An international team of astronomers, led by scientists at the University of Manchester have produced new evidence that most of the energy in the Universe is in the form of the mysterious "Dark Energy". The new evidence comes from a 10-year census of the sky for examples of gravitational lenses, which are seen when a galaxy bends the light from a distant quasar to form several images of the same quasar. Linking the number of lenses they found with the latest information on the numbers of galaxies, the scientists have been able to infer that most of the energy in the Universe is likely to be in an invisible, and presently unknown, form.
Dark Energy is closely related to the idea of a Cosmological Constant introduced by Einstein over 80 years ago, but most astronomers, including Einstein himself, have always strongly doubted its reality. However, in the past 5 years several independent groups of astronomers have amassed evidence suggesting that Dark Energy exists and could well dominate the total energy of the Universe.
Dark Energy only affects the properties of the Universe over very large distances. As a result, the observations which are sensitive to its presence, in particular studies of exploding stars in distant galaxies, are all close to the limit of current capabilities. Astronomers have therefore been keen to exploit many different tests and Dr. Ian Browne makes the point that "the new gravitational lens test is based on completely different physical arguments to the previous ones and so provides independent evidence in support of Dark Energy".
Ian Browne | alfa
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Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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