Why isn't Earth's atmosphere mostly hydrogen?
A) Earth formed too close to the Sun for any planetesimals to have hydrogen.
B) All the hydrogen was blasted away during the early bombardment stage of the solar system.
C) Light gases such as hydrogen move faster than heavier gases and escape from Earth's gravitational field.
D) The hydrogen is frozen in the polar ice caps.
E) All the hydrogen reacted with oxygen and formed the oceans.
Question 2
Which of the following best describes the current status of our understanding of the solar neutrino problem?
A) Experimental evidence indicates that the problem is solved and the expected number of solar neutrinos are indeed being produced by the Sun.
B) The problem arose only because experimental data were being misinterpreted; on re-examination, the old data showed that the expected number of neutrinos were being detected.
C) We have learned that the Sun's interior undergoes fusion at a lower rate than we had expected, and that is why we had observed fewer neutrinos than expected.
D) The solar neutrino problem remains as perplexing as ever, and indeed makes everything we think we know about stars suspect.
The Mass of Impacts on Earth
Earth’s Heat Budget
The rock cycle and the Earth’s physical environment
A close relationship between greenhouse gas emissions and a country’s gross domestic product
Formation of the Early Earth
Composition of the Atmosphere