When you imagine a haunted house, there are a few things that come to mind. A rundown mansion, clusters of blood-thirsty bats, a soundtrack of howling wolves, and of course, a full moon that offers the only light in sight. However, space has a lot more to offer to the most frightful night of the year than just the full moon (after all, there won’t be a full moon on Halloween until 2039). So to celebrate Halloween 2021, here is our list of the top 5 spookiest sights in space!
Asteroid 2015 TB145
To start off our list, we visit a celestial body that lies pretty close to home. Asteroid 2015 TB145 was discovered in early October of 2015 and was calculated to fly by Earth on Halloween of the same year. Fittingly, as Earth-based telescopes began to observe the body, it turned out that the 650-meter wide asteroid took on the shape of a skull when seen from certain angles. 2015 TB145 flew past Earth at a distance of about 486,000 kilometers, the first time such a bright object had done so since 2004. It later returned for another flyby in November of 2018 and will do so again in 2082, although that one will not come as close as its Halloween flyby in 2015.
The Face on Mars
In 1976, the Viking 1 spacecraft returned an image that has come to define Mars for a generation of alien fanatics. Just a month after it entered Martian orbit, the spacecraft snapped a photo of the Cydonia region on Mars, and strangely enough, scientists were greeted with what appeared to be a two-mile wide face on the Martian surface staring back at them. Although there is a simple scientific explanation for the feature (if you haven’t guessed, it’s all about light and shadows), it caused quite a stir within the general public. Since then, the “Face on Mars” has become an icon of Martian exploration, and it has been featured in many books, television shows and movies. In 2001, NASA’s Mars Reconnaissance Orbiter took another photo at a much higher resolution, which revealed the “face” to be an isolated hill known as a mesa. Now the only question that remains is whose face is this?
Witch’s Head Nebula
Our next stop on this journey takes us about 900 light-years away to the constellation Orion, where we can find Rigel, a blue supergiant star. Rigel is actually part of a quadruple star system where it shines with the power of about 40 000 Suns, making it one of the brightest stars in the sky. The light from Rigel is so intense that it can light up surrounding regions of gas and dust, creating objects that are known as reflection nebulae. One of these reflection nebulae is IC 2118, which has come to be known as the Witch’s Head Nebula and for good reason. With just a little bit of imagination, it’s pretty easy to make out the eyes, nose, and chin of a cosmic witch. Even at a distance of 200 light-years from Rigel, the star gives the nebula a slight blue glow which can be seen from Earth. This particular nebula is thought to be either a normal gas cloud or the remains of an ancient star that exploded as a supernova long ago. Scientists have even detected signs that new stars are actively forming inside of the Witch’s Head Nebula, so it might not be long before this head gains some luminous eyes. You could even make an argument that this witch is magical; after all, it does have an uncanny ability to transfix mortal humans.
Ghost Nebula
It turns out that the Witch’s Head Nebula doesn’t have a monopoly on spooky-themed nebulae. Slightly closer to Earth in the constellation Cassiopeia lies IC 63, another eerie reflection nebula. Since it is only about 3 light-years from the star Gamma Cassiopeiae, the nebula has a unique double colour scheme: blue from the dust reflecting the light of the nearby blue giant star, and red from the ionization of hydrogen gas by the ultraviolet light from the star. Along with this strange colouration, the nebula also takes on the shape of a cosmic ghost floating through the night sky! Spooky, right?
Franken Nebula
We’ve seen witches and ghosts, now all that’s left is a nebula that is straight out of the pages of Mary Shelley’s Frankenstein! NGC 2467, which is also known as the Franken Nebula or the Skull and Crossbones Nebula, lies about 4000 light-years away from Earth. It is thought to be just a few million years old, but that hasn’t stopped it from taking on the strenuous task of producing new stars. You could even think of it as an enormous stellar nursery. Who knew Frankenstein would be fond of children?
Sources & Further Reading
Space.com's Halloween list
National Geographic's Halloween list
Cover image credit: T.A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOIRLab/NSF/AURA