#1 Flashcards
what is the average distance between the Earth and the Sun
1 astronomical unit
Strong Nuclear
fundamental force responsible for binding protons and neutrons together when they are sufficiently close together
Gravity
fundamental force responsible for mass being attracted to other mass
electromagnetic
fundamental force responsible for like electric (magnetic) charges repelling and unlike charges attracting
weak nuclear
fundamental force responsible for radioactive decay process
what equation refers to relationship that quantifies how much energy can be derived from the complete conversion of mass, or amount of mass that can be created from the complete conversion of energy
E = mc2
Pair Production
the process by which mass is created out of photons (energy)
Annihilation
The process by which photons are created out of two particles of mass
Andromeda is about 2 million light years away, so the light we see from it…?
left the galaxy 2 million years ago
what two things are inextricably linked?
space and time
if Observer A, who is traveling at the 150,00 km/sec and they measure the speed for which the beam of light travels to be 300,000 km/sec, what did Observer B, who is standing on the side of the road measure?
They both measured the same thing (300,000 km/sec)
if you’re driving your car at the speed of light, an observer beside the road will see…?
the car’s bumper shorten
the same observer, looking at YOUR wristwatch will see…?
your watch moving slower (registering time more slowly)
YOU driving the car will see…?
no difference in height or length
YOU looking at your own wrist watch will see…?
no difference in time
Temperature
the measure that quantifies average atomic and molecular motion
at what point does all atomic/molecular motion stop?
0 kelvin
ionization
removal of electrons from a given atom
isotopes
the same # of protons and electrons, but different # of neutrons
Isotropy
the universe is the same everywhere
homogeneity
everything is evenly distributed within galaxies; no voids
universality
laws of nature in our universe are the same everywhere else
cosmological principle
every observer in any other galaxy sees the same principles; there can’t be a preferential position (we are not at the center and there are no boundaries)
What did Edwin Hubble find?
Nearly all galaxies were receding and therefore the universe is expanding
@ t=0 the state of the universe is
very hot and very small
@ t=0 what is also assumed?
that the four fundamental forces are completely unified
Nuclear fusion reactions made very few heavy elements because
the universe cooled too quickly to build nuclei bigger than helium
how long did it take the universe to build the basic building blocks of matter
3 min
after the universe is created the first force to decouple is
Gravity
strong nuclear
inflationary period (the universe expanded faster than the speed of light)
in the Era of recombination, the Cosmic Background Radiation what happened?
stable, neutral atoms were formed
what phenomenon had to occur to discover the relative size of the moon with respect to the Earth
total lunar eclipse
how was the size of the earth founded?
by measuring the distance from Syene to Alexandria
What is an Ecliptic?
the path the sun appears to follow on the celestial sphere
When would a new moon 1st rise above the horizon?
at 6 am
ptolemy cosmology places the Earth @
the center of the Universe
longitude
right ascension
latitude
declination
when is it best to see taurus and Venus
taurus = morning
venus= evening
During the month of January the Earth is physically closer to the sun by approximately 3,000,000 miles. The effect of this closer proximity on our winter is overwhelmingly counteracted by:
the relative angle between the Sun’s rays and the Earth’s surface
if you are viewing from the North Celestial Pole - what time of day is it for the observer at position A?
6 pm
Constellation
A is on of the 88 officially recognized grouping of stars
the zodiacal constellations lie along the
path that the sun appears to follow on the celestial sphere
In the diagram, what season is it in the Northern and Southern Hemispheres?
North = winter
South = summer
The measurement that was proposed by the ancients (Aristotle) to distinguish between the Geocentric and Heliocentric cosmologies was:
Stellar Parallax
open universe
when there is insufficient gravity or mass to stop expansion of the universe
closed universe
when there is sufficient gravity or mass to stop the universe from expanding
what type of universe do we have?
we have a flat universe (depends on mass density)
