Earth is, despite its comparatively weak native dominant species, the single most important planet in the multiverse. In nearly every timeline it is home to some version of Ben Tennyson or his cousin Gwen Tennyson. Although the planet had no influence on the events of the Heaven Wars, the influence the people of Earth had on the events of the later Time Wars and later galactic affairs in general solidifies the planet's unique status.
A lesser known fact is that the Earth is also the single most densely populated planet in the universe by number of unique native species. The only planet that comes close to this number of unique genetic inhabitants is the artificial planet Primus, however these species are not native and do not exist on the planet outside of the presence of their genetic code in the planet's streams. Even then, this number only considers fauna. The Earth has no near match anywhere in the universe when floral species are considered.
A small exploratory crew of Bystaline landed on the Earth some 540 million years ago. Some, if not all, of them died during the mission.
Human history is short by galactic standards, although their rapid advancement from nomadic lifestyles to a static and educated civilisation has allowed them to compile a comparatively full picture of their undocumented past. Their knowledge of the past 5'000 years of their own history is mostly complete, with some knowledge of their societies dating back as far as 60'000 years.
The Human race first made attempts to leave their planet some 70 years ago, however manned attempts have dwindled greatly since then. The earliest known contact between Humans and alien races dates back around 250 years ago at the foundation of a Human branch of the Plumbers. This branch was founded with no relation to the galactic Plumbers, and was assimilated into the galactic Plumbers nearly 130 years ago.
Humanity's exposure to the greater universe has increased exponentially over the last ten years after the Prototype Omnitrix crashed there and fell into the possession of Ben Tennyson.
In Death of Ben 10, the planet Pyros declared war on the Earth under leadership of the warlord Apollo. The invading fleet was fended off by a small team of Ben Tennysons lead by Professor Paradox backed up by a Plumber blockade. A small force of Pyronites made planetfall, however Apollo was slain and the remaining invaders were sent home by Paradox and Eon.