We knew that the isotopic compositions of noble gases observed in space (like those measured in meteorites and cosmic dust) were clearly distinct from those found on the earth.
We knew that the isotopic compositions of noble gases observed in space (like those measured in meteorites and cosmic dust) were clearly distinct from those found on the earth.
我们知道太空中惰性气体的同位素组成（像在陨石与彗尘中测量到的情形），与地球上的截然不同。