Nebulae… (series: Beauty in Noise, part 6)

…stunning visual noise.

by Dave Skipper

Introduction

The night sky has fascinated me for as long as I can remember, and it has been a lifelong dream (still as yet unrealised) to own a big telescope for late-night stargazing. Maybe one day!

Few things in the universe capture my imagination quite as much as nebulae, those stunningly colourful clouds of wispy gas and remnants of exploding stars. Here are just two examples from the mind-bogglingly diverse array of nebular images captured by the Hubble Space Telescope:

Veil Nebula

[Veil Nebular. Source: http://hubblesite.org/image/3620]

Lagoon Nebula

 

[Lagoon Nebula. Source: http://hubblesite.org/image/4150]

Nebulae defined

The word nebula comes from Latin, meaning cloud or fog. (Did you know that fog is my favourite kind of weather?)

What are these incredible and mysterious phenomena? Nebulae are clouds of dust, hydrogen, helium, and other ionised gases lying in interstellar space, between the stars. Some nebulae form from gases already floating between stars. Others are produced directly by stars, for example planetary nebulae which are formed from the outer layers of a star being shed from its pulsating atmosphere. The most dramatic way some nebulae are created are from supernova explosions: exploding stars. Nebulae can become star-forming regions as the gases, dust, and other materials slowly gravitate together, eventually becoming dense enough to form stars.

[Source: info edited from https://en.wikipedia.org/wiki/Nebula]

Nebulae explored

What would it be like to travel through a nebula? If it were possible to hurtle through nebulae at breakneck speed, how would those extraordinary colours and patterns shift and mutate through three dimensions? It would surely be a mesmerising and awe-inspiring experience! Could the technology and physics of space travel advance far enough in future millenia to allow for this possibility?

Nebulae modelled

In the meantime, how about attempting to model the structures and intricacies of imaginary nebulae with computer graphics? I hadn’t thought of this option, but recently stumbled across a guy called Salmonick Atelier doing just this. Intriguingly, as he describes how he attempts to create convincing 3D nebula graphics, the crucial mathematical algorithms that have enabled him to achieve superb results are forms of noise:

“While experimenting with the [Perlin] noise algorithm, I find out that this was not good enough for the base of the nebula system. Therefore I had to use multiple and different noise fields to produce a more lifelike nebula form. It became clear through experiments that I needed a starting point to build on. First I create a primal object designed by a procedural algorithm based on Perlin Noise. After that I transform the object to particles and manipulate these with the noise algorithm. The result is the base nebula without all the detail. In the second phase I deform the base through maps that are based on fractal noise. The final result is a dense and highly detailed particle system. This way I can create close-up, medium and total shots of the nebula.”

[Source: https://www.salmonick-atelier.com/about]

What is Perlin noise?

Developed by Ken Perlin in the early 1980s while working on computer graphics for the cult sci-fi film Tron, Perlin noise is a pseudorandom algorithm in computer code. It was developed to help computer artists draw and render more realistic textures and patterns than had been possible at the time. The noise element, i.e. the pseudorandom nature of the code, makes it possible to draw the complex details of a wide range of naturally-occurring phenomena such as clouds or smoke more effectively and efficiently than previous techniques.

Generating random numbers in computer algorithms requires being able to obtain results that show no discernible patterns or relationships between the numbers. A small dose of randomness can be very helpful when attempting to simulate organic or natural behaviours. The great advantage of Perlin noise over ‘pure’ randomness is that it gives more natural results. The reason for this is that it produces smoother sequences of pseudorandom numbers.

And what is fractal noise? In concept it is easy to understand: fractal noise is simply Perlin noise that is rescaled and added into itself to add further layers of detail and complexity without needing to make the algorithm itself proportionately more complex.

What does Perlin noise sound like?

Of course this is what I want to know! Well, to get an idea here is one example of Perlin noise running at 440Hz (A above middle C):

[Source: https://gpfault.net/posts/perlin-sound.txt.html]

Noise-formed nebulae!

So, thanks to great swashes of noise of the Perlin and fractal varieties are you ready to zip gently around and inside some gorgeous nebulae? My dream can come true! All that’s missing are some noise soundtracks based directly on the Perlin/fractal noise algorithms… Enjoy…

[Source: https://www.salmonick-atelier.com/kopie-van-interstellar-clouds]

Check out Salmonick Atelier’s other awesome nebula videos here: https://www.salmonick-atelier.com/projects

Conclusion

The explicit theme of this article series Beauty in Noise is also one of the implicit themes of this whole blog, and is exemplified in the above excursion: don’t underestimate the power and potential of noise to augment beauty, to facilitate beauty, to contribute to beauty, and to help redefine notions of beauty…

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