In 1974 we transmitted a message toward the globular cluster M13 which is 21,000 ly away. What is one reason that this object was probably not ideal for sending a message to?
A) it is so far away that we will probably have stopped communicating before we receive and return signal
B) globular clusters contain young, high mass stars with insufficiently long main sequence lifetimes and hence are unsuitable places for life
C) the message will be absorbed by interstellar dust before it reaches the cluster
D) globular clusters contain, old, low mass stars with fewer heavy elements and hence are not ideal places for life
D
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Which of the following is true of spring tides?
A) They occur at noon and midnight every day. B) They occur at first- and third-quarter moons. C) They occur at dawn and dusk every day. D) They occur at new moon and full moon.
The energy of a molecule can normally be divided into the following categories:
a. rotational and vibrational b. translational, rotational and vibrational c. electronic, translational, rotational, and vibrational d. rotational e. electronic
__________ is the prediction of special relativity that moving clocks run slow
Fill in the blank(s) with correct word
A satellite coasting at constant speed in a circular orbit
A) is beyond the pull of Earth's gravity B) is nevertheless accelerating. C) undergoes changes in its potential energy. D) none of the above