Astronomy Chapter 5

In order for an electron to jump up two energy levels in an atom at once, it requires

More energy, a precises amount of energy, and a bluer photon than to jump one energy level.

As a blackbody becomes hotter, it also becomes __________ and __________.

More luminous; bluer

When you turn on a lightbulb in a room, the entire room appears to flood with light at the same time. Your eyes cannot perceive light originating at the bulb and then moving outward from it. This either means that light has infinite speed, or it moves so fast that it is difficult to tell the difference. How might you improve your chances of detecting the motion of light if it moves at finite speed?

Move farther away from the light source.

Rank the types of radiation in order of their energy, from least to greatest.

Radio - Infrared - Visible Rainbow - Xrays - Gamma rays (hulk)

Rank the types of light in order of increasing energy.

Radio, Infrared, Orange, Green, Ultraviolet, and gamma ray.

What can astronomers determine from the spectrum of an object?

Speed toward or away from an observer Temperature Composition

Based on this fact, what can we find from the wavelengths of absorption lines seen in the spectrum of a star?

The composition of any gas between the light-emitting "surface" of the star and the observer

What shows how someone on Earth can view Jupiter's moon eclipses when Earth is closer to are farther from Jupiter.

If light has infinite speed, an eclipse would be seen to happen at the same time regardless of how faraway Earth is from Jupiter. If light has finite speed, it would take longer for it to travel from Jupiter to Earth when Earth is farther from Jupiter.

The bright, colorful "stripes" of a rainbow such as the one shown here follow a particular order. Rank each color of the rainbow by how much energy is carried by its electromagnetic waves, from highest to lowest.

Blue - Yellow - Orange - Red

Imagine that you observe a star/planet system, edge-on. When the planet is moving away from Earth, the light from the star is

Blueshifted

What would automatically happen if the wavelength of light were increased.

The frequency and the energy of the light would decrease.

If these stars are moving away from Earth, rank them in order from slowest to fastest speed, based on wavelength.

The higher the frequency the slower the speed and vice versa.

Why don't we see cars as bluer when they approach and redder when they recede?

They are too slow.

Star A and star B appear equally bright in the sky. Star A is 2 times as far away from Earth as star B.

This means that Star A is 4.00 times as lumininous as star B.

Imagine that you observe a star-planet system, edge-on. When the planet is moving away from Earth, in which direction is the star moving?

Toward Earth

What are some implications of the finite speed of light?

When we gaze at the Andromeda Galaxy, we are looking back in tie to the way it used to appear millions of years ago. There would be a noticeable delay in communications at the speed of light between Earth and astronauts on the Moon.

The "square" in the inverse square law for intensity of light means that

at three times the distance, the intensity is 1/9 as great.

The "square" in the inverse square law comes from the fact that

surface area increase like the radius of a sphere multiplied by itself.