It is marvelous indeed to watch on television the rings of Saturn close; and to speculate on what we may yet find at galaxy’s edge. But in the process, we have lost the human element; not to mention the high hope of those quaint days when flight would create ”one world.” Instead of one world, we have ”star wars,” and a future in which dumb dented human toys will drift mindlessly about the cosmos long after our small planet’s dead. -Gore Vidal
Someone woke up on the wrong side of the bed when they wrote that, didn’t you, Mr. Vidal? Because the marvelous is right in front of us. Yesterday’s Astronomy Picture of the Day was this shot, from 2005, of Saturn.
Looking at one picture like this, what strikes me is just how much we can learn about our giant, ringed neighbor just by looking at this shot. (Click here for the full-size image.) First off, the rings of Saturn are seen edge-on, and you can learn — almost immediately — that they are incredibly thin. Saturn’s rings, as you’re probably familiar with them, are huge and expansive, stretching out to be well over 200,000 km in diameter!
But let’s take that section of the top image where the rings lie in a plane. Do you notice that there are a couple of Saturn’s moons in there that seem to be far thicker than the ring plane?
It turns out that Saturn’s rings, hundreds of thousands of kilometers wide, are estimated to be only 10 meters thick, or about the height of a pretty standard tree. To put that in perspective, if you scaled Saturn’s Rings down so that they were the size of Texas (still huge), they would be 6 cm (2.3 inches) thick, or thinner than your forearm.
But you can learn even more about Saturn from this one image. Do you notice that there are stripes running horizontally across Saturn? Like all of the gas giants (and to a lesser extent, Earth), the atmosphere is broken up into bands that move at different relative speeds. (Voyager’s famous time-lapse video of Jupiter is shown below to illustrate this.)
Oh no, my friends. Those are not the bands of Saturn’s atmosphere. Take a look at the part of Saturn that’s illuminated: can you figure out where the Sun is? Can you tell it comes from below and to the right of Saturn in this image?
Those dark bands around the North Pole of Saturn are shadows of its rings! You can see an amazing amount of detail in these shadows, including some very thin, diffuse outer rings that leave wispy shadows on the planet’s surface.
So what do you do if you want to see a little more detail? All you have to do is let Cassini — the spacecraft that took this picture — travel around a little farther until you get a different angle. What can it show you then?
(And, of course, click for full-size.) Isn’t that amazing? If all you had of Saturn was the one picture at the top, you would still be able to learn an amazing amount about this ringed wonder. So don’t tell me we’ve lost the human element; we’re more a part of the Solar System than ever before. Just remember to look up, and wonder, and think.