NASA Astronomy Picture of the Day Collection

A Laser Strike at the Galactic Center

Why are these people shooting a powerful laser into the center of our Galaxy? Fortunately, this is not meant to be the first step in a Galactic war [ http://en.wikipedia…]. Rather, astronomers at the Very Large Telescope [ http://antwrp.gsfc.…] (VLT) site in Chile [ http://en.wikipedia…] are trying to measure the distortions of Earth's ever changing atmosphere [ http://antwrp.gsfc.…]. Constant imaging of high-altitude atoms excited by the laser -- which appear like an artificial star [ http://antwrp.gsfc.…] -- allow astronomers to instantly measure atmospheric blurring [ http://www2.keck.ha…]. This information is fed back to a VLT telescope mirror which is then slightly deformed [ http://www.eso.org/…] to minimize this blurring. In this case, a VLT was observing our Galaxy's center [ http://www.astro.uc…], and so Earth's atmospheric blurring in that direction was needed. As for inter-galaxy warfare [ http://en.wikipedia…], when viewed from our Galaxy's center [ http://antwrp.gsfc.…], no casualties are expected. In fact, the light from this powerful laser [ http://www.eso.org/…] would combine with light from our Sun to together appear only as bright [ http://www.oreilly.…] as a faint and distant star.

Yuri Beletsky [ mailto:ybialets at eso.org ] (ESO [ http://www.eso.org/])

Hawaii

Chile

Goddard Space Flight Center (GSFC)

Earth

ESO

Sun

VLT

Very Large Telescope

http://antwrp.gsfc.…

SPD-APOD-ap070731