28 February 2015

The cosmos seen as a bubble

Moving through this crowded space, the pilgrim enters into the underlying “emptiness” — really a kind of infinite spaciousness—that is the stuff of Tibetan Buddhist reality. It may be strange to think that a universe so densely populated is actually, in some profound sense, empty. Judging by the literary sources we have available, to take this spaciousness into oneself, momentarily clearing heart and mind of the detritus that normally clogs our perceptions, provides a sense of vast psychic relief. The seemingly empty space is, however, a highly active arena within which our minds weave the web that we take to be the world—a world filled with objects such as Maitreya’s towers and manifold creatures and, of course, these same Buddhas and Bodhisattvas continuously emerging out of empty space and dissolving back into it.
David Shulman

The description in the Gaṇḍa-vyūha of Sudhana's vision of the towers of Maitreya could almost be from Italo Calvino's Invisible Cities:
He saw the tower immensely vast and wide, hundreds of thousands of leagues wide, as measureless as the sky, as vast as all of space, adorned with countless attributes; countless canopies, banners, pennants, jewels, garlands of pearls and gems, moons and half-moons, censers giving off fragrant fumes, showers of gold dust….Also, inside the great tower he saw hundreds of thousands of other towers similarly arrayed; he saw those towers as infinitely vast as space, evenly arrayed in all directions, yet these towers were not mixed up with one another, being each mutually distinct, while appearing reflected in each and every object of all the other towers.

View of the Tabo monastery by Christian Luczanits

27 February 2015

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

26 February 2015

SDSS J0100+2802

The black hole at the centre of our galaxy has a mass about three million times that of our sun. 
The black hole at the centre of the ultra luminous quasar SDSS J0100+2802 is twelve billion times more massive than the sun. 
The luminosity of this quasar is 420 trillion times greater than that of our sun.
  — sci-news.com
The winds blasting out of the quasar PDS 456 carry more energy every second than is emitted by more than a trillion suns. 

Image is artist's impression of ULAS J1120+0641. Credit: ESO/M.Kornmesser.

25 February 2015

"There is no us and them"

Our adaptive immune system, the branch of our immune system that develops long-lasting immunity, is thought to have been borrowed its essential technology from the DNA of a virus. Some of our white blood cells recombine their genetic material like random number generators, shuffling genetic material like random number generators, shuffling their sequences to create an immense variety of cells capable of recognizing an immense variety of pathogens. This technology was viral technology before it was ours. Of humans and viruses, Carl Zimmer observes, "There is no us and them."
from On Immunity by Eula Biss (2015)

24 February 2015

The bowl of heaven

It's an unsettling experience, projecting an image of someone's inner eye so neatly into your own, retina examining retina through the intermediary of a lens. It can be disorientating too: gazing down the axis of the beam is like looking up into the night sky with an eyeglass. If the central retinal vein is blocked, the resultant scarlet haemorrhages are described in the textbooks as 'stormy sunset appearance.' I sometimes see pale retinal spots caused by diabetes, and they're reminiscent of cumulus clouds. In patients with high blood pressure the branching, silvered shine on the retinal arteries resembles jagged forks of lightning. The first time I looked into the curved vault of a patient's eyeball I was reminded of those medieval diagrams that showed the heavens as an upturned bowl.
from Adventures in Human Being by Gavin Francis (2015)

Image from Utriusque Cosmi by Robert Fludd (1617)

23 February 2015

Signposts


At a talk for non-specialists on 21 February, David Tong outlined three big problems in physics [1], which I oversimplify/misrepresent as follows:
Dark energy.  We've known for nearly a hundred years that the universe is expanding. It as if there is an antigravity force causing everything to repel everything else. We have no idea what it is. It’s 70% of the energy of the universe, it’s increasing all the time and we don’t understand it. Our best calculations are wrong by a factor of 1060 .

Black holes.  Information that goes into a black hole is lost forever. It does not reappear in Hawking radiation. But this cannot be.

Holography. It may be that our three dimensional world is actually a mirage. The correct description will be one in which the laws of physics are written on a two dimensional surface, and the laws of physics we can see in the universe are encoded on this surface in the same way that a hologram encodes a three dimensional surface.
So, Tong concluded, there is a lot in the fundamental physics that we simply don’t understand, and that it seems unlikely we’re going to get guidance from experiment. Looking to history, however, it is precisely when there is a crisis that physics has thrived. He is optimistic about progress.


Note [1]: Some people say there are three great mysteries in science as a whole: the origin of the universe, the origin of life and the origin of consciousness.

Image: Douglas Griffin

The ash tree just is

Kayaking fast downstream
Late winter sun
The ash tree just is