Look deeply into these galaxies. They look like blood rushing to the top of a fleshless face. The long, eerie “gaze” of their burning eye-like cores shines into the cosmic darkness.
Fortunately, appearances can be deceiving.
Until now, these galaxies have only been grazing on each other, with the smaller spiral on the left, cataloged as IC 2163, very slowly “creeping” behind NGC 2207, the spiral galaxy on the right, millions of years ago.
The pair’s moody colors are a combination of mid-infrared light from NASA ‘s James Webb Space Telescope and visible and ultraviolet light from NASA’s Hubble Space Telescope.
Look for potential evidence of their “light scraping” in shock fronts where material from the galaxies may have collided with each other. These lines, shown in brighter red, including the “eyelids,” can give rise to the bulging, vein-like arms of galaxies.
The first passage of the galaxies could also have distorted their delicately curved arms, pulling out tidal extensions in several places. An example of such activity can be seen in the scattered tiny spiral arms between the core of IC 2163 and its leftmost arm. More tendrils appear to be hanging between the galaxy nuclei. Another extension “drifts” from the top of the larger galaxy, forming a thin, translucent sleeve that almost runs off the screen.
Both galaxies have high rates of star formation, like countless individual hearts beating throughout their sleeves. Each year, the galaxies produce the equivalent of two dozen new stars the size of the Sun. Our Milky Way galaxy only produces the equivalent of two to three new Sun-like stars per year. In recent decades, there have been seven known supernovae in both galaxies, a very high number compared to the average of one every 50 years in the Milky Way. Each supernova may have cleared space in its embrace, rearranging gas and dust that subsequently cooled and allowed many new stars to form.
To identify the “sequence of events” of star formation, look for the bright blue areas captured by Hubble in ultraviolet light, as well as the pink and white areas detailed primarily by Webb in the mid-infrared. Larger star clusters are known as supernovae. Look for examples of these clusters in the upper spiral arm that wraps around a larger galaxy and points to the left. Other bright areas in galaxies are mini-flashes of stars – places where many stars form in rapid succession. In addition, the upper and lower “eyelids” of IC 2163, the smaller galaxy on the left, are filled with new stars and burning brightly.
What happens to these spirals? Over the course of many millions of years, galaxies can repeatedly fly past each other. It is quite possible that their cores and arms will merge, leaving behind completely altered arms and an even brighter, cyclopean-like “eye” in the core. The star formation process will also slow down when the gas and dust reserves are exhausted and the scene calms down.