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The East African : November 25th 2013
The EastAfrican 28 OUTLOOK NOVEMBER 23-29,2013 S CI E N C E NASA’s Kepler spacecraft data shows billions of earth-like planets in galaxy One of eve≥y five sun-like sta≥s in the galaxy has a planet the size of Ea≥th By DENNIS OVERBYE Special Correspondent A stronomers reported recently that there could be as many as 40 billion habitable Earth-size planets in the galaxy, based on a new analysis of data from NASA’s Kepler spacecraft. One of every five sun-like stars in the galaxy has a planet the size of Earth circling it in the Goldilocks zone — not too hot, not too cold — where surface temperatures should be compatible with liquid water, according to a herculean threeyear calculation based on data from the Kepler spacecraft by Erik Petigura, a graduate student at the University of California, Berkeley. Mr Petigura’s analysis repre- sents a major step toward the main goal of the Kepler mission, which was to measure what fraction of sun-like stars in the galaxy have Earth-size planets. Sometimes called etaEarth, it is an important factor in the so-called Drake equation used to estimate the number of intelligent civilisations in the universe. Petigura’s paper, published in the journal Proceedings of the National Academy of Science, puts another smiley face on a cosmos that has become increasingly friendly and fecundlooking over the past 20 years. “It seems that the universe produces plentiful real estate for life that somehow resembles life on Earth,” said Mr Petigura. Over the past two decades, astronomers have logged more than 1,000 planets around other stars, so-called exoplanets, and Kepler, in its four years of life before being derailed by a mechanical pointing malfunction last May, has compiled a list of some 3,500 more candidates. The new result could steer plans in the next few years and decades to find a twin of the Earth — Earth 2.0, in the argot — that is close enough to here to study. The nearest such planet might be only 12 light-years away. “Such a star would be visible to the naked eye,” said Mr Petigura. His result builds on a report earlier this year by David Charbonneau and Courtney Dressing of the Harvard-Smithsonian Centre for Astrophysics, who found that about 15 per cent of the smaller and more numerous stars known as red dwarfs have Earth-like planets in their habitable zones. Using slightly less conservative assumptions, Ravi Kopparapu from Pennsylvania State University found that half of all red dwarfs have such planets. Astronomers estimate that there are at least 200 billion stars of all types in the Milky Way galaxy, room for the imagination, and — who knows — perhaps for a few microbes or more complicated creatures to roam. Geoffrey Marcy of the Uni- versity of California, Berkeley, who supervised Mr Petigura’s research and was a co-author of the paper along with Andrew Howard of the University of Hawaii, said: “This is the most important work I’ve ever been involved with. This is it. Are there inhabitable Earths out there? I’m feeling a little tingly,” he said. At a news conference two weeks ago discussing the results, astronomers erupted in praise of the Kepler mission and its team. Natalie Batalha, a Kepler leader from the NASA Ames Research Centre, described the project and its members as NASA’s Kepler mission has confirmed the existence of an Earth-likeNASA’s Kepler mission confirmed the existence of an Earth-like planet planet in the “habitable zone” around a star similar to our own sun. Kepler-22b is more like Earth than any planet yet found and could prove a key discovery in the ongoing quest for extraterrestrial life #/0.-,-+(./ '*/&-1(. 3$%.0)"/ 02*,4 in the “habitable zone” around a star similar to our own sun in 2011. Earth’s twin in the habitable zone KEPLER-22 SYSTEM HABITABLE ZONE: Area around star where SOLAR SYSTEM temperatures are right for water to exist in liquid form the Earth, though it is too hot to support life. “Nature,” as Mr Petigura put it, “knows how to make rocky Earth-size planets.” Also, the number is more uncertain than it might have been because Kepler’s pointing system failed before it could complete its prime survey. As a result, Mr Petigura and his colleagues had to extrapolate from planets slightly larger than Earth and with slightly smaller, tighter orbits. For the purposes of his analysis “Earth-size” was anything from one to two times the diameter of the Earth, and Earth-like orbits were between 400 and 200 days. Ms Batalha said, “We don’t yet have any planet candidates that are exact analogues of the Earth in terms of size, orbit or star type.” Mr Charbonneau said that raised “the terrifying question that haunts us exoplaneteers: Did the Kepler mission get enough data?” Though Kepler itself is side- Kepler-22b lies about 15% closer to its star than Earth to our sun. Its sun puts out about 25% less light, keeping planet at about 22C KEPLER-22b Size: 2.4 times that of Earth Length of year: About 290 days Distance from Earth: 600 light-years Composition: Not yet known whether made mostly of rock, gas or liquid Kepler Telescope has so far found 2,326 candidate planets of which 207 are Earth-sized. Kepler-22b is first of 48 habitable zone candidates to be confirmed © GRAPHIC NEWS Source: NASA “The universe produces plentiful real estate for life that somehow resembles life on Earth.” Erik Petigura, UC Berkeley “the best of humanity rising to the occasion.” According to Mr Petigura’s new calculation, the fraction of stars with Earth-like planets is 22 per cent, plus or minus eight per cent, depending on exactly how you define the habitable zone. There are several caveats. Al- though these planets are Earthsize, nobody knows what their masses are and thus whether they are rocky like the Earth, Mercury Venus Earth Mars &2(3,87 (3+ 46)087 84 7*(2, ����������������������� '89+0,7 =;,+ 7:(8/, 430./8 71< *438(0303. (6493+ $%#"### 78(67" 2 44103. -46 +057 03 )60./83,77 (7 52(3,87 86(3708 (*6477 -(*, 4- /478 78(67 or balls of ice or gas, let alone whether anything can, or does — or ever will — live on them. There is reason to believe, from recent observations of other worlds, however, that at least some Earth-size planets, if not all of them, are indeed rocky. Two groups of astronomers recently announced that an Earth-size planet named Kepler 78b that orbits its sun in 8.5 hours has the same density as lined while astronomers devise a new programme it can accomplish with less flexible pointing ability, it has sent back so much data that there is still a whole year’s worth of results left to analyse, Ms Batalha said, and more improvements to make to the data already obtained. “Scientists,” she said, “are going to work on Kepler data for decades.” She said it would be about three years before they would be able to arrive at a viable rate for the occurrence of habitable Earths. Kepler was launched in 2009 to perform a kind of cosmic census, monitoring the brightness of 150,000 far-off stars in the Cygnus and Lyra constellations, looking for dips in brightness when planets pass in front of them. Mr Petigura and his colleagues restricted themselves to a subset of some 42,000 brighter and well-behaved stars. They found 603 planets, of which 10 were between one Earth and two Earths in diameter, and circled in what Mr Petigura defined as the habitable zone, where they would receive between a quarter of the light the Earth gets, and four times as much. New York Times News Service Global mala≥ia expe≥ts push fo≥ vaccines with 75pc e∞cacy by 2030 By CHRISTABEL LIGAMI Special Correspondent GLOBAL MALARIA experts and partners have agreed on a new approach for developing vaccines capable of reducing malaria cases by 75 per cent, and eliminating it. The new Malaria Vaccines Road- map will target next generation products by 2030. The updated 2013 Malaria Vaccine Technology Roadmap indicates that the world should aim to have licensed vaccines that reduce malaria cases by 75 per cent, and are capable of eliminating it by 2030. It comes in addition to the origi- nal 2006 Roadmap’s goal of having a licensed vaccine against Plasmodium falciparum malaria — the most deadly form of the disease — for children under five years in sub-Saharan Africa by 2015. “Safe, effective, affordable vac- cines could play a critical role in defeating malaria,” said Robert Newman, director of the World Health Organisation’s Global Malaria Programme adding that “despite all the recent progress countries have made, and despite important innovations in diagnostics, drugs and vector control, the global burden of malaria remains unacceptably high.” The new roadmap aims to iden- tify where additional funding and activities will be particularly key in developing second generation malaria vaccines both for protection against malaria disease and for malaria elimination. These include next-generation vaccines that target both Plasmodium falciparum and Plasmodium vivax species of malaria. 300,000 “The new vaccines should show at least 75 per cent efficacy against clinical malaria, be suitable for use in all malaria-endemic areas, and be licensed by 2030. The roadmap also sets a target for malaria vaccines that reduce transmission of the parasite,” said Jean-Marie Okwo Bele, director of WHO’s department of Immunisation, Vaccines and Biologicals. Reason for the update The 2013 Malaria Vaccine Tech- The number of deaths that occur annually in East Africa as a result of malaria cases according to WHO nology Roadmap cites several reasons for the update, among them: changing malaria epidemiology associated with the successful scale- up of malaria control measures in the past decade; a renewed focus on malaria elimination and eradication in addition to the ongoing need to sustain malaria control activities and new technological innovations since 2006 including promising early work on so-called transmission-blocking malaria vaccines. The most recent figures by WHO indicate that malaria causes an estimated 660,000 deaths each year from 219 million cases of illness. In East Africa, WHO indicates that 16 to 18 million malaria cases are reported every year and more than 300,000 deaths.
November 18th 2013
December 2nd 2013