8.4 Light & Telescopes

Do Now!1. What is the difference between apparent

magnitude and absolute magnitude?2. What two characteristics of stars does a H-R

diagram show?3. List out the 7 consecutive stages of a sun-like

star (medium-mass).4. What type of star ends as a neutron star or

black hole?5. How long is Earth’s rotation and revolution?

Math EOC Quiz (4min)

1. Write down the equation y = mx + b2. What does the m represent?3. What does b represent?4. Write the equation y = 45x + 55, create a

situation that can be represented by this equation. An example, a plumber charges a flat fee of $55 to come to your house, plus an additional $45 per hour to fix your plumbing.

Objective

• Explain how astronomers utilize knowledge of electromagnetic radiation to understand our galaxies and universe.

Agenda

• Do Now• NASA Telescope Virtual Fieldtrip• Light & Telescopes Guided Notes• Telescope Research & Group Project• Toilet Paper Solar System Scale• Exit Ticket

NASA Telescopes

• Images from the Hubble Telescope• http://www.youtube.com/watch?v=khySM1Y

BQvA&feature=related• As you view these images, try to explain in

words the images you are viewing (e.g. colors, brightness, objects, patterns, etc.).

Hubble’s Law• According to this law, galaxies are

moving away at a speed that is proportional to their distance.

Electromagnetic Spectrum• Take 5 minutes to label the diagram in

your notes (Refer to page 674 in text)

Electromagnetic Spectrum

Electromagnetic Radiation• Includes gamma rays, X-rays,

ultraviolet light, visible light, infrared radiation, microwaves, and radio waves (list next to picture in notes)

Electromagnetic Radiation•Red light has the longest wavelength which means that the object is moving away from the observer. This light has the least energy (radio waves).

Electromagnetic Radiation•Violet/blue light has the shortest wavelength which means that the object is moving towards the observer. This light has the most energy.

Doppler Effect• Describes the change in wavelength

of light or sound that occurs when an object moves toward or away from you.

Doppler Effect

• Astronomers are only concerned with the changes of light wavelengths, not sound.

• Doppler Effect tells us whether an object is moving towards or away from Earth

• Large Doppler shifts indicate higher speeds

Red Shift

• “Red Shift” means that an object in space is moving away from Earth indicating that the universe is expanding

Red Shift

Greater red shifts in the color spectrum Greater red shifts in the color spectrum of distant galaxies indicate faster speedsof distant galaxies indicate faster speeds

Telescopes• Galileo is the first person to have used

telescopes for astronomy.

• There are 3 main types of telescopes: Refracting, Reflecting & Radio.

Telescopes

• There are also telescopes in space that are capable of seeing other forms of electromagnetic radiation (x-rays and gamma rays)

Telescopes

• Refracting: Uses a lens to bend and refract light

• Reflecting: Uses a concave mirror that focuses the light in front of the mirror.

Telescopes

• Radio: Focuses incoming radio waves on an antenna that absorbs and transmits the waves to an amplifier.

• Radio telescopes can see through dust and gas in space which produces clearer images.

Hubble Telescope

• 1st space telescope built by NASA.

• Hubble has provided us with information about stars, black holes, and the age and expansion of the universe.

Space Telescopes

• A major advantage of space telescopes is that they are not affected by Earth’s atmosphere, thus producing a high quality image.

Space Tools & Light Research• Use Section 24.2-Tools for Studying Space (pgs.

678-683) to create a poster comparing the 4 major types of telescopes.

• For each telescope include the following: -Picture (label parts if possible)

*2 Paragraphs:-Who invented it & How it works-Advantages/Disadvantages

• Synthesis: Which telescope is the best & why?

Exit Ticket1. How does the wavelength and energy of red

and violet/blue light compare?2. What is the significance of the Doppler Effect?3. What are the 3 types of telescopes?4. What is the name of the 1st telescope built by

NASA?5. What is the major advantage of space

telescopes?