There’s a general rule in media reporting called Betteridge’s Law: Whenever a headline poses a question–especially a sensational one–the answer is “no.” I’m going to break the law this time. An orbiting laser cannon is not only an intriguing technology but, yes, it’s one of the most promising ways to clean up the ever-thickening cloud of dangerous debris surrounding the Earth.
And just to be clear, space junk is a danger. There are about 25,000 human-made objects larger than your fist flying around in orbit, and about half a million pieces bigger than a dime. If you include millimeter-scale shrapnel, the number of rogue bits reaches deep into the millions. Typical speeds in low-Earth orbit are about 30,000 kilometers per hour (18,000 miles per hour), ten times the velocity of a rifle bullet. You see the problem: A little impact can pack a big wallop.
Through most of its life, NASA’s scrappy Messenger probe was something of a unsung hero. The first spacecraft ever to orbit Mercury didn’t have the you-are-there immediacy of a Mars rover, the daredevil appeal of landing on a comet, or the romance of visiting a beautiful ringed planet. But with today’s death–the result of a long-anticipated crash into the planet it studied–we can clearly see what an incredibly successful explorer Messenger was.
Mercury has long been a solar-system enigma. It is not particularly small (roughly halfway in size between Mars and the moon), and it is not particularly far away (third closest planet to Earth after Mars and Venus), but the first planet from the sun is devilishly hard to study. Seen from Earth it hangs low in the sky; from space it hugs so close to the solar glare that the Hubble telescope cannot aim at it. Astronomers were so stymied that they didn’t even know how quickly Mercury rotated until 1965, when they found out, not by looking but by bouncing radar signals off its surface.
If you are old enough to remember news stories from 1990 (or if you are a devoted student of astronomy), you’ll recall that the Hubble Space Telescope was not always regarded as the technological triumph that NASA is loudly celebrating today, on its 25th anniversary. The orbiting observatory debuted as a king-size disaster: the telescope that couldn’t see straight, built with a mirror that was ground perfectly…but perfectly incorrect.
The story of how the error was discovered and ultimately fixed has been told many times, most recently in a beautiful retrospective by my colleague Ian Sample at The Guardian. But today it is hard to appreciate the magnitude of Hubble’s turnaround–the depth of the scientific despair right after launch, and the many resurrections that transformed Hubble into the most famous and productive observatory in history. Since Hubble may not live to celebrate a 30th anniversary, there is no time like the present to tell the tale.
The new image of Ceres that NASA released today is doubly thrilling. It unveils more of the landscape of this mysterious in-betweener world–an object classified both as a giant asteroid and as a dwarf planet, a type of object never before observed up close. But it also taps into the unique significance of the crescent shape, both to our culture and to our science.
The crescent is one of the most recognizable icons in astronomy. It is the signature element of the oldest known representation of the heavens, the 4,000-year-old Nebra Sky Disc; it appears on numerous national flags; and it is a staple of the artwork in children’s books. For the scientist, the crescent holds special significance far beyond that, however. To observe a crescent, you must be farther from the sun than the object you are viewing. For any body that is farther out than Earth–that is, for all of the solar system other than Mercury, Venus, and the moon–space probes are the only way to see a crescent.
In short, a crescent is the no-brainer test of exploration: It tells you in one glance that humans have gone to an exotic place in space.
You don’t have to wonder what is on Alan Stern’s mind. The planetary scientist and former NASA associate administrator is a relentless champion of all things Pluto; he is both the principal investigator and the prime mover behind the New Horizons mission, which will fly past Pluto and its moons this July 14. In advance of the encounter, Stern’s passion is building to a white heat, and he is letting everyone know it.
The excitement is infectious. Pluto is looking far more interesting than researchers realized just a few years ago. Ironically, its scientific importance has skyrocketed in the years since the International Astronomical Union demoted Pluto to “dwarf planet.” Recent theoretical models indicate that the Kuiper Belt–the population of objects, including Pluto, that orbits beyond Neptune–is key to understanding the early evolution of the outer solar system. It is home to multiple big, round objects that record the movements of water and organic chemicals at the time when Earth was forming.
Call these things in the Kuiper Belt dwarf planets, call them planets (or call them “Plutoids” and duck before Stern comes after you), whatever. They are major players in the sun’s family, many of them larger than any asteroid, and Pluto is the brightest and most complex of them all. Stern is a Pluto obsessive, but more and more it looks like the science is on his side: Pluto really is something special, and the New Horizons encounter promises to be a unique experience. Here, Stern makes his case–and reveals surprising details about another great mission that almost happened.
If you pay attention to news about space exploration, you may have seen some skeptical stories about NASA’s proposed Asteroid Redirect Mission. (And even if you don’t follow such things, you might well have been dismayed by headlines announcing a “less ambitious asteroid mission” that is “unlikely to get funded.”) This is not another one of them.
I think the asteroid mission is a cool idea, and an important one. I think it will advance the cause of space exploration in several meaningful ways. And it is exactly the kind of medium-scale, focused mission that could revitalize the whole idea of sending humans on grand adventures beyond Earth orbit–if only it can make its way past the naysayers, political opponents, and misguided scientific skeptics who threaten to derail it before it even gets started.
The past couple weeks have seen a brain-sparking series of discoveries that advance the search for life beyond Earth. Enceladus is emitting burps of methane, which strongly indicate the presence of a warm ocean under its ice (and which could, just possibly, hint at biological activity down there). Ganymede seems to have its own buried ocean, one that may contain more water than all of Earth’s oceans combined. A new study shows that organisms could potentially evolve in the frigid methane lakes dotting the surface of Titan. And NASA is poised to send a spacecraft to Europa to see if anything could be alive in the extensive waters below its fractured, frozen surface.
There is a surprising—no, revolutionary—theme to these announcements. All four of these bodies are icy moons in the outer solar system; Europa and Ganymede orbit Jupiter, while Enceladus and Titan circle Saturn. Titan, the largest, is less than half the diameter of Earth and is the only one with an atmosphere. Enceladus, the smallest, is just 300 miles wide. These are not at all the traditional places scientists have talked about when they considered the possibility of alien life elsewhere in the solar system.
The story used to be all about Mars. Now it is clear that most of the water, most of the organic chemistry, and by extension most of the potentially habitable territory in the solar system resides on or in ice moons. If that’s true in our solar system, there’s a good chance it’s true around other stars across our galaxy and beyond.
What is consciousness?
That question has been fertile ground for millennia of philosophical debates, centuries of scientific research, and decades of juicy movie plots, going back at least to Fritz Lang’s Metropolis. This week it gets a workout yet again in Chappie, a new movie directed by Neill Blomkamp (District 9) and starring sci-fi stalwarts Sigourney Weaver and Hugh Jackman along with—less predictably—Dev Patel, best known as the star of Slumdog Millionaire.
Broadly speaking, there are three classes of machine intelligence fiction. Class One assumes that human consciousness is unique and can exist in a machine only if that machine is part human (RoboCop is a prime example). Class Two assumes that machines can mimic many aspects of human consciousness but lack the essential soul (the Terminator movies are a modern archetype). Class Three treats consciousness as a solvable programming problem: Put in the right code, or give the wrong code some kind of mysterious scramble, and a conscious machine emerges. Familiar examples of Class Three movies include Her, AI: Artificial Intelligence and, er, Short Circuit.
Chappie falls squarely into Class Three, with all of the dramatic potentials and conceptual pitfalls it entails. I spoke with Blomkamp and his cast about why they went down this path. Their commentary explains a lot about the movie’s take on artificial intelligence and its confusing scientific politics. Chappie turns out to be a great case study in the challenges of squeezing an expansive concept into the tight confines of mainstream Hollywood entertainment.
The death of Leonard Nimoy yesterday inspired an outpouring of moving testimonials about his vast impact: as an actor, as a supporter of science and smart science fiction, as a voice of reason in media both traditional and digital. You can find these memorials all over Twitter, often accompanied by incredible photos, such as this on-set candid moment and a look at his sensitive moment as an advice columnist. Look at #LLAP (live long and prosper) and see what I mean. Even President Obama weighed in with an appreciation of Nimoy.
Nimoy’s indelible, decades-long performance as Mr. Spock is one of the greatest performances ever in science fiction. He was, in many ways, the central axis of Star Trek, and Trek‘s inspiring influence on three generations of young researchers is widely acknowledged. Spock’s great importance as a role model of rational thought is also undeniable; in his tribute, Obama praised the character as “cool, logical, big-eared and level-headed.” Spock’s catch phrase was “fascinating.” No wonder that Nimoy was so beloved by so many scientists.
But the most interesting aspect of Spock is that he was not just a logical Vulcan. He was half-human, and the war between his ostensibly “rational” and “emotional” sides provided some remarkably subtle and insightful commentary on how science really works.
There is a cliche you hear all the time when scientists describe their experiments: “We expect the unexpected,” or its jokier cousin, “If we knew what we were doing it wouldn’t be called research.” (That second one is often, but dubiously, attributed to Albert Einstein.) But like many cliches, this one is built on a foundation of truth–as the comet explorations by the Rosetta spacecraft and Philae lander keep reminding us.
The latest shocks come from the huge batch of science results released last week, but the Rosetta mission has been a series of surprises going all the way back to its origins. And with another 11 months of exploring to go (the nominal mission runs to December 31) , it is safe to say that the surprises are far from over. Comet 67P/Gerisimayev-Churisamenko is not what we expected, the landing was not what we expected, and even the spacecraft itself is not what its designers intended.
You can read a nice summary of the brand new Rosetta results here, but those specific findings only begin to capture the story.