Introduction Astronomy Tools Concepts 1. Electromagnetic Spectrum 2. Atmosphere Limitations 3. Space Observations Equipment 1. Telescopes 2. Radio 3. Space Tools 4. Photography 5. Spectroscopy 6. Computers 7. Advanced Methods 8. Radio Astronomy Basic Mathematics Algebra Statistics Geometry Scientific Notation Log Scales Calculus Physics Concepts - Basic Units of Measure - Mass & Density - Temperature - Velocity & Acceleration - Force, Pressure & Energy - Atoms - Quantum Physics - Nature of Light Formulas - Brightness - Cepheid Rulers - Distance - Doppler Shift - Frequency & Wavelength - Hubble's Law - Inverse Square Law - Kinetic Energy - Luminosity - Magnitudes - Convert Mass to Energy - Kepler & Newton - Orbits - Parallax - Planck's Law - Relativistic Redshift - Relativity - Schwarzschild Radius  - Synodic & Sidereal Periods - Sidereal Time - Small Angle Formula - Stellar Properties  - Stephan-Boltzmann Law - Telescope Related - Temperature - Tidal Forces - Wien's Law Constants Computer Models Additional Resources 1. Advanced Topics 2. Guest Contributions
 Physics - Formulas - Relativity Relativity is the effects of Gravity to Space-Time. Relativity is also the reactions of matter as they approach the speed of light. In regards to matter, two very curious things occur as the speed of light is approached: Time is affected Length is affected These two effects are called Lorentz Transformations. Time is affected when the speed of light is approached. To determine this, use the Lorentz Time Transformation: As an example, imagine Bob watching a phenomenon and Bill is traveling with the phenomenon. Bob sees Bill traveling at 0.98 times the speed of light for 1 minute: According to Bill (traveling with the phenomenon), 5 minutes past on his watch while Bob saw the phenomenon lasted only 1 minute. The same effects occur with the apparent length of an object: Bob measures an object at rest to be 1 meter in length. He sets the object in motion at 0.98 times the speed of light, then measures while the object is moving: Bob notices the object is only 0.20 meters when he measured it moving. So to an observer, when an object is traveling near the speed of light, the phenomenon appears to move much faster and appears to be shorter than the same phenomenon at rest. Back to Top