Chat with AIExam 2: A User S Guide to the Sky
In 1928, the International Astronomical Union (IAU) established _______________ official constellations with carefully defined boundaries that together include every part of the sky.
(39) 
Verified88
The sky appears to rotate eastward around Earth each day, but that is a consequence of the westward rotation of Earth.
(38) VerifiedFalse
Describe the magnitude scale and compare the ancient method to the current methodology used today.
(43) VerifiedAstronomers describe the brightness of stars using the magnitude scale, a system that first appeared in the writings of the astronomer Claudius Ptolemy about the year 140. Those early astronomers divided the stars into six classes. The brightest stars were called first-magnitude stars and the next brightest set, second-magnitude stars. The scale continued downward to sixth-magnitude stars, the faintest visible to the human eye. Thus, the larger the magnitude number, the fainter the star. This might make sense if you think of the brightest stars as first-class stars and the faintest visible stars as sixth-class stars. Ancient astronomers could only estimate magnitudes by eye, but modern astronomers can use scientific instruments to measure the brightness of stars to high precision; so they have carefully redefined the magnitude scale. These numbers are known as apparent visual magnitudes ( m V because they describe how the stars look to human eyes observing from Earth.
Student should give some comparative values of star magnitudes.
The eastward rotation of Earth causes the Sun, Moon, planets, and stars to move _______________ in the sky.
(42) The International Astronomical Union established 88 constellations that represent a defined area of the sky.
(35) What was the purpose of the IAU establishing 88 official constellations?
(36) When can Sirius, a famous star of the Northern Hemisphere, be observed?
(26) In a given constellation, the star designated with the Greek letter α is always brighter than the star designated with the Greek letter β .
(32) If two stars have a magnitude difference of 5, what is their flux ratio?
(31) If Earth rotated about its axis completely upright, what would we fail to experience?
(36) Scientists constructed a history of ocean temperatures using deep ocean cores that convincingly matched the predictions of the _______________, describing the cause of multiple ice ages on Earth.
(39) Earth's rotation is connected with a very slow celestial motion that can be detected only over _____
(45) Earth's rapid rotation makes its axis sweep out the shape of a cone, like a heavy top slowing down. This motion is known as ____.
(37) Even though modern astronomers know that stars are scattered through space at different distances, they still use what scientific model to describe celestial locations in the sky?
(36) What date is the autumnal equinox for the Southern hemisphere?
(45) What is the Milankovitch hypothesis and what evidence is there to support this hypothesis?
(27) Which planet is often called our most brilliant "morning star"?
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