Properties of Light and Black Body Radiation Quiz

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What is responsible for causing the seasons on Earth?

The spin direction of Earth

The tilt of Earth's rotation axis to the plane of its orbit around the Sun (correct)

The Moon's orbit about the Earth

The crossing of the celestial equator by the Sun

What is the equivalent of celestial longitude fixed by?

The summer solstice

The vernal equinox (correct)

The tilt of the celestial equator

The crossing of the celestial equator by the Moon

Why are eclipses only possible when the Moon's orbit crosses the ecliptic plane?

Because the Moon's phases are synchronized with this crossing

Because this alignment ensures that the Moon, Earth, and Sun are in a straight line (correct)

Because the Moon's orbit is perfectly aligned with the ecliptic plane

Because the ecliptic is tilted 23.5º to the celestial equator

Who proposed a model of planetary motions with circular orbits about the Earth and epicycles?

Ptolemy Signup and view all the answers

What is one major problem associated with the Ptolemaic model of planetary motion?

Large epicycles needed for retrograde planet motions Signup and view all the answers

Why is understanding the Copernican Revolution considered important in science?

It is a classic example of the scientific method in action Signup and view all the answers

Where do comets with orbits that are not in the plane of the orbits of the planets come from?

The Oort Cloud Signup and view all the answers

What are comets primarily made of?

Ices, including water ice, with some rocky material Signup and view all the answers

If Mars were to have an ocean at one point in time, where would it most likely have been located?

In the present permafrost and ice caps Signup and view all the answers

Why is the evidence for liquid water on Mars considered important?

It indicates past habitability on Mars Signup and view all the answers

What regions in the outer solar system are populated by objects left over from the formation of the solar system?

Oort Cloud and Kuiper Belt Signup and view all the answers

How might we establish if there has been life on Mars at some point?

By analyzing Martian meteorites found on Earth Signup and view all the answers

Why can we approximate a red star as a 'black body'?

Because of the dependence of the amount of energy radiated by a 'black body' on its temperature. Signup and view all the answers

Why do spectral lines appear in emission when observed without intervening material?

Because the light is emitted by an intervening material hotter than a black body behind it. Signup and view all the answers

What allows us to determine how fast a distant object is rotating by examining the spreading out of spectral lines?

The spreading out of spectral lines. Signup and view all the answers

What do spectral lines appearing in absorption indicate?

The intervening absorbing material is cooler than the light-emitting material behind it. Signup and view all the answers

How do we determine the velocity of a distant object relative to us using spectral lines?

By recognizing spectral lines of elements and measuring their Doppler shifts. Signup and view all the answers

What does the Doppler shift allow us to determine?

The velocity of a distant object relative to us. Signup and view all the answers

What is the main role of greenhouse gases in a planet's atmosphere?

Absorbing and reradiating infrared light to keep the surface warm Signup and view all the answers

Why is the planet's solid surface heated by sunlight but at a lower temperature than the sun's surface?

Because the sunlight is absorbed by the solid surface and then reradiated as infrared light Signup and view all the answers

Why do small planets like Mercury cool faster than larger planets?

Lack of greenhouse gases in their atmosphere Signup and view all the answers

Which characteristic differentiates Venus from Mercury in terms of their atmospheres?

Veiled by clouds Signup and view all the answers

How does the rotation rate of Venus contribute to maintaining fairly even temperatures on its day and night sides?

By making the atmosphere rotate faster than the planet Signup and view all the answers

Why do greenhouse gases absorb and reradiate infrared light in an atmosphere?

To prevent excessive cooling by trapping heat near the surface Signup and view all the answers

Why did the guiding centers for the epicycles in Ptolemy's model have to speed up and slow down on each circuit?

To mimic the irregular motion observed in the sky. Signup and view all the answers

What suspicious feature of Ptolemy's model related to the planets Mars, Jupiter, and Saturn is mentioned in the text?

Their periods of revolution around their epicycles matched the period of the sun around Earth. Signup and view all the answers

How did Copernicus' model address the features of Ptolemy's model that were considered questionable?

By providing a simpler explanation for the observed planetary motions. Signup and view all the answers

What was one unusual aspect of Ptolemy's model regarding the distance from Earth to celestial bodies?

The distances were considered arbitrary and could not be calculated within the model. Signup and view all the answers

In Ptolemy's model, what was one reason given for not having epicycles for the sun and moon?

Their motions were already accounted for by other celestial bodies. Signup and view all the answers