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Thursday, 22 October 2015

Mystery star KIC 8462852: If it's not aliens then it could be bad news for Earth....

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Alien megastructure? Hold your horses, it could just be a masive natural disaster...

The star named KIC 8462852 continues to make waves in the astronomy community, as various explanations for the strange way it's light dims at random intervals are advanced - the most obviously interesting of which is 'gasp...aliens!'. But there might be practical reasons why - even if this isn't another civilisation - we need to be interested in this star. KIC 8462852 is somewhat bigger and brighter than our sun, but not hugely different. In the title link Steinn SigurĂ°sson, Professor of Astrophysics at Pennsylvania State University, has a theory that a comet which has been pulverised into a huge cloud of dust might be able to dim the star in the way observed. 

I'm not au fait enough with the astrophysics to say if that's likely to be the right explanation or not, but at the end of his post he makes an obvious but chilling* observation: "We just learned that normal middle aged stars can naturally have stuff come and dim them by 10-20% for multiple days. Imagine that happening to the Sun."

Above: Comet Shoemaker-Levy 9, which was torn apart by Jupiter's gravity.

A series of such events, like the ones we've seen at KIC 8462852, might be seriously damaging to the environment here on Earth. So perhaps, aliens or  not, it's all for the best that so many people are working on solving this stars' enigma. Which brings me to.....

SETI astronomers to beef up their radio antennas' in search for KIC 8462852 signal

Seth Shostak, senior astronomer at SETI, has written a blog post that gives away a few more details about their search fro radio signals that might betray the presence of technology around KIC 8462852. In the post (linked above) he has said:

"Since October 16, the SETI institute has been using its Allen Telescope Array to observe KIC 846 2852 over a wide range of radio frequencies (1 to 10 GHz), looking for any artificial signals. Keep in mind that this star system is relatively far, roughly 1400 light-years away. That's more distant than the Orion Nebula, and getting there (if you feel the need) would require a 23 million year ride in our fastest rocket. But more to the point, any signals detectable here on Earth would have to be exceptionally powerful.
We're continuing to analyse the data. In another week, our SETI team will once again observe KIC 846 2852 using some new receivers being affixed to the Allen Array - known as Antonio feeds - that will increase the sensitivity by a factor of two."

Above: The Allen array. Courtesy of SETI.

'Oxia Planum' chosen as site for ESA's ExoMars rover

The Landing Site Selection Working Group at ESA has recommended Oxia Planum as  the destination for the ExoMars rover. Exo Mars will be a two part mission: An orbiter will study trace gasses in the atmosphere, and the Schiaparelli rover will study the surface, seeking signs of past or present life on Mars. The rover is equipped with a drill, to take samples from subsurface environments that might be more hospitable than the current Martian surface.

Above: False colour view of Oxia Panum, courtesy of the Mars Reconnaissance Orbiter.

Above: A snapshot of the vast sunspot seen on the star XX-Tri.Courtesy of the Leibniz Institute for Astrophysics

Our abilities to study other stars continue to improve: Following on from the first direct images of planets around other stars over the last few years, Astronomers from the Leibniz Institute for Astrophysics have managed to make the first film of the surface of another star. In particular they've found that the sunspots that often mark are own Sun are replicated hugely on the star they've observed - a red giant called XX Tri - revealing similar magnetic forces at play. The video was taken using two robotic 1.2m telescopes at the Teide Observatory in Tenerife, Spain, named STELLA, (short for “STELLar Activity”).
Above: The STELLA telescopes. Courtesy of the Leibniz Institute for Astrophysics.

NASA’s K2 Finds Dead Star Vaporising a Mini “Planet”

In times of tight budgets space agencies become good at using what they have to hand, and this was exactly the case when the reaction wheels on the Kepler space telescope began failing. Rather than abandon the mission NASA engineers used a technique closely related to solar sailing to stabilise the craft, re-christened the mission 'K2' and carried on hunting for exo planets. This week they've discovered the smoking gun for a cosmic mystery: Why some white  dwarfs - the remnants of the cores of middle weight stars that have died - seem to be polluted by elements like silicon. It looks like there're asteroids orbiting close to the surface of some white dwarfs, and a combination of the radiation and gravity from the white dwarf are blasting the asteroid apart - with some of the material ending up in the dwarf's atmosphere.
“For the last decade we’ve suspected that white dwarf stars were feeding on the remains of rocky objects, and this result may be the smoking gun we’re looking for,” said Fergal Mullally, staff scientist of K2 at SETI and NASA’s Ames Research Centre in Moffett Field, California. “However, there's still a lot more work to be done figuring out the history of this system.
Above: The asteroid Ida. Courtesy of NASA/JPL.

Charon in super-close up

Lastly, here's a really amazing high resolution close up of Pluto's largest moon, Charon, from the New Horizons mission. The resolution here is down to 310 meters, and shows a terrain oddly like parts of our Moon - strange considering that Charon is made of various kinds of ice!

Above: Charon in close up. Courtesy of NASA/JPL.

* I punned. Sorry.

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