Sciency Words: Centaur (An A to Z Challenge Post)

April 4, 2017

Today’s post is a special A to Z Challenge edition of Sciency Words, an ongoing series here on Planet Pailly where we take a look at some interesting science or science related term so we can all expand our scientific vocabularies together. In today’s post, C is for:


As I mentioned in my first Sciency Words: A to Z Challenge post, some scientific terms are kind of dumb. This isn’t one of them. I actually think this one’s pretty clever. There’s a class of large objects in the Solar System that astronomers have decided to call centaurs.

Eh… no. These objects have nothing to do with horses, but they are sort of half one thing and half another! When they were first discovered, astronomers were confused because centaurs appeared to have the characteristics of both asteroids and comets.

I first learned about centaurs in this article from Discovery News. It’s now believed that centaurs originally came from the Kuiper belt—a sort of second asteroid belt that lies beyond the orbit of Neptune. Basically, they came from Pluto’s neighborhood.

Due to gravitational interactions with the gas giants, these objects were pulled inward. The now have highly unstable orbits crossing between the orbits of Neptune and Jupiter. Eventually, further gravitational interactions may hurl a centaur into the inner Solar System, putting it within melting distance of the Sun and transforming it into a full-fledged comet.

Originally, the International Astronomy Union wanted to name all the centaurs after actual centaurs from Greek mythology. But they quickly ran out of names. Now the official naming theme includes all mythical hybrids and/or shape-shifters. Examples include Typhon (half man, half dragon), Ceto (half woman, half sea monster) and Narcissus (a man who transformed into a flower).

Next time on Sciency Words: A to Z Challenge, we’ll find out why dimetrodon is not a dinosaur.

Sciency Words: The Tunguska Event

May 6, 2016

Sciency Words PHYS copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us all expand our scientific vocabularies together. Today’s term is:


June 30, 1908, was a bad day to be a tree. At least, it was a bad day for a heck of a lot of trees in the middle of nowhere, Russia.

My03 Tunguska Event

Something—there’s debate over what exactly is was—fell from space that day. It didn’t make it to the ground. Instead, it exploded midair above the Tunguska River.

According to human eyewitnesses, who were many miles away, the sky appeared to be split in two by fire. They heard a series of loud booms. The ground shook, and there was a sudden and intensely hot burst of wind so strong it apparently knocked people off their feet.

According to tree eyewitnesses… actually, we can’t ask the trees what they saw. They died. About 2,000 square kilometers (almost 800 square miles) of forest were scorched and flattened.

Scientific debate continues over what caused the Tunguska Event. It could have been an asteroid; however, asteroid debris can usually be identified by the presence of certain rare metals, such as iridium and osmium. These metals have not been found in the Tunguska region, at least not in quantities that would be atypical for Earth.

Another possibility (which makes the most sense to me) is that is was a comet. Comets are composed of lighter, more volatile chemicals like water. So when the Tunguska comet exploded, it would have been completely vaporized, leaving no debris.

The absurdly huge asteroid that killed the dinosaurs gets a lot of attention in popular culture, but asteroids (and comets) don’t have to be mass-extinction-sized to cause considerable damage. If the Tunguska Event had been the New York Event, there would be no more New York. And if something that big fell over the ocean, the resulting tsunamis could obliterate hundreds of miles of nearby coastlines.

Much like the Carrington Event of 1859, the Tunguska Event serves as a warning. Space is dangerous. Space is deadly. Earth can’t protect us from everything.