The best suggestion is that Jupiter is still contracting gravitationally despite its age of several billion years.

最好的说明是：木星尽管已有几十亿年的历史，但由于引力作用，它仍在收缩。

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But a number below 50 indicates that output is still contracting, as it has since August 2000.

ECONOMIST: Overview | The

But that is still no guarantee for not contracting a new Syrian cyberbug, "Susan" reminds.

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"It is quite possible for some parts of the country to grow while others are actually still contracting, " said Dr Nolan.

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