Natalie Batalha has had copiousness of knowledge fielding questions from both layfolk and other scientists over a past integrate of years  and with good reason. Batalha is a emissary principal questioner for a spectacularly successful Kepler space telescope, that has found justification of some-more than 2,000 planets orbiting apart stars so distant  including, usually final week, .
But Kepler is also giving astronomers all sorts of new information about stars as well, and that's what a European TV match wanted to know about during an talk final year. Was it true, she asked, that stars like a Sun will eventually bloat adult and destroy their planets? It's a common question, and Batalha shouted a informed answer, one that's been in astronomy textbooks for during slightest half a century: Yes, it's true. Five or 6 billion years from now, Earth will be burnt to a cinder. This aged news was apparently utterly new to a European correspondent, since when she reported her terrifying scoop, she combined a soupçon of swindling speculation to it: NASA, she suggested was perplexing to downplay, and maybe even suppress, a story.
It was not a unapproachable impulse for scholarship journalism, though unexpectedly, during about a same time a European match was stating her non-bulletin, Kepler scientists did learn a whole new fold to a planet-eating star scenario: it's apparently probable for planets to be swallowed adult by their suns and live to tell a tale. According to a paper usually published in Nature, a Kepler examine has taken a closer demeanour during a star called KOI 55 and identified it to be a "B subdwarf," a impassioned remains of a Sun-like star, one that already went by a lethal expansion. Around it, whirling in orbits so parsimonious they final usually about 5 and 8 hours, respectively, are dual planets, both a bit smaller than Earth  and both so tighten to their home star that even a minute solar enlargement ought to have consumed them whole. And nonetheless they seem, writes University of California, Santa Cruz, astronomer Eliza Kempton in a Nature commentary, "to be alive and well. Which begs a question, how did they survive?"
How indeed? A star like a Sun is powered by chief fusion, in that hydrogen is converted to helium and releases large amounts of appetite in a process. It takes about 10 billion years to use adult a hydrogen supply, that means that a sun, that is 5 billion years old, is using on a half-empty fuel tank. Once a hydrogen is gone, a star cools from white-hot to red-hot, and swells dramatically: in a box of a solar system, a Sun's outdoor layers will strech all a approach to Earth. Eventually, those outdoor layers will rush pided to form what's called a , while a core shrinks behind into an intent usually like KOI 55.
If a world like Earth spent a billion years simmering in a outdoor layers of a star  a trustworthy time span, given what astronomers know of stellar expansion  it would, says University of Arizona astronomer Betsy Green, a co-author on a Nature paper, in a press release, "just evaporate. Only planets with masses unequivocally most incomparable than a Earth, like Jupiter or Saturn, could presumably survive."
And nonetheless these dual worlds, famous as KOI 55.01 and KOI 55.02, lived by a distress anyway. The pivotal to this ostensible impossibility, advise a astronomers, is that a planets competence have begun life as gas giants like Jupiter or Saturn, with hilly cores surrounds by vast, abrasive atmospheres. As a star expanded, a gas giants would have spiraled central until they dipped into a stellar aspect itself. The thrust would have been adequate to frame off their atmospheres, though their hilly interiors could have survived  leaving, eventually, a dour tableau of a exposed cores of dual planets orbiting a exposed core of an aged star.
What creates this find doubly startling is that a astronomers who done it weren't looking for planets in a initial place: they were perplexing to get a hoop on a final stages of stellar expansion  specifically, on a pulsations aged stars go by in their extended genocide throes. KOI 55 was pulsing all right, in most a approach theorists have described, and that supposing a clues that led to a find of a star's dry-roasted offspring.
Superimposed on a days-long pulsations, a astronomers discovered, were changes in liughtness that came on timescales of usually hours. Unlike a worlds Kepler routinely finds, these changes weren't found to be a outcome of a planets flitting on front of a star and dimming some of a light. They occurred instead since a planets go by phases like a Moon  entirely bright when they're on a distant side of a star, scarcely dim when they're on a nearby side.
That nifty bit of vast reduction was sparkling for astronomers, though it offers small soundness for those fretting about how we'll transport when a possess Sun bloats out to Earth-frying size. Waiting for Jupiter to turn in and remove a atmosphere, afterwards hopping on over, doesn't unequivocally feel like a applicable solution. But  note to that European TV contributor  never fear. Given that we have 5 billion years to figure things out, it competence be a small beforehand to panic.
News referensi http://www.time.com/time/health/article/0%2C8599%2C2103159%2C00.html
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3:01 AM Thursday, December 29, 2011