A roar on the other side of silence

You only have to imagine being in a desert to realise the variety of sounds a microphone on the surface of Mars could record – and how they can be interpreted. First of all, the wind, whistling across the planetary landscape – how fast is it travelling? How often does it vary in speed or direction? What does a dust devil sound like? Or a dust storm? What about the crack of thunder associated with a lightning bolt? Or the variation in pressure during an electric storm? Once the wind drops, the gentle sounds that break the silence can be heard: the settling of dust grains disturbed by the wind.

– from What does the solar system sound like? by Monica Grady.

In a review of Trevor Cox's delightful Sonic Wonderland, I invited meditation on: the sound from black holes (B flat 56 octaves below middle C); reverberations through loops in the Sun's outer atmosphere; and a wind shuffling rock grains through the Martian air.

Sound waves from the great storm that is the red spot on Jupiter may be the cause of heating in its upper atmosphere.

A creative interpretation of the old idea of  the 'music of the spheres.'  , which I have come across thanks to Stephon Alexander's The Jazz of Physics is an interpretation of Johannes Kepler's The Harmony of the World by Willie Ruff and John Rogers.


Image via APOD

A perfit description of the Coelestiall Orbes

This orbe of starres fixed infinitely up extendeth hit self in altitude sphericallye, and therefore immovable the palace of foelicitye garnished with perpetuall shininge glorious lights innumerable farr excelling our sonne both in quantitye and quality the very court of coelestiall angelles devoide of griefe and replenished with perfite endless ioye the habitacle for the elect.

legend by Thomas Digges from his 1576 translation of Copernicus’s De revolutionibus.

Digges, writes David Wootton in The Invention of Science, was the first competent astronomer to explicitly propose an infinite universe (Nicholas of Cusa had argued that an omnipotent God would make an infinite universe, but this was a philosophical, not an astronomical argument).

Not death

This image of Pluto from the New Horizons mission brings the following to mind:

The whole landscape, as far as the eye can reach, is a realisation of a fearful dream of desolation and lifelessness — not a dream of death, for that implies evidence of pre-existing life, but a vision of a world upon which the light of life has never dawned.

The words are from The Moon Considered as a Planet, a World, and a Satellite by James Nasmyth and James Carpenter, 1874

Image: NASA

Cloud city

If you [go] all the way to the top of Venus’s [hostile] atmosphere, you’re rewarded with — shockingly — pleasant, livable conditions. Randomly, at the top of Venus’s clouds is a layer where the temperature and pressure are similar to those on Earth, and because oxygen and nitrogen both rise in Venus’s dense atmosphere (like helium does on Earth), the air in that layer might actually be close to breathable. That’s led some scientists to actually discuss human colonization of Venus’s high atmosphere, building “cities designed to float at about fifty kilometer altitude in the atmosphere of Venus.”

Wait by Why Tim Urban

Suspended over the abyss, the life of Octavia's inhabitants is less uncertain than in other cities. They know the net will only last so long.

Invisible Cities Italo Calvino


Image NASA

Landscapes of Titan

Titan’s lacustrine depressions develop in relatively flat areas. They lie between 300 and 800 meters above the level of the northern seas. They are typically rounded or lobate in shape and some of them seem to be interconnected. Their widths vary from a few tens of kilometes, such as for most of Titan’s lacunae, up to a few hundred kilometres, such as Ontario Lacus or Jingpo Lacus. Their depths have been tentatively estimated to range from a few meters to 100 - 300 meters, with “steep”-sided walls. The liquid-covered depressions would lie 250 meters below the floor of the empty depressions, which could be indicative of the presence of an alkanofer in the sub-surface, analog to terrestrial aquifers, filling or not the depressions depending on their base level. The depressions sometimes possess a raised rim, ranging from a few hundred meters up to 600 meters in height.

Dissolution on Titan and on Earth: Towards the age of Titan’s karstic landscapes (pdf)

h/t LB

Images: Lakes of Titan, Sikun Labyrinthus. NASA

A garden of storms

Jupiter's Great Red Spot probably began in one of two ways: It could have been a large, upward plume that hit the stratosphere and rolled up to produce a vortex. If a rising plume can reach upward to a part of the atmosphere that’s really stable, it will spread outward horizontally, and when it starts to spread out, if it’s in a really rapidly rotating system like Jupiter, the spreading out produces a vortex. The other possibility is that a jet stream went unstable and started a wavy oscillation, and when the amplitude of the wave became big enough, it broke, making vortices that then merged together.

Philip Marcus


Image: NASA via It's Okay to be Smart

Kraken mare

At 400,000 km², Kraken Mare is believed to be the largest sea in Titan's north polar region. The maximum depth appears to be 160 meters. Shallow capillary waves 1.5 centimeters high moving at 0.7 meters per second have been detected.

— Wikipedia

Dune worlds

Domes, Barchan, Barchanoid Ridge, Transverse Ridge, Linear or Longitudinal, Reversing, Star

Sheet, Streak, Shadow, Climbing (and Falling), Echo (Reflection), Lunette, Nebka, Parabolic, Blowout, Compound and Complex

Booming or Singing

— from the contents page of Dune Worlds: How Windblown Sand Shapes Planetary Landscapes by Ralph D. Lorenz, James R. Zimbelman (2014)

Image: Barchan dunes, Hellespontus region of Mars from HiRise. The dunes are about 60 metres across (left to right) and resolution is about 1.5 metres. (Image of whole region here)

The light backward

When we see images of distant stars and galaxies we look far back in time.  It is an extraordinary and rather wonderful fact, but also alien from normal experience.

Looking at this image of 67P/Churyumov-Gerasimenko is different.  Because light reflected off the comet takes only about half an hour to reach the Earth we are seeing it almost as it is in real time – that is, in the time of actual lived experience.

We see a degree of detail so far unrealised for such a distant object – albeit one that is of course vastly closer than any star.

We see a strange mini-world with terrain imaginable for human feet.



Image: ESA

Totality

I was on a boat off Baja, Mexico. It was July, but about ten minutes before totality the air started to get noticeably colder, seemingly every second, as the Moon blocked off more and more sunlight. The Sun visibly became a crescent, and the optical effects were overwhelming. Everything seemed to be swimming, the shadows were all distorted into little crescents, and the light was becoming very sharp and angular. I looked up and saw shadow bands flowing overhead as the light [shone] through convection cells in the upper atmosphere. I looked down and saw the eclipse's shadow sweeping across the ocean towards me at breathtaking speed. Then the Moon slid into place, and sunlight shining through its mountains and valleys drew a diamond ring in the sky. The Sun's corona popped out, white and glowing and wavering. I could see the planets all stretched out along the elliptic -- Mercury, Venus, Mars, Jupiter. The whole solar system was right in front of my eyes. Everyone was hooting and hollering and yelling. It was pure primal joy, like that feeling right after a big football touchdown. The eclipse itself lasted something like seven minutes, but it went by in a flash.

 – Greg Laughlin quoted by Lee Billings in Five Billion Years of Solitude

Image: Ben Cooper via APOD

Ice spires, double sunrises, methane seas

...the ice spires of Callisto; Verona Rupes a great cliff on Miranda, a tiny moon of Uranus; the weird sunrises and sunsets of Mercury; the equatorial mountain range on Iapetus; the asteroid Hektor; Herschel Crater on Mimas; the methane seas of Titan; and, of course, the fabulous geysers of Enceladus.

– phenomena nominated as candidates for sixth and seventh place in a list of wonders of the solar system.

And so they tell us that Anaxagoras answered a man who was...asking why one should choose rather to be born than not – “for the sake of viewing the heavens and the whole order of the universe.”

– from the Eudemian Ethics of Aristotle, quoted by Jonathan Glover.


Image: geysers on Enceladus. NASA/JPL/Space Science Institute via wikimedia.