What is the primary form of evidence that has led astronomers to conclude that the expansion of the universe is accelerating?
A) observations of the speeds of individual galaxies in clusters
B) measurements of how galaxy speeds away from the Milky Way have increased during the past century
C) observations of white dwarf supernovae
D) measurements of the rotation curve for the universe
C
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____ occur when the Moon is in the first or third quarter of its lunar cycle
A) Spring tides B) Total solar eclipses C) Neap tides D) Annular eclipses
Wave Characteristics: Which one of the following types of electromagnetic wave travels through space the fastest?
A. radio waves B. infrared C. ultraviolet D. microwaves E. They all travel through space at the same speed.
An atom of the element iron has an atomic number of 26 and an atomic weight of 56. If it is neutral, how many protons, neutrons, and electrons does it have?
A) 26 protons, 30 neutrons, 26 electrons B) 26 protons, 30 neutrons, 30 electrons C) 26 protons, 56 neutrons, 26 electrons D) 13 protons, 43 neutrons, 13 electrons E) 13 protons, 56 neutrons, 13 electrons
The addition of Na2O to SiO2 to form soda glass reduces the _____________of SiO2.
Fill in the blank(s) with the appropriate word(s).