14 DAY TRIAL // One of the major problems facing astronomers in their attempt of taking sky images which are as clear as possible is the problem of atmospheric disturbances. This is why telescopes are usually placed at high altitudes and it is why Hubble telescope was placed on orbit, above the atmosphere. This allows Hubble telescope to take better pictures than ground level telescopes although its dimensions are smaller.
Anrdeea Ghez, from UCLA, has found a method of increasing the clarity of the pictures taken by ground telescopes. She used a laser in order to create an artificial star. Due to laser's extremely convergent beam this "star" is 'very localized' - the astronomer knows exactly where the star actually is. Then, by observing the "star" with the telescope, one can map the atmospheric conditions. Thus, by knowing the atmospheric conditions, the astronomer can later modify the images taken with the telescope, which are unclear due to atmospheric disturbances, and can make them much clearer.
Ghez and her colleagues have started by taking pictures of the center of the Milky Way and have obtained the clearest image so far. The center of the galaxy is covered by a cloud of gas and dust. This prevents astronomers from taking images in the visible spectrum of light (because visible light is absorbed), and thus only infrared or radio waves pictures can be taken (infrared light and radio waves are less absorbed). In the above image, taken by Ghez at the W.M Keck Observatory, which is the world's first 10-meter telescope with a laser on it, the left photograph is obtained with the help of the new technology, while the right picture is without correction. The resolution of the images taken with the new system is 82 milliarcseconds, which, according to Dr. Ghez, is the equivalent of being able to distinguish a pair of headlights in New York while standing in Los Angeles.
The center of the galaxy is interesting because it is assumed a huge black hole is there - a black hole with a mass 2 million times greater than our Sun (in order for an object to become a black hole it is sufficient of having even 25 times the mass of the Sun). The black hole is an object which generates such an intense gravitational pull than not even light can escape its attraction. This is why black holes cannot be directly observed (there's nothing coming from them), one can only observe the effect they have on the surrounding matter. In the nearby image one can see how matter is being attracted inside the black hole which exists in the middle of our galaxy.
