What evidence led astronomers to conclude that the Oort cloud is a spherical distribution of comets?
A) the observation that comets enter the solar system from random directions
B) direct observation of comets orbiting the sun in the Oort cloud
C) Astronomers did not draw that conclusion; the Oort cloud is shaped like a flat ring in the same plane as the planets.
D) observations of comets getting flung out by Jupiter's gravity in random directions
A) the observation that comets enter the solar system from random directions
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The top panorama shows our view of the Milky Way in all directions as it appears in visible light. The bottom panorama shows the same view, but in a different wavelength of light. What wavelength band are we seeing in the bottom photo, and how do you know?
A) infrared light, because the dust that appears dark in the visible light photo glows in infrared light B) x-ray light, because only x-rays allow us to see through the disk of our galaxy C) radio waves, because clouds of gas in the disk of our galaxy appear pinkish when we look at them with radio telescopes D) infrared light, because clouds of gas and dust appear pinkish when we look at them with infrared telescopes
Which is Saturn's largest satellite?
a. Ganymede b. Enceladus c. Phoebe d. Titan e. Callisto
Which of these was NOT true about the limitations of Bohr's model?
a. The Bohr model failed to explain why electrons do not radiate. b. The Bohr model could not predict spectral lines for elements which have more than one electron in the outer shell. c. The Bohr model could not account for splitting of spectral lines. d. The Bohr model could not account for the basic periodic nature of the elements. e. The Bohr model could not explain why each shell held the number of electrons that it did.
Which of the following stars has the hottest stellar surface temperature?
A. A0 B. K9 C. B2 D. G5 E. M6