The equation for force is mass times acceleration. Well, the mass of any particular object is constant throughout the universe, just its weight changes, right? According to this logic, lifting things should be just as difficult in space as it should be here on earth, yet astronauts can lift a fridge with their pinky, and not even the one on their writing hand for that matter. What gives? What piece of information am I accidentally ignoring?

The inertia of the object is the same, so it still takes effort to get the fridge to accelerate. It's just that the pinky doesn't have to support any weight, only transmit some force.

Weight is a force.

 

To accelerate an object in space at a, you apply a force F. But on earth, you need to exert a force equal to the weight (and in the opposite direction) just to get you to the point where the object has a zero net force on it. To accelerate it vertically you need to apply that force, plus the weight of the object.

when ever you are lifing an object, you are doing work on the object. work by definition would be a force carried out in a certain distance. since the force to lift an object is the opposite of the weight, then the acceleration due to gravity is multiplied by the inertia. since the acceleration due to gravity on the moon is far less than that on earth, then the object would weight less, therefore less work would be needed to move the object.