Sun – 8 light-minutes
Ike as seen from the ISS
Mysterious
Glow!
UFO?
Nope, Urine
Energy and Light
Mr. Hibbetts
Thanks to
Dr. Dan Bruton, SFA
What is universe made
of?
• Answers:
• Spacetime
• Energy
• Matter
• e.g. rock, water, air
• What is Energy?
• It is the mover of matter.
• Or, the ability to do work
• It is measured in Joules or BTU’s.
Types of Energy
• What are some types of
energy?
Types of Energy
•
•
•
•
•
•
Kinetic
Potential
Radiative
Thermal
Mass-energy
And others...
Kinetic Energy
• Kinetic Energy is the energy of
motion.
• Kinetic Energy = ½ mass  speed2
1
2
KE  mv
2
Kinetic Energy
• Do planets have small amounts or
large amounts of kinetic energy?
• Large Mass = Greater Energy
• Faster Velocity = Greater Energy
• The Earth:
- Mass = 5.98 x 1024 kg
- Average Velocity = 29500 m / s
(that’s 66000 mph)
Cosmic Connections
Comet Schumaker-Levy 9 collided with Jupiter.
The more massive fragments imparted more
energy into the atmosphere of Jupiter.
Thermal Energy
• Is the kinetic energy of molecules in
a substance
• Particles move faster in hot objects.
Thermal Energy
Cool
Hot
Potential Energy
• The energy that is stored is
called potential energy.
• Examples:
•
•
•
•
•
•
Rubber bands
Springs
Bows
Batteries
Chemical
Gravity
Mass-Energy
• E=mc2
• Energy from converted matter
• Is it possible to convert mass
into pure energy?
• Answer: Yes, our Sun does this.
Radiative Energy
• The energy of electromagnetic
wave
• Also known as electromagnetic
radiation
• Including light in all its forms
Conservation of Energy
• “Energy cannot be created or
destroyed...
• ....it may be transformed from one
form into another.”
• Example
• Our Sun coverts mass energy into
radiative energy (i.e. light).
Radiative energy is also
known as...
•Light
*pure energy
•Electromagnetic
Waves
*energy-carrying waves
emitted by vibrating
electrons
•Photons
*particles of light
Electromagnetic
Radiation
Photons
Light
Waves
• Wavelength - the distance between
two successive peaks in a wave.
• It is measured in meters or
nanometers.
• 1 nanometer = 1 × 10-9 meters
• Amplitude - the maximum departure
of a wave from the undisturbed state
• This corresponds to intensity for
light.
Waves
• Wave Period - the amount of time
for a wave to repeat itself at a
specific point in space
• It is measured in seconds.
• Frequency - is the number of
wave crests passing a given
point per unit time
• It is measured in Hertz (cycles per
second).
Waves
• Wave Speed - is the speed with
which a wave crest passes by a
particular point in space
• It is measured in meters/second.
• Wave Speed = Frequency 
Wavelength
Shock Wave
Light and The
Electromagnetic
Spectrum
Rember ….
• Light is electromagnetic
radiation.
• So where does it come from?
Light
• Comes from the vibrations of
electrical charges particles
Protons
And
Electrons
Light
• But what is light?...
• How can it be both a wave of
energy and a particle of energy
at the same time?...
Light
• It gets weirder…
• When directly observed light acts
light a particle
• When indirectly observed light
acts like a wave
Light
• So the observer influences
lights behavior?
• According to quantum
physics…Yes!
Light
• Solution: Light exits in packets
of waves called quanta
• But how and why?
• We do not know….(yet!)
The Electromagnetic
Spectrum
• A range of light waves
extending in wavelength from
radio waves to gamma rays
The Electromagnetic
Spectrum
•
•
•
•
•
•
•
Radio Waves
Microwaves
Infrared
mnemonic
Visible Light
Ultraviolet
X-rays
Gamma Rays
•
•
•
•
•
•
•
Raging
Martians
Invade
Roy G. Biv
Using
X-rays and
Gamma
Rays
Radio Waves
• Lowest frequency
• Highest wavelength
• Omnipresent
• Uses?
Microwaves
• Highest frequency radiowaves
(some don’t make a distinction)
Uses?
Infrared
• Just below visible light in
frequency
• Classic “Heat” vision
• Uses?
Visible Light Spectrum
• What we see
Low Frequency
Higher Frequency
High Wavelength
Lower Wavelength
Ultraviolet
• Higher fequency than visible
light
• The first “dangerous” light
waves
• Majority of the Sun’s light when
it reaches earth
• Uses?
X-Ray
• Can fully penetrate most living
tissue
• Soft and Hard X-rays overlap
other forms of light in
wavelength and frequency
• Generated from electrons
• Uses?
Gamma Rays
•
•
•
•
Will destroy most living tissue
Generated by atomic nuclei
Highest frequency
Lowest wavelength (about the
size of an atomic nucleus)
• Uses?
Gamma Ray Burst in Space
Earth’s Atmosphere
• Transparent - the term applied
to materials through which light
can pass in straight lines
• Opaque - the term applied to
materials that absorb light
Earth’s Atmosphere
Transparent to
•visible, radio
•infrared (partially)
• Opaque
•gamma, X-rays, UV,
Microwave