The Pluto Files: The Rise and Fall of America's Favorite Planet (5 page)

Figure 3.6.
Illustration of our solar system that is sure to confuse aliens. The
Pioneer 10
and
Pioneer 11
space probes were launched in the early 1970s and acquired enough energy to escape the gravitation bonds of the Sun. Each craft carried an etched plaque with this iconic view of the planets, intended to alert aliens of the basic structure of our solar system and that the craft itself was launched from the third planet. Given the size of Jupiter and Saturn as illustrated, the scale requires that Pluto not be a small circle as shown, but a pinprick. Furthermore, seven moons that are larger than Pluto are absent from the view, and all four gas giants (Jupiter, Saturn, Uranus, Neptune) have rings, not just Saturn. So an actual alien who used this map in search of our solar system would surely pass us by, certain our map was for some other star system and not the Sun’s.

The curious aliens would also be surprised to learn that on Pluto you would weigh about 10 pounds, while on Jupiter’s (undrawn) four largest moons you would weigh upward of 20 pounds. In each of these cases, however, the gravity field sits well above the threshold to overcome tendencies to look like potatoes. Pluto and Charon are in good company, but that company is large and includes nearly all moons, all planets, and all stars.

With an average
orbital distance of 40 times that of the Earth from the Sun, Pluto is far. With an average high temperature of -365°F, Pluto is cold. With a diameter smaller than the distance from San Francisco to Topeka (and with Charon checking in at still half that width), Pluto is small. And since no probe has ever visited Pluto, Pluto remains among the least known objects in the solar system. But all that will soon change. After a decade of fits and starts in Congress, the New Horizons flyby mission to Pluto is on its way (Figures 3.7 and 3.8).

The fastest hunk of hardware ever launched, the
New Horizons
spacecraft left Cape Canaveral, Florida, on January 19, 2006, atop the powerful Atlas V rocket. After the second-and third-stage rockets fired, the half-ton, piano-sized spacecraft was endowed with enough speed to pass the Moon’s orbit in 9 hours (the Apollo astronauts took 31/2 days) and to reach Jupiter for a gravity assist in just over a year. After Jupiter’s gravity assist, the craft will be traveling at a breakneck 53,000 miles per hour, nearly 15 miles per second.

Figure 3.7.
Masked MIT planetary scientist Richard Binzel gives a thumbs-up for the
New Horizons
spacecraft, shown behind him. The craft is in a clean room at the Applied Physics Laboratories of Johns Hopkins University, being prepared for launch. Binzel appears unmasked in Figure 3.10.

Figure 3.8.
Patch for the New Horizons mission, a joint venture of the Southwest Research Institute, NASA, and the Johns Hopkins University’s Applied Physics Laboratory. Notice that it has nine sides—one of many occasions where the number nine appears in mission materials. A coincidence? Or a subliminal ploy to sway the emotions of the viewer?

Figure 3.9.
Alan Stern (left), principal investigator of the New Horizons mission to Pluto, poses next to the author, both in a desperate attempt to show that astrophysicists can be cool. Photographed at Kennedy Space Center just before the scheduled launch of the New Horizons mission to Pluto, January 2006.

Figure 3.10.
James Christy (left), the discoverer of Pluto’s moon Charon, stands with Richard Binzel, the first person to measure Charon passing in front of Pluto, which allowed significant conclusions to be drawn about the Pluto-Charon orbiting system.

The lead scientists packed the
New Horizons
spacecraft with seven scientific experiments to answer fundamental questions, such as: What is Pluto’s atmosphere made of, and how does it behave? What does the surface of Pluto look like? Are there big geological structures? How do particles ejected from the Sun (the solar wind) interact with Pluto’s atmosphere? How empty of dust is the space between Earth and Pluto?

I was kindly invited to the launch by Southwest Research Institute’s Alan Stern (Figure 3.9), a Pluto expert, the mission’s principal investigator, and a lifelong Plutophile. A magnanimous gesture on Alan’s part, knowing my spotty public position regarding Pluto’s planethood. I was honored to be asked and I gladly accepted. Also in attendance at Kennedy Space Center that day were the discoverers of Pluto’s moon Charon, James Christy and Richard Binzel, as well as Bill Nye the Science Guy
^®
(Figures 3.10 and 3.11). Bill was a student at Cornell when Carl Sagan was a professor there. While known primarily for his expositions of every-day science, the classes he took with Carl imprinted him with a love of the solar system and the rest of the universe that persists to this day.

One of the stated goals for the New Horizons mission was to “complete the reconnaissance of the solar system.” This marching order never sat well with me. It conveys a needless tone of finality to the mission. One can just as easily assert that we are “beginning the reconnaissance of a new part of the solar system, previously unvisited,” as I consistently conveyed in my public appearances.

In the meantime,
the Hubble Space Telescope, famous for its detailed, high-resolution images of gossamer gas clouds across our Milky Way galaxy and of galaxies that reside in the distant universe, was trained on the surrounding environs of Pluto itself. This enabled the Pluto Companion Search Team, led by Hal Weaver and Alan Stern (seen in Figure 3.9), to discover in June 2005 two additional moons in orbit around Pluto (Figure 3.13). A year later, the International Astronomical Union (IAU) officially named them Nix (or Pluto II, the inner of the two moons) and Hydra (or Pluto III, the outer moon).
¹⁵

Figure 3.11.
Like the Academy Awards, but for science, celebrities abound at the January 2006 New Horizons launch to Pluto. One of the nation’s leading educators, Bill Nye the Science Guy
^®
poses with the author. In this rare photo, Bill Nye appears without his trademark bow tie. And the author wears an embarrassingly loud necktie that displays eight planets in full view, with Pluto buried in the knot.

Figure 3.12.
Four onlookers stand agape at the Atlas V rocket, posed to launch the
New Horizons
spacecraft on a fast track to Pluto and beyond. The bulbous nose cone contains the space probe itself. Everything else—the copper cylinder and the white, strap-on boosters—are all rocket fuel.
New Horizons
successfully launched on January 19, 2006. At a peak speed of about 35,000 miles per hour (10 miles per second), it is the fastest-traveling spacecraft ever sent anywhere.

Figure 3.13.
Hubble Space Telescope images of two additional moons of Pluto, visible in each of the long-exposure photographs. Here identified as “candidate satellites,” but later confirmed and named Nix and Hydra, they were discovered in orbit around Pluto, allowing Plutophiles the world over to now refer to the “Pluto system” of host planet and three moons, Charon included. Alan Stern (see Figure 3.9), one of the world’s leading Pluto researchers, and Hal Weaver were the lead members of the Pluto Companion Search Team responsible for the discovery.