There are a couple of reasons why I decided to make November space month, but the biggest one – which is also the topic of this article – is by far the most interesting and/or terrifying; take your pick. On October 31, a dead comet officially named “2015 TB145” passed by us and the moon at 487,446 kilometers. To lend some perspective to that, the moon is about 384,448 kilometers away from us, so it passed by about 102,998 kilometers away from the moon’s orbit. That’s pretty far if the furthest measurement you’re familiar with is your trip to and from school every day, but in space the distance is much smaller than it seems, especially when you take into account that 2015 TB145 is taller than the Empire State Building at 0.61 kilometers (or 2,000 feet) in diameter. Now don’t get too bent out of shape about the potential end of the world, we weren’t in any real danger from this comet. The fact of the matter is that 487,446km really is still quite a large distance and NASA has been tracking it since October 10th. Plus, we all made it through the night right? Even despite the giant screaming space skull hurtling toward us from the void beyond.
Oh did I not mention that part? 2015 TB145 has a nickname, and that name is “Spooky”, based on not only the timing of its arrival on Halloween night, but also on it’s appearance. If you like you can visit http://bit.ly/1RK2yva on your favorite internet viewing device (perhaps a new smartphone you recently learned about??) to see the tweet NASA put out with an image of Spooky and see for yourself. That’s right, it’s a skull. Could it be from an ancient alien civilization sending us a message? An intergalactic practical joke? Or is it perhaps just us humans seeing what we want to see? Probably the latter but hey, who says science can’t be entertaining? That being said, I would actually like to teach you guys something about all this so let’s take a look at some of the technical stuff behind this almost world-shattering event.
Ok so maybe world-shattering is a little extreme. Spooky is only 0.61 kilometers wide which is big, but not that big. For perspective, the estimated size of the asteroid that scientists claim put an end to the dinosaur era was 9.7 kilometers. There is also another key difference between that asteroid and 2015 TB145, and that is the type of giant space rock they are. Spooky is probably not actually an asteroid like NASA originally thought. As per the most recent records, it is believed to be a comet – or more precisely, a dead comet. The difference between a comet and an asteroid is composition. While asteroids are made entirely of rocky materials, comets also have dust and ice components, which are what give it a tail. This is because asteroids are formed much closer to the sun where ice cannot remain solid due to the heat. The distinction of a dead comet however, means that the comet has lost all of its ice and dust coating, leaving only a rocky core. Also it was Halloween, so having the word “dead” in the title just adds to the mood.
So there you have it, a little science with our tech, and a little spook with our space. Next time we’ll talk about the technology that gave us that beautiful image of Spooky, as well as many of the other views of the distant areas surrounding our planet: Giant Telescopes.