PHY 150 Study Questions with Correct Answers.
In what ways is the celestial sphere a scientific model?
The celestial sphere is an excellent scientific model. It is an accurate representation of what we
observe when we view the night sky. Note that as we look out at the night sky, all the stars
appear to be an equal distance away as if they were dots painted on a giant ceiling.
Consequently, the celestial sphere does represent what we see, and permits us to discuss what
would happen if Earth is at the center and Earth rotated on its axis, and/or revolved around the
sun. It provides us with a way to step back and picture in our minds what is going on as Earth
rotates on its axis and revolves around the sun.
What causes the seasons?
Because Earth orbits the sun, the sun appears to move eastward along the ecliptic. The
inclination of the ecliptic means the sun is in the northern hemisphere half the year and the
southern hemisphere the other half. In the summer, the sun is above the horizon longer and
shines more directly down on the ground. Both effects cause warmer weather.
GALILEO Galilei
Galilei (1564-1642)
Resolved the stars in the Milky Way, discovered sunspots and measured the Sun's rotation,
observed Venus phases, discovered four moons of Jupiter, observed lunar features and measured
lunar wobble, supported the Copernican system of planetary movement via his observations.
KEPLER Johannes (1571 - 1630)
,Using Brahe's precise data derived his three laws of planetary elliptical motion, provided
explanation of optical image formation through small apertures, the first enunciation of the
inverse square law for intensity of illumination.
HERSCHEL William (1738 - 1822)
The discoverer of Uranus and several satellites of Saturn and Uranus, discovered that some
double stars orbit each other, discovered infrared radiation, attempted to map the Milky Way's
shape, known for building state-of-the-art telescopes.
LAPLACE Pierre-Simon (1749 - 1827)
Postulated the solar system evolved from a large flattened cloud of gas, published differential
equations describing planetary orbits and tides, determined the masses of Jupiter, Saturn and
Uranus, applied probability theory to errors in observations.
COPERNICUS Nicolaus (1473 - 1543)
Proposed Earth orbited the Sun via De Revolutionibus Orbium Coelestium contradicting the long
held Ptolomic belief that the Sun orbited the Earth thereby laying the groundwork for Galileo
and Kepler.
PTOLOMY Claudius (2nd century AD)
Through his Almagest constructed an accurate geocentric model of the solar system consisting of
a series of deferents and epicycles that was followed for 15 centuries until Copernicus.
BRAHE Tycho (1546 - 1601)
, Chronicled supernova of 1572 and discovered it had no diurnal parallax proving it lay beyond
the Moon, plotted the motion of the comet of 1577, accurately plotted motions of planets used by
Kepler after his death.
HALLEY Edmond (1656 - 1742)
Astronomer Royal, discovered Omega Centauri, paid for publishing Newton's Principia, using
Newton' gravitational law predicted the comet of 1682 would return in 76 years, invented the
idea of using transits of Mercury and Venus to determine distance to the Sun.
HUBBLE Edwin (1889 - 1953)
Discovered the Hubble classification of galaxies, using Cepheid variables in M31 and M33
calculated their distances, showed that galaxy distribution was cosmologically uniform, showed
galaxies were moving away from us at speeds proportional to their distance (Hubble's Law).
KUIPER Gerard (1905 - 73)
First planetary scientist, spectroscopically detected CH4 on Titan and CO2 on Mars, identified
the comet-like debris of Kuiper's Belt at the edge of the solar system.
What is the difference between mass and weight?
Mass is a scientific measure of the amount of matter an object is made up of. No matter where
you are at given moment in time, mass is constant.
Weight is a form of measurement that is dependent on gravity and, unlike mass, your weight can
vary depending on where you are in the universe.
Describe two ways atoms can become excited, that is, can gain energy.
In what ways is the celestial sphere a scientific model?
The celestial sphere is an excellent scientific model. It is an accurate representation of what we
observe when we view the night sky. Note that as we look out at the night sky, all the stars
appear to be an equal distance away as if they were dots painted on a giant ceiling.
Consequently, the celestial sphere does represent what we see, and permits us to discuss what
would happen if Earth is at the center and Earth rotated on its axis, and/or revolved around the
sun. It provides us with a way to step back and picture in our minds what is going on as Earth
rotates on its axis and revolves around the sun.
What causes the seasons?
Because Earth orbits the sun, the sun appears to move eastward along the ecliptic. The
inclination of the ecliptic means the sun is in the northern hemisphere half the year and the
southern hemisphere the other half. In the summer, the sun is above the horizon longer and
shines more directly down on the ground. Both effects cause warmer weather.
GALILEO Galilei
Galilei (1564-1642)
Resolved the stars in the Milky Way, discovered sunspots and measured the Sun's rotation,
observed Venus phases, discovered four moons of Jupiter, observed lunar features and measured
lunar wobble, supported the Copernican system of planetary movement via his observations.
KEPLER Johannes (1571 - 1630)
,Using Brahe's precise data derived his three laws of planetary elliptical motion, provided
explanation of optical image formation through small apertures, the first enunciation of the
inverse square law for intensity of illumination.
HERSCHEL William (1738 - 1822)
The discoverer of Uranus and several satellites of Saturn and Uranus, discovered that some
double stars orbit each other, discovered infrared radiation, attempted to map the Milky Way's
shape, known for building state-of-the-art telescopes.
LAPLACE Pierre-Simon (1749 - 1827)
Postulated the solar system evolved from a large flattened cloud of gas, published differential
equations describing planetary orbits and tides, determined the masses of Jupiter, Saturn and
Uranus, applied probability theory to errors in observations.
COPERNICUS Nicolaus (1473 - 1543)
Proposed Earth orbited the Sun via De Revolutionibus Orbium Coelestium contradicting the long
held Ptolomic belief that the Sun orbited the Earth thereby laying the groundwork for Galileo
and Kepler.
PTOLOMY Claudius (2nd century AD)
Through his Almagest constructed an accurate geocentric model of the solar system consisting of
a series of deferents and epicycles that was followed for 15 centuries until Copernicus.
BRAHE Tycho (1546 - 1601)
, Chronicled supernova of 1572 and discovered it had no diurnal parallax proving it lay beyond
the Moon, plotted the motion of the comet of 1577, accurately plotted motions of planets used by
Kepler after his death.
HALLEY Edmond (1656 - 1742)
Astronomer Royal, discovered Omega Centauri, paid for publishing Newton's Principia, using
Newton' gravitational law predicted the comet of 1682 would return in 76 years, invented the
idea of using transits of Mercury and Venus to determine distance to the Sun.
HUBBLE Edwin (1889 - 1953)
Discovered the Hubble classification of galaxies, using Cepheid variables in M31 and M33
calculated their distances, showed that galaxy distribution was cosmologically uniform, showed
galaxies were moving away from us at speeds proportional to their distance (Hubble's Law).
KUIPER Gerard (1905 - 73)
First planetary scientist, spectroscopically detected CH4 on Titan and CO2 on Mars, identified
the comet-like debris of Kuiper's Belt at the edge of the solar system.
What is the difference between mass and weight?
Mass is a scientific measure of the amount of matter an object is made up of. No matter where
you are at given moment in time, mass is constant.
Weight is a form of measurement that is dependent on gravity and, unlike mass, your weight can
vary depending on where you are in the universe.
Describe two ways atoms can become excited, that is, can gain energy.
