Van Cittert–Zernike theorem
Have you ever seen a picture of a faraway star or galaxy taken by a telescope? The picture may appear blurry or fuzzy. This is because of something called "wave interference" - when light waves from the star or galaxy travel through our atmosphere, they get jumbled up and mixed together, making the image appear less clear.
Scientists use a technique called "interferometry" to overcome this problem. Basically, they use two or more telescopes to capture the light waves from the same object and then combine them together. This helps to cancel out some of the interference caused by the atmosphere and produce a clearer image.
The van Cittert-Zernike theorem is a mathematical formula that helps scientists to understand how interferometry works. It explains that the combined image created by two telescopes will only be clear if the light waves from both telescopes are in sync with each other - meaning they have the same wavelength and are moving in the same direction. If the waves are not in sync, it will create interference and make the image blurry.
So, scientists use the van Cittert-Zernike theorem as a guide to ensure that their interferometry setups are properly aligned, so that the light waves from each telescope are in sync with each other. This allows them to create much clearer and more detailed images of faraway objects in space, like stars and galaxies.
Scientists use a technique called "interferometry" to overcome this problem. Basically, they use two or more telescopes to capture the light waves from the same object and then combine them together. This helps to cancel out some of the interference caused by the atmosphere and produce a clearer image.
The van Cittert-Zernike theorem is a mathematical formula that helps scientists to understand how interferometry works. It explains that the combined image created by two telescopes will only be clear if the light waves from both telescopes are in sync with each other - meaning they have the same wavelength and are moving in the same direction. If the waves are not in sync, it will create interference and make the image blurry.
So, scientists use the van Cittert-Zernike theorem as a guide to ensure that their interferometry setups are properly aligned, so that the light waves from each telescope are in sync with each other. This allows them to create much clearer and more detailed images of faraway objects in space, like stars and galaxies.