The collective space vision of all the world’s countries at the moment seems to be Mars, Mars, Mars. The U.S. has two operational rovers on the planet; a NASA probe called MAVEN and an Indian Mars orbiter will both arrive in Mars orbit later this month; and European, Chinese and additional NASA missions are in the works. Meanwhile Mars One is in the process of selecting candidates for the first-ever Martian colony, and NASA’s heavy launch vehicle is being developed specifically to launch human missions into deep space, with Mars as one of the prime potential destinations.
But is the Red Planet really the best target for a human colony, or should we look somewhere else? Should we pick a world closer to Earth, namely the moon? Or a world with a surface gravity close to Earth’s, namely Venus?
To explore this issue, let’s be clear about why we’d want an off-world colony in the first place. It’s not because it would be cool to have people on multiple worlds (although it would). It’s not because Earth is becoming overpopulated with humans (although it is). It’s because off-world colonies would improve the chances of human civilization surviving in the event of a planetary disaster on Earth. Examining things from this perspective, let’s consider what an off-world colony would need, and see how those requirements mesh with different locations.
We humans like to think ourselves pretty advanced – and with no other technology-bearing beings to compare ourselves to, our back-patting doesn’t have to take context into account. After all, we harnessed fire, invented stone tools and the wheel, developed agriculture and writing, built cities, and learned to use metals.
Then, a mere few moments ago from the perspective of cosmic time, we advanced even more rapidly, developing telescopes and steam power; discovering gravity and electromagnetism and the forces that hold the nuclei of atoms together.
Meanwhile, the age of electricity was transforming human civilization. You could light up a building at night, speak with somebody in another city, or ride in a vehicle that needed no horse to pull it, and humans were very proud of themselves for achieving all of this. In fact, by the year 1899, purportedly, these developments prompted U.S. patent office commissioner Charles H. Duell to remark, “Everything that can be invented has been invented.”
We really have come a long way from the cave, but how far can we still go? Is there a limit to our technological progress? Put another way, if Duell was dead wrong in the year 1899, might his words be prophetic for the year 2099, or 2199? And what does that mean for humanity’s distant future?
In 1971—16 years after Einstein’s death—the definitive experiment to test Einstein’s relativity was finally carried out. It required not a rocket launch but eight round-the-world plane tickets that cost the United States Naval Observatory, funded by taxpayers, a total of $7,600.
The brainchild of Joseph Hafele (Washington University in St. Louis) and Richard Keating (United States Naval Observatory) were “Mr. Clocks,” passengers on four round-the-world flights. (Since the Mr. Clocks were quite large, they were required to purchase two tickets per flight. The accompanying humans, however, took up only one seat each as they sat next to their attention-getting companions.)
The Mr. Clocks had all been synchronized with the atomic clock standards at the Naval Observatory before flight. They were, in effect, the “twins” (or quadruplets, in this case) from Einstein’s famous twin paradox, wherein one twin leaves Earth and travels nearly at the speed of light. Upon returning home, the traveling twin finds that she is much younger than her earthbound counterpart.
In fact, a twin traveling at 80 percent the speed of light on a round-trip journey to the Sun’s nearest stellar neighbor, Proxima Centauri, would arrive home fully four years younger than her sister. Although it was impossible to make the Mr. Clocks travel at any decent percentage of the speed of light for such a long time, physicists could get them going at jet speeds—about 300 meters (0.2 mile) per second, or a millionth the speed of light—for a couple of days. In addition, they could get the Mr. Clocks out of Earth’s gravitational pit by about ten kilometers (six miles) relative to sea level. And with the accuracy that the Mr. Clocks were known to be capable of, the time differences should be easy to measure.
Your mission, should you choose to accept it: Find and reanimate an ailing spacecraft, prevent it from hurtling into deep space, and guide it back to stable orbit near Earth. This setup could be the plot of a cheesy computer game, but it was actually the summer plan of a team of renegade spacemen.
The group of ambitious volunteer-engineers made contact with a 1970s spacecraft, downloaded its data, and attempted to shift its trajectory homeward. They wanted to resume the craft’s mission and siphon its data back down to Earth. Their initial plan, however, failed on Wednesday when they discovered the thrusters were out of juice—but in the wake of that setback they are altering, rather than abandoning, their plans.
A hundred and one years ago, in 1913, the famous British mathematician G. H. Hardy received a letter out of the blue. The Indian (British colonial) stamps and curious handwriting caught his attention, and when he opened it, he was flabbergasted. Its pages were crammed with equations – many of which he had never seen before. There were many kinds of formulas there, and those that first caught his attention had to do with algebraic numbers. Hardy was the leading number theorist in the world – how could he not recognize the identities relating to such numbers, scribbled on the rough paper? Were these new derivations, or were they just nonsensical math scrawls? Later, Hardy would say this about the formulas: “They defeated me completely. I had never seen anything in the least like it before!”
Now, for the first time, mathematicians have identified the mathematics behind these breakthrough scrawls – shedding further light on the genius who made them.
This article was originally published on The Conversation.
Last week, scientists announced the discovery of Kepler-186f, a planet 492 light years away in the Cygnus constellation. Kepler-186f is special because it marks the first planet almost exactly the same size as Earth orbiting in the “habitable zone” – the distance from a star in which we might expect liquid water, and perhaps life.
What did not make the news, however, is that this discovery also slightly increases how much credence we give to the possibility of near-term human extinction. This because of a concept known as the Great Filter.
The Great Filter is an argument that attempts to resolve the Fermi Paradox: why have we not found aliens, despite the existence of hundreds of billions of solar systems in our galactic neighborhood in which life might evolve? As the namesake physicist Enrico Fermi noted, it seems rather extraordinary that not a single extraterrestrial signal or engineering project has been detected (UFO conspiracy theorists notwithstanding).
This apparent absence of thriving extraterrestrial civilizations suggests that at least one of the steps from humble planet to interstellar civilization is exceedingly unlikely. The absence could be caused because either intelligent life is extremely rare or intelligent life has a tendency to go extinct. This bottleneck for the emergence of alien civilizations from any one of the many billions of planets is referred to as the Great Filter.
“Interdisciplinary” is a huge buzzword in academia right now. But for science, it has a long history of success. Some of the best science happens when researchers cross-pollinate, applying knowledge from other fields to inform their research.
One of the best such examples in physics was the concept of a Higgs field, which led to the 2013 Nobel Prize in physics. Few people outside the physics community know that the insight to the behavior of the proposed Higgs particle actually came from solid state physics, a branch of study that looks at the processes that take place inside condensed matter such as a superconductor.
Now cosmologists are trying to borrow some ideas of their own. The new discovery of gravitational waves — the biggest news in cosmology this century — focuses fresh attention on a field in which recent progress has otherwise been slow. Cosmologists are now attempting to explore novel ways of trying to understand what happened in the Big Bang, and what, if anything, caused the gargantuan explosion believed to have launched our universe on its way. To do so they’ve turned their attention to areas of physics far removed from outer space: hydrology and turbulence. The idea is pretty clever: to view the universe as an ocean.
In 1917, a year after Albert Einstein’s general theory of relativity was published—but still two years before he would become the international celebrity we know—Einstein chose to tackle the entire universe. For anyone else, this might seem an exceedingly ambitious task—but this was Einstein.
Einstein began by applying his field equations of gravitation to what he considered to be the entire universe. The field equations were the mathematical essence of his general theory of relativity, which extended Newton’s theory of gravity to realms where speeds approach that of light and masses are very large. But his math was better than he wanted to believe—his equations told him that the universe could not stay static: it had to either expand or contract. Einstein chose to ignore what his mathematics was telling him.
The story of Einstein’s solution to this problem—the maligned “cosmological constant” (also called lambda)—is well known in the history of science. But this story, it turns out, has a different ending than everyone thought: Einstein late in life returned to considering his disgraced lambda. And his conversion foretold lambda’s use in an unexpected new setting, with immense relevance to a key conundrum in modern physics and cosmology: dark energy.
There’s something rejuvenating about escaping civilization for the quiet isolation of unadulterated wilderness. But could you leave it all behind — forever? That’s the fate that awaits the men and women still in contention for a one-way ticket to the Red Planet.
Earlier this month, when a few high-traffic news websites reported a strange object or wedge-shaped craft on Google Moon, I was skeptical. Surprised, too, because when I opened the application, there it was, a distinct V-shape of bright lights inside a tiny crater on the moon’s far side. It did not look natural. I marked its location at 142 degrees and 34 minutes east and 22 degrees 42 minutes north, at the edge of Mare Moscoviense.