Atmospheric lasers

One of the four Unit Telescopes (UTs) of the VLT at Paranal Observatory in Chile using its cutting-edge Adaptive Optics (AO) system. Natural fluctuations in Earth's atmosphere interfere with and blur the light from distant objects out in space. AO can be used to correct for this and obtain sharper images by shining lasers high into the atmosphere to create an artificial "star". Since it is known what this "star" should look like, it is possible to modify the shape of the mirrors in the UTs to counteract the distorting effect.