The first discovery concerns a better understanding about what constitutes life—or at least life as we know it. We’ll learn more about the chemical composition of stuff in our solar system and perhaps where the elements of life as we know it arose. We might learn more about the chemistry, or at least some physical properties, of planets in other solar systems, and perhaps deduce more about where life (if not necessarily complex life) might arise. We will probably also examine the fossil record in greater detail as new chemical and physical methods allow us to probe deeper into Earth’s history. All this will stay news, since we won’t know how life arose for a long time to come, but small pieces of the puzzle will continue to emerge.
There will also be many new developments in artificial intelligence and robotics. These advances fall into the second category, since a lot of the real news about the role of automation will occur behind the scenes, where technology will make some tasks we already do simpler or more effective, or will replace workers and reduce (or at least change the nature of ) employment. We’ll read about drones and medical robotics and advances in AI, but those factory robots won’t be big news except for a few days on the business pages and of course for the families of workers who find themselves on unemployment lines.
I hope that the third category will include discoveries that tell us more about the fundamental nature of dark matter. Dark matter is the matter that carries five times the energy of ordinary matter and interacts with gravity but very little or not at all with light. Experiments already in the news look for dark matter in different ways. Some of these, like XENON1T and LUX-ZEPLIN, use huge containers of material deep underground which might detect a tiny recoil of a dark-matter particle passing through. Also possible is that dark matter annihilates when two dark-matter particles get together and turns into photons.
There are less conventional searches that might tell us more about the nature of dark matter and that rely on comparing simulations of how structures like galaxies form from dark-matter collapse with actual data exploring the distribution of stars or other matter in galaxies. These more detailed observations of the role of dark matter might reveal some interesting aspects of how it interacts. Perhaps dark matter has interactions or forces that familiar matter doesn’t experience—just as dark matter doesn’t experience forces like the electromagnetism of the visible world.
If such properties of dark matter are found, or if a dark-matter particle is discovered, scientists will try to learn more about its properties and the implications for cosmology and astrophysics. But that will be a long slog, from the perspective of outsiders. The true sign that dark-matter searches have succeeded will be that the discovery will be taken for granted and cease to be news.
Space Exploration, New and Old
Robert Provine
Psychologist; research professor/professor emeritus, University of Maryland, Baltimore County; author, Curious Behavior: Yawning, Laughing, Hiccupping, and Beyond
Surprising images of dwarf planet Pluto from a flyby of the New Horizons spacecraft put space exploration back in the headlines as one of the biggest science stories of 2015. Instead of a barren, frigid globe, Plato proved to be colorful, contrasty, and complex, with diverse geological structure including mountains, valleys, and plains of water-ice and nitrogen-ice, evidence of past and present glacial flows, possible volcanoes spewing water-ice from a warmer core, and a thin atmosphere that extends hundreds of miles above the planetary surface. Similar insights are being gleaned from Charon, the largest of Pluto’s five moons.
2015 also brought Pluto news of a more arcane sort. The historic 24-inch Clark refracting telescope of Lowell Observatory was refurbished and opened to the public for viewing. As a young Lowell employee, Clyde Tombaugh discovered Pluto in 1930 on photographic plates taken with a Lowell instrument. Telescopes, whether optical leviathans or the modest backyard variety, are spaceships for the eye and mind which provide a compelling sensory immediacy lacking in the pricier technological tour de force of a spacecraft. Recall the aesthetic impact of the starry night viewed from a dark country path, or seeing Saturn for the first time through a telescope. Although modern Earth-based telescopes continue to provide astronomical breakthroughs, old telescopes and the observatories that house them survive as domed, verdigris-covered cathedrals of science. The Pluto flyby of 2015 is an occasion to celebrate space exploration new and old, and the value of looking upward and outward.
Pluto Is a Bump in the Road
Nicholas A. Christakis
Physician, social scientist; director, Human Nature Lab, Yale University; co-author (with James H. Fowler), Connected
On July 14 of last year, NASA’s New Horizons spacecraft flew within 7,800 miles of Pluto, after traversing 3 billion miles since its 2006 launch, and began sending back astonishing and detailed images of mountains and plains composed of ice from the last planet in our system to be explored. But for me, these images were not the most newsworthy aspect of its mission.
The science involved in accomplishing this feat is amazing. New Horizons is an engineering marvel, with radioisotope power generation, sophisticated batteries, optical and plasma scientific instruments, complex navigation and telemetry, and so on. Its primary missions—all successfully completed—were to map the surface of Pluto and its main moon, Charon; to characterize the geology and composition of these bodies; and to analyze their atmosphere. In the process, New Horizons has also shed light on the formation of our solar system.
We succeed in this kind of solar-system exploration so reliably nowadays that it seems to us routine, just a bump in the road of our endless inquiry. But the exploration of Pluto is, alas, a bump in the road in another, rather more dispiriting way.
Most Americans (58 percent, in a 2011 Pew survey) are supportive of space exploration, valuing its contributions both to science and to national pride. And most Americans (59 percent, in a 2015 Pew survey) approve of sending astronauts into space. Yet Americans and their politicians appear unwilling to spend more money on our space program; a 2014 General Social Survey indicated that just 23 percent of Americans think we should do so. By contrast, 70 percent of Americans think we should spend more on education and 57 percent think we should spend more on health. NASA’s budget has been roughly constant in real dollars since 1985 (it’s now 0.5 percent of the federal budget), but it is well below its peak in 1965, when it was more than 4 percent of the federal budget (and it’s below even the 1-percent level of 1990).
The captivating photos of Pluto occupied a week or so in the news cycle in the middle of last summer, and we moved on. What amazed me about the news from Pluto was that there weren’t more people who found this accomplishment astonishing, that there was not even a more sustained support for space exploration. NASA’s entirely sensible push to make both manned and unmanned space exploration reliable, standardized, and safe has had the unfortunate side effect of making it routine and even boring for many people. For me, this is the real newsworthy part of the Pluto mission.
My paternal grandfather, who was born in Greece in the 1890s, used to tell me that he simply could not believe that he had heard about the first heavier-than-air flight of the Wright brothers when it happened, in 1903, and had also watched the Moon landing in 1969. He had fought in World War I and would tell me stories about how his unit was transferred from Ankara to Kiev on horseback “when the Bolsheviks revolted” and about how, during World War II, he kept his family alive in Athens “when the Nazis invaded.” But space exploration interested him more, because it was so much more optimistic. Humans had gone from skimming over a beach in a plane made of canvas and bicycle parts to operating a lunar lander in sixty-six years. It amazed him, and the pace and sheer wonder of it astonish me even as I write this.
I realize, of course, that the great accomplishments in space exploration of the 1960s and 70s were largely motivated by the Cold War. I realize as well that many people are now arguing that private enterprise should take over space exploration. And I
know that commitment to space exploration is low because many see better uses for our money. Is it better to vaccinate children, care for the poor, and invest in public health and medical research rather than invest in space exploration? Part of my response is the customary one that science and discovery are the ultimate drivers of our wealth and security. But my main response is that this is a false dichotomy. The real question is whether we would rather wage war or colonize Mars. Which would be, and should be, more newsworthy? In this I think my grandfather had it right.
Pluto Now, Then on to 550 AU
Gregory Benford
Novelist and emeritus professor of physics and astronomy, UC Irvine; co-author (with Larry Niven), Shipstar
The most long-range portentous event of 2015 was NASA’s New Horizons spacecraft arrowing by Pluto, snapping clean views of the planet and its waltzing moon system. It carries an ounce of Clyde Tombaugh’s ashes, commemorating his discovery of Pluto in 1930. Tombaugh would have loved seeing the colorful contrasts of this remarkable globe, far out into the dark of near-interstellar space. Pluto is now a sharply seen world, with much to teach us.
As the spacecraft zooms near an iceteroid on New Year’s Day, 2019, it will show us the first member of the chilly realm beyond, where primordial objects quite different from the wildly eccentric Pluto also dwell. These will show us what sort of matter made up the early disk that clumped into planets like ours—a sort of family tree of worlds. But that’s just an appetizer. New Horizons is important not just for completing our first look at every major world in the solar system. It points outward, to a great theater in the sky, where the worlds of the galaxy itself are on display.
Beyond Pluto looms a zone where the Sun’s mass acts as a giant lens, its gravitation focusing the light of other stars to a small area. Think of it as gravity gathering starlight into an intense pencil, focused down as dots on a chilly sphere. Einstein calculated such gravitational bending of light in 1912, though Newton knew the effect should occur in his own theory of mechanics and optics.
Images of whole galaxies made by this effect were not discovered until 1988. Such magnification of light from a star and the planets near it naturally creates a telescope of unparalleled power. It can amplify images by factors that can vary from 100 million to a quadrillion, depending on frequency. This suggests using such power to study worlds far across the interstellar reaches. We have already detected more than 2,000 planets around other stars, thanks to the Kepler mission and other telescopes. We can sense the atmospheres of some, when they pass across our view of their stars, silhouetted against that glare. Many more will come.
The space telescopes envisioned for the next several decades can tease out information about a planet at interstellar distances only by studying how light reflects or absorbs changes. At best, such worlds will be dots of faint light. But at the lensing distance, under enormously better resolution, we can see the worlds themselves—their atmospheres and moons, their seas and lands, perhaps even their cities.
Hardy New Horizons now zooms along at about 15 km a second, or (more usefully said) at about 3 astronomical units (AU, the distance between Earth and our Sun) in a year, relative to the Sun. The focus spot of the Sun is 550 AU out, as Einstein predicted in 1936. New Horizons will take 180 years to get to that focus—and will be long dead, as its nuclear power supply fades. So future missions to put a telescope out there demand speeds ten or more times faster. (Voyager, flying after thirty-eight-plus years, is only 108 AU away from Earth.)
We know of ways to propel spacecraft to such speeds. Most involve flying near the Sun and picking up velocity by firing rockets near it, or getting a boost from its intense light using unfurled solar sails, and other astro-tricks. Those feats we can fashion within decades, if we wish.
Our goal could be to put an observing spacecraft that can maneuver out at the focus of “God’s zoom lens”—a 70-billion-mile-long telescope that light takes more than three days to traverse. An observing spacecraft could see whatever is behind the Sun from it, many light-years away.
This would vastly improve our survey of other worlds, to pick off strings of stars and examine their planets. Using the Sun as a lens works on all wavelengths, so we could look for signs of life—say, oxygen in an atmosphere—and perhaps even eavesdrop on aliens’ radio stations squawking into the galactic night. At first, such a telescope could scrutinize Alpha Centauri’s planets, if it has some—the next big step before trying to travel there. The craft could trace out a spiral pattern perpendicular to its outward path, slightly shifting its position relative to scan the Alpha Centauri system. Then look farther still—because the focus effect remains beyond 550 AU as a spacecraft moves outward, still seeing the immense magnifications.
New Horizons may be the best-named spacecraft of all, for it does indeed portend fresh, bold perspectives.
The Universe Surprised Us, Close to Home
Lawrence M. Krauss
Physicist, cosmologist, Arizona State University; author, A Universe from Nothing
When the first close-up pictures of Pluto came in from the New Horizon satellite, which flew by the planet last year, they shocked pretty well everyone who had thought about the now-demoted dwarf planet. Common sense suggested that Pluto should be a frozen ball, with a pockmarked surface reflecting billions of years of comet impacts. Instead, what was revealed was a dynamic object, with mountains 3–4 km high and a huge, 1,000-km-wide plain of ice with no impact craters—which means this plain cannot be older than 100 million years. Which in turn implies that the surface of Pluto is dynamic. Since there are no other large planets nearby that might be sources of tidal heating, this means that Pluto still has an active internal engine continuing to mold its surface. We have no idea how that could be the case.
Similar surprises have accompanied flybys of other solar-system objects—namely, the subsurface liquid-water ocean and organic-water geysers of Saturn’s moon Encedalus and the volcanoes on Jupiter’s moon Io. While these oddities are now understood to be powered by the huge tidal influence of their giant host planets, no one had expected this kind of extreme activity.
As we peer out farther to other stars, we have found them to be rife with planetary systems once thought to be impossible: gas giants like Jupiter and Saturn orbiting closer to their stars than Mercury is to our Sun. It had been thought that inner planets would be small and rocky and outer planets larger and gaseous, as in our own solar system; we now understand that dynamical effects may have caused large planets to migrate inward over time in these systems.
Similarly, classical dynamics had suggested that binary star systems should not contain planets, as gravitational perturbations would expel such orbiting objects. But planets have now been discovered around binary stars, suggesting some new stabilizing mechanism at work.
We are accustomed to recognizing that at the extremes of scale the universe is a mysterious place. For example, dark energy—the energy of empty space—appears to dominate the dynamics of the universe on its largest scales, producing a gravitational repulsion that is causing the expansion of the universe to accelerate. On small scales, we currently have no idea why the newly discovered Higgs particle is as light as it is, one of the reasons the four forces in nature have the vastly different strengths we measure on laboratory scales.
But what we are learning as we explore our solar neighborhood is that the physics governing the formation and evolution of planetary-scale objects like Pluto, Io, and Enceladus—physics we thought was well understood—is far richer and more complex than we imagined. This not only gives the lie to claims that there would be no more new results of relevance to understanding human-scale physics but also puts in perspective the hyperbolic claims that a quantum theory of gravity (such as the most popular candidates, superstrings or M-theory) would be a Theory of Everything. Although such a theory would be of vital importance for understanding the origin of the universe and the nature of space and time, it would be irrelevant for understanding comple
x phenomena on human scales, like the boiling of oatmeal or formations of sand on the beach.
While oatmeal and sand may not capture the public’s imagination, the exotic new worlds inside and outside our solar system certainly do. And our recent discoveries suggest that much conventional wisdom about even our nearest neighbors, and physics as classical as Newton’s, will have to be rethought. The result of such revisions will likely shed new light on vital questions, including the big one: Are we alone in the universe? It’s hard to see how our cosmic backyard could get more interesting!
Progress in Rocketry
George Dyson
Science historian; author, Turing’s Cathedral: The Origins of the Digital Universe
Toward the end of 2015, in close succession, two rockets left the ground, crossed the Kármán line (at 100 km altitude) into space, and returned intact under their own power to a soft landing on the surface of the Earth. In the space business, new rockets are launched at regular intervals, but the launch of a used rocket is important news.
In December 1966, Project Orion pioneer Theodore B. Taylor complained that the high cost of sending anything into even low Earth orbit was “roughly equivalent to using jet transport planes to carry freight from, let us say, Madrid to Moscow, making one flight every few weeks, throwing away each aircraft after each flight, and including the entire construction and operation costs of several major airports in the cost of the flights!”
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