If you do the same measurementsten metres away, or ten days later, the results can be totally different.
如果距离10米之外，或10天以后你做同样的测量，其结果可能是完全不同的。
2
But instead of measuring one period, I'm going to measure ten periods, because that gives me a smaller uncertainty, a smaller relative error in my measurements.
并不是，测量一个周期，而是，测量10个周期，因为这样，不确定性减小，测量值的，相对误差减小。
3
But as Dr Solomon and her colleagues note, satellite measurements show that rather less has been doing so over the past ten years than was the case previously.