Origins: Fourteen Billion Years of Cosmic Evolution (37 page)

35:
This photograph of the Martian surface, taken by the
Spirit
rover in January 2004, shows hills on the horizon a few miles away. NASA has now named seven of these hills in honor of the astronauts who died in the
Columbia
shuttle disaster on February 1, 2003. Like the two sites where the
Viking
spacecraft landed in 1976, the locations where the
Spirit
and
Opportunity
rovers touched down in 2004 show rock-strewn plains with no visible signs of life.

36:
A close-up view of the immediate surroundings of the
Spirit
rover shows what may be ancient bedrock, as well as younger rocks rich in compounds that on Earth typically form underwater. The prevailing reddish hue comes from iron oxides (rust) in the surface rocks and soils.

37:
UCLA Professor of Biology Ken Nealson on location with one of the authors (NDT) in Death Valley during the shooting of the PBS NOVA special
Origins.
As an expert in geologically stressed microorganisms, Nealson knows that this hot, arid, and otherwise hostile environment serves as a thriving ecosystem for bacteria that live just fine within the cracks of rocks, or on their underside, shadowed from the oppressive sunlight. The reddish hue of Death Valley rocks greatly resembles that of the Martian surface.

38:
Bad Day on Earth. A view by space artist Don Davis of the collision between an asteroid and Earth 65 million years ago, which precipitated the extinction of non-avian dinosaurs as well as 70 percent of land species, including all animals larger than a breadbox. The ecological niches left vacant by the dinosaurs’ demise enabled mammals to evolve from tree shrews—that had been nothing more than dino-hors d’oevres—to the many and varied mammal forms we see today.

39:
This “black smoker” rock formation, shown in vertical cross section, was hauled from the Pacific Ocean’s Juan de Fuca Ridge, and now sits on display in the Hall of Planet Earth at the American Museum of Natural History in New York. Along mid-ocean ridges, water can seep through the crust and become superheated, dissolving minerals along the way. Wherever the water spews back into the ocean bottom, we find chimneylike structures, formed by the precipitation of minerals from the cooling water. The porosity of these structures, and the chemical and temperature gradients they sustain, allow an entire ecosystem to thrive on geothermal and geochemical energy sources, without regard to the Sun as a source of life-sustaining energy. The newly discovered hardiness of some forms of bacteria and other life forms on Earth has expanded the list of environments where we may hope to find life in the universe.

40:
Dr. Seth Shostak, of the SETI Insitute (Search for Extra-Terrestrial Intelligence), and one of the authors (NDT) take a moment to pose between takes of
Origins
on location at the Arecibo Radio Telescope in Puerto Rico. Shostak used this largest telescope in the world to “listen” for possible intelligent signals produced by distant civilizations. The Arecibo telescope sits in a natural limestone crater. Shostak and Tyson were filmed walking and talking under the wire-mesh dish—itself an otherworldly environment.

*
Albert Einstein,
The Principle of Relativity
, trans. by W. Perrett and G. B. Jeffery (London: Methuen and Company, 1923), pp. 69–71.

*
Galileo Galilei,
Siderius Nuncius
, trans. Albert van Helden (Chicago: University of Chicago Press, 1989), p. 62.

†
J. C. Kapteyn,
Astrophysical Journal
29, 46, 1909; 30, 284, 1909.