unit 11/12 Flashcards
5/2/24
the study of electromagnetic spectra— provides important information about the chemical composition of remote astronomical objects.
Spectroscopy
serve as distinctive “fingerprints” that identify the chemical elements and compounds comprising a light source.
Spectral Lines
A device that separates incoming light by its wavelengths AND records the spectrum.
Spectrograph
Usually starts from a source that gives off all wavelengths of light (like a star), but is missing specific wavelengths that were absorbed on its way to us
Absorption Spectrum
The specific set of wavelengths emitted by a source.
Emission Spectrum
When the source and observer are moving towards each other, the observed wavelength is shorter. Therefore, the frequency (pitch) is higher.
When the source and observer are moving away from each other, the observed wavelength is longer. Therefore, the frequency (pitch) is lower.
The Doppler Effect & Sound
When the source and observer are moving towards each other, the observed wavelength is shorter. Therefore, the color is blueshifted.
When the source and observer are moving away from each other, the observed wavelength is longer. Therefore, the color is redshifted.
The Doppler Effect & Light
Moving away from us
the further away the astronomical object is, the faster it is moving away from us.
Redshift
an idealized perfect light absorber that absorbs all the photons that strike it (no reflection). It re-emits the absorbed energy through thermal radiation,
Blackbody spectrum
states that the peak wavelength of radiation emitted by a blackbody is inversely proportional to its temperature - the higher its temperature, the shorter the peak wavelength.
Wien’s Law
a scientific field within the life and environmental sciences that studies the origins, early evolution, distribution, and future of life in the universe.
Astrobiology
Godi lock Zone: a planet where water can exist as a liquid, not too hot or too cold for life.
depends on the star’s size and temperature, and the planet’s atmosphere and distance.
Bigger and hotter stars have wider and farther habitable zones, while smaller and cooler stars have narrower and closer ones.
Habitable Zones
used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy
The DRAKE equation
Which of the following are colors of stars that you can see?
Blue, white, yellow, orange, and red
What color are the hottest stars?
blue
What color are the coolest stars?
red
Our star, The Sun, gives off more green light than any other visible color of light. So, why does our Sun not look green
The sun appears orangish-yellow because the blue light it emits has a shorter wavelength and is scattered in the atmosphere—the same process that makes the sky appear blue. Astronomers, however, call the sun a “yellow dwarf” star because its colors fall within the yellow-green section of the electromagnetic spectrum.
A star has a surface temperature of 7000 K. What color is it?
white or slightly yellowish in color.
The color of a star is an indication of its surface temperature: blue stars are the hottest, followed by white, yellow, orange, and red being the coolest.
