system
Given the following post, respond as if you're commenting on Reddit:
human
[General] What incarnation of Earth is most powerful?

Excluding Earths where main power comes from aliens and other non-Earth beings (Superman for example) 

How strong can Earth become in science-ficton?
gpt
The Doctor Who Earth can get pretty damn powerful depending on the time period.

Humanity discovered time travel in the early 22nd century and it had become common by the 51st century. They even had a Time Agency which was created to fill the power vacuum left by the Time Lords' disappearance.

In the year 4126, the Second Great and Bountiful Human Empire stretched across three galaxies. In the year 200,000, the Fourth Great and Bountiful Human Empire was still at the height of its power. Earth was the hub of a galactic domain stretching across a million planets and a millions species. Earth itself was covered with mega-cities and it had five moons and a population of ninety-six billion.

A quarter of a million years into the future, Emperor Ludens Nimrod Kendrick Cord Longstaff XLI ruled a human empire which spanned a thousand galaxies. A thousand years earlier, the Cyber-Wars had been fought between Humanity and the Cyberiad. The conflict only ended when Humanity blew up the Tiberian Spiral Galaxy in an attempt to wipe out the Cybermen. This galaxy contained a million star systems, a hundred million worlds and a billion trillion people.