Answers to all homework questions will be posted on the class website

First exam: Monday, October 3.

If the wavelength of an electromagnetic wave increases, its velocity

(red) Decreases

(yellow) Increases

(blue) Remains the same

(green) Not enough information

If the wavelength of an electromagnetic wave increases, its velocity

(red) Decreases

(yellow) Increases

(blue) Remains the same

(green) Not enough information

If the wavelength of an electromagnetic wave increases, its frequency

(red) Decreases

(yellow) Increases

(blue) Remains the same

(green) Not enough information

If the wavelength of an electromagnetic wave increases, its frequency

(red) Decreases

(yellow) Increases

(blue) Remains the same

(green) Not enough information

If the wavelength of an electromagnetic wave increases, its energy

(red) Decreases

(yellow) Increases

(blue) Remains the same

(green) Not enough information

If the wavelength of an electromagnetic wave increases, its energy

(red) Decreases

(yellow) Increases

(blue) Remains the same

(green) Not enough information

You are an astronaut taking a spacewalk to fix your spacecraft with a hammer. Your lifeline breaks and the jets on your back pack are out of fuel. To return safely to your spacecraft (without the help of someone else), you should

a) throw the hammer at the space ship to get someone's attention. b) throw the hammer away from the space ship. c) use a swimming motion with your arms. d) kiss your ship good bye.

You are an astronaut taking a spacewalk to fix your spacecraft with a hammer. Your lifeline breaks and the jets on your back pack are out of fuel. To return safely to your spacecraft (without the help of someone else), you should

a) throw the hammer at the space ship to get someone's attention. b) throw the hammer away from the space ship. c) use a swimming motion with your arms. d) kiss your ship good bye.

The Doppler Shift:

A shift in wavelength due to a wave emitter moving towards (shorter wavelength) or away (longer wavelength) from an observer.

v c

=

The Doppler Effect

1. Light emitted from an object moving towards you will have its wavelength shortened.

2. Light emitted from an object moving away from you will have its wavelength lengthened.

3. Light emitted from an object moving perpendicular to your line-of-sight will not change its wavelength.

BLUESHIFTBLUESHIFT

REDSHIFTREDSHIFT

Measuring Radial Velocity● We can measure the Doppler

shift of emission or absorption lines in the spectrum of an astronomical object.

● We can then calculate the velocity of the object in the direction either towards or away from Earth. (radial velocity)

v c

=

Measuring Rotational Velocity

In conducting a search for life, we must understand how planets are formed and what determines their habitability.

What does any theory of the formation and evolution of the solar

System have to account for,

i.e., what are the “observed facts”?

The Sun:

A central star

Predominately H and He

Most of the mass in the solar system.

Rotates in same sense that planets

orbit.

Terrestrial Jovian

Two “flavors” of planets

Size: small large Location: closer to Sun more

distant Composition: rocky/metallic gaseous/icy Temperature: hotter colder Rings: none ubiquitous Rotation rate: slow rapid Surface: solid not solid Atmosphere: minimal

substantial Moons: few to none many

Terrestrial Planets Jovian Planets

Planetary orbits:

1) Prograde

2) approximately coplanar

3) approximately circular

Rotation:

1) Mostly Prograde

2) Includes sun

3) Includes large moons

There are large numbers of smaller objects in the Solar System

moons: both rocky & icy asteroids: rocky comets: icy

Craters are ubiquitous on solid objects

small

Rocky

Odd-shapes

nearly circular orbits

orbit planes are near Ecliptic Plane

orbits in inner part of solar system

Asteroids

The “asteroid belt”

small nucleus

“dirty snow ball”

very large tails

highly eccentric orbits

all orbit inclinations

Comets

Comets are found mainly in two regions of the solar system

Largest Known Kuiper Belt Objects