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Requiem for the World’s Greatest Planet Hunter
After more than four years in space, restlessly searching for planets orbiting other stars, NASA’s Kepler space telescope may have met its demise.
A bewildering variety of planets have been found by the Kepler spacecraft. This illustration is based on best guesses about what those planets are like. Further study almost guarantees more surprises. (Credit: C. Pulliam & D. Aguilar/CfA)
The Kepler project is typically described in terms of raw numbers. As of the last official announcement, it had found 2,740 likely new planets–including 1,200 Neptune-size planets, 350 Earth-size planets, and at least 4 planets that orbit within the “habitable zone” where liquid water can exist. All of those numbers are sure to increase, as more observations are confirmed and as mission scientists continue to dig through a trove of archived data. But spirit, not statistics, is what really defines Kepler. It is a modern version of the expedition of Lewis and Clark, or the great voyages of Vasco da Gama and Ferdinand Magellan. It is a headlong plunge into the unknown cosmic territory around us.
Extrapolating from Kepler’s results, astronomers now estimate there are at least 17 billion Earth-size planets in our galaxy. That is another number, yes, but one with a powerful message: Another age of exploration awaits, one that may very well lead to the discovery that humanity is not alone in the universe. Read More
Your Biggest, Darkest Cosmic Questions Answered (Part 2)
Dark energy is the single most important element in the universe. It influenced how the cosmos was born, how it is evolving today, and how it all will end trillions of years in the future. Right now, this energy is causing the universe to expand faster and faster; in the far future, the expansion may become so rapid that space itself will be torn apart. And yet we know next to nothing about what dark energy is. We don’t even have a proper name for it—the very term “dark energy” is little more than a scientific shrug.
OUR COSMIC FATE hangs in the balance, depending on the behavior of dark energy. If dark energy increases, everything will be torn apart; if it changes direction, the cosmos could end in a big crunch. (Credit: NASA/CXC/M.Weiss)
Small wonder, then, that our recent DISCOVER magazine cover story about the mystery of dark energy (Confronting the Dark by Zeeya Merali) produced such an outpouring of curious reader mail. In a previous post, I addressed some of the key cosmological questions submitted by our readers. But really, that first set of responses only scratched the surface. For every letter writer who asked broadly about the nature of the Big Bang, someone else who wanted to know more about dark energy itself.
So as promised, here is a second installment addressing how scientists came to realize that energy, not matter, rules the universe. Read More
Your Biggest Cosmic Questions, Answered (Part 1)
Fifteen years ago, a small cabal of researchers took some of the most firmly held notions about how the universe works and turned them on their head. Until then, everyone was sure that the expanding universe was born in an explosive Big Bang and had been slowing down ever since, dragged by the gravitational pull of untold billions of galaxies. But in fact the expansion is speeding up. Everyone was sure that matter was what dominated the overall behavior of the universe. But in fact it seems that “dark energy,” not matter, is running the show. Whoops.
In Stephan’s Quintet, the ruddy galaxies are 8 times as far away as the bluish one at upper left. Astronomer deduce distances by measuring how light is affected by the expansion of the universe. (Credit: NASA, ESA and the Hubble SM4 ERO Team)
The May cover story in DISCOVER magazine (Confronting the Dark by Zeeya Merali) chronicles that game-changing discovery, and lays out the latest thinking about what dark energy is and how it affects the fate of the universe. As soon as the article was published, DISCOVER’s inbox began to fill with letters from curious readers wanting to know more. Here I will address sweeping, big-picture questions about cosmology. I’ll consider more specific queries about dark energy and dark matter in a following post. Read More
Update: The Battle Over Who Gets to Name Planets
Last Thursday, a team of scientists working with NASA’s Kepler space telescope described three intriguing new planets circling distant stars. They are just slightly larger than Earth and orbit in the “habitable zone” where temperatures could be right for liquid water and for life. The names of these amazing worlds? Kepler 62f, Kepler 62e, and Kepler 69c. Not to be confused with other much-celebrated recent discoveries like Kepler 64b, Kepler 22b, or Gliese 581g.
Scientific illustrations of recently discovered, potentially habitable worlds. Left to right: Kepler-22b, Kepler-69c, Kepler-62e, and Kepler-62f, compared with Earth at far right. (Credit: NASA/Ames/JPL-Caltech)
Alan Stern, a former NASA associate administrator and founder of a startup called Uwingu, thinks these newfound worlds should have real names, and that the general public should be able to have a say. The International Astronomical Union–the organization the organization that officially validates astronomical nomenclature–strongly objects to Uwingu’s approach, and has effectively thwarted it. After the IAU’s blistering April 12 press release attacking Uwingu, submissions to Uwingu’s fee-based online planetary naming database plummeted. Stern calls it a “torpedo attack.” Read More
Want to Have a Planet Named After You?
Or perhaps you would like to name it “Tatooine” or “Wrigley’s Pleasure Planet”? If so, you are in luck–all you need to pay a small fee and keep voting. A startup company called Uwingu is holding a “people’s choice contest” to pick a name for the nearest planet outside our solar system. It orbits Alpha Centauri B, an orange star located just 4.3 light years from Earth, and currently has the ungainly name Alpha Centauri Bb. For $4.99 you can propose a name of your own, and for $0.99 you can vote on the winner. The contest runs until April 22; there is also a broader, ongoing campaign for other alien worlds.
Illustration of the Earth-size planet orbiting Alpha Centauri B, part of the closest star system to home. The planet is currently known only as Alpha Centauri Bb. (Credit: ESO/L. Calçada/Nick Risinger)
Uwingu’s name-that-planet project has a noble aim. Alan Stern–the founder of the company, lead scientist for the New Horizons mission to Pluto, and a former associate administrator at NASA–is using the money raised by the contest to restore funding to NASA’s education and outreach efforts, which have been hit hard by sequester-related budget cuts. [Full disclosure: DISCOVER magazine and its sister publication, Astronomy, have partnered with Uwingu on its efforts to raise private funds for astronomical research.] But as one side effect, Stern has found himself embroiled in a battle with the International Astronomical Union (IAU), the self-described arbiter of “unambiguous astronomical nomenclature.” In a testy statement released on April 12, the IAU declared that private competitions (the union never cites Uwingu by name) will “have no bearing on the official naming process.”
All of which raises a big question for the rest of us: Who gets to name new astronomical objects, and how exactly do they get that right?
What Science Can Learn from “American Idol”
Although it’s been fading steadily in the TV ratings (despite the best efforts of Nicki Minaj), American Idol remains a cultural touchstone, and for good reason. It casts a wide net in the search for quality; it creates intense performance pressure that weeds out weak performers; and it rewards contestants who are able to connect with a broad audience. For those reasons, I thought that American Idol would be the perfect template for a symposium on how to help scientists do a better job communicating with the public.
America’s Science Idol cast: Gillian Bowser; judge Corey S. Powell; host Chris Mooney; judge Indre Viskontas; Joshua Schroeder; winner Tom DiLiberto; Maura Hahnenberger; and runner-up Jenna Jadin. (Not pictured: Dan Gareau and judge Jennifer Bogo.)
Or maybe I just thought it would be a lot of fun. Read More
Your 7-Step Guide to the Shadow Universe
Five-sixths of the universe is missing. That statement feels strange to write, and I’m sure it feels pretty strange to read as well. Given the vastness of the cosmos–and given how little of it humans have explored–how can we know for sure that anything is out of place? The claim sounds positively arrogant, if not delusional.
Color-coded, composite of the galaxy cluster Abell 520. Green denotes hot gas; orange highlights starlight from galaxies; blue shows the inferred location of dark matter. (Credit: NASA, ESA, CFHT, CXO, M.J. Jee, and A. Mahdavi)
And yet scientists have assembled a nearly airtight case that the majority of the matter in the universe consists dark matter, a substance which is both intrinsically invisible and fundamentally different in composition than the familiar atoms that make up stars and planets. In the face of staggering difficulties, researchers like Samuel Ting of MIT are even making progress in figuring out what dark matter is, as evidence by teasing headlines from last week. Time to come to terms, then, with the new reality about our place in the universe. Here are seven key things every informed citizen of the cosmos should know. Read More
The Explosive Truth About Cosmic Rays
What are those strange particles raining down on our planet from the depths of outer space?
Victor Hess (center) rode up in a balloon in 1912 to prove that Earth is bombarded by radiation from outer space. Astronomers are only now making sense of those enigmatic “cosmic rays.” (Credit: American Physical Society)
Physicists have been wrestling with that question for a century now, but the past couple months have seen remarkable progress toward a meaningful answer. It’s taken so long because researchers have had to overcome a lot of obstacles along the way. Even the name of the thing they are studying is confusing. The particles are formally known as cosmic rays even though they are not rays at all, but fragments of atoms that are moving at extremely high velocities. And those fragments are extremely difficult to study, because cosmic rays do not move in straight lines. They are electrically charged, so they bend to the will of the magnetic fields that snake almost everywhere through deep space. By the time a particular cosmic ray reaches Earth, its path may have nothing to do with the place where it started out. Looking at cosmic rays is like pointing a telescope into a set of funhouse mirrors. Read More
Four Surprises in Planck’s New Map of the Cosmos
By now you’ve probably heard about the amazing new cosmic snapshot from the European Space Agency’s Planck spacecraft. It is one of those scientific achievements so mind-boggling that you have to spend a bit of time with it to truly appreciate what you are seeing. This is relic radiation from when the universe was 370,000 years old, still all aglow from the Big Bang. The radiation has been traveling 13.8 billion years since then, across ever-expanding stretches of space, before landing in Planck’s detectors. Then it took a tremendous feat of imagination and insight to translate that noisy signal into a comprehensible map of what the universe looked like in its infancy.
Lopsided universe: Planck’s new skymap shows that one half of the microwave background is brighter than the other, and the universe has a large cold spot. Credit: ESA and the Planck Collaboration
So let’s step back for a moment, look at how this image came to be, and consider some of the more surprising details hidden within it. Read More
What Color is the Red Planet, Really?
Sounds like a trick question, doesn’t it? Sort of like “Who is buried in Grant’s Tomb?” And yet the answer keeps confounding a lot of smart people. (DISCOVER even published a whole feature on the question.) Now the issue keeps coming up again in the latest images from the Curiosity rover. Blue skies on Mars? Can that be right? Which of these images shows what Mars really looks like?
Is this the real Mars? A mosaic from NASA’s Curiosity rover shows Mount Sharp in raw color. NASA describes raw color as the way the scene would look “in a typical smart-phone camera photo.” (Credit: NASA/JPL-Caltech/MSSS)
The very first Viking images from the surface of Mars in July, 1976 showed blue skies, largely because that’s what people were expecting and so that is how the imaging experts initially set the color balance. They quickly realized their error and reissued the image with tangerine skies.
Or is this the real Mars? The scene has been given a white-balanced color adjustment that turns the sky blue. That change simulates Earth-like lighting, making it easier to interpret the geology. (Credit: NASA/JPL-Caltech/MSSS)
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