What do a penguin, an egg and a distant galaxy have in common? Why, an image snapped by NASA’s Spitzer and Hubble space telescopes, of course.
Many of us have experienced the phenomenon of pareidolia whereby, through pure chance, a seemingly normal object appears to resemble someone or something, such as the famous ‘Batman iceberg’.
In fact, in astronomy, it has persisted for centuries, with many of the famous constellations named after objects common to the people gazing at them.
However, in the 21st century, that leads us to the situation where our most powerful space telescopes, looking 23m light years into space, can see two galaxies and think they look like a penguin guarding its egg.
At this distance, these two galaxies are roughly 10 times farther away than our nearest major galactic neighbour, the Andromeda galaxy.
The interacting galaxies are collectively known as Arp 142. The image was created by combined data from NASA’s Spitzer and Hubble space telescopes, showing these dramatic galaxies in light that spans the visible and infrared parts of the spectrum.
The starkly contrasting galaxies are so different because their mutual gravitational attraction slowly drags them closer together.
Will eventually merge
According to NASA, the ‘penguin’ galaxy – officially called NGC 2336 – was likely once a pretty standard galaxy with smoothly symmetrical, spiral arms emitting from a flat disc.
Over time, it has become rich with newly formed hot stars, seen in visible light from Hubble as bluish filaments, resulting in the twisted and distorted appearance as it responds to the gravitational tugs of its neighbour.
Spitzer was able to show the strands of gas mixed with dust – giving the red colour – detected at longer wavelengths of infrared light.
Meanwhile, the ‘egg’ galaxy – NGC 2937 – is an almost featureless galaxy, but its greenish glow tells us of its history as a source of much older stars.
The absence of glowing red dust features informs us that it has long since lost its reservoir of gas and dust from which new stars can form.
While this galaxy is certainly reacting to the presence of its neighbour, its smooth distribution of stars obscures any obvious distortions of its shape.
Eventually, it is expected that the two galaxies will merge to form a single object – including their populations of stars, gas and dust – similar to what happened aeons ago with our Milky Way galaxy.