Please Plan-It
Astronomers infer that the universe is expanding because distant galaxies all appear to?
be moving away from us, with more distant ones moving faster
According to Kepler’s third law (p2 = a3), how does a planet’s mass affect its orbit around the Sun?
A planet’s mass has no effect on its orbit around the Sun.
Suppose you have a 100-watt light bulb that you leave turned on for one minute. How much energy does it use?
6,000 joules
Around June 21, the Northern Hemisphere is tipped most directly toward the Sun. This moment is called the _____.
Summer Solstice
During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space?
Earth is catching up with and passing by Mars in their respective orbits.
What is an astronomical unit?
Average distance from the sun to the earth.
Describe the set of conditions under which archaeoastronomers would conclude that an ancient structure was used for astronomical purposes?
The structure has numerous features that align with the Sun’s path at special times of year and cultural heritage claimed that the rulers were descendants of the Sun.
Gamma rays have a small ______.
wavelength
What does it mean when we state something is 'beyond our observable universe"?
We cannot see beyond a distance of 14 billion light years.
Suppose the planet Uranus were much brighter in the sky, so that it was as easily visible to the naked eye as Jupiter or Saturn.
A week would have 8 days instead of 7.
What is the “cosmic address” in the correct order?
You, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
How did the Ptolemaic model explain the apparent retrograde motion of the planets?
The planets moved along small circles that moved on larger circles around the Earth.
Consider an atom of oxygen in which the nucleus contains 8 protons and 8 neutrons. If it is doubly ionized, what is the charge of the oxygen ion and how many electrons remain in the ion?
Charge = +2; number of remaining electrons = 6.
Stars that remain perpetually above the horizon, circling a celestial pole, are called _____ stars.
Circumpolar
Suppose you live in the United States and you see a crescent moon in your evening sky tonight. What will a friend in South America see tonight?
Your friend will also see a crescent moon.
Galileo challenged the idea that objects in the heavens were perfect by _________.
observing sunspots on the Sun and mountains on the Moon
By how many degrees is Earth's axis tilted from a line perpendicular to the ecliptic plane?
23.5 degrees
The idea that scientists should prefer the simpler of two models that agree equally well with observations is known as _____.
Occam's razor
For most of history, the lack of observable stellar parallax was interpreted to mean that?
Earth is stationary at the center of the universe
Which observation offered direct proof of a planet orbiting the Sun?
Phases of Venus
What is precession in the context of Earth's motion?
Precession is a gradual wobble that alters the orientation of Earth's axis in space, with one cycle taking about 26,000 years.
The technique of linking two or more telescopes to achieve the angular resolution of a much larger one is known as _____.
interferometry