One of my favorite missions made the news this past week. The Voyager 2 spacecraft, which is on its way out of the solar system on a trajectory to deep space, is nearing the limits of the Sun’s influence on space. In August of this year it crossed the solar wind termination shock, a point in space where the solar wind smashes into the thin gas that exists between the stars. The solar wind basically blows a big bubble of gas (from the Sun) into surrounding space; the “edge” of that bubble is called the heliopause. Crossing the “membrane” of that bubble registers as a blip in the data the spacecraft sends back, alerting astronomers that a momentous event has occurred. Voyager passed this goalpost in space did so a bit earlier than astronomers expected, which implies that the heliopause is not as symmetrical as they thought. Because the solar wind varies a bit in its extent, Voyager may well bounce and out of the heliopause.
I first heard about the Voyager mission back in the late 70s, just after it was launched. It sent back some amazing images of Jupiter, and by the time Voyager 2 got to Saturn in 1981, I was working at a newspaper in Denver, Colorado. I asked the managing editor if I could go out to Jet Propulsion Labs in Pasadena, California for the Voyager 2 Encounter of Saturn, and before I knew it, I was on my way, duly accredited as a reporter.
It was an interesting experience, and only whetted my appetite for more planetary science. A few years later, I went back to school to study more astronomy and planetary science, and so I always look back on the Voyager 2 flyby of Saturn with fond memories. Sometime in the next few years, Voyager 2 will get completely free of the heliopause and truly be in deep space. I remember back in 1981 thinking about Voyager 2 and its future mission; here we are, three decades later, and it’s just NOW getting to the heliopause. This tells us in a very visceral way that space is big!
We are lucky to live in a time when images of the cosmos are pouring in from various telescopes (both on and OFF Earth) at a prodigious rate. Every day I can check upwards of a dozen or so websites where the “latest from space” shows up in full, glorious color; everything from pictures of Mars to images of the most distant galaxies in the cosmos.
The spectrum of Charon obtained by NIRI at Gemini North. It is centered at 2.2 microns for the sub-Pluto (top) and anti-Pluto (bottom) hemispheres of Charon. The solid line denotes the best fit for a model of a surface with ammonia hydrate and water ices. The dashed lines are data that indicate the position of the ammonia hydrate feature. The sub-Pluto and anti-Pluto ammonia hydrate minima are located at 2.2131 and 2.1995, respectively. (The error bars represent 1 sigma.). (Spectrum by Jason Cook.)
Sometimes data about distant objects isn’t even in picture form, but looks more like a graph. It’s still important information, but not quite so photogenic as a picture. And, like it or not, humans are still enticed more by a pretty picture than a graph, even if the graph is like the one below, telling us something really exciting about the discovery of geyser-like plumes on Charon, a companion world to distant Pluto. Since the general reader might not pick up on the “excitement” just by looking at a graph of data, it’s often up to science writers and scientists who bring the story alive.
A few weeks ago I was working on a press release for Gemini Observatory about Charon. We got the graph above from the scientist who had done the observations, which were made using a special infrared-sensitive imager/spectrograph and adaptive optics at the Gemini North telescope on Mauna Kea, Hawai’i. It’s an important piece of science, but we knew we needed a pretty picture to bring the story home to readers who don’t know a lot about spectroscopy or infrared imaging. So, I worked on a mockup of what I thought Charon would look like if it had geyser-type formations spewing water ice across the surface. Planetary scientists have a term for this kind of action: cryovolcanism.
An artist’s conception of Charon (with Pluto in the background) against the backdrop of the Milky Way. The plumes and brighter spots depicted at left on Charon are thought to be created as water (with some ammonia hydrate mixed in) “erupts” from deep beneath the surface. The material sprays out through cracks in the icy crust, immediately freezes and snows crystalline ice down onto the surface, creating a water-ammonia hydrate ice field. Such fields were detected and studied using the near-infrared imager on Gemini North. (This composite image includes Pluto and Charon models (enhanced), courtesy of Software Bisque. www.seeker3d.com, with plumes and ice fields added by Mark C. Petersen, Loch Ness Productions. Star field from DigitalSky 2, courtesy Sky-Skan, Inc.)
Even though this was the first time that cryovolcanism had been “seen” on Charon, I knew from past experience with other icy worlds (and comets) about what it should look like. Ultimately, using worlds created for Seeker3D by Software Bisque, a DigitalSky starfield from Sky-Skan, Inc. plus some Adobe Photoshop® wizardry by Mark Petersen (and a little additional Photoshop® work of my own), I created a composite scene of what I thought the Charon cryovolcanism action would look like, and sent it off to the folks at Gemini to use with the press release and subsequent story/caption.
Coupled with the graphed data, the subsequent story (which you can read here) gives every kind of reader something to grasp in this story of exploration of our outer solar system.
Having gone through the process of image creation (along with the writing of the press release (with valuable input from astronomers Jason Cook, Scott Fisher, Steven Desch, and Tom Geballe)), I appreciated once again the power of the written word coupled with strong illustrations that tell both a scientific and visual story. Judging by the number of places that picked up the story and image and ran with it, I’d guess all of us who worked on this story succeeded in bringing that story home!
