The gouge is where a branch used to be. It has been removed and the stump has started disintegrating. The next step in how trees heal wounds is for the tissue around the branch to start growing and eventually seal the hole. Trees react to injury by compartmentalizing or walling off the area.
I note that there is a larger injury that starts from the base of the trunk and goes above where the stump is. This has gone through the bark to the heartwood and appears to extend upwards.
The crack in the trunk and the gouge where the branch used to be will not kill the tree but they are points of weakness and may be a point of structural failure in the future.
Best practice would be to to ask yourself if anything would be damaged by branches falling from this tree as these trees can shed branches in wind or ice storms. The Guelph Arboretum indicates that Silver Maples have "notoriously weak wood". This commercial arborist site confirms my own observations that these trees grow fast, have invasive root systems and are best placed at a distance from houses, driveways and pools.
Take a look at it yearly and if the crack widens or gets longer get an arborist to look at it.
