Some galaxies are so positively massive that their gravity actually distorts the light from objects behind it, turning the entire galaxy into our very own intergalactic magnifying glass. And now, NASA’s Hubble Space Telescope just found the most distant one ever.
This “lensing galaxy” is so far away that we’re actually seeing it as it looked over 9.6 billion years ago. What’s more, light from the tiny spiral galaxy being magnified behind is coming to us from 10.7 billion years in the past — and a find like this is incredibly rare. According to lead researcher Kim-Vy Tran of Texas A&M University in College Station:
When you look more than 9 billion years ago in the early universe, you don’t expect to find this type of galaxy lensing at all. It’s very difficult to see an alignment between two galaxies in the early universe.
Imagine holding a magnifying glass close to you and then moving it much farther away. When you look through a magnifying glass held at arm’s length, the chances that you will see an enlarged object are high. But if you move the magnifying glass across the room, your chances of seeing the magnifying glass nearly perfectly aligned with another object beyond it diminishes.
Because we’ve stumbled upon this chance alignment, though, we’re able to use the lensing galaxies distorting effects to determine its total mass (including dark matter) by “gauging the intensity of its lensing effects on the background galaxy’s light.” So how much does a record-breaking lensing galaxy weigh? Over 180 billion times more than our sun.
The recently discovered galaxy is part of the IRC 0218 galaxy cluster, and it beats the previous lensing-galaxy distance by a mere 200 million years. And this galaxy — along with others like it — could offer some major insights into how galaxies of the early universe build them up into the “massive dark-matter-dominated galaxies” we see today (and much closer to home). [NASA via Washington Post]