Asteroids are already creepy enough, with their distant connection to the one that vaporized the dinosaurs, but this one is even creepier because it actually looks like the Grim Reaper.
When seen in the right (or you could say wrong) light, asteroid 2015 TB145—called what else but the Halloween asteroid for making a ghostly appearance a little over 300,000 miles away from Earth on October 31 of 2015—comes eerily close to resembling a human skull. The skullsteroid is expected to haunt us around the same time next year after a three-year orbit around the sun.
Researcher Pablo Santos-Sanz of the Institute of Astrophysics of Andalusia (IAA-CSIC) and his colleagues have been observing the strange object to determine its characteristics besides the fact that it looks like a disembodied skull. After using optical telescopes from three observatories and obtaining mid-infrared observations from the Very Large Telescope’s VISIR instrument to just barely see it, they recently published their findings in the journal Astronomy & Astrophysics.
What makes the Halloween asteroid even scarier than its ghoulish visage is that it acts like a haunted house prop should. An albedo of 5 to 6% means it reflects no more than that much sunlight, which makes it hardly more reflective than your average lump of charcoal. Its low magnitude also shrouds it in mystery.
Absolute magnitude is how someone on Earth would see an asteroid if it were at exactly one Astronomical Unit (au) away from both the observer and the sun and at a zero phase angle, meaning it would align with the object shining light on it (the sun) and the object it would be reflecting light onto (Earth). Asteroids are notoriously difficult to put a size to, which is why their approximate diameters are a function of their magnitude and albedo.
Skullsteroid’s magnitude of 26.5 next to its low albedo means it’s basically a ghost when it comes to visibility, so much so that its absolute magnitude has yet to be determined. You need a superpowered telescope just to glimpse it in the darkness.
“In general, a high-quality physical and thermal characterization of a close-encounter object from two-week apparition data is not easily possible,” said Santos-Sanz and colleagues.
This cosmic memento mori has scientists dying to get more data on it when it whizzes past our planet next November, even though it will be even further away than last time at 105 times the distance of the moon. Even though there is optimism about what else can possibly be illuminated about this object that is dark in more than one sense of the word, especially if it really is the extinct comet it is believed to be (which just makes it even scarier), the 2015 encounter looks like the closest one we will have had for a while.
“The next slightly more exciting encounter will be around Halloween's day in the year 2088, when the object approaches Earth to a distance of about 20 lunar distances,” said researcher Thomas G. Müller of the Max Planck Institute in Germany.
Unfortunately, we might all be skeletons by then.