The reason why there is no light in space and space appears dark is because the light from the stars, which includes the sun, is not scattered or reflected in space in a way that our yes can perceive in the vast emptiness of space.
Space is filled with light, but there's not enough particles to scatter the light or reflect the light to our eyes, which causes space to appear black.
On Earth, the sunlight interacts with the molecules in the atmosphere, which causes it to scatter.
The scattering is what makes the sky appear blue during the day and allows us to see light from various directions, even when the sun is not directly in our line of sight.
In the near vacuum of space, there are also very few particles to scatter the light and without the scattering of the light travels in a straight line from it's source and we only see what directly faces us.
There is some oxygen in space as oxygen atoms exist in space, although they are not combined into breathable molecules or O2 in significant quantities like there is on Earth.
Space is mainly a vacuum, which means there isn't much matter in general, which includes oxygen molecules.
The oxygen atoms that are present in space are often bound to other particles or are also too far apart to form breathable oxygen molecules.
Space being a vacuum also means that it lacks the atmospheric pressure and density that is needed to support free floating oxygen molecules.
Because there's no readily available breathable oxygen in space, astronauts rely on space suits and spacecraft to provide breathable air and pressure that is often generating oxygen from water through electrolysis.
Although rarely, molecular oxygen has been detected in places such as the Orion Nebula and the Rho Ophiuchi cloud.
The reason why space is cold even if the sun is there is because space lacks the significant amount of matter to absorb the heat and retain the heat, which makes space appear cold.
While the sun is a source of heat, the vast emptiness of space means that there's little to absorb the heat and distribute it, which results in low temperatures in the absence of matter in space.
The Sun also heats the earth by emitting electromagnetic radiation, which can travel through the vacuum of space until it hits the earth and warms it up.
Space also used to be extremely hot.
Immediately after the Big Bang occurred, the universe was a hot, dense state and was far hotter than anything we now observe.
And over time, as the universe expanded, the universe also cooled down.
And the cosmic microwave background radiation is also remnant of the early, hot phase and it also provides evidence of the universe's initial high temperature.
The universe began in an extremely hot and dense state and the Big Bang theory describes the initial expansion.
As the universe expanded, the energy density decreased and the temperature dropped.
The cosmic microwave background is the afterglow of the Big Bang, which is a faint radiation which permeates all of space.
And it's currently at a temperature of about 2.7 Kelvin or -455F, although it was much hotter in the early universe.
After the Big Bang, the universe was about 10 billion degrees Celsius and other research says that within minutes the temperature had dropped enough for the formation of hydrogen and helium nuclei.
The universe still continues to expand and the CMB radiation also continues to cool.
The early universe was a fiery place.
Space has a smell that is like gunpowder, sulfur, ozone and a faint acid smell.
We can't smell space directly, because our noses don't work in a vacuum.
However the astronauts aboard the ISS have reported that they notice a metallic aroma – like the smell of welding fumes – on the surface of their spacesuits once the airlock has re-pressurized.
Life in space is similar to life on earth however if yo go out into space you have to wear a space suit and other times you have to be in the space shuttle and there's also no gravity to hold you down.
Space is very dangerous – and without protection, people would not be able to survive there.
In space, there's no air – so you couldn't breathe. It's cold – so you'd freeze.
And there's lots of nasty radiation (from the Sun, and from the rest of the Universe), so you'd get really, really bad sunburn.
The only significant differences from living on Earth are that they operate in the confined space of the Space Shuttle orbiter cabin and that they, and all objects inside the cabin, float.
Because of microgravity on the Space Shuttle, some jobs, like handling tools and fluids, become more difficult.
There have been several people that have died in space.
There have been at least 18 deaths in space which include preparation for entry in space and those in space and some on return to earth from space.
A total of 18 people have lost their lives either while in space or in preparation for a space mission, in four separate incidents.