Why Space Is Dark?

You may be asking why the universe is dark or black? Let answer that! 

Space is packed with a variety of gases, yet there is no atmosphere with molecules to reflect light. In other words, space is devoid of everything. That is why, even when the Sun is blazing brightly, space appears to be a dark nothingness.

But why there is so much light on earth?

You might think because the Earth turns on its axis, it is light during the day and dark at night, and the Sunlights either hemisphere.That's is one explanation, but there is more to it. Our star, after all, glows on the Moon, but the sky above it is always black!

It all boils down to the unique atmosphere that surrounds our planet. It's covered in dust, dirt, gases, and water droplets, all of which function as tiny mirrors and reflect sunlight. When sunlight collides with these microscopic particles, it diffuses and produces a variety of colors. That is why we see a blue sky and all those beautiful colors at sunrise and sunset.

Why don't other stars shine brightly at night?

You are not the first person to wonder about this. In the 16th century, an astronomer named Thomas Digges investigated this subject. Digges was certain that the Universe had no beginning and no end, and that the stars in it could not be counted.

He attempted but failed, to explain why all these stars don't blind us with their blazing light. His questions were simply too advanced for his time, and he lacked the resources to uncover the answers.

In the early 19th century, German astronomer Wilhelm Olbers proposed that the reason the sky is dark at night was due to a dusty veil that obscured most of the stars from our view. This notion was eventually proven to be incorrect as well.

The stars emit only light but also enormous amounts of energy, which can heat dust particles and cause them to shine. In that scenario, the night sky would still be light due to shining dust, despite the fact that the sky darkens every evening after sunset.

So, what's the problem with this theory?

Digges, Olbers, and other ancient astronomers thought the Universe was limitless, but present astronomy knows better. The amount of stars, no matter how many they appear, is simply insufficient to brighten the night sky. The sky darkens because stars, like the Universe, do not last forever. They are limited in number.

The Universe, you see, has its own boundaries and isn't as old as scientists formerly thought.

Sure, just shy of 14 billion years isn't exactly a whirlwind in human terms, but it's still a remarkably young age in cosmic ones. And it doesn't take much for all of the light from the farthest stars to reach Earth.

In other words, thanks to our very powerful telescopes, we now know that light from the distant stars takes billion of years to reach us. This means that when we look at the sky, we are seeing into the distant past.

Light began its trip to Earth around 10 billion years ago, according to modern telescopes. The grater the strength of telescopes, the further back in time we can look. We'll be able to glimpse anything that existed before stars, most likely through analyzing the dark gaps between them, one day.

Stars don't shine brightly in our night sky because they're very old even when we look up at them, and they're unimaginably far away.

Why don't stars further away light as brightly as the sun?

Thousands of stars should be much closer than those on the edges of the Universe. As an example, consider our nearest neighbor in space, Proxima Centauri. It's literally in our backyard, only a little more than 4 light-years distant. But without a telescope, we can't even see it in the sky!.

The problem is that it is 7 times smaller than our Sun and emits only a fraction of 1% of the Sun's light. And our "nearby" neighbor, despite being only 4 light-years away, is still quite far away – roughly 25 trillion miles.

In comparison, our own blazing Sun is only 93 million miles away. As a result, our star is more larger and closer. Other stars may be brighter than the Sun, but they are also much farther away from us.

But don't all those distant stars provide at least some light?

To put it another way, it'd be like turning on a slew of small halogen light bulbs. They aren't as bright as a single large LED bulb, but they do emit some of its light. So, yes, they offer us a tiny little bit of something, but it's nearly invisible.

Remember that, while space may appear to be empty in comparison to the Earth's atmosphere, there are many gases out there. They move around, build clouds, and act as a sort of veil, blocking off most of the light in the Milky Way.

That's why we can't observe everything that's going on in our galaxy, we need specialized technology for that. But, as it turns out, Olbers was partially correct, the curtain that hides the light is formed of gas, not dust!

Big Bang Theory

This is when the Big Bang enters the picture. According to the hypothesis, the Universe was created 13.8 billion years ago in a Big Bang. Since then, everything has been drifting away from the starting place. That is, the Universe is expanding, and objects within it are becoming increasingly distant from one another over time.

Light sources are also moving away and spreading out, which means that space is becoming darker and the number of black areas is increasing. They move at their own speed for billions of years, and our fancy telescopes and satellites can't detect or track this movement.

How do we know these black areas even exis't?

For the purpose of clarity, they investigate how visible things behave. How celestial bodies move around stars in an elliptical orbit or have gravity. Only the presence of an unknown space object or set of objects may explain this.

Astronomers believe that the vast majority of matter in the cosmos is invisible, and it appears. To the human sight, it seems as black void.

But how does it look through a telescope?

All of that blackness transforms into a wonderful spectrum of colors! We can't see it since our vision is confined to visible light. However, if you recall the electromagnetic spectrum from high school, you'll recall that visible light is only a fragment of all those wavelengths and frequencies.

There are radio waves, microwaves, infrared rays, ultraviolet rays, X-rays, and gamma rays. They exist in space and can be detected by current telescopes even though they are beyond the visible spectrum. And what they show us are nebulae that appear to be dark or invisible, but are actually illuminated in every color imaginable!

Depending on which gases are present, the color wheel can range from red to blue to purple to yellow to orange. Who knows, perhaps one day we'll have special glasses that allow us to see all the colors of space simply by looking up at the night sky!