The 20-year stretch since the discovery of the first exoplanet—a planet circling a star other than the sun—has seen a wholesale relocation of cool ideas from science fiction over to science fact. By 1999, scientists found a way to study the composition of exoplanets. By 2004, they identified a rocky planet, broadly similar to Earth in structure. By 2014, they tracked down an Earth-size world that is the right distance from its star for liquid water. The Star Trek vision of a galaxy full of habitable planets doesn’t look farfetched anymore.
Despite that remarkable progress, we are still far from answering the big question: Is anybody (or anything) out there? What we all want to find is not just an Earth-size world, or an Earth-temperature world, or a vaguely Earth-like world. We want to find Earth 2.0: a wet, warm, living, breathing planet just like our own. To do that, we need to go far beyond the search techniques that astronomers have used so far. There needs to be a more ambitious plan. And there is.
Twenty years ago today, an invisible object circling an obscure star in the constellation Pegasus overturned everything astronomers knew about planets around other stars. No, the fallout was even bigger than that. The indirect detection of 51 Pegasi b—the first planet ever found around a star similar to the sun—revealed that they had never really known anything to begin with.
At the time, even the most adventurous minds blithely assumed that our solar system was more or less typical, a template for all the others. 51 Peg b threw a big splash of reality in their faces. The newfound world was bizarre, a Jupiter-size world skimming the surface of its star in a blistering-fast “year” that lasted just 4.2 days. Its existence ran counter to the standard theories of how planets form and evolve. It answered one big question: Yes, other planetary systems really do exist. But it raised a thousand others.
NASA scientists were conferring today about a nearby planet that is shockingly similar to Earth. It is just 5% smaller in radius and 15% smaller in mass. It is almost the exact same age as our planet, and gets its warmth from an identical star. The only thing that’s a bit off is that it orbits a bit closer to its star than Earth does, so it receives nearly twice as much radiation. On the other, it also reflects away a lot of that radiation. Its theoretical (equilibrium) temperature is just below freezing, so with a little natural greenhouse warming it would be quite an inviting place.
If we found it orbiting another star, this world would surely be hailed as the most Earthlike exoplanet known: the best place yet to search for alien life.
No doubt you sense there is a catch, and indeed there is. The world I’m talking about is Venus. It is not orbiting another star; it is the planet closest to home right here in our own solar system. But I’m not just being coy. Despite its proximity, Venus is a profound enigma. It really should be a hospitable world, but the truth is that it is more like hell on almost-Earth. Understanding why that is–why our planet went right while Venus went terribly wrong–is crucial for finding out whether habitable planets are common or rare throughout the universe.
NASA generated quite a bit of buzz today with the apparent discovery of flowing water on Mars. Now to anybody who follows science news–especially news about space and alien life–those words may sound awfully familiar. It seems like NASA has been discovering water on Mars every year for the last decade. This time really is different, however. For one thing, scientists are talking about water on Mars right now. For another, the evidence is much stronger than it was in past reports; I wrote about some of those earlier speculations here.
Although the news just broke earlier today, there has already been extensive discussion of the results online. I’ve read through the early conversations (so you don’t have to). Here are some of the key things you should know. I’ll start with the bad news, since I always like to get it out of the way first.
Today is the day when, according to a widely circulated email/Facebook hoax, Mars will appear as large in the sky as the full moon. In reality, nothing short of the catastrophic disruption of the entire solar system could allow such a thing to happen (and if that were happening, you probably would have heard the news). Still, I have sympathy for those who were taken in by the hoax. We live in an age of amazing space imagery: snapshots of nitrogen glaciers on Pluto, a robot bouncing off a comet, ice moons hovering over the rings of Saturn. If you don’t think too hard about it, one more wild view doesn’t seem so implausible.
The barrage of genuine scientific amazement surely also explains why so many people credulously accept other erroneous or at least misleading stories, such as the ongoing reports that NASA has validated an “impossible space drive”–or, in some variations, that NASA “accidentally created a warp drive.” I’m sympathetic again. After all, NASA really did send an ion-powered spacecraft to the dwarf planet Ceres. That’s pretty wild. Again, if you don’t think too hard about it, why not accept another, even more staggering technological breakthrough?
Some quick online research will usually separate the serious stuff from the hoaxes and the hype, but many people lack the time or even the inclination. What would be truly helpful is a set of basic reality-check tests that anyone can apply: an all-purpose science BS-detector kit that requires little more than getting past that first hurdle of thinking. I’m going to attempt to build one right here. I’d love to hear your ideas as well.
The most consistently reliable meteor shower—the Perseids—peaks tonight. Under clear, dark, unobstructed skies you might see 60 to 100 meteors an hour. And this year, nature is cooperating: The moon is a thin crescent that does not rise until dawn, meaning that the astronomical sky will remain wonderfully dark all night through. (Clouds are another matter; getting away from buildings, trees, and city lights is all up to you.)
For tips on how to watch the Perseids, read through this helpful viewer’s guide prepared by our friends at Astronomy magazine. That will tell you what you need to know about how to watch. It’s a lot harder to find good information about what you are seeing. That’s why I’m here.
I spent the past week at Pluto central–aka, the Johns Hopkins University Applied Physics Lab in Laurel, Maryland–watching images and data come in from the New Horizons spacecraft. You don’t need me to tell you how incredible those first views are. They’ve been covered widely in the science media, including right here on this site, and have thoroughly (and gratifyingly) crossed over into the mainstream. I even got a chance to talk about them on Fox News. But there is a lot more to the story than the new landscapes of Pluto, stunning as they may be.
First and foremost, there is the enormous amount of scientific surprise embedded within those images. Alan Stern, the principal investigator and prime mover behind New Horizons, routinely declared that we should all be prepared for surprises when we got a first look at Pluto. What he added, in his quieter moments, is that we should be prepared even for unpleasant surprises. Pluto might look just like Neptune’s moon Triton. Worse, it might be an inert ball of ice, covered with ancient craters and decorated only with dark, carbon-rich discolorations. Of course, that turned out not to be the case. Stern’s eye-popping reaction, shown up above, says it all.
As the New Horizons probe closes in on Pluto–now less than two days away!–there have been a lot of thoughtful articles looking back at the people responsible for the discovery of this remarkable little world. They have focused mostly on Clyde Tombaugh, the man who spotted Pluto amidst a sea of stars in 1930. Some articles have also told the story of Venetia Burney, the 11-year-old girl who gave Pluto its name, or Percival Lowell, whose obsession with finding “Planet X” inspired Tombaugh’s search. In all these stories, though, one name is conspicuously missing: Vesto Slipher.
It was Slipher who initiated the planet search and who directed its outcome. He was probably the first to set eyes on Pluto. He was also a meticulous deep-sky observer who collected the first evidence of the expanding universe, more than a decade before Edwin Hubble’s landmark publication that led to the modern idea of the Big Bang. So why is there no Slipher Space Telescope? Why have you never even heard of him and his connection to Pluto?
Therein lies a tale.
In space exploration, there are a million ways that things can go wrong and just one way that they can go right. When the New Horizons probe skims less than 8,000 miles past the surface of Pluto on July 14, it will happen only because a large team of scientists, engineers, and mission planners managed to eliminate all the wrong and navigate their way to the right, a process that has taken more than 40 years to fully unfold.
The engineers have become so good at fixing problems that most of the time the public has no idea what they are up against—until something goes wrong, as happened to New Horizons last weekend, when a software glitch caused the probe to shut down into “safe” mode. For a moment, this was a news story. Then, once again, the engineers stepped up and solved the problem (caused by an obscure timing flaw in a command sequence sent to the probe in preparation for flyby). Within three days, all was back to normal. As New Horizons principal investigator Alan Stern says, “In terms of science, it won’t change an A-plus even into an A.”
But software problems are hardly the only glitches that nearly derailed the mission to Pluto. Politics and personalities can go wrong, too, and they frequently did.
“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka’ but ‘That’s funny…'” That quote, delivered by the brilliant science writer Isaac Asimov, keeps popping into my head as I look at the remarkable new images of Ceres. NASA’s Dawn spacecraft has been orbiting the dwarf planet since March 6, scrutinizing a landscape that is not quite like anything humans have ever seen before.
One detail on Ceres jumped out almost immediately: a bizarre white spot, drastically brighter than its drab surroundings. As Dawn got closer, the probe’s camera showed that the white spot is actually a patch of at least eight smaller white areas; there are also smaller white spots and extended light-ish splotches scattered across Ceres’s 950-kilometer-wide 590-mile wide globe. What are they? No idea, except not alien landing lights (they don’t show up in the dark). Subsequent images revealed a solitary, 3-mile-high mountain; long ridges and apparent streamers of impact debris; giant frozen surface flows; and craters with unusual distorted, vaguely hexagonal shapes.
The initial scientific reaction to these Ceres images boils down to three simple words that Asimov would well recognize: “That looks funny.”