What are the most likely sources of the methane gas detected in the Martian atmosphere by the Mars Express orbiter and the Curiosity rover?
A) biological activity only
B) biological or geological activity
C) comet impacts only
D) geological activity only
B
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________ is the concept that all large samples of the universe are alike in appearance anywhere in the universe
Fill in the blank(s) with correct word
The relative brightness of the stars as we see them in our sky is represented by their
A. luminosity. B. absolute magnitude. C. apparent magnitude. D. surface temperature.
What was the key physical property in determining the two categories of planets during solar system formation?
a. pressure b. gravity c. density d. momentum e. temperature
Three terrestrial-sized planets in orbits of a fraction of an AU have been found near:
A) Cygnus X-1. B) a magnetar. C) Supernova 1987A. D) a millisecond pulsar. E) a white dwarf.