What is a superbubble?
A) a very low-density region of interstellar space, formed by the merger of several bubbles
B) a very high-density region of interstellar space, filled with gas ejected from nearby star systems
C) a bubble so large that it fills much of the galactic halo
D) the region of space cleared by a powerful supernova
E) a cloud of gas that can form a million or more stars
A
You might also like to view...
A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical frictional force that the pole exerts on the fireman. When this force equals the weight of the fireman, what happens?
A) The fireman comes to a stop. B) The fireman descends with slower and slower speed. C) The fireman descends with a smaller acceleration. D) The fireman continues to descend, but with constant speed. E) Cannot be determined without additional information.
The Moon's maria, or plains, are believed to have been caused by ______________
Fill in the blank(s) with correct word
A proton strikes an Oxygen-18 nucleus producing Fluorine-18 and another particle. What other particle is produced by this nuclear reaction?
A) a neutron B) an alpha particle C) a gamma particle D) a ?- particle E) a ?+ particle
A proton moves around a circular path (radius = 2.0 mm) in a uniform 0.25-T magnetic field. What total distance does this proton travel during a 1.0-s time interval? (m = 1.67 × 10^-27 kg, q = 1.6 × 10^-19 C)
a. 82 km b. 59 km c. 71 km d. 48 km e. 7.5 km