Smallest Planet Outside Our Solar System Found 91
mikkl666 writes "Following the recent story about the discovery of the youngest planet outside our solar system, Spanish researchers now report that they found the smallest exoplanet observed so far. The planet, known as GJ 436c, was found by analyzing distortions in the orbit of another, larger planet, and its radius is only about 50 percent greater than the Earth's. The scientists are confident that their new method will lead to a series of further discoveries: 'I think we are very close, just a few years away, from detecting a planet like Earth.' You can also reference the the original paper online for further details."
OK, dumb question... (Score:2, Interesting)
Think about this for just a moment. Bright star, probably a hundred timed the diameter of the planet, and many thousands of times more luminous; assuming the planet is rocky (and barren, and a colouration about that of bleached tarmac), it'll have a reflectivity of about 15-20% (also known as albedo). Earth's blue-green marble surface and average 40% cloud cover gives it an albedo of around 35%. Given that the Voyager panorama barely picked up Earth from a distance of four billion miles, lost in the glare of our own sun, what chance do we in fact have of directly observing a body this close to its parent star, however dim it's a star and it's radiating stupid levels of energy, to be able to tell its rotation? And all from a distance of one hundred fifty trillion miles? You are not even going to see the planet in the glare, never mind seeing enough surface detail to determine how fast the bloody thing is spinning!
I think that they pulled the 22-day rotation out of their arses. Unless someone can tell me different?