ELECTROMAGNETIC ENERGY

What is ELECTROMAGNETISM? b It is called ENERGY b Can be converted into matter & visa versa b Travels at speed of light b Moves in straight lines into space

What does it “look like”? b A stream of force particles (like sparkly bubbles) b Called PHOTONS b Comes in all sizes and densities Comes in different sizes

What does it look like? b All Photons move forward in straight lines, but travel along wavelike paths. b One strength of photon will take a different path than another kind

The problem - how can something be both a particle, and a wave? b A stream of Particles would be expected to pass through a hole in a wall in a straight line. b Sometimes, photons do!

Sometimes they don’t! b Photons can also spread out and bend when they pass through a hole, just like a wave would. b This is called Diffraction

In fact, we can measure all of their wavelike characteristics Frequency The number of waves passing by each second Amplitude

Photons have certain “energies” o When they hit something, the target “feels” the impact. o They can either bounce off their target or be absorbed (atom jiggle) o Photons come in millions of energies, so targets can get hit by many strengths of photons.

Photons have certain “energies” Mr. Sun here sheds all kinds of photons Here comes a photon now! Let’s slow that down, and put something in its way! I’m the target. Gulp! Three things happened to this target when hit by the photon. What are they?

Let’s watch it again! Mr. Sun here sheds all kinds of photons Let’s slow that down, and put something in its way! I’m the target. Gulp! The target moved, it absorbed the photon and quickly re-radiated a red photon

Photons have certain “energies”. When they hit something, they will warm it up. Warm objects emit different colors! This heated bar glows red (gives off “red” photons) as it gets hotter

Glowing means that photons striking an object cause it to heat up. If it gets hot enough, new photons are re-radiated out that are a size your eyes can see. If you keep heating it, it glows yellow, then white, then blue-white

Photons hit = heat = new photons out The hotter an object is, the more white or blue color it radiates Cooler Hotter

Photons have no MASS but they are attracted by gravity??

There are billions of photon sizes/energy levels o For convenience, we clump those energies into seven (7) groups, called the Electromagnetic “Spectrum”.

THE ELECTROMAGNETIC SPECTRUM b RADIO b MICROWAVE b INFRARED b VISIBLE b ULTRAVIOLET b X-RAY b GAMMA Ricky Martin Is Very Ugly and X-tremely Gay

THE ELECTROMAGNETIC SPECTRUM

b The visible spectrum has 7 subparts RedR RedR Orange O Orange O Yellow Y Yellow Y Green G Green G Blue B Blue B Indigo I Indigo I Violet V Violet V THE ELECTROMAGNETIC SPECTRUM Your eyes are sensitive to 7 color regions

b Radio photons make metals vibrate b Microwave (Radar) photons make water and metals vibrate b Infrared photons make all objects they hit vibrate (heat up), even gases b Visible Light Photons react with our eyes, chemical dyes and chlorophyll Electromagnetic photons or waves transfer energy to things that they hit

b Ultraviolet photons make everything they hit vibrate strongly b X-Ray photons penetrate solids and knock atoms around b Gamma photons penetrate into the nuclei of atoms and disrupt most everything they hit (knock quarks) Electromagnetic photons or waves transfer energy to things that they hit

All Quarks and Leptons constantly emit some form of electromagnetic photons b All galaxies, stars and most nebula pour out all 7 types of electromagnetic radiation

b b Stars, nebula, pulsars and accretion disks of Black Holes b b Electronics, TV and radio antennas, cell phones, power lines Sources of Radio photons Giant Black hole in the center of the Milky Way shown in radio photons

b b Stars, some nebula, pulsars, black holes b b Microwave ovens and radar dishes Sources of Microwave photons

b All objects above absolute zero emit Infrared photons, to include all stars, all nebula, pulsars, black holes, all planets and moons b Animals, fire, all matter on Earth Sources of Infrared Photons

b b All objects hot enough to glow, including all stars, galaxies, some nebula, pulsars and black holes b b Lights, fireflies, lightning, fire, etc. Sources of visible photons

b b Hot violent objects emit ultraviolet photons. These include all stars, some exploding nebula, pulsars and black holes b b man-made UV lights (Black lights), bombs, molten metals Sources of UV photons

Sources of X-Ray and Gamma Photons b Very Violent objects emit X-ray and Gamma photons that can kill you b These include all star cores, white dwarfs, supernova, neutron stars, black holes, pulsars and some radioactive elements, X-ray machines, bombs, atom smashers Our Sun viewed with a X-ray camera Milky Way center in X-ray

Our Atmosphere blocks five photon regions but allows two through Radio – passes Microwave and IR - blocked UV, X-ray and Gamma - blocked Visible and some UV – passes

We can see radio and visible photon regions from space on the ground. Other regions require spacecraft above the atmosphere to be seen. Radio telescopes Spacecraft telescopes Optical Telescopes