Astronomers have discovered an object that appears to be an invisible galaxy made almost entirely of dark matter.

The team, led by Cardiff University, UK, claims it is the first such object to be detected.

A dark galaxy is an area in the Universe containing a large amount of mass that rotates like a galaxy, but contains no stars.

It was found 50 million light-years away using radio telescopes in England and Puerto Rico.

Watch your grandfather clock next time there's an eclipse. It might be trying to tell you something, says Govert Schilling.

Nothing is more captivating than a total eclipse of the sun. Darkness races across the surface of the Earth. The sky turns stale blue. Temperatures drop. Dogs bark. And then, of course, there is the alien beauty of the sun's pearly white corona surrounding the black silhouette of the moon.

But there may be more to an eclipse than meets the eye. Swinging pendulums go wild as if some mysterious force were tugging on them. Sensitive gravimeters give readings that fluctuate violently. Gravity itself seems to quiver a bit. Or so say a small band of physicists who claim that these mysterious phenomena hint at a fundamental flaw in Einstein's general theory of relativity.

Needless to say, such claims have proved controversial. Celestial alignments, pendulum experiments, Einstein bashing - it all smacks of fringe science that deserves to be ignored. Surely there must be some conventional explanation.

by Robert Wright

Oct. 8, 2004

Oct. 10 update appended below

This week I published a piece in Beliefnet about an interview I did with the philosopher Daniel Dennett for my video website meaningoflife.tv. In the piece I asserted that Dennett (long famously atheist) had said that, as I paraphrased it, “life on earth shows signs of having a higher purpose.” In other words: the process of natural selection may itself have been set in motion by a designer (in some sense of that word), and the ensuing biological/cultural evolution may be moving toward some purpose that we don’t yet understand.

Dennett, in statements that have gotten wide circulation on the internet, has since complained that my piece misrepresents the views he expressed in that interview. So far as I can tell, he’s wrong.

Including cause-and-effect in equations produces 4-dimensional space-time.

Is causality an inherent and necessary characteristic of the Universe, or just an illusion produced by the way our brains interpret the world?

It's real, say physicists, who believe they have worked out how the Universe is constructed from the tiniest building-blocks of space-time. The finding could also help the development of a theory of quantum gravity, which would marry the two currently estranged physical theories of the Universe: quantum theory and relativity.

Quantum theory describes the Universe at the tiniest possible scale - about 10-35 metres (about 1020 times smaller than the radius of a proton). It predicts that on this scale the apparently smooth fabric of space and time must degenerate into a kind of 'foam' in which connections between different points are constantly appearing and vanishing.

Physicists have long been trying to figure out how the fuzzy nature of space-time at this tiny scale can give rise to the large four-dimensional Universe we see around us, as described by Einstein's theory of relativity.

Scientists studying the problem assume that each tiny piece of the foam is a kind of four-dimensional triangle, with three dimensions of space and one corresponding to time. The smooth fabric of space-time can be built up by gluing these triangular tiles together, just as a smoothly curved surface can be made from flat, two-dimensional tiles.

Because the quantum foam fluctuates through all kinds of configurations, constructing the physical Universe means adding up all the possible tiling patterns. You might think that this would inevitably generate a four-dimensional Universe - but it doesn't. Earlier researchers found that they got a space-time with either an infinite number of dimensions or just two. Neither of these looks at all like our Universe.

Construction work

Renate Loll of Utrecht University in the Netherlands and her co-workers have now found a way to assemble the pieces so that they inevitably produce a four-dimensional Universe. Instead of assuming that all tilings are allowed, they impose two constraints.

First, the theory of relativity must apply within each individual tile (so that nothing can travel through it faster than light) and second, the assembly must preserve causality. This means that a piece of space-time cannot be constructed in such a way that an 'event' - some change in the Universe - precedes its cause.

If cosmologists were to make a movie of the universe's entire history, the show would start, of course, with the scorching blast of the Big Bang. The universe—absolutely every bit of mass we can detect or even infer today—would expand at unfathomable speeds, going from smaller than a proton to larger than a galaxy in the blink of an eye. As the expansion continued, the universe would cool down, and by the time the opening credits of the movie finished scrolling, a superhot soup of elementary particles would fill the whole cosmos, ready to cook the first protons and neutrons.But what would happen next?

The fact is, cosmologists are still working out the rest of the plot—what exactly took place during the more than 13 billion years since that primeval blast. For this article, in keeping with the current trend in international scientific publishing, IEEE Spectrum uses the words \"billion\" to mean 109 and \"trillion\" to mean 1012. A particular piece of the story that has kept researchers scratching their heads is how galaxies formed and evolved. How did that amorphous particle soup transform itself into billions and billions of galaxies of breathtakingly different shapes and sizes? Why did these galaxies gather together in clusters, and clusters of clusters, embedded along unimaginably enormous structures of matter shaped like bubbles, filaments, and sheets?

To answer these and other fundamental questions in cosmology, an international group of scientists from Canada, Germany, the United Kingdom, and the United States has been working on an ambitious project whose goal is to simulate on a supercomputer the evolution of the entire universe, from just after the Big Bang until the present.

The group, dubbed the Virgo Consortium—a name borrowed from the galaxy cluster closest to our own—is creating the largest and most detailed computer model of the universe ever made. While other groups have simulated chunks of the cosmos, the Virgo simulation is going for the whole thing. The cosmologists' best theories about the universe's matter distribution and galaxy formation will become equations, numbers, variables, and other parameters in simulations running on one of Germany's most powerful supercomputers, an IBM Unix cluster at the Max Planck Society's Computing Center in Garching, near Munich.

In the golden years of the Liberal Party in England, before the First World War, Herbert Asquith was the patrician prime minister and Winston Churchill was an obstreperous young politician. At question time in the House of Commons, Churchill frequently challenged Asquith with provocative statements and awkward questions. After one of these Churchillian assaults, Asquith lamented, "I wish I knew as much about anything as that young man knows about everything." Reading this eloquent book in which Brian Greene lays out before us his vision of the cosmos, I feel some sympathy for Asquith. Asquith expresses my reaction to the book precisely.

Elegance is more than just a frill in life; it is one of the driving criteria behind survival.
- Douglas Hofstadter

I am nothing and nobody; atoms that have learned to look at themselves; dirt that has learned to see the awe and the majesty of the universe.
- Geoffrey A. Landis

Astrobiologists disagree about whether advanced life is common or rare in our universe. But new research suggests that one thing is pretty certain – if an Earthlike world with significant water is needed for advanced life to evolve, there could be many candidates.

"To how many places does nature carry out PI when she makes each successive bubble in the white-cresting surf of each successive wave before nature finds out that PI can never be resolved?... And at what moment in the making of each separate bubble in Universe does nature decide to terminate her eternally frustrated calculating and instead turn out a fake sphere? I answered myself that I don't think nature is using PI or any of the irrational fraction constants of physics."
-Buckminster Fuller(Synergetics II, p. 233).

The atom is a pattern, and the molecule is a pattern, and the crystal is a pattern; but the stone, although it is made up of these patterns, is just a mere confusion.
—Aldous Huxley

Imagine that the history of the universe is compressed into one year�with the big bang occurring in the first seconds of New Year�s Day, and all our known history occurring in the final seconds before midnight on December 31. Using this scale of time, each month would equal a little over a billion years. Here�s a closer look at when important events would occur when we imagine the universe in one year.

Imagine you can play God and fiddle with the settings of the great cosmic machine. Turn this knob and make electrons a bit heavier; twiddle that one and make gravitation a trifle weaker. What would be the effect? The universe would look very different � so different, in fact, that there wouldn't be anyone around to see the result, because the existence of life depends rather critically on the actual settings that Mother Nature selected.