The last day where all humans were together on Earth was actually 25 years ago

It's been a whopping 25 years since all humans have been together on Earth, and the realisation has left people seriously scratching their heads.

That's right, since the year 2000, there has not been a single moment where all of mankind has been together on our planet.

More specifically, 2 November 2000 marked the beginning of the staggering 25-year streak, but what happened on that date?

Well, essentially, it was the day of the historic Russian Soyuz rocket launch, which was carrying one US astronaut, William Shepherd, and Russian cosmonauts Sergei Krikalev and Yuri Gidzenko up into the cosmos to dock onto the International Space Station (ISS).

The Russian Soyuz launch took off on October 31, 2000, and on November 2, Expedition 1 arrived at the ISS, aiming to establish a human presence on board the ISS using the first long-duration crew.

Cosmonaut Sergei K. Krikalev, Expedition 1's flight engineer, pictured in 2000 (NASA/Newsmakers)

Inside Russia's Expedition One mission

Ever since the launch, there has not been a single moment when humans haven't been out among the stars, with ISS having been continuously occupied since the Russian Soyuz rocket launch marked its first resident crew.

For the most part, they've been on board the ISS, apart from one point where the three crew members had to board the Soyuz and move it from one docking port to another for Expedition 15.

In total, the crew were on board the station for four and a half months before returning to Earth in mid-March 2001.

Over on Reddit, people started reacting to the revelation, as one reflected on the future progress for space travel: "*Woah* Never even though of that. Then one day it'll be year XXXX (or more) that we were last all in the same solar system. Same corner of the galaxy. Same galaxy.

Apart from one time where they had to move a soyuz, the ISS has been constantly manned since 2000 (NASA via Getty Images)

"Same cluster. So on and so forth.... my only regret in life is not being able to witness it all eventually happen (if it ever does)."

Why do planes not count?

Some people on Reddit began to query whether planes would also count, given how high they fly in the sky and how frequently they take off.

One said: "What about planes? I read a few years ago that, at any point in time, there were at least 50,000 people not on the earth’s surface."

However, conventional airplanes cannot physically fly up into space as the air needed for lift and propulsion would be too thin at such a high altitude.

Most planes fly way below the Kármán line - largely considered the boundary for space - which is 62 miles (100km) above sea level.

Who knows when we'll all be together on Earth again?