Beautiful But Not Hospitable – A Sensory Tour of the Solar System
Boyko Ranguelov (Bulgarian Academy of Science and Arts, Bulgaria) considers how human senses might respond to objects in the Solar System.
Read article in the fully formatted PDF of the Europlanet Magazine.
rganoleptic properties are subjective feelings that depend on human perceptions stimulated by our senses. Some people like colour, others are interested in the dynamics of colour changes. Some people respond to different properties, like sound, smell or taste. At first glance, these subjective human feelings are difficult to determine quantitatively. However, in recent years it has become increasingly an engineering challenge to translate physical and chemical properties into human sensory experiences.
We can all see the beauty of the Moon from Earth during nights with clear skies (and even during the day), and it is the only space body visited by human crews so far. The exploration of planets in the Solar System and other astronomical objects by robotic spacecraft is developing at a rapid pace. Missions orbiting nearby objects (like the Moon) and more distant objects (like Jupiter) are now a common occurrence that bring more and more reliable information about various physical and chemical properties of the planets and remote measurements. The number of Solar System missions already runs into the hundreds, which has required enormous scientific, technical and financial investment by the various countries with space exploration programmes.
Could organoleptic properties and beauty of the planets of the Solar System add to the frontiers of knowledge for space science? Beauty is a subjective feeling that is most often associated with the colour range and dynamics of the layers (atmospheres, oceans, etc) enveloping the Solar System bodies. But what about the taste, smell and possible sounds that humans might experience if they visited planets, satellites, comets, or asteroids?
Collecting Data
The basis of planetary studies is the analysis of the solid, liquid and gaseous envelopes of the objects, using information collected about their chemical composition (atoms, molecules and chemical compounds) and physical parameters (elevation, gravitational and magnetic fields, radiation, etc).
Planetary analysis techniques are based both on remote methods from Earth and on the capabilities of the various instrumentation used by spacecraft (remote or direct sampling), as well as by direct sampling by astronauts (to date, only on the Moon). These methods include several well-developed and reliable techniques, such as spectral analysis (investigating transmitted or reflected light e.g. in the infrared and/or ultraviolet spectral windows), imaging, gas chromatography, probing with lasers, or direct testing methods that use various indicator reactions between chemicals.
You may be familiar with security checks that swab surfaces to test whether they have touched prohibited substances. The sensitivity of such methods is extraordinary: concentrations of up to 1 part per million – or even billion – of the substance can be determined. Similar high-sensitivity methods are often used to determine the presence or absence of a substance e.g. in the atmosphere of planets, moons or other space objects.
Organoleptic Transformation
After having reliably determined chemical composition, it is possible to convert the data on the concentrations of various substances into an organoleptic sensation. This is especially true for detecting the smell of the space object. The cells in the human nose are specialised to sense and differentiate the odours of chemical elements and compounds. The matter of taste is more complicated, but the mechanism of transformation works in an analogous way to smell. Beauty is dictated by the colour spectrum, the mutual arrangement of colours on the images of objects, as well as changing dynamics and variations.
It is most difficult to transform the sounds emitted by the various cosmic objects into frequencies perceptible to the human ear. But the synthesisers of sounds can achieve this task: after spectral analysis, shifting the frequency band to that perceived by the human ear is much easier. It should be noted that the lack of air (or atmosphere) around some space objects is not an obstacle to ‘sounding’ in this context. Seismic waves, along with other elastic vibrations, are wave processes that can also be subject to spectral analysis and transformed so that they are placed within the audible range of the human ear. Thus, all recordings of wave processes can be transformed into sounds perceived by the hearing apparatus of humans, creating the feeling of ‘sounds’ of space objects.
The Tour of the Solar System
In this tour of the Solar System, the smell, taste, sounds, and the beauty of the objects are extracted from their chemical composition and adapted for the human senses. The outer gas planets, Uranus and Neptune, are bluish in colour and have similar chemical contents and properties to Jupiter and Saturn. They are likely to have similar smells and sounds to the other gas giants but, because they are so far away and have not been explored much by missions, we have less-exact information.
Beyond our Solar System, there are many beautiful objects that might be acceptable to other human senses. For example, the Sagittarius Nebula B2 smells of vodka and tastes of sour pickles!
Our tour of the Solar System shows that beautiful objects in space are frequently not very hospitable to humans. In fact, they are really dangerous for potential visitors. All the bodies of the Solar System, with the exception of the Earth, are too unfavourable for humans and living organisms of the terrestrial type to inhabit. So, let’s protect our planet!
| MOON | ||
|---|---|---|
| Main chemical substances | Hydrogen, helium, oxygen, sulphur, iron and silicates. | |
| Smell | Gunpowder was organoleptically detected by the astronauts when lunar dust and samples came into contact with oxygen in the lunar module. This smell disappeared over time. | |
| Taste | Matchsticks with a sour undertone. | |
| Sounds | Sharp tones resounding from the collected solid rock samples when kicked. Seismographs register seismic waves (their ‘sound’ is much longer than seismic sounds on Earth). Crackling sound of meteorite impacts. | |
| Beauty | Colour | Brownish-grey. |
| Topography | Full of craters. | |
| Scenery | Like a volcanic desert. Weird lights, probably generated by meteorite impacts. |
| MERCURY | ||
|---|---|---|
| Main chemical substances | Hydrogen, helium, sulphur and silicates. | |
| Smell | Probably like the Moon. | |
| Taste | Sour. | |
| Sounds | Low-frequency echo (boom on impact). | |
| Beauty | Colour | Brownish-grey. |
| Topography | Full of craters. | |
| Scenery | A shining volcanic desert. |
| VENUS | ||
|---|---|---|
| Main chemical substances | Sulphuric acid, Carbon monoxide and dioxide, Hydrogen sulphide, Phosphine, Silicates. | |
| Smell | Stifling, rotten eggs, rotten fish – a highly poisonous atmosphere. | |
| Taste | Intensively sour. | |
| Sounds | Blowing winds and thunder. Seismic waves recorded. | |
| Beauty | Colour | Silvery, with brown components, lightning in thunderstorms |
| Topography | Heavily broken up with sinuous valleys and plateaus. | |
| Scenery | Quite similar to Earth: predominantly desert, with mountains and plains, volcanic craters and meteorite impacts. |
| MARS | ||
|---|---|---|
| Main chemical substances | Sulphur, hydrogen sulphide, iron and iron oxides, silicates. | |
| Smell | Safety matches, gunpowder, rotten eggs, rust. | |
| Taste | Rust. | |
| Sounds | Blowing winds, seismic waves, sometimes rolling stones. | |
| Beauty | Colour | Predominantly grey reddish-brown. |
| Topography | Craters, river valleys and the plateaus, strongly cut and with high amplitudes. | |
| Scenery | Most similar to Earth: predominantly desert, with mountains and plains, volcanic craters and meteorite impacts. |
| JUPITER | ||
|---|---|---|
| Main chemical substances | Hydrogen, helium, hydrogen sulphide, ammonia, phosphine, hydrogen cyanide. | |
| Smell | Strong stench of rotten eggs, intestinal gases, urine, rotten fish, bitter almonds. | |
| Taste | Sharp sour-bitter, poisoning. | |
| Sounds | Roaring, low-frequency humming, frightening sounds. | |
| Beauty | Colour | Silvery white, light brown and tan. |
| Topography | Undulations from heavy storms and hurricanes. | |
| Scenery | Attractive. |
| SATURN | ||
|---|---|---|
| Main chemical substances | Hydrogen, helium, hydrogen sulphide, ammonia, phosphine, hydrogen cyanide, ammonium hydrosulphide. | |
| Smell | Very strong stench of rotten eggs, intestinal gases, urine, rotten fish, bitter almonds, hair dye. | |
| Taste | Sour-bitter, poisoning. | |
| Sounds | Roaring, low-frequency humming, heavy wheezing. | |
| Beauty | Colour | Bluish-brown. |
| Topography | Gas giant. | |
| Scenery | Famous rings and many satellites – possibly the most beautiful view of all extraterrestrial bodies. |
| TITAN | ||
|---|---|---|
| Main chemical substances | Nitrogen (98%), methylacetylene, cyanoacetylene | |
| Smell | Gas station. | |
| Taste | Extremely unpleasant. | |
| Sounds | Whistling from geysers. | |
| Beauty | Colour | Bluish, brown, violet. |
| Topography | Thick atmospheric envelope and liquids (rivers, lakes and oceans) marking the surface. | |
| Scenery | Beautiful, probably most similar in colours to the Earth’s. |
