Why astronomers shoot lasers at the Carina nebula


The European Southern Observatory has released a snapshot of the workflow that looks like a shot from a sci-fi action movie. Powerful lasers strike synchronously from Earth at a distant target – the Carina Nebula, which is a bright purple spot in the night sky. The idea seems pointless, because the nebula is 7.5 thousand light years away, and what will several lasers do to it? However, the shooting continues – because it helps astronomers make scientific discoveries.

There are several star clusters in the Carina Nebula, with both old and young stars. Most notable is Eta Carinae, a supergiant double star with a brightness of 5 million Suns. It is at the end of its life cycle, very unstable and constantly ejects gas and matter, which form the nebula. Astronomers believe that the star will go supernova any minute, it is allotted no more than a couple of thousand years – everyone is extremely interested in watching its behavior.

But there is a big problem – turbulence, eddies in the atmosphere of our planet, due to which the light coming from distant stars is distorted. Because of this, they flicker beautifully in the night, but making accurate observations due to this effect is extremely problematic. Therefore, in the construction of the Large Telescope Group in the Atacama Desert in Chile, they were provided with two technical know-how. Firstly, the 8-meter telescope mirrors are made adaptable, and secondly, the same lasers help them in their work.

Before observing, lasers are aimed at a given area of ​​the sky and, using their radiation, they excite sodium atoms in the upper atmosphere. They begin to glow like small stars, while the supercomputer knows exactly their parameters and, analyzing optical distortions when observing these beacons, calculates the current meteorological situation. The data is turned into commands for telescope mirrors that adjust to the weather and can observe Eta Carinae with little or no interference. With the help of this technology, it has already been possible to make a number of important astronomical discoveries.

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