What evidence in Mars's atmosphere supports the idea that Mars once had flowing, liquid water?
What will be an ideal response?
The abundant presence of deuterium in the atmosphere. Deuterium is 5.5 times more abundant than normal (light) hydrogen in the atmosphere of Mars, suggesting that Mars once had about 20 times more water than it has now. Presumably, much of the water was broken up and the normal hydrogen mostly lost to space.
You might also like to view...
A beam of light in water (of refractive index of 1.33 ) enters a glass slab (of refractive index 1.50 ) at an angle of incidence of 60.0°. What is the angle of refraction in the glass?
A) 27.5° B) 39.8° C) 60.0° D) 90.0° E) 50.2°
Recent measurements of the expansion rate of the universe reveal that the expansion rate of the universe is doing something astronomers did not expect. What is that?
A) The measurements show that the universe may not be expanding at all. B) The measurements show that the universe may be shrinking rather than expanding. C) The measurements show that the expansion is accelerating, rather than slowing under the influence of gravity. D) The measurements indicate that the universe is at least 30 billion years old, meaning that more than 10 billion years passed between the Big Bang and the formation of the first stars and galaxies. E) The data show that the expansion rate varies widely in different parts of the universe.
Sediments are classified according to the source of their constituents into two main groups. One is chemical. What is the other?
a. Physical b. Clastic c. Detrital d. Inorganic
A 1000-kg barge is being towed by means of two horizontal cables. One cable is pulling with a force of 80.0 N in a direction 30.0° west of north
In what direction should the second cable pull so that the barge will accelerate northward, if the force exerted by the cable is 120 N? Assume that the water exerts no appreciable frictional drag on the barge. A) 47.5° east of north B) 19.5° east of north C) 39.0° east of north D) 21.1° east of north E) 54.7° east of north