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View Full Version : Planet Found in Habitable Zone Around Nearest Star Piquerobi 24 August 2016 Pale Red Dot campaign reveals Earth-mass world in orbit around Proxima Centauri Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016. Just over four light-years from the Solar System lies a red dwarf star that has been named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star in the constellation of Centaurus is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB. During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world [1]. This was the Pale Red Dot campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet [2]. As this was a topic with very wide public interest, the progress of the campaign between mid-January and April 2016 was shared publicly as it happened on the Pale Red Dot website and via social media. The reports were accompanied by numerous outreach articles written by specialists around the world. Guillem Anglada-Escudé explains the background to this unique search: “The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning.” The Pale Red Dot data, when combined with earlier observations made at ESO observatories and elsewhere, revealed the clear signal of a truly exciting result. At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance [3]. Guillem Anglada-Escudé comments on the excitement of the last few months: "I kept checking the consistency of the signal every single day during the 60 nights of the Pale Red Dot campaign. The first 10 were promising, the first 20 were consistent with expectations, and at 30 days the result was pretty much definitive, so we started drafting the paper!" Red dwarfs like Proxima Centauri are active stars and can vary in ways that would mimic the presence of a planet. To exclude this possibility the team also monitored the changing brightness of the star very carefully during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity data taken when the star was flaring were excluded from the final analysis. Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the Sun [4]. Two separate papers discuss the habitability of Proxima b and its climate. They find that the existence of liquid water on the planet today cannot be ruled out and, in such case, it may be present over the surface of the planet only in the sunniest regions, either in an area in the hemisphere of the planet facing the star (synchronous rotation) or in a tropical belt (3:2 resonance rotation). Proxima b's rotation, the strong radiation from its star and the formation history of the planet makes its climate quite different from that of the Earth, and it is unlikely that Proxima b has seasons. This discovery will be the beginning of extensive further observations, both with current instruments [5] and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind’s first attempt to travel to another star system, the StarShot project. Guillem Anglada-Escudé concludes: "Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us. Many people’s stories and efforts have converged on this discovery. The result is also a tribute to all of them. The search for life on Proxima b comes next..." http://www.eso.org/public/news/eso1629/ Piquerobi Hopefully it will not take too long for our first interstellar trip, even if unmanned: Stephen Hawking Helps Launch Project 'Starshot' for Interstellar Space Exploration Stephen Hawking wants humanity to reach the stars. The famed cosmologist, along with a group of scientists and billionaire investor Yuri Milner, unveiled an ambitious new $100 million project today (April 12) called Breakthrough Starshot, which aims to build the prototype for a tiny, light-propelled robotic spacecraft that could visit the nearby star Alpha Centauri after a journey of just 20 years. "With light beams, light sails and the lightest spacecraft ever built, we can launch a mission to Alpha Centauri within a generation," he added. "Today, we commit to this next great leap into the cosmos. Because we are human, and our nature is to fly." The Starshot spacecraft will consist of a wafer-size chip attached to a super-thin sail. This paired duo will be launched to space aboard a mothership, and then propelled to the stars by laser light beamed from a high-altitude facility here on Earth. Such a craft, Milner said, could be accelerated up to 20 percent the speed of light — fast enough to make it to the Alpha Centauri system, which lies 4.37 light-years away, just two decades after launch. (It would take a conventionally propelled probe about 30,000 years to make such a trip.) "We call it the Nanocraft," Milner said. "Our interstellar sailboat." The Nanocraft "could capture images of possible planets and other scientific data and send them back home in a beam of light," Milner added. "If this mission succeeds, it will tell us as much about ourselves as it will about Alpha Centauri. "Breakthrough Starshot is based on technology either available or likely to be available in the near future," Milner said, adding that all of its work is based on data in the public domain. Developing and proving out Starshot technology will be time-consuming and expensive; sending Nanocraft to Alpha Centauri will probably end up costing about as much as the largest scientific experiments operating today, team members said. But subsequent missions should be much cheaper, and economies of scale will allow many Nanocraft to launch on a single flight to provide redundancy and increase photographic coverage of the target star system. (The chip at the heart of each Nanocraft costs about as much as an iPhone to produce, Breakthrough Starshot representatives said.) Today's announcement comes on the 55th anniversary of cosmonaut Yuri Gagarin's historic launch on Vostok 1 in 1961, a mission that ushered in the era of human spaceflight. Milner, who was born in Moscow, has said he was named in honor of Gagarin. Today is also the 35th anniversary of NASA's first space shuttle flight, STS-1, aboard Columbia. "The human story is one of great leaps," Milner said in a statement. "Fifty-five years ago today, Yuri Gagarin became the first human in space. Today, we are preparing for the next great leap — to the stars." Breakthrough Starshot's board consists of Hawking, Milner and Mark Zuckerberg, the founder and CEO of Facebook. This is not the first time Hawking and Milner have worked together: Hawking helped unveil Milner's 10-year, $100 million initiative to search for signs of intelligent life called Breakthrough Listen last July. That project, which is billed as the most powerful search ever for extraterrestrial life, will survey 1 million stars in the Milky Way closest to Earth. The 10-year project will also scan the 100 closest galaxies to our own for any traces of intelligent life. Milner, meanwhile, is also funding the Breakthrough Message project, which will award up to $1 million in prizes to people who craft the best messages to send out to any intelligent life that may be listening. http://www.space.com/32546-interstellar-spaceflight-stephen-hawking-project-starshot.html Mestace It's a great timing to find investors for Starshot. Thinking that in our neareast system, we already find a very good exoplanet candidate with a comparable mass of earth says a lot. On the other hand it was so close and it tooks us so much time to find/confirm it, but tellurics are always tricky. MikeWhalen more on the starshot idea...sounds way cool! 20 yrs to figure out how to build it and then 20 years to send the little wee probes to Proxima b https://www.yahoo.com/news/could-visit-possibly-earth-planet-proxima-b-142417076.html "How We Could Visit the Possibly Earth-Like Planet Proxima b Calla Cofield, Space.com Staff Writer August 25, 2016 How We Could Visit the Possibly Earth-Like Planet Proxima b This illustration shows a Breakthrough Starshot nanocraft, which could travel to the star Proxima Centauri, where a potentially Earth-like planet was recently discovered. More A potentially Earth-like planet has been discovered orbiting a star located right next door to the sun. Should humanity try to send a probe there as soon as possible? The newly discovered planet, known as Proxima b, orbits the star Proxima Centauri, the closest star to the sun. Proxima Centauri is about 4.22 light-years — or 25 trillion miles (40 trillion kilometers) — from Earth. That's a daunting distance. But an initiative announced earlier this year aims to send superfast miniature probes to Proxima Centauri, on a journey that would take about 20 years. With the discovery of Proxima b, the founders of that initiative are even more eager to get going. [Proxima Centauri's Alien Planet Closer Than You Think (Video)] It's a long trip In 2015, NASA's New Horizons probe completed its 3-billion-mile (4.8 billion km) journey to Pluto after traveling for about 9.5 years. The spacecraft traveled at speeds topping 52,000 mph (84,000 km/h). At that rate, it would take New Horizons about 54,400 years to reach Proxima Centauri. Last month, NASA's Juno probe reached speeds of about 165,000 mph (265,000 km/h) as it entered into orbit around Jupiter. At that rate, a probe could reach Proxima Centauri in about 17,157 years. (It should also be noted that there is currently no feasible way to accelerate a craft large enough to carry humans to those speeds.) In other words, sending a probe to the nearest star system would not be easy. The founders of the Breakthrough Starshot initiative want to send wafer-thin probes to Proxima Centauri at very high speeds. The plan calls for equipping these probes with thin sails, which would capture the energy imparted by a powerful Earth-based laser. This laser would accelerate the probes to 20 percent the speed of light (about 134.12 million mph, or 215.85 million km/h), according to the program scientists. At that rate, the probes could reach Proxima Centauri in 20 to 25 years. But first, scientists and engineers have to build the apparatus that will launch the tiny probes on their journey. In a news conference today (Aug. 24), Pete Worden, chairman of the Breakthrough Prize Foundation, said that a group of experts had convened earlier this week and discussed plans to build a prototype of the Starshot system. However, he added that the full-scale apparatus is at least 20 years off. "We certainly hope that, within a generation, we can launch these nanoprobes," Worden said. "And so perhaps 20, 25 years from now, we could begin to launch them, and then they would travel for 25 years to get there." He added that building the full-scale apparatus would likely cost about the same as building the Large Hadron Collider, the largest particle accelerator in the world; that project is estimated to have cost about $10 billion. "Over the next decade, we will work with experts here at ESO [the European Southern Observatory] and elsewhere to get as much information as possible about the Proxima Centauri planet … even including whether it might bear life, prior to launching mankind's first probe towards the star," Worden said. Worden said the Breakthrough Prize Foundation also hopes to "obtain similar data about the other nearby stars, Alpha Centauri A and B." (The two Alpha Centauri stars lie about 4.37 light-years from Earth; some astronomers think Proxima Centauri and the Alpha Centauri stars are part of the same system.) [Proxima b: Closest Earth-Like Planet Discovery in Pictures] The power of an up-close look The New Horizons mission to Pluto was a good demonstration of the benefits of sending a probe to study a planet (or dwarf planet). Images of Pluto captured by the world's most powerful telescopes could barely resolve any surface features on the icy world. During its 2015 flyby, New Horizons provided an incredibly detailed view of Pluto's surface and a boatload of new information about its history. Could a wafer-thin probe sent to Proxima Centauri b reveal similar details about the planet, or perhaps even reveal the presence of life? There would be some significant limitations to how much information the probes proposed by Breakthrough Starshot would be able to send back to Earth. First and foremost, the data would take 4.22 years to travel back to Earth, on top of the 20 to 25 years it would take the probe to get to Proxima Centauri. Seth Shostak, a senior astronomer at the SETI Institute (SETI stands for "search for extraterrestrial intelligence"), told Space.com that the prospect of sending a miniature probe to Proxima Centauri is "even more interesting now than it was ... six months ago because now we know there is a planet there." "I think [the discovery of Proxima b] has real implications for sending something physical to the star system because now there's a target of interest," Shostak said. But he also brought up some of the unknown variables that people will have to consider when investing in Breakthrough Starshot, including what kind of information the probes could send back from the planet. Those wafer-thin probes would have to carry very small instruments, and thus might be able to do only a very rudimentary study of a planet or star. It's difficult to predict the exact technology that would be on board, because electrical components and other technical gear will likely continue to shrink in size over the next 20 years. Scientists and engineers would have to consider whether, in the time it would take for information to come back from a probe sent to Proxima Centauri, they could build a telescope capable of gathering the same information. Penelope Boston, director of NASA's Astrobiology Institute, thinks the continuing trend of hardware miniaturization will make it possible to equip a wafer-thin probe with instrumentation that would make a trip to Proxima Centauri well worth the investment. Boston said the intricate details of a planet's surface can create a huge variety of specific habitats, and resolving the details of those environments on a planet outside Earth's solar system is "certainly beyond the resolution of any conceivable telescope." "I see the trends in all different kinds of instrumentation going in a kind of ['Star Trek'] tricorder direction, where you have more and more capability packaged into ever-small physical space," Boston told Space.com." Mike Powered by vBulletin® Version 4.2.0 Copyright © 2017 vBulletin Solutions, Inc. All rights reserved.
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Možda i najveće otkriće posljednjih stoljeća: Proxima b – planet sličan Zemlji Osim što je nama najbliži planet koji kruži oko neke zvijezde koja nije Sunce, ovo bi mogao biti i nama najbliži planet prikladan za život izvan Sunčeva sustava. Za znanstvenike Europskog svemirskog opservatorija čije je sjedište u Garchingu kraj Munchena, nema više nikakve dvojbe. U orbiti Proxima Centaurija, zvijezde najbliže našem Suncu, nalazi se planet zasad nazvan Proxima b čija temperatura omogućuje postojanje tekuće vode na njegovoj površini. Upravo onako kako je njemački Der Spiegel najavljivao prošlog tjedna. Taj je stjenoviti planet tek nešto veći od Zemlje, točnije 1,3 puta, te svoju zvijezdu obiđe za 11 dana. Također, osim što je nama najbliži planet koji kruži oko neke zvijezde koja nije Sunce, ovo bi mogao biti i nama najbliži planet prikladan za život izvan Sunčeva sustava. Ovaj znanstveni rad koji će biti već danas objavljen u časopisu Nature, možda je i najveće otkriće posljednjih stoljeća. – Također znamo i za nekoliko otkrivenih planeta u nastanjivim zonama oko drugih zvijezda. Osobitost planeta u nastanjivoj zoni je da mogu posjedovati vodu u tekućem stanju. Postojanje tekuće vode na nekom svemirskom objektu znanstvenicima je pokazatelj da bi tamo mogao postojati život. Pa, tako i u slučaju ovog novootkrivenog planeta. Naglasimo, kako je Alpha Centauri, trostruki sustav zvijezda, pa bi stanovnici planeta Proxima b mogli na nebu vidjeti tri sunca, entuzijastično će dr. Maričić te dodaje kako bi teorijski svemir mogao biti pun života, no za to još nemamo dokaza. Pitanje je to na koje odgovora još nemamo, a možda ćemo odgovor na njega tražiti još generacijama. Od Proxima Centaurija udaljeni smo tek nešto više od četiri svjetlosne godine, točnije 4,25, a planet oko njega kruži na udaljenosti od sedam milijuna kilometara. Što je tek pet posto udaljenosti na kojoj Zemlja kruži oko Sunca. Međutim, zvijezda Proxima Centauri je i daleko slabijeg sjaja od Sunca. Shodno tome, novootkriveni Proxima b nalazi se unutar nastanjive zone. Ipak, uvjeti na njegovoj površini mogli bi biti pod snažnijim utjecajem štetnih ultraljubičastih i X zraka, negoli što takve zrake sa Sunca imaju utjecaj na Zemlju. Znanstvenici potvrđuju kako se postojanje tekuće vode nikako ne može isključiti. Ako je ona tamo prisutna, prilično je sigurno da je ima ponajviše u osunčanim predjelima. Brzina rotacije Proxime b, jaka radijacija Proxime Centauri te povijest stvaranja planeta čini njegovu klimu bitno drugačijom od one na Zemlji, a nije ni izvjesno ima li Proxima b godišnja doba. Planet je otkriven teleskopom s opservatorija La Silla u Čileu. Bila je to inicijativa imenaPale Red Dot u kojem je momčad astronoma na čelu s Guillemom Anglada-Escudeom s Londonskog sveučilišta Queen Mary tražila mogući planet koji bi kružio oko Suncu najbliže zvijezde Proxime Centauri. – Prve smo naznake mogućeg planeta uvidjeli još 2013. godine, no nismo još mogli potvrditi njegovo postojanje. Od tada smo teško radili kako bismo dobili dodatne potvrde uz pomoć Europskog svemirskog i drugih opservatorija, rekao je Anglada-Escude. Proxima b sada će vjerojatno postati središtem nastojanja čovječanstva da pronađe život drugdje u svemiru. – Pronađeno je već puno egzoplaneta i još će ih puno biti pronađeno, no potraga za najbližim planetom sličnim Zemlji i uspijevanje u tome bilo je životno iskustvo za sve nas, rekao je Anglada-Escude te završio kako je sljedeće na redu potraga za životom na planetu Proximi b. Zapravo na zemlji već postoji projekt koji je i sada očito dobio jedan konkretan zadatak. Cilj Breakthrough StarShota je čovjeka prviput odvesti u drugi zvjezdani sustav, konkretno baš u Alpha Centauri. Projekt predviđa kako će se do tog sustava putovati brzinom 15 do 20 posto brzine svjetlosti. Po toj računici, inovativnoj letjelici trebalo bi između 20 i 30 godina da tamo stigne, te još četiri da na Zemlju stigne obavijest kako je putovanje proteklo kako treba. U travnju ove godine StarShot predstavio je nitko drugi doli Stephen Hawking u društvu investitora Yurija Millera. U upravnom odboru tvrtke pod čijim se okriljem razvija StarShot sjedi Mark Zuckerberg, vlasnik Facebooka. Računa se da će ukupni trošak projekta biti između pet i deset milijardi dolara, a prvo pokusno polijetanje moglo bi biti za nekih 20 godina. Izvor: vecernji.hr