Gravity

The trees are losing their leaves quickly now.  The lawn is covered with leaves, and the gutters are full.  When each leaf lets loose, it has a few seconds of freedom as it floats, twirls, flutters, or tumbles to the ground.  There is no escaping the pull of gravity.

Gravity is always there, pulling us towards, roughly, the center of the earth.  Much of the energy we expend is to move against that force, and to balance in the force field.  We are so well constructed that we can go for days, even weeks and months, with no loss of balance, no sense of danger.  But lose that balance, and gravity has you lying on the ground so quickly you're not aware of how it happened.

There are many ways that gravity can kill us.  It can bring a tree limb, or a whole tree, crashing down.  It can bring a loose rock tumbling over a cliff to strike us, or sweep an avalanche of snow around us.  Slip on a patch of ice, and gravity can pull you down with such force that the blow to your head is fatal.

But without gravity, we wouldn't exist.  There'd be nothing to hold the earth together, no stabilizing, unifying force to hold the water in the oceans, cause the rain to fall, or hug the atmosphere to the earth, with its oxygen that we need.

We're part of it, too.  Gravity is an attractive force between matter.  Our mass has a tiny gravitational force, as does everything in the universe.  It's not something other than us.  It's in us, around us, through us.  Gravity binds us to everything.  It never give up, and eventually, when we lose our ability to gather energy and use it for our movement, gravity will pull us down, one last time, like a falling leaf.