RB Editor’s Selections: Left-handed Life, Iceberg Songs, Disappearing Exoplanets and Redefining the Kilogram

Sarah KendrewSarah Kendrew selects interesting and notable ResearchBlogging.org posts in the physical sciences, chemistry, engineering, computer science, geosciences and mathematics. She blogs about astronomy at One Small Step.

[cross-posted from ResearchBlogging.org News]

Welcome to a new week, and a new instalment of physical sciences highlights.

  • The Universe and life is asymmetric: chirality of life. Why is life left-handed? This excellent in-depth post by The Astronomist describes in detail the problem of chirality of biomolecules, with words from a leading expert.
  • Death song of an Iceberg. Using seismometers, geologists can record the sounds made be icebergs as they grind against each other with the tides. This blog post on Now Hear This (“a site about sound”) discusses how such a recording has led scientists to find an iceberg graveyard in the Antarctic. The post contains an interesting video on this type of research, and a link to the researchers’ pretty dramatic sound recording.
  • The amazing disappearing habitable world? Exoplanet Gliese 581g was trumpeted as a potentially habitable exoplanet on its original discovery last year, causing a bit of a media frenzy – but its existence was soon after called into question when other scientists had issues with the analysis of the original data. Greg Fish discusses the latest efforts to single out 581g from the noise.
  • Redefining the Kilogram. Calibration is often considered a dull topic, but any scientist worth their salt knows it’s one of the most important concepts in scientific research. In this post, Ryan of A Quantum of Knowledge describes how research into a more precise determination of Avogadro’s constant could lead to a more scientific standard for the kilogram. In fact, the Royal Society is meeting today to discuss new definitions of measurement units based on fundamental constants. Interestingly, the kilogram is the only physical constant based on an actual physical artifact. Who knew?

As always, thanks for all the great writing!

Lightest exoplanet discovered

ESO yesterday reported the discovery of the lightest exoplanet yet. Gliese 581e, the fourth in a family of exolanets around Gliese 581, is just twice as massive as the Earth, which means it could well be rocky rather than gassy like Jupiter or Saturn. The discovery was made by a team of Swiss an French astronomers led by Michel Mayor of Geneva Observatory, who discovered of the first ever exoplanet in 1995, using ESO’s 3.6m telescope at La Silla, Chile.

But Mayor and his team added a cherry to ESO’s cake. Further study of the orbit of Gliese 581d, one of the new planet’s known siblings, has shown that the planet lies well within the host star’s so-called Habitable Zone, where the existence of liquid water is thought to be possible (though that doesn’t mean that it does!).

Nice work!

Image credit: M. House, F. Kamphues (top)

Kepler sees the light

First light images from NASA’s Kepler space telescope were released last week following the satellite’s sucecssful launch on March 7. The picture shown here shows an (inversted) image of the starfield Kepler will be studying over the course of its exoplanet-finding mission, in the Cygnus-Lyra region of the Galaxy. It may not look like much, but for the Kepler team it’s pretty special to see that their satellite is alive and well, and performing as it should. Congrats!

Go here for the full set of first light images.

Image credit: NASA/Ames/JPL-Caltech

Countdown to Kepler

Astronomers’ eyes are on NASA this week as the agency aims to launch its mission for tracking down Earth-like exoplanets on Friday night (early Saturday morning if you’re in Europe). Over its three-year lifetime, Kepler will observe over 100,000 stars in a small part of the sky, over and over again to spot the tiny dips in brightness caused by a planet casting its shadow onto the star as it passes in front of it. Together with its European cousin CoRoT, which has been in orbit for a while already, Kepler is likely to increase our tally of known exoplanets by a factor of many. There’s been a ton of great media coverage about Kepler already so I’ll round up a few nice links here. And there’ll be much more to follow!

From NASA itself: the mission homepage, launch schedule. A live launch blog will appear here 2 hours before launch.

Follow Kepler on Twitter.

The New York Times have a great feature here.

Seth Shostak of the SETI Institute gives his perspective on Discovery Space. Discovery Space have a little Kepler-themed area even, here.

A BBC story on British industrial involvement in Kepler.

[Update 04/03]

Director of Hubble news Ray Villard (Cosmic Ray) gives his perspective.

A news story in Nature.

Image credit: Ball Aerospace

The benefit of hindsight

planets_comb2

Left: The image of the HR8799 planetary system from data taken with the Keck telescope. Right: the 1998 Hubble data (credit: NRC) (a) original Hubble image, (b) with "traditional" speckle subtraction method, (c-d) 2 images reprocessed showing the planet above the noise (credit: Lafrenière et al., 2009).

An interesting paper turned up on astro-ph last week. Remember HR8799, the star with a whole family of exoplanets imaged directly last year? A Canadian-American team of scientists went back through the archive and re-analysed data taken with the Hubble Space Telescope in 1998. And lo and behold, using new analysis techniques they managed to tease the outermost of HR8799′s planets out of the noise. Very cool. After all, 1998 was only three years after the first ever detection of an exoplanet! Obtaining a direct image of one really was just a glint in our starry eyes back then.

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