“真空度”几帕和几纳帕差多少——为什么太空比冰箱里还空？
How big is the gap between 'a few pascals' and 'a few nanopascals' of vacuum — and why is space emptier than a fridge?
1 帕大约是大气压的十万分之一，1 纳帕又是它的十亿分之一，差出好多个数量级。冰箱里只是不太对流，其实空气满满；而近地太空每立方厘米可能只有几个原子，比冰箱“空”得多。
1 Pa is about one hundred-thousandth of atmospheric pressure, and 1 nPa is a billionth of that — many orders apart. A fridge just doesn't convect much but is full of air; near-Earth space may hold only a few atoms per cubic centimeter, far emptier.
来源 · Source
Alexander Roth 著《Vacuum Technology》（真空技术）
Alexander Roth, Vacuum Technology
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL3935770W：Vacuum technology（首版 19