If we mess up the earth gravity assist, we die.

如果地球引力助推搞砸了，我们会死。

So, they escape Earth's gravity and drift off into space.

因此，它们逃离地球引力，漂向太空。

Now we still need conventional rockets to escape Earth's gravity.

现在我们仍然需要传统的火箭来逃离地球的重力。

Fast enough to escape earth's gravity and begin the shuttle era.

使其能以足够快的速度逃离地球引力，从此开始航天飞机时代。

For one, without the stress of Earth's gravity, her bones lose density.

首先，没有地心引力，她的骨密度会降低。

We've mapped differences as small as 0.001% in Earth's gravity.

我们可以测绘出小至 0.001% 的重力差异。

Can you imagine how heavy you'd be if Earth's gravity doubled?

你能想象重力增加一倍，自己会变得多重吗？

On Dragon-boat Festival noon, it is said the Earth’s gravity is stronger than usual.

在端午节的中午，据说地心引力会比平常的时候更强。

A spacecraft and basically everything else on Earth is held down by Earth's gravity.

地球上几乎所有的物体都受到地球引力的压制。

That's right. We bring him in too late, and he's pushed out of Earth's gravity.

没错。如果减速变轨的时间太迟，舱体将脱离地球的引力范围。

Others thought the moon formed elsewhere in the solar system and was captured by Earth's gravity.

其他人认为月球形成于太阳系的其他地方，并被地球引力捕获。

Elsewhere study finds that spaceflight may pose health risks to anyone spending time beyond earth's gravity.

其他地方的研究发现，太空飞行可能会给任何在地球引力之外度过时间的人带来健康风险。

We watched, amazed as fire broke out on the outside of the spaceship as the earth's gravity increased.

我们惊奇地看着，宇宙飞船的外层燃烧起火，因为地球引力在逐渐增加。

But that at some point it had moved too close to Earth and was captured by Earth's gravity.

但是它有些地方太靠近地球，并被地球的引力所捕获。

We learn at school that we're constantly pulled down by Earth's gravity and that's why things fall.

我们在学校里学过，我们不断地被地球引力拉下，这就是物体下落的原因。

If you're trying to get to another planet, you'll need a fast rocket to overcome Earth's gravity.

如果你想去另一个星球，火箭的速度需要更大以克服重力。

Described as an enormous round plate, it spins slowly in space to imitate the pull of the earth's gravity.

太空站像一个巨大的圆盘，在太空中缓缓的旋转，以仿照出地球重心的引力。

We take on an estimated 40,000 tonnes of space dust that the earth's gravity pulls in like a giant vacuum.

据估计，地球引力像一个巨大的真空吸尘器一样吸进了4万吨太空尘埃。

Even if he stopped and got going again instantly at each house, he'd experience acceleration 1.8 billion times Earth's gravity.

即使他在每个房子上停下来然后立刻出发，他也会体验到 18 亿倍的地球引力的加速度。

For the first time, humans launched rockets that were able to escape Earth's gravity and atmosphere and explore what lay beyond.

人类史上第一次发射火箭，摆脱地球重力，穿过大气层，探索外太空。