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Solar system ‘twin’ discovered
ASTRONOMERS have found a planetary system similar to ours, a Jupiter-like world circling a Sun-like star in roughly the same orbit that Jupiter follows our Sun. Of the 100 or so other planetary systems known, this one more closely resembles ours than any other.
Researchers speculate that this system may contain other worlds, such as smaller rocky planets like Earth, either in orbit around the star or around the Jupiter-like world itself.
The planet’s parent star, called HD 70642, is slightly too faint to be seen with the unaided eye, but is easily visible in the southern sky using binoculars.
At just 95 light-years away, the gas-giant planet, bathed in the light of a yellow-dwarf star is on our galactic doorstep.
Like Jupiter, its atmosphere could be mottled and streaked with wind patterns and weather systems. Dark-red methane clouds may scurry across its face beneath a high-altitude frosting of bright ammonia crystals. At its poles, aurora may glisten and lightning bolts pulse across its night-time face.
The planet detected orbiting HD 70642 is not the first Jupiter-class world to be found circling another star. All of the planetary systems found so far contain gas giants like Jupiter.
“This is the closest we have yet got to a real Solar System-like planet, and advances our search for systems that are even more like our own,” says Hugh Jones of Liverpool John Moores University, UK, who helped discover the new world.
The planet was found using the 3.9-metre Anglo-Australian Telescope in New South Wales, Australia. The discovery is being announced at a conference in France.
The research reported was sponsored by the UK’s Particle Physics and Astronomy Research Council (PParc).
Particle discovery confirmed
The discovery involves quarks - particles that make up the protons and neutrons usually found in the nuclei of atoms.
The new particle is the so-called pentaquark, five quarks in formation. Until now, physicists had only seen quarks packed into two- or three-quark combinations.
They say that the discovery of this new particle should have far-reaching consequences for our understanding of the structure of matter.
Physicist Ken Hicks of Ohio University, who took part in the two experiments and the confirmatory work at the Jefferson Lab, says it took him two months to convince himself that the pentaquark was real.
More than 99.9 per cent of the mass of everyday objects is contained within the nucleus of atoms. This means that most of your body mass comes from subatomic particles that are made up of quarks.
There are hundreds of subatomic particles known and most are composites of simpler particles. They all fit into two categories, baryons and mesons.
Baryons are made of three quarks and mesons are comprised of two quarks, a quark and an anti-quark.
The discovery of the pentaquark, also known as a new exotic baryon state, should have far-reaching consequences for our theory of particle interactions that attempt to explain the structure of matter.
Stem cell for spinal injuries
Cells from human embryos have been used to make paralysed rats walk again.
The US researchers who carried out the experiments hope it should be possible to begin similar trials on human subjects in just two years.
Embryonic stem cells (ESCs) have huge potential use for scientists because they have the ability to turn into many different forms of tissue. However, their use remains highly controversial.
Britain has allowed scientists to conduct embryonic stem cell experiments, but they could soon be banned by the European Union, and the US is still considering the issue.
New Scientist magazine reports that the US team harvested cells from human embryos at an early stage of development.
They then manipulated them in the laboratory to turn them into specialized cells that form myelin, the insulating layer than surrounds nerve fibres.
These cells were transplanted into paralysed rats with bruised spines.
After nine weeks, the rats fully regained the ability to walk.
Analysis of the rats’ spinal cords showed that the cells had wrapped themselves around nerve cells and formed new myelin sheaths.
They also secreted substances that appeared to have stimulated the formation of new nerves.
Dr Hans Keirstead and his team from the University of California at Irvine now plan to use the same technique to treat human patients who have sustained recent spinal cord injuries.
However, treating people who have been paralysed for years or suffer from degenerative nerve diseases will be far more difficult.
Scientists have tried using adult stem cells derived from bone marrow and nerve cells to repair damaged spines.
But Thomas Okarma, of US biotech company Geron Corporation, which funded the new research, believes only ESCs stand a real chance of success.
They are more versatile than adult stem cells, and, unlike them, can be mass-produced.
Mr Okarma said: “At this moment, there is very little hard evidence that a bone marrow stem cell can turn into anything but blood or that a skin stem cell can become anything but skin.” — Dawn ScienceDotcom Report
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