A. recently B. affects C. pattern D. varies E. moves
F. warm G. regularly H. special I. effect J. evidence
Big climate changes in the last million years might have come from something very small: dust from outer space. Earth changes between ice ages and warm periods in a (n) ___37___ that includes several cycles, including a___38____ one that lasts 100,000 years. Scientists____39____ suggested this cycle might be due to changes in the inflow of cosmic (宇宙的)dust.
The idea is that Earth ___40__ above and below the imaginary orbit that runs through the sun and Jupiter(木星), completing a cycle every 100,000 years. So maybe it ___41____ meets amounts of dust during each cycle that produce the climate trend.
Now there is some___42____, from ancient cosmic dust near the Azores islands west of Portugal. The large quantity of the dust rises and falls with a wonderful 100,000 year cycle during the period 253,000 years to 458,000 years ago. Periods of more dust are related to ___43____ climates.
But that is a long way from showing that the dust ___44____ climate. Some scientists argue that it is not clear how cosmic dust would make the climate warmer while dust from volcanoes is known to make it cooler. They say the cosmic dust is so thin that it is hard to see how it could have any climate ____45____.