They had been on our planets for millions of years, but 2018 was the year several species officially died off forever.

这几个物种已经在我们的地球上存在了数百万年，但是官方称2018年它们已经陆续灭亡。

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This diagram shows the location of all our planets and comet ELENIN.

这个图可以显示所有这些行星和Elenin彗星的位置。

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Other planets in our solar system lack the oxygen atmosphere that helps explain why life exists on Earth.

我们太阳系的其他行星缺乏氧气大气层，这有助于解释为什么地球上存在生命。

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Some scientists have called Jupiter the protector of the inner planets and our own Earth -- from objects from the outer solar system.

VOA: special.2009.08.25

Mr.Lissauer says the five inner planets are among the smallest confirmed planets beyond our solar system.

VOA: special.2011.02.09

Or Venus? Or on any of the other planets either inside or outside our solar system?

VOA: special.2010.05.25

The Kepler mission has identified 132 planets beyond our solar system since its launch in 2009, leading scientists to believe that most stars in our galaxy have planets circling them.

CNN: Planet-hunting Kepler spacecraft in trouble

Since Kepler 62 is a cooler star than our sun, planets can orbit closer to it than the Earth can to our sun before overheating.

CNN: Three more homes for life in the universe?

All the time, the knowledge that we are whiling away months, years, sometimes decades, of our life waiting for the planets to perfectly align before we take our first step forward weighs more heavily on our hearts and minds, both conscious and subconsciously.

FORBES: Procrastination, At What Price?