Bit of Administration.

Transcription

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2 Lab 2 Bit of Administration. ew observation dates: March 22 - April 5 o need to duplicate observations in hand! ew due date: April 9 at my office Homework Reading BV pp o office hours today Feel free to e for later in week

3 Astronautics Interplanetary Travel The Central Concept The paths of interplanetary spacecraft are simply orbits around the un And the spacecraft obey the same physical laws as do planets.

4 Astronautics Transfer Orbit = Minimum Launch Energy Launch in the direction of motion of the launch platform. Arrive at destination at aphelion ( for outer target) or perihelion (for inner target) of spacecraft orbit. (Aphelion - point of orbit most distant from un Perihelion - point of orbit closest to un)

5 Transfer Orbit for the Moon

6 Astronautics Transfer Orbit = Minimum Launch Energy Launch in the direction of motion of the launch platform. Arrive at destination at aphelion ( for outer target) or perihelion (for inner target) of spacecraft orbit. (Aphelion - point of orbit most distant from un Perihelion - point of orbit closest to un) Advantages - Fuel efficiency Disadvantages - Long travel time

7 Astronautics Gravity Boosts Gain in energy due to gravitational slingshot around a more massive body. ote: More massive body loses energy, but in case of planet and spacecraft this is not a problem!

8 Gravity Boosts In frame of Jupiter Astronautics but Jupiter is moving In frame of olar ystem

9 Astronautics Gravity Boosts - AA missions

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11 The Physics of Light Light as a Wave = Electromagnetic Radiation Wavelength (λ)( ) has units of length Frequency (ν)( - number of crests passing per second - has units of cycles per second, or Hertz peed - for light, c = 3x10 5 km/sec Wavelength 3 x 10 5 km/sec

12 The Physics of Light Light as a Wave = Electromagnetic Radiation Wavelength (λ)( ) has units of length Frequency (ν)( - number of crests per second peed - for light, c = 3x10 5 km/sec mall wavelength Large frequency Large wavelength mall frequency

13 The Physics of Light Light as a Wave = Electromagnetic Radiation Wavelength (λ)( ) has units of length Frequency (ν)( - number of crests passing per second - has units of cycles per second, or Hertz peed - for light, c = 3x10 5 km/sec ν = c λ

14 Electromagnetic pectrum The Physics of Light 1 km = 1000 m 1 m 1 mm = m = 10-3 m 1 µm m = 10-6 m ( micron ) 1 nm = 10-9 m (nanometer)

15 Electromagnetic Radiation The Physics of Light Light acts as an electric force Light acts as a magnetic force

16 Electromagnetic Radiation The Physics of Light Antenna

17 Doppler hift The Physics of Light

18 Doppler hift The Physics of Light ource moving toward observer or observer moving toward light source horter Wavelength Higher Frequency Blueshift Light source moving away from observer or observer moving away from light source Longer Wavelength Lower Frequency Redshift

19 The Physics of Light Doppler hift ource across observer s line of sight ame Wavelength as emitted ame Frequency as emitted o hift

20 The Physics of Light Doppler hift λ λ rest = v c v = velocity of light source or observer (+ => toward each other) λ = rest wavelength λ = change (shift) in wavelength c = 3 x 10 5 km/sec

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