Light's Journey - Colors Are More Than They Seem

Image Credit to Stanislav Volskiy - Stanislav Volskiy

Every time I see a new photo of our universe, my jaw hits the ground, and I sit there gawking at the photo for hours... days... months... (no exaggeration of course). The colors are so beautiful: from the soft smudges of gases to the sharp contrast of the dark universe creating a natural masterpiece. Despite this I can't help but think, "if we lived on a planet or anywhere where the sight of nebulas was normal and could be seen right outside our kitchen window, would it still leave us in shock? What if it was colorless? Would we still call it beautiful? It's no hidden secret that our eyes are attracted to color but appeal to the eyes isn't color's only use, the way it might seem at first. In fact, they carry a lot of information which allows us to better know our universe. Ever since I learnt the basics of light in school, I've just been obsessed with the question of color's existence and its functions in our daily lives, and it turns out that light and colors are truly more essential to our survival than appears at first e.g. In medical devices for blood analysis.  In this blog I'll refrain from talking about color's true” existence” and rather explore its use in space research.

Colors are everywhere, so much so that we simply accept their existence without much thought. The sky is blue; the grass is green... but yet when you look through a telescope to something afar, it suddenly looks different to the photos you've seen online. Online, photos boast their bright beautiful colors while your eyes through a telescope seem to see something like an 80s TV screen (grey and black). Even with the naked eye, most stars appear white, and this is due to the fact that our human mind can't create any colors when light is faint. The space pictures we see go through rigorous editing, but that doesn't mean the colors used are randomly chosen but rather are based on scientific facts. As can be seen in the photo, the editing process to take a raw image to the final product.

Image Credit - https://www.nasa.gov

Photos picturing three different stages of processing the Pillars of Creation in the Eagle Nebula.

The detection of elements and molecules.

Taking NASAs Hubble Space Telescope as an example: The telescope's various filters are directed to detect certain elements and molecules. E.g., some filters might be designed to detect hydrogen and iron. These filters are layered to create a composition of the object pictured. While at this, point the photo will still appear grey and black at this point, it will however not be empty but will contain the elements detected by the filters. In a specialized computer program, Astronomers take this data & "stretch" it to slowly expose the details within. The universe is very dim and the telescope acts like a bucket collecting any light in space, the ionized particles give out different wavelengths which can help determine the correct color to use.

Light and colors allow us to learn about the structure and composition of stars and things in space that we can't physically reach and research. Studying the visible-light spectrum (the range of the electromagnetic spectrum that our human eyes can see) of the stars shows a pattern of dark lines called absorption lines. As light passes through gases and atoms it absorbs various colors, creating a pattern. These can be considered to be like human fingerprints, everyone's fingerprints are unique to them and are used to identify each of us, the same way each element absorbs different amounts of light and in turn it creates a unique pattern. Due to the fact that no element can have the same absorption spectrum, it significantly helps research the composition of any new stars, planets, etc. being formed. 

Image Credit - byjus.com/chemistry/emission-spectrum-atomic-spectra/

Image of hydrogen absorption and emission spectra

Temperature based on colors

Colors not only help figure out elements but also the temperature of certain stars. If you look up at the dark sky and luckily enough the clear sky. Then you might realize that within the ocean of white dots in the sky, there are a few of different colors. Take for example two stars that appear in the Orion constellation: Rigel and Betelgeuse. These two stars allow you to see the effect that temperature has on color with the naked eye. I still remember clearly the day my former physics teacher told the class about these two stars. The same day, I ran outside the second that stars appeared and felt the need to tell everyone I know about how interesting it is that one appears to shine blue while the other red because of the large difference in temperature. If you ever get the chance to go outside on a clear night, I definitely recommend finding them, its simplicity is truly fascinating! How does our sun compare to this? Well, our Sun produces more yellow light than any other color because its surface temperature is around 5,500°C, but if the Sun's surface were to drop in temperature to around 3,000° C it would look reddish, like the star Betelgeuse. While if the Sun was to increase to around 12,000°C it would look blue, like the star Rigel. Thanks to this, colors can provide insight not only on the star's temperature but also their ages.

In summary, colors are so fascinating and are far deeper than they appear. They can be enjoyed for their simplicity but also deeply explored for their complexity. Providing us with endless important information on space. 

“For the rays, to speak properly, have no colour. In them there is nothing else but a certain power and disposition to stir up a sensation of this colour or that “. -Isaac Newton.