Webb spots galactic smoke signals from across the universe
The James Webb Space Telescope has spotted complex organic molecules, which usually form in smoke and smog, in the very distant universe. With help from a galactic gravitational anomaly, the telescope could see the molecules from more than 12 billion light-years away.
The molecules in question are known as polycyclic aromatic hydrocarbons (PAHs), and here on Earth, they’re usually present in smoke and smog from burning wood, coal, oil, gas and other materials. They’ve been detected throughout the universe, and were often thought of as the smoke to the fire of star formation. But the new Webb observations suggest that might not be the case.
“These big molecules are actually pretty common in space,” said Justin Spilker, lead author of the study. “Astronomers used to think they were a good sign that new stars were forming. Anywhere you saw these molecules, baby stars were also right there blazing away. Thanks to the high-definition images from Webb, we found a lot of regions with smoke but no star formation, and others with new stars forming but no smoke.”
The telescope spotted PAHs much farther back in space and time than ever before – in a galaxy located more than 12 billion light-years away. That means we’re seeing it as it existed just 1.5 billion years after the Big Bang, marking the first time these molecules have been detected in the early universe.
The galaxy itself was first discovered in 2013, but it took the extraordinary eyesight of the James Webb Space Telescope before the molecules could be picked up. Even then, it needed a boost from a cosmic magnifying glass.
Massive objects like galaxies can distort the very fabric of spacetime, which in turn can bend the path of passing light. This can magnify a distant object that would be otherwise invisible to us and make it detectable, through a phenomenon called gravitational lensing.
In this case, the target galaxy was magnified by the gravity of another galaxy much closer to us, which just so happens to be perfectly aligned from our perspective. This creates an effect known as an Einstein ring, where the background galaxy is stretched into a ring shape surrounding the foreground galaxy. In doing so, the telescope could pick up the “smoke signals” from farther away than ever before.
This may be the first such detection, but the researchers say it likely won’t be the last. Future observations could help astronomers unravel the connection between these molecules and star formation.
“These are early days for the Webb Telescope, so astronomers are excited to see all the new things it can do for us,” said Spilker. “Maybe we’ll even be able to find galaxies that are so young that complex molecules like these haven’t had time to form in the vacuum of space yet, so galaxies are all fire and no smoke. The only way to know for sure is to look at more galaxies, hopefully even further away than this one.”
The research was published in the journal Nature.
Source: Texas A&M