Tag Archives: stars

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The Galactic Area Network

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The wonderfully named John Learned of the University of Hawaii theorises that alien intelligences could use Cepheid variable stars as nodes on a sort of intragalactic communications network [via @spacearcheology, who retweeted @swadeshine]:

Jolting the star with a kick of energy – possibly by shooting it with a beam of high-energy particles called neutrinos – could advance the pulsation by causing its core to heat up and expand, they say.

That could shorten its brightness cycle – just as an electric stimulus to a human heart at the right time can advance a heartbeat. The normal and shortened cycles could be used to encode binary “0”s and “1”s.

The team says information could thus be shuttled around our galaxy’s network of 500 or so Cepheids – and out as far as the Virgo cluster of galaxies.

Because a civilisation capable of such engineering feats would be sure to turn them to the task of… er, using stars as Morse keys. This guy has made exactly the mistake that Sam Vaknin was on about.

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Alpha Centauri ‘should have an Earth-like planet’

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An artist’s impression of an earth-like planet around Alpha CentauriAlpha Centauri is the closest star system to our own but with a bonus: there are three stars rather than one. It’s also one of the best chances we know in the local area to have a planet similar to Earth capable of developing life like ours.

If any planet were to harbour earth-like life in the three-star system, it would likely be around Alpha Centauri A, which is most similar to the sun. However astronomer Javier Guedes and his coauthors believe that Alpha Centauri B is likely to have terrestrial planets in its habitable region. Based on computer simulations of planet formation, Guedes and his team found that no matter what starting conditions, a terrestrial planet always formed around the star. By studying the ‘wobbles’ the planet causes on its parent star, the team reckon they could find any potential planets within a few years.

[story via Daily Galaxy, image via Solstation]

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First images from the Large Binocular Telescope

The first of many images by the new telescope

The Large Binocular Telescope in Arizona has ‘opened its eyes’ for the first time, marking one of the first in a new wave of high-tech astronomical devices to come online. The LBT combines two 8m mirrors working in tandem to take pictures of the sky in a wide range of wavelengths at resolutions higher than that of Hubble.

Another couple of new telescopes, Herschel and Planck, will come online this year following their launch into space in April. Laser Interferometer LISA, which measures the bending of space time, has been given the go ahead but won’t be ready for a decade. A spate of advanced telescopes are in planning and construction, taking advantage of the computer advances of the last decade to give more accurate and detailed pictures of the sky than ever before.

[story and image via BBC]

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Reionisation and the future of telescopes

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The 42m European Extremely Large Telescope will be a feat of engineering ingenuityAs astronomers look further back in time, they need more powerful, higher resolution instruments. As well as the search for extrasolar planets, one of the key areas the new technology will be looking at is the epoch of reionisation, some one billion years after the big bang. 400,000 years after the big bang, the universe cooled enough to become opaque, so that very little light was being emitted for us to observe. Later the universe began to change and objects like stars and galaxies formed. The heat from these first objects began ionising the neutral gas of the universe, creating more stars and galaxies in bubbles of hotter regions that eventually spread to form the reionised universe we see today.

Some of the designs for new telescopes are incredible. The picture shows the E-ELT, one of the new designs of Extremely Large Telescopes (anything over 20m in diameter). The small white shape in the bottom left is a car! The awesome James Webb Space Telescope will launch in 2013 to replace the Hubble Telescope. Its mirror and tennis court-sized sunshield unfold in space once it reaches its home orbiting L2, some 1.5 Million km from Earth. ALMA, LOFAR and SKA will links tens or even thousands of smaller radio telescopes together as one massive array, stretching out across continents. The next decade will truly be a revolution in the devices astronomers use to study the sky.

[This is a version of a talk I gave as part of my masters course at Bristol University last week]

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New supernova changes the way astronomers think about star explosions

supernovas are one of the most incredible sights in the universeEarlier in the year a gigantic explosion lit up the sky. Supernova SN 2006gy, around 100 times brighter than a typical example, created a real puzzle to astronomers – how did such a big event occur? Currently there are two main models for Supernovae – type I occur when a white dwarf accretes too much material from another partner star and crosses the unstable Chandrasekhar limit, forcing nuclear fusion in the core. The second principle type, type II has a larger older star running out of hydrogen in its core to burn, leaving the outer layers cooling and falling inward. When the pressure from the infalling layers gets high enough, the helium ignites – a type II supernova.

The sheer brightness of SN 2006gy doesn’t fit any current theories, and has left astronomers baffled. A new model suggests that the star exploded not once but twice or as much as SIX time, with the outward material from later novas hitting earlier remnants to create the bright lights in the sky. A somewhat similar star, Eta Carina, is not too far off exploding in our own galaxy, which should provide an amazing night show.

[story and image via Science Daily]