How many planets are in our galaxy? Billions and billions of them at least. That’s the conclusion of a new study by astronomers at the California Institute of Technology, which provides yet more evidence that planetary systems are the cosmic norm. The team made their estimate while analyzing planets orbiting a star called Kepler-32 — planets that are representative, they say, of the vast majority of planets in our galaxy and thus serve as a perfect case study for understanding how most of these worlds form. “There are at least 100 billion planets in the galaxy, just our galaxy,” says John Johnson, assistant professor of planetary astronomy at Caltech and coauthor of the study, which was recently accepted for publication in the Astrophysical Journal. “That’s mind-boggling.” “It’s a staggering number, if you think about it,” adds Jonathan Swift, a postdoctoral student at Caltech and lead author of the paper. “Basically, there’s one of these planets per star.” M-dwarf study Like the Caltech group, other teams of astronomers have estimated that there is roughly one planet per star, but this is the first time researchers have made such an estimate by studying M-dwarf systems, the most numerous population of planets known. The planetary system in question, which was detected by NASA’s Kepler space telescope, contains five planets. Two of the planets orbiting Kepler-32 had previously been discovered by other astronomers. The Caltech team confirmed the remaining three, then analyzed the five-planet system and compared it to other systems found by Kepler. M-dwarf systems like Kepler-32′s are quite different from our own solar system. For one, M dwarfs are cooler and much smaller than the sun. Kepler-32, for example, has half the mass of the sun and half its radius. The radii of its five planets range from 0.8 to 2.7 times that of Earth, and those planets orbit extremely close to their star. The whole Kepler-32 system fits within just over a tenth of an astronomical unit (the average distance between Earth and the sun) — a distance that is about a third of the radius of Mercury’s orbit around the sun. The fact that M-dwarf systems vastly outnumber other kinds of systems carries a profound implication, according to Johnson, which is that our solar system is extremely rare. “It’s just a weirdo,” he says. (via Billions and billions of planets | KurzweilAI)
Posts Tagged ‘Space’
Films suggest that our future is full of fantastically large spacecraft in galaxies far, far away. But the reality is that our ambitions in space are small – and seemingly getting smaller – says Quentin Cooper.
Space is big. Really big. You just won’t believe how vastly, hugely, mind- bogglingly big it is. Spaceships are really big too. The first few lines, as you probably recognised, are from Douglas Adams’ Hitchhiker’s Guide to the Galaxy. The other line about spaceships? That’s from pretty much every other off-world sci-fi movie of the last few decades. But it’s beginning to look like – at least for the foreseeable future – it’s wrong. It’s tempting to blame the error on something that happened a long time ago in a cinema far, far away – the overwhelming opening shot of the first Star Wars film. That’s first as in the first one made and the first good one in the finished sequence. After the backstory has crawled by, Princess Leia’s (fairly sizeable) spaceship zips across the screen. Then behind it, with the speakers shaking the seats, comes the Imperial Star Destroyer which takes a full 12 seconds to rumble over our point of view. Twelve seconds – we’re into a whole new galactic scale of bigness. That was 1977, and its success, coupled with giant strides in CGI, has ensured our visions of exploring the galaxy are full of fleets of fantastically large spacecraft. Even ignoring the huge shadow cast by alien visitors like the mothership in Close Encounters or the landmark-zapping saucers in Independence Day, we’ve grown used to the idea of humans criss-crossing the cosmos in vast vessels like Nostromo in Alien, the titular Event Horizon, the six mile-long Red Dwarf, or the many colossal starships in series like Stargate and Battlestar Galapagos (as it’s always known in my house). (via BBC – Future – Science & Environment – Space ambitions shrink in scale)
Astronauts are limited to spending six months on the International Space Station, around 200 miles above Earth, for a good reason. The loss of bone and muscle mass they experience in space is so profound that they cannot stay any longer. But what about the health impact of forthcoming suborbital flights for space tourists who are not fit, highly-trained individuals? According to North American scientists writing in the British Medical Journal article, GPs should be prepared to answer patients’ queries about their suitability for space travel in the near future. Yet there will be few GPs experienced enough in space medicine to provide advice. Continue reading the main story “Start Quote We don’t want to have so many medical restrictions that no one can fly, but we want to make sure we truly understand the effects of these flights” Dr Jon Scott space scientist Past research tells us that spaceflight causes changes in the physiology of the human body, but how it might affect underlying medical conditions in an unfit, 50-year-old space tourist is not yet clearly known. (via BBC News – What are the health risks of space travel?)
There is, in this crazy world, one thing we know for sure: Our world is the world. Our planet is the planet — for creating life, for supporting life, for letting us humans and our fellow species become what we are. And so, as we take our first tentative steps from a warm, watery Earth out into the universe, we set our sights toward the worlds that look like the one we know — toward planets that are, in their way, “Earth-like.” But: What if there are planets that are better at being Earth-like than Earth itself? What if there are worlds that are more homey than home? What if other planets are better at supporting life than our own? It’s a possibility, actually, according to new work coming out of Ohio State — and just a little bit of cosmic conjecture. A team of astronomers and geologists at the university, using data gathered by the High Accuracy Radial Velocity Planet Searcher spectrometer at the European Southern Observatory in Chile, made a study of eight stars that are “solar twins” to our sun — similar in factors like size, age, and composition — and measured the amounts of radioactive elements those stars contain. Combining those analyses with theories about the conditions that made Earth hospitable to life, the team has made an exciting, if preliminary, finding: that the terrestrial planets orbiting those stars could be hotter and more dynamic than Earth. Which might make them, according to the theory, more hospitable to life than Earth. (via Are There Planets Better at Supporting Life Than Earth? – Megan Garber – The Atlantic)
Nasa’s Voyager 1 spacecraft has entered a new region at the edge of the solar system and is close to becoming the first spaceship to journey into interstellar space.
Scientists have dubbed this previously unknown region the “magnetic highway” and it’s the last stop before interstellar space, or the space between stars. The region allows charged particles from inside the heliosphere to flow outward and particles from the galaxy outside to come in. The news of Voyager’s progress was presented on Monday at a meeting of the American Geophysical Union meeting in San Francisco. “We do believe this may be the very last layer between us and interstellar space,” MSNBC reported Edward Stone, a Voyager project scientist, as saying. “This region was not anticipated, was not predicted.” (via Voyager 1 on the brink of leaving the solar system – Telegraph)