The use of the short version space, as meaning 'the region beyond Earth's sky', predates the use of full term "outer space", with the earliest recorded use of this meaning in an epic poem by John Milton called See more

Outer space is the closest known approximation to a perfect vacuum. It has effectively no friction, allowing stars, planets, and moons to move freely along their ideal orbits, following the initial formation stage. The deep vacuum of intergalactic space is … See more

In 350 BCE, Greek philosopher Aristotle suggested that nature abhors a vacuum, a principle that became known as the horror vacui. This concept built upon a 5th-century BCE ontological argument by the Greek philosopher Parmenides, who denied the possible … See more

The size of the whole universe is unknown, and it might be infinite in extent. According to the Big Bang theory, the very early universe was an extremely hot and dense state about See more

Effect on biology and human bodies
Despite the harsh environment, several life forms have been found that can withstand extreme space … See more

Regions near the Earth
Space in proximity to the Earth is physically similar to the remainder of interplanetary space, but is home to a multitude of … See more

For most of human history, space was explored by observations made from the Earth's surface—initially with the unaided eye and then with the telescope. Before reliable rocket technology, the closest that humans had come to reaching outer space was through … See more