Update

It has been a while since I have posted on the blog.  This is mainly because I have been busy. The manuscript of A New Map of Wonders is just about done, and the book will be published in 2017.

Here are two among many passing wonders from the last few weeks. There is no particular connection between them apart from the fact that they both expand our sense of reality.

• Plants may ‘see’ underground by channelling light to their roots. Their stems may act like a fibre-optic cables, conducting light down to receptors in the roots known as phytochromes. These may trigger the production of a protein which promotes healthy root growth.

• Weather systems have been observed on an exoplanet for the first time. Massive storms move across the surface of HAT-P-7b, a thousand light years away. The clouds in its atmosphere are likely made of corundum, the mineral which forms rubies and sapphires.

Shadows of the sky

Thinking about neutrinos, I also came across this:

This light tells us much, but I think in the course of time still more delicate and subtle mediums will be found to exist, and through these we shall see into the shadows of the sky. 

Photo NSF / B. Gudbjartsson via APOD

'Such a light as we could not have imagined a moment before'

Re-reading Philip Fisher — Wonder is a horizon-effect of the known, the unknown and the unknowable — I was turning it over in contrast with a well-known passage from Walking by Henry David Thoreau:

My desire for knowledge is intermittent; but my desire to bathe my head in atmospheres unknown to my feet is perennial and constant. The highest that we can attain to is not Knowledge, but Sympathy with Intelligence...

Reading on, I came again to a passage which I hadn't thought about in a while:

We had a remarkable sunset one day last November. I was walking in a meadow the source of a small brook, when the sun at last, just before setting, after a cold grey day, reached a clear stratum in the horizon, and the softest brightest morning sun-light fell on the dry grass and on the stems of the trees in the opposite horizon, and on the leaves of the shrub-oaks on the hill-side, while our shadows stretched long over the meadow eastward, as if we were the only motes in its beams. It was such a light as we could not have imagined a moment before, and the air also was so warm and serene that nothing was wanting to make a paradise of that meadow. When we reflected that this was not a solitary phenomenon, never to happen again, but that it would happen forever and ever an infinite number of evenings, and cheer and reassure the latest child that walked there, it was more glorious still.

On this November day, however, there has been no break in the grey, cold and wind.

'A vacuum is never really empty'

In... quantum field theory, a vacuum is never really empty... It is an arena in which quantum fluctuations produce evanescent energies and elementary particles. 

These short-lived phenomena might seem to be a ghostly form of reality. But they do have measurable effects, including electromagnetic ones. That’s because these fleeting excitations of the quantum vacuum appear as pairs of particles and antiparticles with equal and opposite electric charge, such as electrons and positrons. An electric field applied to the vacuum distorts these pairs to produce an electric response, and a magnetic field affects them to create a magnetic response. This behaviour gives us a way to calculate, not just measure, the electromagnetic properties of the quantum vacuum and, from them, to derive the value of c.

Why is light so fast? Sydney Perkowitz

Black Square by Kazimir Malevitch. Tate

Light passes through light...

Light passes freely through light. Were that not true, the visual messages we receive from the world would be scrambled by scattering, and much more complicated to interpret. In QED, that basic fact makes good sense: photons respond to electric charge, but photons themselves are electrically neutral.

A Beautiful Question by Frank Wilczek (2015)

Photo by author

Any-angled light

A photon at the centre of the Sun may collide with atoms between about 49 billion trillion and 49 trillion trillion times before it reaches the surface. Even moving at the speed of light between collisions that will take from around five thousand to half a million years.

Sunshine's Crazy Sloppy Path to You by Robert Krulwich

A physical impossibility

White light contains a mixture of all wavelengths in the visible spectrum. It is the dirtiest, muddiest color possible. But the visual system does not model it in that way. Instead, the visual system encodes the information of high brightness and low color. That is the brain’s model of white light— a high value of brightness and a low value of color, a purity of luminance— a physical impossibility.

Consciousness and the Social Brain by Michael Graziano

Image from here

Earthshine

Leonardo sketched it.

Galileo explained it as he sought to show the earth was not excluded from "the dance of stars." 

Recent research shows that the brightness of the earthshine varies as the Earth rotates because of the greater reflection from the mirror-like oceans compared to the continents. 

Earthshine is most often experienced in still and gentle conditions.

Photo Kevin Bourque via APOD

Slow light

Not the kind explored here by Radiolab but the 'normal' kind:



Remember, however, that from the point of view of a photon, whether from the Sun or the Andromeda galaxy, what we perceive as the distance to any object is traversed instantaneously. As Jim Al Khalili puts it:

For a particle of light, time stands still, such that the past, the present and future all collapse into one eternal moment.

Living colour

Our eyes can distinguish between wavelengths that differ by just one nanometer, but only in the green section of the colour palette: human vision can simultaneously detect about fifty different shades of green

The daytime sky is actually violet but our retinas are so insensitive to this hue...that we instead see the next most prevalent color, blue.

— from The Sun's Heartbeat by Bob Berman (2011)

Image: 7 and 12 colour circles from Traité de la peinture en mignature by Claude Boutet (1708) via Wiki

Light, half-light

blunter     dazzle, but with a particular sense of cold dazzle; winter stars or ice splinters catching low midwinter sun   Scotland

fireflacht     lightning without thunder; a flash of light which is seen in the sky, near the horizon, on autumn nights   Shetland

grimlins     night hours around midsummer when dusk blends into dawn and it is hard to say if day is ending or beginning   Orkney

plathadh-grèine     sudden temporary glimpse of the sun between passing clouds   Gaelic

hjalta dance, simmer ree, simmermal ton, titbow dance     different names for the peculiar dancing appearance of light on the horizon, along the top of the hills, which is seen in sunny summer weather   Shetland

— words connected with dusk, dawn, night and light from Landmarks (2015) by Robert Macfarlane

No underneath, no above

Here was the centre of the world, the sun swung round us; we rode at night straight away into the space of the stars. On a dry summer night, when there was no dew, I used to lie down on my back at full length (looking to the east), on the grass footpath by the orchard, and gaze up into the sky. This is the only way to get at it and feel the stars: while you stand upright, the eye, and through the eye, the mind, is biased by the usual aspect of things: the house there, the trees yonder; it is difficult to forget the mere appearance of rising and setting. Looking straight up like this, from the path to the stars, it was clear and evident that I was really riding among them; they were not above, nor all round, but I was in the midst of them. There was no underneath, no above: everything was on a level with me; the sense of measurement and distance disappeared. As one walks in a wood, with trees all about, so then by day (when the light only hid them) I walked amongst the stars. I had not got then to leave this world to enter space: I was already there.

— from The Old House at Coate by Richard Jefferies, quoted by Rebecca Welshman

I would drink deeper; fish in the sky, whose bottom is pebbly with stars.

— Henry David Thoreau

"We rarely recall our sense of being in the stars," says Charles Ross. His sculpture Star Axis is meant to offer "a place for that remembering."


Image: part of Eagle Nebula seen in infrared. NASA, ESA/Hubble and the Hubble Heritage Team via Ethan Siegel.

Photon buckets

Caleb Scharf celebrates the go-ahead for the European Extremely Large Telescope:

Equipped with adaptive optics E-ELT should.... be able to routinely study Jupiter down to scales of about 20 kilometers – by comparison the Great Red Spot is at present about 20,000 kilometers across. Mars can be imaged to roughly 5 kilometer resolution (depending of course on the relative separation of Earth). In other words, on a nightly basis we will be able to monitor the worlds in our solar system with a fidelity comparable to fly-by missions of yore. [1]

Images like this (but not this) might become commonplace.

I guess the adaptive optics resemble those at the Keck observatory in Hawaii, where lasers are beamed into the night sky to create artificial stars. The false stars become reference points because astronomers know what the laser should look like in the heavens were there no atmospheric distortion. That, at least, is part of how Steven Johnson describes them in How We Got to Now.

Johnson's reference to Keck is brief as his book explores a range of innovations that make the modern world.  None of those innovations are more important than those that transform the way humans extract energy from their surroundings, and in this regard the book highlights research at the US National Ignition Facility, which seeks "to create an artificial sun on Earth."  In Johnson's analysis this is looks likely to be a, if not the, great hope for meeting the energy challenge. [2]

But could solar technologies such as those being developed by the physicist and astronomer Roger Angel be a significant part of the way forward?   The technologies are, as Lee Billings puts it in this article, essentially clever ways of maximising efficiency in collecting, concentrating, channelling, or diverting the energy radiating from an already existing star. That could, I think, be rather wonderful. [3]


Notes

[1] I reviewed Scharf's book here. He has kindly said that my Book of Barely Imagined Beings contains "some fantastic ideas and insights to the nature of life."

[2] Brian Cox comes to the same conclusion in the last episode of his recent TV series The Human Universe.  A website for Johnson's TV series identifies some solar projects as sources for hope on a small scale.  Thanks to TH for loan of a copy of Johnson's book.

[3] On some environmental impacts of solar concentrators, and other technologies, see Rebecca Solnit.


Image: the site for the future E-ELT looks almost like Mars...if you ignore the blue sky, the snow on the peak and the extensive tracks.

On Light, 2

Like nothing else in our ordinary [experience], light exists simultaneously as waves and particles... 

[Alone] among all the elementary particles, photons are the only ones to which humans directly and regularly respond...

— from Empire of Light by Sidney Perkowitz (1996)

Later in the book Perkowitz writes:

We create and carry fields of order through an enigmatic cosmos. If we do not yet understand light, our minds [nevertheless] know how to assemble its wave particles into comprehension.

Image: Light-Toned Deposits in Noctis Labyrinthus, Mars. HIRISE

On Light, 1

When the universe was only a fraction of a nanosecond old, photons formed, along with other elementary particles such as quarks. According to Einstein’s theory of relativity, energy and matter can change into each other, so when photons collided they turned into elementary particles with mass: for instance, electrons, and their anti-matter partners, positrons. This may seem surprising, for we perceive light as something pure and ethereal, beautiful in its intangibility. Yet even weighty materials, even dense metals such as lead and gold, can ultimately trace their origins back to light.

– from Slow Light by Sidney Perkowitz (2011)

Image: The standard model of particle physics recognizes four kinds of gauge bosons: of which photons are one

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

"Life took me by the shoulder..."

One afternoon soon after her death, I entered her empty room, into which the good evening sun was shining, gladdening it with rose-bright, gay and soft colors. There I saw on the bed the things which the poor lady had till recently worn, her dress, her hat, her sunshade, and her umbrella, and, on the floor, her small delicate boots. The strange sight of them made me unspeakably sad, and my peculiar state of mind made it seem to me almost that I had died myself…. For a long time I looked at Frau Wilke’s possessions, which now had lost their mistress and lost all purpose, and at the golden room, glorified by the smile of the evening sun….

Yet, after standing there dumbly for a time, I was gratified and grew calm. Life took me by the shoulder and its wonderful gaze rested on mine. The world was as living as ever and beautiful as at the most beautiful time. I quietly left the room and went out into the street.

from Frau Wilke by Robert Walser, extracted here.

Matter, a photograph by August Sander (1925), here.

Zodiacal Light

There is something else [besides planets, asteroids, comets etc] that fills the interstices of our solar system every so slightly, a component of interplanetary dust. Tiny grains of silicates and carbon-rich material are spread in an enormous and tenuous haze that blankets the inner planets. Distributed in the form of a puffed-up disk, this cloud reaches from around the orbit of Jupiter to within that of Mercury.

At their largest these grains are only a tenth of a millimetre across...and they number no more than one in every cubic kilometer. But...the solar system is a very big place, and a colossal number of these particles spread across local space can scatter and reflect light just as if they were motes glimmering in a sunbeam as they float across a room.

...Ancient Islamic astronomers called this glow in the heavens the “false dawn,” since it can...appear in the east an hour or so before the sun rises – as if time itself disappears and the Sun returns early to light up the world again. In fact it's not so much the world that's being illuminated, but the framework of the solar system, a dusty impression of the alignment of the planets in their huge disk of orbital paths, and of all the other objects sharing this same space...

–  from The Copernicus Complex by Caleb Scharf (2014)

Image: Jack Fusco via APOD

Seeing things

Newton’s wrong guesses are...as interesting as his correct ones. A well-known example is his conviction that light is made of particles, not waves. What he had in mind were solid ‘corpuscles’, not the photons of modern physics, but it’s still tempting to see him as having been half right. And in trying to explain the splitting of white light into a spectrum, he came up with the beautiful notion that the width of the coloured bands matches the mathematical proportions of a musical scale. People had traditionally counted no more than five colours in a rainbow, but for his theory to work Newton needed more, so he introduced two ‘semitones’, orange and indigo, and we’ve been counting seven colours in a rainbow ever since.

-- Andrew Crumey in Aeon

Image: iridescent cloud above Thamserku, a 6,600-meter peak in Nepal by Oleg Bartunov via APOD