Milky Way galaxy's Great Rift
Space is the void and the physical universe that exists outside Earth's atmosphere and between celestial bodies. Space is a near-perfect vacuum with little matter, save for dispersed particles, radiation, dark matter and dark energy.
Space is virtually limitless, and its size is difficult to define or comprehend. Scientists estimate there are more than 100 billion galaxies in space, with the largest containing 400 billion stars. Our galaxy, the Milky Way, has 100 billion stars. Other celestial bodies, such as planets, nebulae, asteroids, black holes, quasars, etc. litter space as well. Owing to space's incalculable size, these objects are often immense, numerous in number and spread vastly far apart from each other.
Humans developed adequate technology and began exploring space in the 20th century. While space agencies such as NASA have launched various probes and unmanned spacecraft to explore our solar system, humans themselves have only landed on the moon thus far. Advancements in telescope technology, however, have given us a remarkably sweeping view across the known universe. (Photo: Shutterstock)

A black hole met a neutron star and swallowed it 'Pac-man' style

Starman's Tesla completes orbit around the sun

Life on other planets may glow like coral to protect itself from an angry sun

Scientists detect more repeating radio signals from deep space

For the first time, scientists capture a shockwave bursting from the sun

Scientists baffled by sudden brightness of our galaxy's supermassive black hole

Dead planets sing sad, sad songs

Scientists find vast, ancient galaxies hiding in plain sight

Why Bill Nye's solar sail matters for the future of space travel

Perseid meteor shower: What you need to know

Plans for orbiting lunar outpost take shape