Why is space dark while on earth we have light

Space appears dark primarily because it is a vacuum, devoid of matter, including air and dust particles, that would scatter or reflect light. Here's why space is dark:

Lack of Atmosphere: Earth's atmosphere scatters sunlight in all directions, creating a bright blue sky during the day and allowing us to see the Sun, Moon, stars, and other celestial objects. In space, there is no atmosphere to scatter sunlight, so it doesn't create a continuous glow.

Vast Distances: Space is incredibly vast, with vast distances between stars and galaxies. The light from distant stars has to travel immense distances to reach us, and it can become extremely dim by the time it reaches our telescopes or eyes.

Absence of Nearby Light Sources: Unlike Earth, where artificial lights, cityscapes, and the Sun illuminate our surroundings, space often lacks nearby light sources. Even stars are typically separated by large expanses of empty space, contributing to the overall darkness.

Cosmic Background Radiation: Space isn't completely devoid of radiation. There is a faint background radiation called the cosmic microwave background (CMB), which is a remnant of the Big Bang. However, this radiation is very low in energy and is not visible to the human eye.

Human Vision Limitations: Our eyes are adapted to perceive light within a certain range of wavelengths, known as the visible spectrum. Objects in space, like stars, emit light primarily in this range, but not all of it falls within our perception, which can contribute to the perception of darkness.

So, while space itself is not intrinsically dark, it appears dark to our eyes due to the absence of scattering, the vastness of space, and the limitations of our vision. In reality, space can be filled with a stunning array of celestial objects and phenomena, but their faintness and distance make them appear dim or dark to us without the aid of telescopes and specialized equipment.