Why does the sun not illuminate space?

With the support of the researcher, we explain why the sun does not illuminate space or rather why the sun does not illuminate the earth.

A frequently asked and well justified question is the one posed here. It’s not just about sunBut any other star Universe. These luminous objects emit such powerful energy that it is at least curious to note that the universe is still in relative darkness. So, Why does the sun not illuminate space?

To solve the problem, we spoke with Dr. Vladimir Avila Reis, a researcher at the Institute of Astronomy of the National Autonomous University of Mexico (UNAM). In an exclusive interview with National Geographic in SpanishThis is what he told us.

The real question

At first, the expert points out that the question should really be Why does the sun shine on earth? Hence you can see a sky with this characteristic, while the space appears dark.

Something similar is happening with lamp in the dark, represents Avila-Reese, as it can light well in a room but poorly outdoors at night. What is seen, to a larger dimension, is that sun It shines well in the half of Earth’s atmosphere to which it points, though not in the other half or in interplanetary space, where Darkness prevails.

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To understand Why does the sun not illuminate space?, should go in parts. Below is the explanation.

light source

The sun is a star Thus, it generates energy that exits its spherical surface mainly in the form of electromagnetic radiation or photons. Most of this radiation is visible in itThis is the light.

The star of our planetary system is A strong light source. Radiation from the Sun travels in all directions in spherical space. Flux decreases rapidly with distance, and is more inversely proportional to the square of distance.

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However, someone in space is looking forward to sun You will see a weaker and weaker flow the farther you go. But also, you will only see the light by looking in its direction, because it propagates in a straight line; in other directions, Interplanetary space is very dark. This is where the second point comes from.

Light scattering and reflection

To illuminate a specific area in a fairly uniform manner requires a A medium that reflects and/or scatters light in all directions that come from a source.

Let’s take the example of a light bulb again: an object like this can light up a room well because the walls reflect light, however, in an open space, it lights up a bit at night. At this time, factors such as Distance, light scattering, and even the presence of lights and other haze.

In case Landthe light that falls directly from sunin the half to which it refers, is spread across atmospheres Produce that it is all uniformly lit. In addition, the effect mentioned is just that It gives the blue color to the daytime skysince the radiation in this color is better scattering by small particles than atmospheres.

“from here, The answer to the question: Why does the sun not illuminate space? Because space is relatively empty, there are not enough particles to scatter sunlight efficiently, unlike what happens in the atmosphere of that point in cosmic space called Earth.”

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