It’s an Inbound Chunk of Ice and Dust

You may have heard there’s a comet coming. Its formal name is C/2012 S1, and its less formal name is Comet ISON. It was first discovered in 2012 by observers using an automated telescope that is part of the International Scientific Optical Network in Russia. Comet ISON is a sungrazer, which means that its orbit will take it very close to the Sun when it reaches perihelion on November 28th of this year. There’s some chance that the comet will break up if it gets too close to the Sun, but that remains to be seen.

Astronomers analyzing the orbit of Comet ISON say that it’s nearly parabolic, which suggests that the comet is on its first trip out from its origin in the Oort Cloud. That makes it particularly fascinating to study since the comet’s nucleus has not been modified by previous passages close to the Sun and thus, its icy materials will be “pristine” (meaning that they will be largely unchanged since they formed some 4.5 billion years ago).

Since Comet ISON is on its first trip around the Sun, we know little about the comet’s icy composition. It’s probably got a significant amount of water ice, mixed with methane or ammonia ices, and some amount of dust. It has already sprouted a tail, and it will likely brighten to at least be seen through binoculars or a small telescope. There’s some chance it could get bright enough to see with the naked eye before and after perihelion (its point of closest approach to the Sun in its orbit). There have been some claims that Comet ISON could look spectacular, but as of right now, it’s not clear if it will brighten enough to be as spectacular as Comet Hale-Bopp was in 1997.  We’ll know more as the comet gets closer to the Sun in the coming months, and I expect to see more images from Hubble, a number of groundbased observatories and possibly even from the Curiosity rover on Mars.

It looks like Comet ISON is doing what all comets do as these chunks of ice and dust follow along their orbits. They brighten up as they approach the Sun. The comet may sprout a plasma tail soon, which is also normal and nothing to get worked up about. I spent some of my time in graduate school studying comets and their plasma tails. They tell us a lot about what’s happening in the solar wind (we often called plasma tails “solar wind socks”), and this year it could be quite interesting to see how our solar max Sun cycle will treat the comet. Other people are more interested in the dust tail, and still others are hoping to learn more about its nucleus and its ices and dust as they sublimate and create the tails. In that respect, Comet ISON is a perfect target to study with instruments that can sense not just visible wavelengths of light, but also ultraviolet and infrared. Those will tell us about the ices in the comet as well as something about the dust component. And, in turn, that knowledge will give astronomers insight into conditions in the solar nebula as the Sun and planets were forming billions of years ago.

It’s Not a Mysterious Spacecraft or Rogue Planet…

Of course, there’s a HUGE whack job contingent out there making all kinds of claims about Comet ISON that are, to put it politely, not supportable by science facts and reality. This happens every time there’s a comet.  It occurred with Hale-Bopp, with Hyakutake, with Comet Halley. In the case of Hale-Bopp, people actually killed themselves due to the wild theories put forth by a cult that had some pretty wacky ideas about the comet.

I don’t know why making up unreal, unscientific stuff about comets is so attractive, but it’s something we all have to put up with from time to time. Mention a new comet and the whack jobs just coming streaming come out of the woodwork. I’m not a psychologist, but I’m guessing that maybe the people who come up with weird unscientific theories about comets are deprived of attention and this is their way of getting it.

Some of them think that Comet ISON is traveling with companions that scientists aren’t talking about. That’s because there ARE no companions to talk about. What these comet nutjobs think are mysterious space ships turn out to be hot pixels in the camera that was used to take the images. There have been many images of the comet taken already, and none of them show these mysterious companions. They show a comet, doing what comets have done since the solar system formed. Think about this: there are thousands of amateurs with good telescopes and cameras out there, taking pictures of the comet. NONE of them have seen anything like what the nutjobs are claiming.

Others claim that the comet is actually headed right at Earth and NASA is hiding that information from us. I find that one particularly amusing since anybody who ever studied a little physics or astronomy (and that includes a lot of high school and college students), can calculate an orbit from the data we already have about the comet and figure out that it will not hit Earth. It won’t even come close.

Yet another bunch is screeching around about how the comet will cause earthquakes. Yeah, okay, that one’s fairly easy to use as  “PROOF!! PROOF, I TELL YOU, THAT COMETS ARE OUT TO GET US!!! RUN AND HIDE (BUT GIVE US YOUR MONEY, FIRST)!!!!”  That’s because Earth has thousands of quakes each day and any ignorant lout can fake a connection between an earthquake and something else.

Truth is, earthquakes are not caused by little chunks of ice thousands of kilometers away.  I mean, think about it. The comet’s nucleus is quite small—possibly only a kilometer or so across. That’s WAY too small to have much of a gravitational pull on anything in its own vicinity, much less on Earth, which at this point is thousands and thousands of kilometers away from the comet.  You can actually do the math on this and figure it for yourself.

More to the point, the earthquakes Earth does have are due to its being a planet with plate tectonics and crustal motions that are caused by the normal stresses of BEING a rocky planet. There are many factors that go into making earthquakes, but a chunk of ice out in space isn’t one of them.

So, over the next few months, if you see fantastical claims about how the comet caused an earthquake, smile indulgently and don’t take it seriously. Fantastical claims require fantastical evidence, which the comet fanatics aren’t providing. You’re a smart, thinking person; don’t fall for wild claims by nutjobs. Be amused by these fanciful tales because that’s all they are. The real comet and the real universe are so much more fascinating than any conspiracy theory anybody ever dreamed up.

Across Space, Time, and History

I found an interesting press release in my mailbox this morning. It was from the International Dark-Sky Association, reporting that the Chaco Culture National Historical Park in New Mexico is the IDA’s newest Dark Sky Park.  If you’ve ever been to Chaco, you know how dark its skies are, so this is an extremely fitting designation for what is actually quite a wonderful (but rugged and demanding) place to visit.

We visited there in 2002 and spent time hiking to the major sites in the park. I had visited it once before, and it was Mark’s first visit. Some years earlier, he had done the soundtrack for a show about the Anasazi (music which comprises the Geodesium album Anasazi), and so for him it was a chance to reconnect with a place that he had described in music.

Throughout the visit I really did get a wonderful sense of the place’s history. For example, there is a pictograph that is about half a day’s hike from the center of the park that is thought to depict the supernova of 1054. There’s a hand pictured next to a star-like object and a crescent moon, almost as if the ancient stargazer who put it there was measuring the sky.

When you look at things like this, or such things as the depiction of a comet in the painting Adoration of the Magi by the Italian artist Giotto di Bondone, you are seeing the sky as those people did. In a sense, you’re entering their thoughts about the objects they saw. There are ancient observatories around the world, purpose-built by architects who saw the sky as someplace important enough to dedicate years of work and effort. From the Jantar Mantar in India to the Bighorn Medicine Wheel in Wyoming in the United States to other ancient and modern observatories scattered across the planet and through near-Earth space, these places allow us to see the sky in the way their builders intended.

In a very real sense, the sky is an amazing unifying principle that unites us all as we stargaze and explore the many celestial sights available to us “up there”.  Another unifying principle in astronomy lies in the names we give objects in the sky. For the brightest objects, at least, we use many names that come to us from antiquity, from a time when all astronomy was observational only, and it was naked-eye. So, for example, many constellation names come to us from the ancient Greeks and the legends they told of their gods and goddesses. Many star names are Arabic or Greek in origin, and they all have Latin names stemming back to ancient Rome when Latin was the language of civilization. So, for example, the brightest star in Canis Major is Sirius, which comes to us from the Greek. It’s also known as Alpha Canis Majoris. Betelgeuse, the bright star in the constellation Orion, is of Arabic derivation, from the phrase “Yad al-Jauza” which means “the hand of al Jawza”.  It’s also known as alpha Orionis.

Each name we use has a history, and it tells us something about the people who named it and the vision of the sky they had. Orion is seen as a figure of a hunter in many cultures, and so it was not a stretch to think of his brightest star as being part of his arm.  The Chinese had a very different view of this guy in the sky. They saw it as a lunar mansion.  Many cultures focused on the three belt stars in Orion, naming them after hunting animals or the hunting staff of a goddess, or the stick of a wise man or a judge. Each of these interpretation gives great insight into the minds and thinking of the people who used those terms.

Throughout history, through all the wars, the battles, the conquests, the occupations, the peaceful times, the expansions of humanity to new frontiers, modern times the stars have always been there.  They’re under threat from overuse of lights, which is something that IDA is working to fix (along with people around the world who recognize that dark skies are part of our heritage).  The starry skies are worth preserving and protecting. Stars and constellations have been a source of stability, something that all people could use, and share. And, when you visit places such as Chaco Culture National Historical Park, not only can you enjoy the beauty of the night sky, you can put yourself in the place of the people who lived there before, and shared the sky with you, through a link that exists only through time and the sky.