Astronomy Part 1 Section 1 Flashcards
1 Astronomical Unit
150,000,000 km
Describe the Earth
Rocky Planet with Iron Core 15,000 kilometers
Describe the Sun
A typical star, ball of hot gas, mostly hydrogen and helium 1,500,000 kilometers.
The sun is _____ times larger in diameter than the earth
100 times
The sun is _______ times larger the volume than the earth
1,000,000 times
Describe the Milkyway Galaxy
100,000 light years across, contains 100 billion stars, contains gas and dust clouds (new stars come from clusters of galaxies)
What is a scientific Theory?
an idea that proposes to explain observations. Consists of: observation, explanation, and prediction
What is a constellation?
Apparent groupings of bright stars in the sky usually at large ranges of distances, not physically associated.
How many constellations is the sky divided into?
88 constellations
What direction does the sky appear to rotate daily around the north star?
counterclockwise
Most Celestial objects rise in the _____ and set in the _____
Most Celestial objects rise in the east and set in the west
What do the pointer stars point to?
polaris, or the “north star”
Where is the polaris located?
At the end of the handle of the little dipper
What is the constellation Orion also known as?
Also known as “The Great Hunter”
Describe Orion (What it contains)
Brightest winter constellation, red supergiant, blue supergiant, orion nebula (region of very active star formation)
Hotter objects produce what color light?
Blue light
You can only see constellations located on the side of the sky _______ of the sun.
opposite
How many times does the Sun appear to move around the sky?
Once per year
How many constellations are located along the sun’s apparent path?
12 constellations
How long does the sun spend on each constellation?
One month
Define Astrology
Ancient superstition not based on the scientific method, not tested by observation or experiment
Deine Astronomy
A modern science, based on the laws of physics, verified by observation and experiment
Scientific Notation Problem: 1,000,000,000= ?
1.0 x 10^9 = 10^9
Scientific Notation Problem:
0.000000001 = 1.0 x 10^-9 = 10^-9
When you drop a rock in a pond the wave crests travel in what direction?
Outward
How does water travel when the rock hits it?
It moves in a small circle
What direction does energy travel in a wave?
outward
What is radiation?
Means of transporting energy across space
What is an example of a form of electromagnetic radiation?
Light
What is electromagnetic radiation?
electric and magnetic disturbances that travel as a wave through space
What is the absolute speed limit in the universe?
Speed of light
What is the crest of a wave?
high point in a wave
What is the trough of a wave?
the low point in a wave
what is the amplitude?
heigh of a wave
what is wavelength?
distance between successive crests
what is a spectrum?
a separation of light into its constituent wave lengths using a prism or grating
What are the colors of visible light, long to short wavelengths
ROY G BIV red, orange, yellow, green, blue, indigo, violet
Describe the electromagnetic spectrum from long wavelength to short wavelength. (there should be 7)
Radio, microwave, infared, visible, ultraviolet, x-ray, gamma ray
1 nanometer
10^-9 m
What is a photon?
A packet of energy which acts like a particle, they are the smallest unit
What is the equation for photon energy?
E= hv= hc/lambda
The higher the frequency of a photon the ______ the energy?
higher
The longer the wavelength the ______ the energy
lower
Which of the electromagnetic spectrum has the least energy?
Radio
Which of the electromagnetic spectrum has the highest amount of energy?
gamma ray
What is a transverse wave?
oscillation is perpendicular to its travel direction
What is a longitudinal wave?
oscillation is parallel to its travel direction
What color is the earth’s atmosphere?
opaque
What are the two “windows” of transparency in the earth’s atmosphere?
radio and optical
All objects absorb and emit what kind of radiation?
electromagnetic
Hot objects emit more or less electromagnetic radiation than cooler objects?
more
Hotter objects have more or less energetic photons emitted?
More energetic
The color of a hot object shifts to what color when its temperature rises?
blue
Dark= cooler or hotter, and more or less infared?
Cooler, less IR
Light = cooler or hotter, and more or less infared?
Hotter, more IR
What happened in the demo with lighting the match with infared light?
heating a coil creates IR radiation which strikes the first reflector, the first reflector makes light rays parallel, second reflector focuses light on match head, the match bursts into flames. Thus, energy has traveled through space as a IR electromagnetic wave
What are the numbers for the temperature scale (absolute, zero, water freezing temp and water boil temp) for farenheit, celsius, and kelvin
Farenheit: -460, 32, 212
Celsius: -273, 0, 100
Kelvin: 0, 273, 373
What is a blackbody?
ideal absorber and emitter of electromagnetic radiation
What is an example of a blackbody?
heated bar of iron, stellar photosphere
Describe the blackbody curve spectrum
plot of intensity versus wavelength for a blackbody of a given temperature. LOOK AT THE DIAGRAM the wavelength decreases as the temperature increases. The hotter the black body the more peak shifts to the blue. at any wavelength a hotter black body has a larger intensity.
What is the formula for a blackbody?
lambda = const/temperature ( in kelvin)
What is Kirchoff’s first law?
a hot solid object or dense gas produces a continuous spectrum, complete rainbow, all wavelengths seen, no spectral lines (heated bar of iron, ideal black body)
What is Kirchoff’s second law?
A low density, hot gas produces a emission line spectrum, series of bright lines, no emission between lines, (neon signs, bright interstellar clouds)
What is the constellation Gemini also known as?
“The Twins”
Where can you see Gemini in the evening?
high in the east
Describe the constellation Gemini
symbol Roman II, rectangular shape, brightest two stars: castor and pollux, consits of six stars, 3 binaries in mutual orbit, jupiter is now in Gemini
Where can jupiter be found?
Jupiter is presently nearly opposite the sun in the sky, it is visible throughout the night
Where can venus be found?
Venus is nearly between the earth and the sun, rises in the south east just before the sun, best between 7 and 9 am
What is kirchoffs third law?
A low density cooler gas produces an absorption line spectrum when viewed in front of a hotter continuous source, see continuous spectrum with dips at certain wavelengths, dark lines among colors of the rainbow (galaxies, other stars, photosphere of the sun)
What is the visible spectrum of hydrogen called?
the balmer series
What are the first three balmer lines?
H (fish) 656 nm red
H B 486 nm blue/green
H V 434 nm Blue, violet
What is the spectroscopic method?
every element or compound produces a unique set of lines, a finger print. Wavelengths of lines can be calculated theoretically and measure in a lab, identification of lines in spectra of celestial object gives composition and physical state of object
Describe an atomic structure
nucleus: central structure, protons and neutrons, electrons orbit around nucleus
What does a normal hydrogen atom consist of?
nucleus: 1 proton
1 electron orbits nucleus
Larger orbit means a _____ energy level
higher
When are photons emitted or absorbed?
when an electron changes orbit
What happens when a larger orbit changes to a smaller orbit?
Higher energy, to lower energy, photon is emitted
What happens when a smaller orbit changes to a larger orbit?
Lower energy to higher energy, photon is absorbed
What is photon energy?
the energy different between two orbits
What is ionization?
An atom absorbs sufficiently energetic photon to cause the electron to jump out of the atom
