over time since creation has the earth gotten heavier or has it become lighter?

Answer 1

Heavier. But not significantly so.

The earth is constantly sweeping in material from outer space. Meteor showers are still a common occurrance, and even when the meteors burn entirely up in the atmosphere, the stuff they were made of doesn't disappear... it just trickles down as dust instead of smacking into the ground all at once.

It is difficult to measure exactly how much falls. It is even a bit difficult to be sure of the exact mass of the Earth in the first place. Most estimates of the Earth's mass are made by calculating backward from a measured gravitational force. But due to inconsistancies in the Earth's density and a non-spherical shape, the force of gravity is not constant and therefore this method isn't exactly perfect.

Still, we can guess about these things. Scientists estimate that the Earth gains an average of about a hundred million kilograms of mass every day (link 1).

Which may sound like a lot, but compared to the total mass of the Earth (ten thousand million million times more), it's not much at all. In the unlikely event that the Earth continues to accumulate mass like this forever, it would take 10^14 days, or 280 billion years to even accumulate 1% more mass. That's 20 times the current age of the universe. So don't hold your breath.

Answer 2

Hi. Lighter, possibly, early on as out gassing released hydrogen and helium, but heavier over the long run due to impacts of meteors, comets, etc.