superatomic circus

18/08/2010

Pick of the pics and Updating Einstein’s Universe & Magic Universe

Seeing the superatomic circus

When ultra-cold rubidium atoms club together in the superatoms called Bose-Einstein condensates, they usually make untidy crowds, as on the left. But a team led by Stefan Kuhr and Immanuel Bloch at the Max-Planck-Institut für Quantenoptik in Garching, Germany, brings them to order in a neater pattern, as seen in the middle picture. With more rubidium atoms the superatom grows wider (right). Criss-cross laser beams create a lattice-like pattern of pools of light where the atoms like to congregate. When the laser light’s electric field is relatively weak, the atoms jump (by quantum tunnelling) from one pool to another, creating the usual disorder. A stronger field, as in the central and right-hand images, fixes them in the novel state of matter called a Mott insulator. But atoms can be lost from the condensate, which explains the ring-like appearance on the right. Images from MPQ.

[You're recommended to click on the images for a better view]

Single atoms are located at the sites indicated by circles. Fig. 3 in Nature paper, Sherson et al. see ref.

What’s new here, in an advance online publication in Nature,  is not the creation of these kinds of  superatoms but the German team’s success in imaging them, with a specially developed microscope that picks up fluorescence from the atoms caused by the cooling process. In the image on the right individual atoms are pinpointed.

It’s exciting stuff, because we’re probably seeing the dawn of a new technology – after electronics comes “atomics”. If individual atoms in a superatom can be manipulated, they might be used to carry “addressable” information in an atomic computer.

Read the rest of this entry »


Guided hurricanes

17/08/2010

Predictions revisited and Climate Change: News and Comments

Guided hurricanes

When speculating four decades ago about the military uses of geophysics, Gordon J.F. MacDonald of UCLA contemplated the triggering of earthquakes or tsunamis, or melting polar ice with nuclear weapons. And he didn’t overlook the idea of steering hurricanes to ravage the enemy’s coasts. Reminding me of that prediction is a report now in press in Geophysical Research Letters, about how natural variations in the colour of the sea help to guide cyclones in the Pacific. A cyclone, remember, is a loosely used generic term that includes the major storms called hurricanes (Atlantic), typhoons (Pacific) or tropical cyclones (Indian Ocean and Australia).

Contributing to Unless Peace Comes, (1968), in a chapter entitled “How to Wreck the Environment”, MacDonald wrote:

… preliminary experiments have been carried out on the seeding of hurricanes. The dynamics of hurricanes and the mechanism by which energy is transferred from the ocean into the atmosphere supporting the hurricane are poorly understood. Yet various schemes for both dissipation and steering can be imagined. Although hurricanes originate in tropical regions, they can travel into temperate latitudes, as the residents of New England know only too well. A controlled hurricane could be used as a weapon to terrorize opponents over substantial parts of the populated world.

Read the rest of this entry »


Misleading meteor photo

14/08/2010

Pick of the pics

Misleading use of a meteor photo

British newspapers today print a Reuters photo of Stonehenge that includes a single meteor from Thursday night’s Perseid shower. Some papers convey the impression that every streak in the photo is a meteor, when in fact all bar one near-vertical streak are just stars inching across the sky as the Earth turns during a long exposure of the camera.

As the photo is copyrighted I’ll not post it here, but you can see a typical offender at http://www.mirror.co.uk/news/weird-world/2010/08/14/stone-me-what-a-weird-shower-115875-22486527/

The Guardian has it correctly captioned at http://www.guardian.co.uk/science/gallery/2010/aug/13/perseid-meteor-shower#/?picture=365714247&index=5

A big meteor shower is well worth watching, and it’s nice to know you’re flying through the dust trail of a comet – Comet Swift-Tuttle in the case of the Perseids. The best I saw was from a small boat at sea — again the Perseids, which come conveniently in the summer sailing season. But you’re lucky if you spot one or two shooting stars every few minutes. Journalistic hyperbole can leave non-astronomers feeling disappointed.


Mother tongue

10/08/2010

Updating Magic Universe

It really is your mother tongue

Amid all the politically correct attempts to minimize the differences between the sexes, and ignore their contrasting roles in child rearing, how refreshing to see knock-down evidence pointing the other way! In results released today, researchers in Japan proclaim the special role of mothers in evolution’s most distinctive task for Homo sapiens – encouraging babies to chat.

The tale is quickly told because the RIKEN Brain Science Institute (located near Tokyo) has provided helpful diagrams. I’ve re-written the captions.

Special brain activity in mothers with babies at the babbling, pre-verbal stage appears in functional magnetic resonance imaging (fMRI) when they hear maternal baby-talk, technically known as infant-directed speech (IDS). The highest activity, denoted in red, is in the key language areas of the left hemisphere, Broca’s and Wernicke’s. Other women show a slightly raised response, but men don’t, whether they are fathers or not.

The fact that the special maternal brain activity switches on when it’s needed, and off again when it isn’t, reveals an astonishing evolutionary program.

The most amusing technical detail is that the investigators wanted to image the brains of mothers actually interacting with their babies, but they couldn’t. It was impossible for the mothers to keep their heads still. Listening passively to playbacks of baby-talk had to do instead. The experimental subjects were 35 first-time parents with pre-verbal infants, 30 men and women without any parenting experience, 16 mothers with toddlers who spoke two-word utterances and 18 mothers with children in elementary school.

Read the rest of this entry »


Do clouds disappear? 3

09/08/2010

Falsification tests of climate hypotheses

Cosmic rays and clouds at various latitudes

An exchange with Prof. Terry Sloan of Lancaster University

I’m promoting to the start of a new post a comment on an earlier post that came from Terry Sloan, together with my reply and his comment on my reply. I’ve included a graph that he sent in an e-mail because it wouldn’t upload into the Comments section.

After that, the discussion continues here with further remarks from me.

Sloan is one of the severest critics of the Svensmark hypothesis that cosmic rays influence the Earth’s low clouds. The earlier post, entitled “Do clouds disappear when cosmic rays get weaker?”, was concerned chiefly with whether or not sudden changes called Forbush decreases have observable effects on cloud cover. You can see that post in full here: http://calderup.wordpress.com/2010/05/03/do-clouds-disappear/

But the present interaction with Sloan mainly concerns a different question, about the influence of the Earth’s magnetic field. To help readers to get quickly up to speed, here’s the most relevant extract from my original post:

Read the rest of this entry »


Pretty magnetic monopoles

05/08/2010

Pick of the pics

A pretty magnetic pattern is pretty surprising too

Against the rules, triplets of magnetic north poles (bright points) and south poles (dark points) chum together with amazing regularity on small islands etched in a honeycomb pattern on an iron surface, using an electron beam. Hartmut Zabel at the Ruhr-Universität Bochum calls it a new magnetic order. The polarities are revealed by a magnetic force microscope, and the 20-micrometre scale line tells us that the width of the picture is about the average thickness of a human hair. Credit: RUB

Who’d have thought it? In kindergarten science you learn that like magnetic poles repel each other. Yet here we see energetically unfavourable triplets of poles occurring not just once or twice by mistake but all across a specially prepared iron surface, when subjected to a magnetic field.

The so-called “magnetic monopoles” created in this pattern are not to be confused with hypothetical fundamental particles of that name. And be wary of attempts to explain the phenomenon to you by reference to “spin ice”, and an analogy with water ice. They may be helpful for experts but can baffle non-physicists. All you really need to know is that the exposed north or south poles belong to atoms that can face one way or the other on the lattice surface.

Watch out for novel information-storage devices exploiting this “new magnetic order”. Prof. Zabel points out that “each node point has eight possible dipole constellations – far more than with conventional storage techniques based on two states”. The islands in the experiments were 3 micrometres long, but they might be made ten times smaller.

References

Alexandra Schumann, Björn Sothmann, Philipp Szary and Hartmut Zabel, “Charge ordering of magnetic dipoles in artificial honeycomb lattices,” Applied Physics Letters, Vol. 97, 022509 (2010). doi:10.1063/1.3463482

RUB press release: http://www.alphagalileo.org/ViewItem.aspx?ItemId=82499&CultureCode=en

For a relevant report last year from Helmholtz-Zentrum Berlin für Materialien und Energie see http://www.sciencedaily.com/releases/2009/09/090903163725.htm


Why is science so sloooow 2

05/08/2010

Updating Magic Universe

WHY IS SCIENCE SO SloooOW? — continued

The modest output of major discoveries compared with a century ago, despite the huge increase in the scientific workforce, was the theme of an earlier post on this subject, which you can see here http://calderup.wordpress.com/2010/05/06/why-is-science-so-sloooow/ . A relevant extract  from the Magic Universe story on “Discovery” included this paragraph about the use of peer review to resist the funding and publication of novel research.

As a self-employed, independent researcher, the British chemist James Lovelock was able to speak his mind, and explain how the system discourages creativity. ‘Before a scientist can be funded to do a research, and before he can publish the results of his work, it must be examined and approved by an anonymous group of so-called peers. This inquisition can’t hang or burn heretics yet, but it can deny them the ability to publish their research, or to receive grants to pay for it. It has the full power to destroy the career of any scientist who rebels.’

Lovelock made those remarks in a lecture in 1989, but the situation remains grim. This month the life sciences magazine The Scientist has interesting articles on peer review.

Read the rest of this entry »


Greenland bedrock

04/08/2010

Pick of the Pics and Climate Change: News and Comments

A drill reaches bedrock under the Greenland Ice Sheet

Dorthe Dahl-Jensen of the Niels Bohr Institute in Copenhagen holds up in triumph the last ice core drilled to a depth of 2537.36 metres at the deep drilling site NEEM on the Greenland Ice Sheet. The core contains rocky debris from a land surface corresponding with the Eemian interglacial period, which was warmer than now about 120,000 years ago. Clues in the ice and the bedrock are expected to give new information about climate change during that warm time, the extent of the residual ice sheet, and in the onset of cold conditions that led to the growth of the present ice sheet. The bedrock material may also include traces of much older life and associated climatic events. Credit: NEEM

Bedrock was reached on 27July, but in company with the American media I’ve just caught up with the news today. Under Danish-US leadership, the North Greenland Eemian Ice Drilling project, NEEM, has kept 300 scientists from 14 countries busy over the past five years. The drilling itself started in June 2009 and proceeded rapidly to its conclusion. It’s striking that they know the depth to within a centimetre.

The first results may be published later this year. Meanwhile you can see more pictures and information at http://neem.nbi.ku.dk/


What Language on Mars?

02/08/2010

Predictions Revisited

What Language Will They Speak on Mars?

The planet Mars in Chinese script. Credit: About.com: Chinese Culture, written by “js”

Chinese, on present showing. Never mind that seven men – Russian (4) European (2) and Chinese (1) – are now two months into a 520-day isolation trial in Moscow, simulating a manned mission to Mars. That’s for show. Political willpower will settle the issue.

In 1964 the rocket engineer Wernher von Braun forecast a human visit to Mars by 1984. That might well have happened had the US not cancelled its proposed Orion rocket in 1965 – the year after von Braun made his prediction. The trouble was that Orion would have had nuclear propulsion, not merely by nuclear motors, but by nuclear bombs. So it had to be abandoned in the aftermath of the nuclear test-ban treaty, much to the annoyance of Freeman J. Dyson and other enthusiasts.

Orion – the gigantic might-have-been

Here’s a diagram from my book Spaceships of the Mind (1978) which accompanied the BBC-OECA series with the same title, produced by Dick Gilling of BBC-TV. Assembled in Earth orbit, Orion would have carried about 2000 10-kiloton nuclear fission bombs, released at a rate of one a second to explode close behind a large spaceship. With a pusher plate absorbing the shocks, the spacecraft would quickly reach a speed that would take about 20 astronauts around Mars and back to Earth in just six months.

It may seem daft now but Orion was a recognition, at the very start of the Space Age, that if human beings are ever to become serious about space travel, they’ll have to think nuclear. That’s still the case, although nuclear fusion will be preferable, of course, with ignition as far from the Earth as possible.

When von Braun contributed to the New Scientist’s 1964 series on “The World in 1984” he remained mute about Orion although he glanced the nuclear option. At the time he was director of NASA’s Marshall Space Flight Center in Huntsville, Alabama, with the Apollo missions to the Moon at the top of his agenda. Here, for a start, are two early extracts from his article entitled “Exploration to the Farthest Planets”:

Read the rest of this entry »


Monsoon 2010

01/08/2010

Climate change: News and Comments

Floods in Pakistan, Relief in India

Harrowing news of lives lost in unusual monsoon floods in NW Pakistan, close to the Afghan border, doesn’t mean that this year’s rains have been exceptional across the subcontinent. On the contrary, the Indians were worried by a shortfall in early July.Their rains have now perked up.

Strong La Niña conditions (the opposite of El Niño) now showing in the Pacific are historically favourable for the Asian monsoon, and the India Meteorological Department seems to be sticking to an earlier forecast that this season’s total rains will be close to normal. See this Reuters interview with D. Sivananda Pai, director of the National Climate Center in Pune. http://in.reuters.com/article/idINSGE66K0IL20100721?loomia_ow=t0:s0:a54:g12:r3:c0.638402:b36099434:z3

For earlier posts here about the Asian monsoons, see http://calderup.wordpress.com/2010/05/01/monsoons-and-the-sun/ and http://calderup.wordpress.com/2010/05/05/maps-of-monsoon-history/


Follow

Get every new post delivered to your Inbox.

Join 147 other followers