Tissues such as those found in the brain are less dense and appear grey. Images that appear black denote organs such as lungs or others that can fill with air.
Inside the donut-shaped machine, a number of X rays are taken, each producing a small slice of the image that doctors need. When passing through dense tissue such as bone, the beams are weak and appear white in the CT images.
Scientists say they have observed a "smoking gun" which confirms that the dense energy of the Big Bang drove an exponential expansion of the boundaries of space.
Scientists say they have observed a "smoking gun" which confirms that the dense energy of the Big Bang drove an exponential expansion of the boundaries of space.
Scientists say they have observed a "smoking gun" which confirms that the dense energy of the Big Bang drove an exponential expansion of the boundaries of space.
Scientists say they have observed a "smoking gun" which confirms that the dense energy of the Big Bang drove an exponential expansion of the boundaries of space.
Giant petrels patrol the beach at St. Andrews Bay, thronged by king penguins and elephant seals. During the breeding season South Georgia hosts the densest mass of marine mammals on Earth.