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
 Concepts - Atmospheric Limitations While the entire electromagnetic spectrum allows us to view phenomenon a variety of different ways, we are limited as to what we can see - at least on Earth. Our atmosphere is a life preserving blanket of protection from particles like microwave, high energy ultraviolet and gamma rays. However, at these frequencies we can learn a lot by studying phenomenon such as accretion disks around black holes and quasars - and these are best "viewed" from space. The solution is to overcome the natural limitations of our atmosphere and place tools capable of viewing high energy phenomenon in orbit around the Earth, high above the atmosphere. The image below demonstrates what we can see on Earth: Only radio waves and the visible spectrum are viewable from the surface, however with a telescope on top of a high mountain (like the Keck Observatory on Mauna Kea, Hawaii) it is possible to view objects in the near-infrared.