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Science/Tech See other Science/Tech Articles Title: Planet Found in Nearest Star System to Earth: HARPS Instrument Finds Earth-Mass Exoplanet Orbiting Alpha Centauri B ScienceDaily (Oct. 16, 2012) — European astronomers have discovered a planet with about the mass of Earth orbiting a star in the Alpha Centauri system -- the nearest to Earth. It is also the lightest exoplanet ever discovered around a star like the Sun. The planet was detected using the HARPS instrument on the 3.6-metre telescope at ESO's La Silla Observatory in Chile. The results will appear online in the journal Nature on Oct. 17, 2012. Alpha Centauri is one of the brightest stars in the southern skies and is the nearest stellar system to our Solar System -- only 4.3 light-years away. It is actually a triple star -- a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri [1]. Since the nineteenth century astronomers have speculated about planets orbiting these bodies, the closest possible abodes for life beyond the Solar System, but searches of increasing precision had revealed nothing. Until now. "Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days," says Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal), lead author of the paper. "It's an extraordinary discovery and it has pushed our technique to the limit!" The European team detected the planet by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet [2]. The effect is minute -- it causes the star to move back and forth by no more than 51 centimetres per second (1.8 km/hour), about the speed of a baby crawling. This is the highest precision ever achieved using this method. Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The newly discovered planet, with a mass of a little more than that of Earth [3], is orbiting about six million kilometres away from the star, much closer than Mercury is to the Sun in the Solar System. The orbit of the other bright component of the double star, Alpha Centauri A, keeps it hundreds of times further away, but it would still be a very brilliant object in the planet's skies. The first exoplanet around a Sun-like star was found by the same team back in 1995 and since then there have been more than 800 confirmed discoveries, but most are much bigger than Earth, and many are as big as Jupiter [4]. The challenge astronomers now face is to detect and characterise a planet of mass comparable to Earth that is orbiting in the habitable zone [5] around another star. The first step has now been taken [6]. "This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it," adds Stéphane Udry (Geneva Observatory), a co-author of the paper and member of the team, "but it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems." "This result represents a major step towards the detection of a twin Earth in the immediate vicinity of the Sun. We live in exciting times!" concludes Xavier Dumusque. Notes [1] The components of a multiple star are named by adding uppercase letters to the name of the star. Alpha Centauri A is the brightest component, Alpha Centauri B is the slightly fainter second star and Alpha Centauri C is the much fainter Proxima Centauri. Proxima Centauri is slightly closer to Earth than A or B and hence is formally the closest star. [2] HARPS measures the radial velocity of a star -- its speed towards or away from Earth -- with extraordinary precision. A planet in orbit around a star causes the star to regularly move towards and away from a distant observer on Earth. Due to the Doppler effect, this radial velocity change induces a shift of the star's spectrum towards longer wavelengths as it moves away (called a redshift) and a blueshift (towards shorter wavelengths) as it approaches. This tiny shift of the star's spectrum can be measured with a high-precision spectrograph such as HARPS and used to infer the presence of a planet. [3] Using the radial velocity method, astronomers can only estimate a minimum mass for a planet as the mass estimate also depends on the tilt of the orbital plane relative to the line of sight, which is unknown. But, from a statistical point of view, this minimum mass is often close to the real mass of the planet. [4] NASA's Kepler mission has found 2300 candidate planets using an alternative method -- searching for the slight drop in the brightness of a star as a planet passes in front of it (transits) and blocks some of the light. The majority of planet candidates detected by this transit method are very distant from us. But, in contrast, the planets found by HARPS are around stars close to the Sun -- with the new discovery being the closest yet. This makes them better targets for many kinds of additional follow-up observations such as characterising the planet's atmosphere. [5] The habitable zone is a narrow annular region around a star in which water may be present in liquid form if conditions are right. [6] ESPRESSO, the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, is to be installed on the ESO Very Large Telescope. Currently undergoing final design, it is scheduled to start operating in late-2016 or early-2017. ESPRESSO will feature radial velocity precision of 0.35 km/hour or less. For comparison, Earth induces a 0.32 km/hour radial velocity on the Sun. This resolution should thus enable ESPRESSO to discover Earth-mass planets in the habitable zone. The ESPRESSO consortium is led by team members responsible for the current discovery. More information This research was presented in a paper "An Earth mass planet orbiting Alpha Centauri B," to appear online in the journal Nature on Oct. 17, 2012. Poster Comment: Extrasolar planet From Wikipedia, the free encyclopedia The three known planets of the star HR8799, as imaged by the Hale Telescope. The light from the central star was blanked out by a vector vortex coronagraph. 2MASS J044144 is a brown dwarf with a companion about 5–10 times the mass of Jupiter. It is not clear whether this companion object is a sub-brown dwarf or a planet. Coronagraphic image of AB Pictoris showing a companion (bottom left), which is either a brown dwarf or a massive planet. The data was obtained on 16 March 2003 with NACO on the VLT, using a 1.4 arcsec occulting mask on top of AB Pictoris. An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of 842 such planets (in 664 planetary systems, including 126 multiple planetary systems) have been identified as of October 16, 2012.[1] Estimates of the frequency of systems strongly suggest that more than 50% of Sun-like stars harbor at least one planet.[2] In a 2012 study, each star of the 100 billion or so in our Milky Way galaxy is estimated to host "on average ... at least 1.6 planets."[3][4] Accordingly, at least 160 billion star-bound planets may exist in the Milky Way Galaxy alone.[3][4] Unbound free-floating planetary-mass bodies in the Milky Way may number in the trillions, with 100,000 objects larger than Pluto for every main-sequence star.[5] For centuries, many philosophers and scientists supposed that extrasolar planets existed, but there was no way of knowing how common they were or how similar they might be to the planets of the Solar System. Various detection claims made starting in the nineteenth century were all eventually rejected by astronomers. The first confirmed detection came in 1992, with the discovery of several terrestrial-mass planets orbiting the pulsar PSR B1257+12.[6] The first confirmed detection of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Due to improved observational techniques, the rate of detections has increased rapidly since then.[1] Some exoplanets have been directly imaged by telescopes, but the vast majority have been detected through indirect methods such as radial velocity measurements.[1] Most known exoplanets are giant planets believed to resemble Jupiter or Neptune. This generalization reflects a sampling bias, as massive planets are more easily observed.[7] Some relatively lightweight exoplanets, only a few times more massive than Earth (now known by the term Super-Earth), are known as well; statistical studies now indicate that they actually outnumber giant planets[8] while recent discoveries have included Earth-sized and smaller planets and a handful that appear to exhibit other Earth-like properties.[9][10][11] There also exist planetary-mass objects that orbit brown dwarfs and other bodies that "float free" in space not bound to any star; however, the term "planet" is not always applied to these objects. The discovery of extrasolar planets, particularly those that orbit in the habitable zone where it is possible for liquid water to exist on the surface (and therefore also life), have intensified interest in the search for extraterrestrial life.[12] Thus, the search for extrasolar planets also includes the study of planetary habitability, which considers a wide range of factors in determining an extrasolar planet's suitability for hosting life. Contents Post Comment Private Reply Ignore Thread Top • Page Up • Full Thread • Page Down • Bottom/Latest
#1. To: Tatarewicz (#0)
This is fascinating but I also find it very bizarrre at the same time. The reason is I had a dream last night that I was floating in space and was looking at a planet that resembled Earth. Not kidding. I wanted to stay in space but somehow something would not allow me to except to visit briefly. But I saw this planet and remember looking towards Russia and the North Pole (Arctic region). I saw a lot of brown mass in those areas. Strange.
I coulda sworn that exo solar planets in habitable zones had already been discovered. www.sciencedaily.com/releases/2011/02/110202133321.htm Yeah man last year..... Me thinks the chilians are just trying to send out a little fluff to bloster their image or national self esteem. ____________________________________________________________ . . . The US government has declared civil war on itself. Its lust for war grew so great... Liberty before death. We run , we live, We fight again, till we win. We did not start this fight. We damn sure did not willingly pay our taxes to buy the bullets and drones that shall be used to kill us. We will correct the violations of this rogue nation....our rogue nation. We will fix this because nobody else can. You will work to help me help us all to fix this failure. After you're done educating yourself, Action!!!
If your radio was on then a news item about the planet could have spawned your dream fantasy. Or if radio off but someone else's (in condo) was on...Lastly, you may have picked up a telepathic wave from elsewhere in the world from someone who heard the news. That's about all I can think of.
I don't sleep with a radio on. And what's even more bizarre is that I've visited this same planet before in my dreams a few years back. At that one time I visited that same planet, I remember going back at home briefly for a minute and its dark outside and next thing I'm whisked back into space again. I cannot make sense of it but I surely enjoyed the view up there tremendously.
Could be something your dream state adapted from a sci-fi movie, tv, comic or other books which you read. Or you may be creating like an author your own space travel adventure.
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