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May the Fourth Be With You!

Happy "Star Wars Day" from PhysicsCentral! In a case of seriously excellent timing, the European Southern Observatory recently released a photo of their telescope being calibrated. Is it just us, or does it look suspiciously familiar?

At the ESO's Panaral observatory, powerful lasers are used to create an artificial "star" in the upper atmosphere, to help calibrate a telescope's optical systems.
Image Credit: F. Kamphues, ESO.

While it certainly looks like the primary firing sequence of a Death Star, this array of four lasers is no weapon. Focused at a point high up in the atmosphere, it creates a hot region of ionized sodium atoms, which give off light of their own. The artificial “star” created by this process—known as a laser guide star—is used to calibrate telescopes like the Very Large Telescope by allowing astronomers to correct for distortions caused by Earth’s atmosphere.


  1. Wow! Star Wars, it would appear we have arrived. Or have we?


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