The answer is in the center of mass.

答案就是质心。

In reality, both circle around their mutual center of mass, located between the two.

事实上，两者都位于两者之间的相互质心旋转。

These are sets of two stars that orbit around a common center of mass.

即由两颗恒星组成的组合，它们一个共同的质心运行。

The 1.52 meters is how much her center of mass is raised above its landing point.

52 米是她的质心比陆点高出多少。

There's a simple way to figure out where the center of mass is.

有一个简单的方法找出质心。

Within a given supercluster, all galaxy motions will be directed inward, toward the center of mass.

而在超星系团内部，所有星系都是向内部质心运动。

With a low center of mass, the wheel just swings back and forth like a pendulum, then stops.

当质心较低时，车轮就像钟摆一样来回摆动，然后停止。

The center of mass is a pointsomewhere along the plank that holds the two kids where their average weight falls.

质心是跷跷板上支撑两个孩子平均重量的一个点。

And yet, collected together, they have a single total amount that they spin about their center of mass.

在一起时，它们有一个单一的总的不变量，他们总是它们的质心旋转。

To make the seesaw work, theheavy kid must push that center of mass forward until it just touches the pivot.

要想让跷跷板摇动，重的孩子就得往中间挪直到质心移到中心。

The stars all orbit the cluster's center of mass, even though there may not be anything at the very center.

所有的恒星都星团的质心旋转，即使在最中心可能没有任何东西。

Three times heavier and the center of mass will be three times closer. And so on.

重三倍，质心的位置就进三倍，以此类推。

A barycentre is the centre of mass between two objects.

重心是两个物体之间的质心。

The moving parts that make one side of the wheel heavier also shift its center of mass downward below the axle.

使车轮一侧更重的运动部件也将其质心向下移至车轴下方。

And so you have an inward force towards the planet's center of mass.

所以你有一个朝向地球质心的内向力。

This is about  Newton's Laws, forces, and center of mass.

这是关于牛顿定律、力和质心的。

In these situations, it’s more useful to describe what the center of mass is doing.

在这些情况下， 描述质心在做什么更有用。

When you throw the hammer, for example, it’ll rotate around its center of mass.

例如，当您扔锤子时， 它会其质心旋转。

And that is: center of mass.

质心。

It just depends on  which direction the center of mass is defined.

这只取决于质心定义的方向。