Why do people see so many animal shapes in space? Seven of the twelve constellations that define the zodiac are animals. Multiple ancient cultures saw the stars in and around the Big Dipper as a bear--even though squint as I may, the best I can do is find one large spoon and some scattered points of light. And it is not just the skygazers of long ago who had animals on the brain. Astronomers today are still very much of the same mindset. A Seagull Take this brand-new image of the Seagull Nebula from the European Southern Observatory’s 2.2 meter (87-inch) telescope at the La Silla Observatory in Chile. There’s a lot to admire about it scientifically. This is an active starforming region in the constellation Monoceros, near the bright star Sirius. It is one of the places where our galaxy is still living and breathing and churning out new stars. The dark areas are clouds of cool, dusty gas that is slowly gathering under the pull of gravity. In places where knots of gas have collapsed completely in on themselves, they grow so hot and dense that they begin to ignite thermonuclear reactions and shine: A star is born. The hottest, most energetic of these newborns flood the nebula with ultraviolet rays that cause ubiquitous hydrogen atoms to glow red. The process is all beautifully laid out here, in colors too subtle for the human eye to perceive direclty. But is there anything about the blobs and waves and ruby swatches that screams “seagull”?
Formally known as IC 2177, these wisps of gas and dust are the birthplace of new stars. Credit: ESO. A Manatee There’s more obvious justification for another stunning animal-themed cosmic image—the Manatee Nebula in the constellation Aquilla. This object actually does resemble its namesake, and it got its name from a real, known person: Heidi Winter, the executive assistant to the director of the National Radio Astronomy Observatory (NRAO), the organization which created the image. NRAO even helpfully distributed a similarly posed photo of a manatee to make the point, although it’s a bit of a cheat. The main image is a map of radio waves, which have no defined color, and the background shows infrared radiation, which likewise has no color. You could depict the manatee as pink and the background glow as yellow and it would be just as truthful.
A tortured bubble of gas is energized by an unseen object at the center, probably a black hole. This is a composite of radio (green) and infrared (red) images. (Credit: NRAO/AUI/NSF, K. Golap, M. Goss; NASA’s Wide Field Survey Explorer) In personality, this Manatee is more like a sea monster. What you are seeing here is a giant bubble of gas blown out from a supernova explosion about 20,000 years ago. The remains of the star collapsed into something tiny and dense, probably a black hole, which is chewing away at another surviving star nearby. As bits of star fall into the black hole, they emit powerful radiation and stir up jets of particles that illuminate and inflate the gas bubble. So this peaceful sea cow is actually the result of a dying, exploded cannibal star. Nessie The ultimate sea monster lends his (her?) name to a sprawling dark nebula described by a group led by Alyssa Goodman at the Harvard-Smithsonian Center for Astrophysics. She nicknamed this cloud “Nessie” because of its long sinuous shape—300 light years long but just 1 to 2 light years thick. It’s also off-the-charts large, containing as much mass as 100,000 suns. So far so good. Trying to see any animal form here requires a huge leap of imagination. Goodman also describes Nessie as one of the “bones” of our Milky Way galaxy, a description both more visual defensible and more astronomically meaningful. It seems to be a basic structural component of the galaxy, one of a large network of dark, straight filaments that run through and out of our galaxy’s spiral arms. Like the Seagull, the Nessie cloud will probably end up forming new stars…some of which will explode and give rise to new bubble clouds like the Manatee.
Within the dotted box is a long tendril of dust and gas that appears dark in this false-color infrared image. It may be a major structural element of our galaxy. (Credit: NASA/JPL/Spitzer Space Telescope) In space as on Earth, all the animals are part of one interrelated ecosystem. In that sense at least, the animal analogies work quite nicely indeed. But back to the original question: Why all the animals? My hunch is that it has something to do with the way that the human brain is hard-wired to recognize faces—the same phenomenon that causes natural rock formations, tree knots, and rumpled shirts in a darkened room also suggest people and animals at a quick glance. Got a different idea? Comment below. Meanwhile, just for fun, a look a few of my favorite classic animals in space, below.
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The Ant Nebula: Fiery lobes of glowing gas protrude from a dying, sun-like star. Our own sun will put on a similar display in about 7 billion years. (Credit: NASA, ESA and the Hubble Heritage Team STScI/AURA)
The Mice: These two colliding galaxies, 300 million light-years away in the constellation Coma Berenices, will eventually merge into a single giant collection of stars. (Credit: NASA/ESA/STScI)
The Eagle Nebula, one of the most famous pictures from the Hubble Space Telescope, is another star-forming region. It is also known as the “Pillars of Creation.” Not an animal, but evocative and very apt for the birthplace of new stars, planets, and possible places for life. (Credit: NASA/HST)