It’s the year 2000. We’re floating in space, and we come across the side view of a spectacular spiral galaxy. It’s called UGC 10043 and is located 150 million light-years away.
Spiral galaxies like this one are vast structures of stars, gas and dust, characterized by swirling arms that extend from their centers. From where we are, we observe a bluish light emanating from the arms of our spiral galaxy, telling us that new stars are being born and growing up. From this side-on view, we actually can’t see UGC 10043’s spiral arms, which are shrouded in a thick cloud of cosmic dust that covers much of the galaxy’s light anyway. Rather, the galaxy appears to us as a thin, striking line across the cosmos.
Though these thoughts sound like mostly a dream to us, for over 30 years in orbit, it has been the Hubble Space Telescope‘s reality. Hubble can see the cosmos with such impossible clarity from its vantage point above the Earth thanks to its advanced instruments and location beyond the distorting effects of the Earth’s atmosphere – and in the year 2000, it focused on UGC 10043. The telescope took a series of snapshots at different times during the year, each capturing its subject in different wavelengths of light. This means Hubble captured images of the galaxy across different parts of the electromagnetic spectrum — from visible light to ultraviolet and infrared — with each wavelength offering unique insights into the galaxy’s gas clouds, star formation, and more.
Fast forward to 2023, when Hubble actually revisited UGC 10043. It repeated the same image-collecting process, taking a new series of snapshots. And with that, astronomers were able to combine the new data with the snapshots from 2000 to create the detailed image of UGC 10043 we see today.
In other words, this image combines data that are 23 years apart.
In general, Hubble’s longevity lets us revisit cosmic objects and track their evolution over time in this way; such snapshots are valuable resources for astronomers to track changes and piece together galactic history. Looking closer at this galaxy, for instance, Hubble captured a glowing bulge at its heart — an egg-shaped structure that rises above and below the flat disk structure. (Bulges in spiral galaxies are populated by older, cooler, redder galaxies.)
Additionally, UGC 10043’s bulge seems to be unusually large — but, why? Well, this is possibly due to interactions with nearby dwarf galaxies, scientists say, which could explain the galaxy’s warped disk, bent at both ends. You can imagine it as a “gravitational tug-of-war:” the smaller galaxy’s gravitational pull can tug on the gas, stars, and dust in the larger galaxy’s disk, causing it to bend or distort.
It certainly can’t be missed that observing this magnificent galaxy from the comfort of our homes reminds us how complicated the universe truly is. Every cosmic object has an individual story to tell a story that continues to reveal new information, even after more than 150 million years have passed. It’s humbling to think that, through Hubble’s eyes, we’re able to witness a small chapter in that story.