LANDING A TRIUMPH OF INGENUITY
“There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”
So wrote Mark Twain in “Life on the Mississippi.”
Twain obviously meant this as a snarky comment on science and scientists, but it still captures something valid about the scientific enterprise: It is about gleaning facts, and those facts inevitably lead to more questions. Technological advancement has enabled an explosion of new ways to gather facts about the world and universe we live in.
The successful landing of the Perseverance rover on Mars was a stunning technological achievement for NASA, this country and the world. The payoff for basic science could be equally stunning. Perseverance’s suite of onboard experiments includes laser spectrometers crafted to search for and measure minerals and organic compounds, the basic stuff of the chemistry of the Martian soil and atmosphere.
These measurements may provide clues about why Mars is the way it is now, how it got that way and maybe even shed some light on a big question: Was there ever life on Mars? Is there life even now? Yes, conjecture, but there is only one way to settle the issue for sure.
Mars is a world tantalizingly similar to Earth, yet starkly different in its current environment and in its history. With a mass roughly a tenth that of Earth’s, and half again as far from the sun as Earth is, it was a world set up for failure from the start — at least by Earth standards. Mars’ current atmosphere, largely carbon dioxide, is desperately thin, with a surface pressure less than 1 percent that of Earth. High temperatures on a summer’s day on the Martian equator in a deep canyon might rival San Diego’s typical temperature, but come nightfall that temperature could plunge to the point where carbon dioxide freezes. However, NASA’s orbiter and lander probes have revealed the handiwork of flowing water. Mars was likely very different in the distant past, warmer, wetter. Maybe life arose there? Conjecture again. Perseverance’s measurements, if nothing else, will narrow the range of conjecture. The spectrometers could find organic molecules or the mineral derivatives and chemical fingerprints of water or life. Or we could find something unexpected.
An inescapable feature of the history of measurement and observation in science is the unexpected. At times, the most exciting times in my view, human prejudice and hubris about the world have not fared well against experimental fact. Discovering the unexpected, the outrageous, has been a key factor in driving scientific and, hence, technological developments. New discoveries may spark new insights, even revolutionary ones.
Finding evidence of past or current life on Mars could profoundly affect our strategy for observational exploration of planets orbiting around other stars, exoplanets. Space-based observation has led to the discovery of thousands of exoplanets. The variety and characters of these exoplanets were unexpected and surprising. Future NASA space-based observatories, and the advent of 30 meter-class ground based telescopes, promise an exciting future of exoplanet exploration. Scientists at UC San Diego are key players in this endeavor in many ways, pioneering the instruments that enable the observations, and the observational strategies to answer key questions. Exoplanet science and astrobiology are priorities for us because the promise of this science is so alluring.
New ways of measuring and exploring the universe have come about in just the last few decades. These include high energy physics experiments, like the Large Hadron Collider, that give insights into subatomic particles, observatories to measure the fossil light (microwaves) left over from the earliest history of the universe, and gravitational wave observatories, like LIGO and Virgo. The latter measure the ripples in spacetime itself emanating from the violent collisions of compact objects, like black holes and neutron stars, and have revealed a universe filled with black holes. Discoveries in one of these areas can enable discoveries in the others — this is another characteristic of science.
The triumph of NASA’s Perseverance landing was a welcome development in an otherwise fairly dark time in the world. We will get more than a trifling of fact from Perseverance and from the other frontiers of science recounted above. Questions will be answered and new, unanticipated questions will result. One thing Twain’s comment misses, however, is the thrill of scientific discovery, of exploration. We are all part of that.
Fuller is a UC San Diego distinguished professor of physics and director of the university’s Center for Astrophysics and Space Sciences. He lives in Mira Mesa.