AST201H5 Lecture Notes - Lecture 4: Nanometre, Radiography, Chemical Element
Document Summary
Light = source of most information in astronomy. White light is a mix of all colours. Light is a wave: has wavelength, amplitude, speed and frequency = speed/wavelength. Brightness = (electric amplitude) (2 angular size / 360 = physical size / 2pie distance where size can be separation) Rosetta satellite of the european space agency woke up on january 20. Will place a lander on the comet, sample it"s matter and drill a hole 20 cm deep into its surface. Will travel with the comet as it orbits in around the sun and heads back out into the solar system. Radio wavelength 1m and longer frequency = 3 x 10 *8 hz and less. X-rays wavelength about 1nm (surprise awarded nobel prize) Gamma (y) rays wavelength less than about 0. 01 nm. Before about 1950, astronomy used only visible light (see by eye and take photographs) Since 1950, astronomy has had the technology to use all forms of radiation.
