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Stars & The Electromagnetic Spectrum NotesTest – Thursday, 1/30
Textbook & Online Resources:Chapter 3 – Lesson 4: Characteristics of StarsChapter 3 – Lesson 6: The SunChapter 6 – Lesson 4: Exploring Space with Images
Star
• Huge sphere of glowing gas, made mostly of hydrogen, that produces energy through nuclear fusion
Stars are classified by the following physical properties…
Temperature & Color
Cool Stars – red – 3,200oC
Our Sun – yellow – 5,500oC
Hot Stars - blue – 20,000oC Image from Hubble Telescope
Size
• Small Stars – White dwarf stars (size of earth) and Neutron stars (20 km in
diameter)
• Medium Stars – Our Sun
• Large Stars – Giant Stars or Supergiant Stars
.Neutron Star
Dwarf Star
Dwarf Star
• ***Size of stars are measured by radius, which is the distance from the center to the outside edge of the circle. (plural = radii)
Brightness
• Apparent Magnitude (AKA – Apparent Brightness)
• A star’s brightness as seen from Earth• Closer stars appear brighter than distant stars
Absolute Brightness
• The brightness a star would have if it were a standard distance from Earth.
• How bright the star REALLY is.• Calculated using the star’s apparent
magnitude & distance from earth.
This shows how large the sun would appear to be if you were on
different planets.
• Brightness of a star depends on temperature & size.Ex: Hot stars = more bright cool stars = less bright
Big stars = more bright small stars = less bright
Hertzsprung-Russell Diagram H-R Diagram
• Proxima Centauri's the nearest star. The celestial bodies that follow are: Alpha Centauri A, Toli, Barnard's Star, Wolf 359, Laland 21185, Sirius A, Sirius B, BL Ceti, UV Ceti, Ross 154, Ross 248, Epsilon Eridani, Lac 9352, Ross 128, EZ Aquarii A, EZ Aquarii B, EZ Aquarii C, Procyon A. Those are the stars that are nearest to me, Tra la la and fiddle dee dee!
http://www.youtube.com/watch?v=Fut0_xU9M6g&safety_mode=true&persist_safety_mode=1&safe=active
The Sun
Facts about the Sun
150 million km from Earth It takes about 8 minutes for light from the sun to
reach Earth.About 1 million Earths could fit inside the sun.Sun’s energy = 6 Trillion nuclear bombs each
second
• The star at the center of our solar system is the sun.
• The sun is a medium-sized star• The sun is about 5 billion years old, and has
about another 5 billion years left to burn
The Sun’s interior is made up of 3 layers
The Core
• Where the sun produces energy by nuclear fusion
• Hydrogen atoms combine to form helium atoms, which releases energy.
The core is over 15,000,000o C
The Radiation Zone• Energy produced in the core moves outward
through the radiation zone.• Moves very slowly because the gas is so dense.
***Takes 100,000 years for energy to move through.
The Convection Zone
• Outermost layer• Hot gases rise from the bottom, cool as they
reach the surface, then sink again.• This moves energy to the sun’s surface.
The sun also has an atmosphere that extends into space.
• The Sun’s atmosphere has 3 layers1. Photosphere2. Chromosphere3. Corona
Sun Rotating Video
• http://apod.nasa.gov/apod/ap140312.html
Sunspots
• Areas of gas on the sun’s surface that are cooler than the gasses around them.
• Cooler gasses are less bright, so they make dark spots.
Prominences
• A huge loop of gas that protrudes from the sun’s surface, linking parts of sunspot regions
Solar Flares• An eruption of gas from the sun’s surface that
occurs when the prominences suddenly connect.
http://www.nasa.gov/mission_pages/sunearth/news/
News041612-M1.7flare.html
Sun’s energy comes to Earth by radiation
• Most of the energy from the Sun is Infrared radiation, visible light, or ultraviolet radiation.
The Electromagnetic
Spectrum
A good way to remember this is…
• Rabbits Meet In Very Unusual eXpensive Gardens
Radio Waves
• Carry Radio, TV, Computer signals• Weakest, least dangerous
Microwaves
• Microwave ovens, cell phones, radar
Infrared Waves
• “Pure” heat, Heat lamps, remote controls, some photography
***Most of the Sun’s energy
Visible Light
• What you can see• White light – “Pure” light, contains all other
colors, if separated by a prism• Colors - Roy G. Biv
Ultraviolet
• Some helps skin produce vitamin D
• Too much causes eye damage, sunburn, & skin cancer
X-Ray
• Used to view bones/teeth• Can cause cancer in high amounts
Gamma Ray• Nuclear Radiation• Can cause radiation poisoning, cancer, death
The electromagnetic spectrum can help scientists view space by allowing
them to see other types of energy that would be invisible with a regular
telescope.
Regular Saturn – Saturn in UV Light
What our galaxy looks like…With your eyes or telescope
infrared
radio
X-ray
gamma ray
