Hovering on our cosmic doorstep is a weird little galaxy — something that looks way too young to live in our neighborhood. Just 39 million light-years away, dwarf galaxy DDO 68 appears primordial in composition and shape.
But is it?
The gossamer mass of stars and gas hasn’t yet coalesced into an identifiable structure, such as a spiral or an ellipse. And its elemental composition is simple, resembling that of the much younger universe. (As an aside, I would strongly recommend visiting the full-size Hubble Space Telescope image and swimming through that amazing sea of stars and background galaxies.)
Normally, such newborn galaxies aren’t found within a billion light-years from home. It takes a long time for light from primordial objects to travel across the universe and get to Earth; so, finding these small, faint time capsules is generally done by looking very, very far away. In other words, astronomers essentially peer back in time to when the universe was much younger. Through the lenses of our biggest eyes in the sky, we see these objects as they were billions of years ago (if all goes according to plan, the James Webb Space Telescope will soon be able to peer even farther back in time and detect even fainter, younger objects).
When we look closer to home, we tend to find galaxies that are older, larger, and more evolved. As these agglomerations of stars matured over the eons, they morphed from younger, simpler versions of themselves into the spectacularly complex structures we see today. They have distinct shapes, are populated by stars that are a mix of old and young, big and small, and have elemental compositions that are more complex.
That’s why finding this little guy was a surprise: It looks way too young for where it lives, kind of like a toddler moving in to a university dormitory and showing up for freshman chemistry lab.
But is DDO 68 as young as it looks? Astronomers aren’t sure. There are some enigmas swirling around in that hazy mass, including hints that some of those sparkling stars might be older than they’re letting on. Scientists are working on solving the mysteries that live in this strange little galaxy, and are attempting to determine its true age.
So is it a precocious youngster or a has-been masquerading as an ingenue?
Only time will tell.