether or not to call them galaxies at all.
When it comes to outer space, scientists know about one thimbleful against an infinite quantity. The general public knows and understands far less, although both bodies of knowledge are growing quickly all the time. Outer space and the deep sea are simply very, very difficult to study, and not through a lack of effort. When taking massive technological steps forward like JWST, we’re basically putting on a new pair of glasses with a much more powerful prescription.
All that is to say, it gets really weird out there, and we’re only beginning to know just how weird. Let’s unpack what’s going on with these galaxy candidates to better understand what’s really possible in the early universe.
How Did Scientists Find These Galaxy Candidates?
Researchers identified the galaxy candidates by studying the patterns and wavelengths of light they emit. For scientists with sophisticated instruments, this can be as mechanically simple as you or I identifying that the sky is blue and the grass is green. We just need a lot of computing and observation power in order to zoom in enough to measure the light from objects so far away.
✅ Know Your Terms: A galaxy is one of the building blocks of our universe. These “vast cosmic islands of stars, gas, dust, and dark matter” are held together by gravity, according to NASA’s HubbleSite. There are three main classes of galaxies: elliptical, spiral, and irregular. They vary in size from dwarf galaxies with just 100 million stars to monstrous galaxies with over 1 trillion stars.
Scientists narrow down their search parameters by starting with how an object would look today, billions of years after its light first emerged so many light years away. They can use bands of light—like ultraviolet and infrared—in addition to the visible spectrum, to gauge the ages of different portions of objects in space. In this case, scientists ruled out any candidate that appears in the visible spectrum, relying instead on a particular profile of other wavelengths of light.
Rethinking the Early Universe
From the detailed profile of the six galaxy candidates they discovered, the team of astronomers drew some interesting conclusions. If these candidates are indeed galaxies, they were somehow able to mature faster than anyone previously thought possible. Their date signature suggests they may have appeared about a billion years after the Big Bang, a time when scientists have typically believed the items in the universe were still a lot more primitive or primeval.
A billion-year difference sounds enormous to us, given the complexity of our universe as it is today, and our own extremely tiny timeframe of life within that estimated 13.8-billion-year history. Surely that’s enough time for some quite complex things to develop in the universe. But it turns out it’s really not—or at least, not in any working model of early galaxy physics and chemistry that scientists have believed up until now.
And that makes an intuitive kind of sense, too. Yes, all of animal and human life fits into less than 1 billion years, but single-celled organisms ruled Earth for an estimated several billion years before the evolution of plants and then animals. Turning from nothing into something requires extraordinary machinations and a long, long time. Heck, even the lightest elements didn’t really begin to emerge until hundreds of thousands of years after the Big Bang. A billion years passed before conditions were right for more protons to simply stick to nuclei.
Heavier elements didn’t even appear until the advent of hot stars an estimated billion years later. That means the very old galaxies—with the mass of the Milky Way, but at 3 percent of the volume—would need to be made of . . . something else? If you imagine trying to create an extremely dense galaxy out of something like helium, you can start to see why the news of these galaxy candidates is so extraordinary. The basic facts about them could clarify or even deny some of the working knowledge astronomers have used for decades.
The study’s lead author, astrophysicist Ivo Labbe of Swinburne University of Technology in Australia, put it this way to Reuters: “If the Milky Way were a regular-sized average adult, say about 5'9" and 160 pounds, these would be 1-year-old babies weighing about the same but standing just under 3 inches tall.” With a timeline so close to when massive elements even emerged in the first place, the galaxy candidates would almost need to have experienced a localized Big Bang of their own.
Galaxies, or Supermassive Black Holes?
If all of this is sounding a little hinky, keep in mind that scientists are using their observations to fit the best hypothesis for the data they have. If these are galaxies, it’s true that they’ll throw into question a number of other things we believe we know about the early universe; so far, the observed patterns and data indicate that they could be galaxies. But the paper calls for next steps, like spectroscopy of the data, in order to rule out other possible explanations. The researchers are circumspect, and their paper is simply about what they measured.
One alternative explanation is that the galaxy candidates could be some kind of supermassive black hole, another area of study that is growing constantly as we observe more of the universe. But if these profiles clearly matched our existing knowledge of supermassive black holes, that explanation would be at the forefront, not a runner-up to explain something no one has observed before. This isn’t a 97-percent match on a dating app; it’s more like two different 65-percent matches who both seem fun enough at a glance. We need more information.
That ambiguity and revelation are all in a day’s work for scientists who study the period of time after the Big Bang, thankfully, so these experts are ready to roll with whatever they find out. “The early universe is a freak show,” Labbe told Reuters.
Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about everything. Her favorite topics include nuclear energy, cosmology, math of everyday things, and the philosophy of it all.
