Water.Earth has loads of H2O.
But did it always?
This question has plagued scientists for decades.
Conventional wisdom has it that the Earth formed without any water.
Then meteorites carrying water smashed into the planet, dumping their precious cargo.
But now, a team of geologists has challenged this idea.
They say water may have been here from the start.
The scientists discovered that the chemical signature of water on Earth matches the signature of water in an ancient group of asteroids called eucrites.
These bodies formed just a few million years after the birth of the solar system.
And because Earth and eucrites seem to share the same source of water, the reasoning goes, Earth must have gotten its water around the same time the eucrites did—which has big implications.
“Because Earth got its water early—really the whole inner solar system got its water early—it means that planets, once they fully formed and got cool enough that water would be stable on the surface, they could be habitable.”
“由于地球很早就有水资源，整个太阳系也在很早就有了水资源 。这就意味着，行星一旦完全成形且温度足够低的话，水资源将会在表面趋于稳定，这样行星就会适于居住 。”
The Woods Hole Oceanographic Institution's Adam Sarafian, who led the research.
“It wasn't like these planets are just waiting around, looking at their watches, saying,Where's the water?
Life's ready to go, we just need water here.
So it pushes the date at which planets can become habitable back.
And we need to go back to the drawing board on how planets are built and how water survives large impacts.”
1.loads of 大量，许多
The first plane-loads of food, children's clothing and medical supplies began arriving.
They didn't exactly sell bucket-loads of records the first time around.
2.smash into 撞击到某处；猛撞
The two cars ran smash into each other.
The fullback's smash into the defensive line.