Why Space Is Dark But There Is light On Earth

Why Space Is Dark But There Is Light On Earth

Space is almost completely devoid of matter, has very low pressure, and is virtually a perfect vacuum. Due to the lack of molecules positioned close enough to one another, sound cannot travel over space. Bits of gas, dust, and other stuff float in the "emptier" (but not quite empty) parts of the cosmos, while planets, stars, and galaxies can be found in the more congested parts. The actual size of space is unknown. Because of what we can see in our detectors, it is challenging to determine. Galaxy is not a topic we cover in this essay. We are excited to discuss "why is space dark" in this. Let's get in to this article.

Why is space black yet Earth is light?

 

We are able to respond to that query. Because of how light from the nearby Sun interacts with molecules in the Earth's atmosphere and scatters, the midday sky looks blue. This scattering effect causes the sky to seem blue. Space seems to be completely dark at night when that portion of Earth is facing away from the Sun since there isn't a powerful source of light like the Sun nearby to scatter light from. On the Moon, which has no atmosphere, both day and night would be pitch-black. Images captured during the Apollo Moon landings show this.

Now for the more challenging part: if the cosmos is full with stars, why doesn't their combined light make the sky always bright? It turns out that we would anticipate the night sky to be dazzling from the light of all those stars if the universe were endlessly big and old. Everywhere you turned in space, a star would be in view. Yet we are aware from experience that nothing exists in space. Olbers' Paradox is the name of this paradox. Because of the seeming discrepancy between our anticipation that the night sky will be brilliant and our reality that it is dark, it is a paradox.

 

 

Olbers' Paradox has been explained in a wide variety of ways. The cosmos isn't eternally ancient; at now, the best explanation is that it's just about 15 billion years old. Therefore, the maximum distance that we can see objects at is the distance that light can travel in 15 billion years. More distant stars' light has not yet had a chance to reach us, so it cannot contribute to the sky's brightness. 

Another reason why the sky might not be fully illuminated by the visible light from all the stars is because a light source's wavelength lengthens as it moves farther away from you (which for light means more red.) This implies that the light from stars that are escaping our view will be skewed towards red and may perhaps become completely invisible. (Note: The Doppler Effect, which causes the siren pitch to drop as the ambulance moves away from you, has the same effect when an ambulance passes you.)

 

Why does Other Stars Shine with Blazing Light at Night?

You are not the only person to think about it, though. In the 16th century, an astronomer by the name of Thomas Digges conducted study on this topic. Digges was certain that the universe had no beginning and that there were too many stars for us to count. He made an attempt to explain why all of these countless stars don't shine so brightly on us, but he was unsuccessful. He just lacked the resources to locate the answers to his queries since they were so far in advance of his time. German astronomer Wilhelm Olbers proposed in the early 19th century that a dusty veil that obscured most of the stars from our view was the cause of the nighttime sky's darkness. Later evidence disproved this notion as well.

 

The stars not only emit light, but also enormous amounts of energy that have the power to heat dust particles and cause them to begin to shine. In that scenario, shining dust would cause the night sky to remain lit. Yet every evening after sunset, the sky darkens. 

 

What, therefore, is wrong with this theory? 

 

Digges, Olbers, and other early astronomers thought the universe had no end, but contemporary astronomy today knows otherwise. Even with how many stars there appear to be, there are just not enough to fill the night sky with light. Because the stars, like the universe as a whole, are impermanent, the sky grows black. They have a limit. You see, the universe has its own borders and isn’t as ancient as scientists used to think. Sure, just shy of 14 billion years is no whippersnapper to us humans, but it’s still surprisingly young in cosmic terms. And it’s not much for all the light from the most distant stars to be able to reach the earth. Thanks to our fancy powerful telescopes, we now know that it takes light billions of years to get to us from the farthest stars. This means, when we look at the sky, we glance into a very distant past.

 

The further back in time we can look, the more powerful the telescopes get. We'll eventually be able to observe anything that existed before to the formation of stars, most likely by examining the black spaces between them. Later in this essay, let's discuss. 

 

Okay, but because stars are so ancient, they don't shine as brightly in our night sky. Even when we glance up at them, their distance from us is unfathomable. if that is the situation. 

Why Don't Less Distant Stars Shine As Bright As The Sun?

The stars on the outside of the Universe should be millions of times further away. Yes, there are certainly plenty. Take Proxima Centauri, our nearest galactic neighbor, as an illustration. With a distance of little over 4 light years, it is almost in our backyard. But without a telescope, we can't even see it in the sky. The problem is that although being 7 times smaller than our sun, it emits light that is just 1% as brilliant. Furthermore, our "nearby" neighbor, who is just 4 light years distant, is still rather far away—about 25 trillion miles. In contrast, the distance between the sun and Earth is a "mere" 93 million miles. Thus, our star is considerably more massive and nearby. Even while some stars are significantly brighter than the sun, they are also located far away from us.

Don’t all those distant stars give at least some noticeable light on this planet?

Comparable to turning on a large number of small halogen light bulbs They don't emit as much light as one large LED bulb, but they do produce some of it. They thereby provide us a tiny bit of stuff, hardly visible. Keep in mind that although space appears to be barren in comparison to the Earth's atmosphere, it is really filled with many gases. They move, create clouds, and act as a type of curtain, obscuring the majority of the Milky Way's brightness. Because of this, we are unable to observe everything occurring in our galaxy. For that, we require specialized equipment. However, it turns out that Olbers was only partially correct because the light's curtain is formed of gas rather than dust.

 

Where does the Big Bang come into consideration?

According to the hypothesis, 13.8 billion years ago, the universe was created in a Big Bang. Since then, everything has been shifting away from the starting position. The Universe is expanding, and as time passes, objects inside it are moving further apart. Additionally, sources of light disperse and move farther apart, making the world darker and producing an increasing amount of black. For billions of years, they have been moving at their own pace, and no matter how sophisticated our satellites and telescopes are, they are unable to detect or follow this motion.