Test 1 Flashcards
What is the subject matter of astronomy?
the scientific investigation of the Universe.
What is the definition of the Universe?
all that exists.
What is the meaning of the term “multiverse?” Do we know it exists?
Multiple Universes, we don’t know for sure.
What is the definition of the subject of cosmology?
the study of the evolution of the Universe, past, present and future.
Did the Universe have a beginning? If so, how long ago was that?
Yes, the Universe had a beginning 13.8 billion years ago.`
Who discovered the cosmic microwave background (CMB)? When did it occur?
Arno Penzias and Robert Wilson, occurred about 380,000 years after the beginning of the universe.
Why did the CMB happen?
Because the universe was dense and hot
Who first theorized the expanding Universe?
a Belgian priest named
George Lemaitre.
Who first discovered the expanding Universe?
Edward Hubble
Is the Universe finite or infinite?
the Universe, if not infinite, is unimaginably large.
What is the apparent geometry of the Universe?
has a flat geometry (like the Euclidean geometry
What does it mean for a universe to have a flat geometry?
It is infinite in extent
How/why did galaxies form?
slight increases in matter density were “seeded” into the then grapefruit sized observable Universe. matter naturally started to clump together around these “seed” points of slightly higher density put into the Universe during the “cosmic inflation” period. These “seed” points grew into the stars and galaxies we see today.
Is the expansion rate of the Universe increasing, decreasing, or staying the same?
It is increasing.
What three items make up the energy and mass of the Universe? What are the percentages for these three items in the Universe?
ordinary matter, dark matter, and dark
energy.
Ordinary matter is 4.6% of the universe, Dark matter is 24% of the universe, dark energy is 71.4% of the universe.
Who discovered the existence of dark matter (two names please)?
einstein
What are the two candidates for dark matter?
weakly interacting massive particle and weakly interacting massive particle
What is the current average temperature of the CMB (of the Universe)?
2.73° Kelvin now
Which elements were formed within the first 20 minutes of the Universe (primordial
nucleosynthesis)?
Hydrogen, helium, and lithium
What did Aristotle say that was so important?
“Knowledge is the product of experience.”
What is an experiment?
a logical procedure that attempts to prove or disprove an
hypothesis, directly or indirectly. It uses qualitative and quantitative observations. It must be repeatable.
What did Mr. Feynman say concerning the scientific method?
It’s a guess
What is a hypothesis?
a scientifically vetted, tentative explanation of a physical phenomenon
What is a theory?
a proven hypothesis. It is a fact.
What is a physical law or physical principle?
A scientific theory of general applicability
What is a conserved physical quantity?
one that can neither be created nor destroyed.
Its amount (within a closed system under observation) is fixed.
What physical quantities are classically conserved?
Mass, energy, charge, linear momentum, angular momentum
What is Galileo’s Law of Falling Bodies?
excluding aerodynamic factors, objects of dissimilar mass, released from the same height off the ground, will hit the ground at the same time.
What is Occam’s Principle?
Whenever there are two competing hypotheses, chances are the simpler of the two is the correct one.
What is the Principle of Falsifiability?
In order for an hypothesis to be considered scientific, it must be possible to show it is false, if in fact it is false.
What is planetary retrograde motion?
moving from east to west
How many constellations are there?
88
How many zodiacal constellations are there?
13
What did Commander Scott drop on the Moon?
A hammer and a feather
If you weigh 180 lbs on Earth, what would you weigh on the Moon?
29 lbs
What are the three parts of a scientific measurement?
Best guess/estimate, tolerance, and unit
Why is a confidence interval called a confidence interval?
no measurement can be written with absolute certainty
What is accuracy?
how close you are to the true value of your measurement
What is precision?
how many significant figures you can legitimately write in your measurement
Is it sufficient to be precise in order to be accurate?
It is necessary but not sufficient to be precise in order to be accurate.
What is a non-trivial systematic error?
an inherent limitation in the equipment or the procedure of an experiment.
What is an astronomical unit? What is a light-year?
the average distance between the Sun
and the Earth.
the distance light travels in the vacuum of space over the period of one year.
How is stellar parallax used to determine a star’s distance?
Used to measure the distance.
Who is Henrietta Swan Leavitt?
stars that vary in brightness (or luminosity) in a regular or
periodic fashion.
What are cepheid variable stars?
discovered This relationship between a cepheid star’s period and intrinsic brightness
