Earth v2.0

Astronomers are claiming to have found another Earth orbiting the star Gleise 581 in the constellation Libra.

Already known to be home to another Neptune-size planet, the little red-dwarf appears to have a planet 5 times the mass of Earth, or about 1.5 times the radius, making it the smallest exoplanet discovered so far.

Its position, orbiting the dim dwarf star every 13 days, places it in a prime orbit to sustain water at its surface.

But is it habitable???

I've already had a few comments on it here:

The next part, that the world is habitable, is more problematic. To get this the authors had to calculate the temperature from the star’s output, and the planet’s orbit. This is a very simplistic approach. For instance, Venus is far hotter than Mercury despite being further out. The reason is its atmosphere, which is mostly CO2 - and thus Venus is a an extreme case of global warming. Atmospheric composition strongly controls planetary temperatures, and this is the biggest uncertainty in this work, as we don’t know the specifics of the planets atmosphere. So take the temperature estimates with a grain of salt.

There are many other caveats to habitability too - Earth’s water likely came from comets that were perturbed and hit Earth late during its formation. If this cometary water source is non existent around a red dwarf then the planet could be bone dry. Etc etc.

Of course these caveats don’t make for as interesting a headline as “First habitable planet found” so bear in mind the reporting of the science here tends towards the more fantastical elements like little green men. But the discovery of this planet is a pretty neat find in its own right, even if we don’t know too much about it yet.

(The original report is at the Australian, or New Scientist).

Already dubbed the 'Goldilocks' planet, as the conditions are reputedly ideal for life. As mentioned above, this is extremely sensitive to the atmospheric composition, which we know little about. The atmosphere itself depends on many factors. Does the planet have plate tectonics? What is it made out of? Is it rocky like Earth, or a gas ball like Neptune, or a ball of metal like Mercury? How much of its early atmosphere was blown away during early star formation? (Earth lost a lot of its early atmosphere this way, particularly the hydrogen, whereas the gas giants are far enough away to keep most).

All these factors need a tick for a planet to be "habitable", but it does make you think nonetheless...

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Researchers have identified a 6m tall fungus in the fossil record called Prototaxites, which from 420-350 million years ago (source: NS).

"A 6-metre fungus would be odd enough in the modern world, but at least we are used to trees quite a bit bigger," says C. Kevin Boyce from University of Chicago.

"Plants at that time were a few feet tall, invertebrate animals were small, and there were no terrestrial vertebrates. This fossil would have been all the more striking in such a diminutive landscape. This gets my vote for being one of the weirdest organisms that ever lived."

So no other tall land plants, 6m tall fungus columns, and only millipedes and centipedes loafy around on land. Why are we looking for strangeness on other planets?



They kinda look a bit phallic.

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Also, smart people are no good at making money, and people actually get paid to study the froth on beer. These guys expanded the work of computing pioneer von Neumann on grain boundaries to study how the bubbles interact. I need to change my research direction.