Ch 5 ISP 205

forms of light astronomy. Visions of the universe

Radio waves are a form of

low frequency light

What spectrum is this?

Continuous Spectrum

What spectrum is this?

Emission Spectrum

What spectrum is this?

Absorption Spectrum

An Absorption Spectrum is caused by:

Light passing through cold gas.

An Emission Spectrum is caused by:

Hot gas emitting light.

A Continuous Spectrum is caused by:

Hot dense light source.

Why do hotter surface temperatures emit more total infrared radiation

A higher temperature makes molecules vibrate and move more intensely, resulting in higher energy

The spectral lines that we see in a star's spectrum depend on the star's:

interior temperature.

A star whose spectrum peaks in the infrared is:

cooler than our sun

How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?

4 times

An atom with more electrons than protons has a negative:

electric charge

The number of protons in an atom is its:

atomic number

The sum of the number of protons and neutrons in an atom is called the:

atomic mass number

The greater the redshift:

the faster the speed away from you.

If you know a photon’s frequency and the speed of light, what else can you determine about the photon?

Wavelength and energy

How can an object composition be determined from its spectrum?

By analyzing unique patterns of absorbed or emitted light at specific wavelengths.

How can we estimate the temperature of an astronomical object from the peak of its thermal radiation spectrum?

The peak of the Planck spectrum is determined by the object's temp. By measuring the wavelength of this peak, we find the temperature of the spectrum's source. (the object that emitted the light).

As temperature decreases:

The wavelength at which the spectrum peaks lengthens (Increases.)

Shortest and hottest color of the visible light spectrum

Blue light

Longest and Coldest color of the visible light spectrum

Red light

Forms of light that CAN pass through Earth’s atmosphere because gases scatter them.

Visible light, radio waves, and some infrared and UV

Forms of light that DON’T pass through Earth’s atmosphere because their energy is Too High.

Gamma-Rays, X-Rays and most UV light