Contrast open and globular star clusters
What will be an ideal response?
Globular clusters are older (as old as the Galaxy, from 10-12 billion years old), contain many more stars (millions of stars for the richest ones), and are very poor in metals. Their brightest members have evolved into red giants, and their color magnitude diagram leaves the main sequence just above the Sun's position and curve into the giant branch to the top right. By contrast, most open clusters are much younger, with hot blue stars the brightest. They are made of a much larger fraction of heavy elements, produced by the many generations of supernovae that happened since the globular clusters formed.
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If we could watch spiral arms from a telescope situated above the Milky Way over 500 million years, what would we see happen?
A) Stars will move through the spiral arms, bunching up closer as they pass through. Young hot stars will form and die within the arms before having a chance to move out. B) The spiral arms will eventually unwind, as centripetal forces send the stars flying outwards into intergalactic space. C) The spiral arms will eventually dissipate and fade away, since they are a temporary phenomenon that should only last for a million years or so. D) The spiral arms will seem to "wind up," to wrap more and more tightly around the center of the Galaxy.
Suppose you're on a hot air balloon ride, carrying a buzzer that emits a sound of frequency f. If you accidentally drop the buzzer over the side while the balloon is rising at constant speed, what can you conclude about the sound you hear as the buzzer falls towards the ground?
1.The frequency and intensity increase. 2.The frequency decreases and the intensity increases. 3.The frequency decreases and the intensity decreases. 4.The frequency remains the same, but the intensity decreases.
The greatest inaccuracy in Copernicus's model of the solar system was that the planets
a. traveled in circular orbits with uniform motion. b. traveled on epicycles whose centers followed orbits around the Sun. c. traveled in elliptical orbits. d. were allowed to travel backwards in their orbits. e. orbited the Sun.
A__________is a small, dark cloud only about 1 ly in diameter that contains 10 to 1000 solar masses of gas and dust, thought to be related to star formation
A) Herbig-Haro object B) brown dwarf C) Bok globule D) T Tauri star