This is a cutting edge article that talks about an invisible scaffolding(dark matter) that gives shape and form to the visible universe that our telescopes see out there. The visible universe makes up only 5% of the total picture. About 25% is made up of invisible dark matter and the rest(70%) is made up of dark energy, also invisible. Dark matter and dark energy are made up of fundamental particles as yet undiscovered by science but their presence in the universe can be inferred by ingenious experiments, some of which are detailed in the article below.
Of what interest is this to an Ismaili drawn towards cosmology-philosophy-theology? Lots, because the Ismaili worldview insists that the material universe(whether visible or invisible) is a critical component of the structure of truth and the goal of religion in the life of an individual Ismaili is to discover the ultimate nature of truth.
Interestingly, our 48th Imam tells us in his legendary 'Usul-e-Din' farman of Bombay, 1899:
"My task is to show you the way to the Truth so that you may reach your ultimate destiny, which is Fanafillah"
The article:
Science & Technology
Cosmology
I spy with my little gravitational lens
Jan 11th 2007
From The Economist print edition
How to map the invisible
SEVENTY years ago Fritz Zwicky, an astronomer at the California Institute of Technology, discovered that galaxies are not big enough. The visible matter they contain (stars, gas and so on) does not have enough gravity to hold them together. To explain this bewildering missing mass—a result verified independently by many of Zwicky's colleagues—he suggested that galaxies (and therefore, by extension, the universe) contain a lot of additional, invisible matter.
Dark matter, as the invisible stuff is now referred to, has turned out to be one of the most mysterious things around. Subsequent work has shown that it cannot be composed of the same particles (ie, protons, neutrons and electrons) as the visible stuff. But its gravity not only holds galaxies together, it controls their distribution in space—as a study announced in Seattle at this week's meeting of the American Astronomical Society, and published simultaneously in Nature, confirms.
The Cosmic Evolution Survey is the single largest project yet undertaken by the Hubble space telescope. It spent over 1,000 hours of the instrument's valuable observing time examining a section of the firmament about nine times the size of a full moon. Richard Massey, one of Zwicky's successors at Caltech, and his colleagues have used the data collected by the survey to draw the most extensive map of dark matter yet attempted.
They did so by employing a technique called gravitational lensing. This exploits one of the predictions of Einstein's general theory of relativity: that the path of a beam of light (which is a straight line in empty space) is bent inwards by the gravity of a massive object. The result is that such objects act as lenses, distorting the images of anything behind them.
Since dark matter is very massive indeed (there is about six times as much of it around as there is visible matter) it makes good gravitational lenses. Dr Massey and his colleagues were able to map the matter (both dark and visible) in the bit of the firmament covered by the Cosmic Evolution Survey by looking for characteristic distortions in the shape of distant galaxies that only Hubble, which is beyond the image-blurring effects of the atmosphere, can see. Regions rich in distorted galaxies were assumed to be places where large amounts of matter were present between the distorted galaxies and Earth.
That, however, only provided the researchers with a two-dimensional map of such concentrations of matter. Two further refinements were necessary: to work out the third dimension—distance from Earth—and to subtract the effect of visible matter in order to be left with the distribution of dark matter pure and simple.
The trick they used to perform the first refinement was a piece of basic optics. This is that a lens produces its biggest effect when it is halfway between source and observer. The most distorted galaxies, therefore, were those twice as far from Earth as the gravitational lens distorting them. And the distance of such galaxies from Earth can be measured.
That measurement uses another sort of optical distortion—this time of the wavelength of light. The expansion of the universe causes galaxies to recede from one another, and light from a receding object appears redder than that from a stationary object. The farther away a galaxy is, the faster it is receding and the bigger this red shift will be. Measure the distance to the most distorted galaxies and halve it, and you know roughly where your lenses are.
The result is a three-dimensional map of matter. To see which bits of it are dark matter simply requires superimposing the known pattern of visible matter.
Doing so is instructive, as Dr Massey's colleague Nick Scoville reported to the meeting. Dark and visible matter usually coincide. Their overlap confirms the hypothesis that dark matter is the skeleton upon which visible matter is supported, and also lends weight to a second idea—that galaxies form where dark matter accumulates at high densities, pulling visible matter with it. This study, then, has cast light on the darkest of matters and promises a far better understanding of the structure of the universe.
easynash
Islam, eminently logical, placing the greatest emphasis on knowledge, purports to understand God's creation:Aga Khan 4.
The God of the Quran is the One whose Ayats(Signs) are the Universe in which we live, move and have our being:Aga Khan 3
