He said: "Nothing like this view has ever been seen on Mars. We'll be looking for signs that the snow may even reach the ground."
Full ArticleSearching for signals from extraterrestrials can be a ticklish business. Astronomer John Learned thinks tickling certain stars in just the right way might be a good strategy for ET to phone Earth.
Those stars, known as Cepheid variables, brighten and dim on a regular schedule. In 1908, after analyzing stars on photographic plates at Harvard College Observatory, Henrietta Swan Leavitt reported that a Cepheid’s maximum brightness depends on the timing of its bright-dim cycle. The longer the period, the brighter the star. Other astronomers soon realized that they could use the period-brightness relationship to measure distances to remote galaxies.
A century later, Learned and colleagues are proposing a new use for Cepheids. In an article recently posted online (arxiv.org/abs/0809.0339), the researchers suggest that tinkering with the core of a Cepheid variable using a beam of neutrinos could be an effective way for advanced civilizations to communicate. This modulation, or “tickling,” would alter the phase at which the star brightens and slightly shorten the time it takes for the star to wax and wane, creating a new pattern that distant observers might detect.
