Engage the Antimatter Drive

GLIESE 581c has got to be the ultimate tourist destination. Discovered in April this year, it is the first rocky planet beyond our solar system with anything like a pleasant climate. How mind-blowing would it be just to stroll along its beaches - surely it must have beaches - or watch the planet's red-dwarf sun setting in a scarlet blaze over the alien landscape.
There's just one little problem to consider before you rush to book your ticket. Gliese 581c is 20 light years away - over a million times the distance from Earth to the sun. The journey there would make NASA's best efforts to explore our own solar system seem like a trip to the shops, and to get there in a human lifetime a craft would need to travel awfully fast. Even at half the speed of light you'd spend the best part of 50 years cooped up in a smelly space capsule. So what are the options?
There is no question that conventional chemical rockets aren't up to the task. The fastest interstellar craft to date, Voyager 1, is now heading out of the solar system at about 17 kilometres per second. At this rate it would take 350,000 years before what's left of your bones reaches Gliese 581c. Making maximum use of gravitational fields to accelerate your starship before it leaves the solar system - swinging close by the sun, say, so its intense gravity acts like a slingshot - isn't likely to make a significant difference. Nuclear-powered rockets that harness the heat from fission reactions to create an exhaust of high-velocity particles would cut nine-tenths off the journey time, but tickets for the 30,000-year trip are unlikely to find many takers.
Another possibility is to cruise through space on a sailing ship: make a reflective sail, unfurl it in space, and it will get nudged along by photons streaming out from the sun. This creates a slow but steady acceleration that can eventually add up to some serious travelling. According to engineers at US space research company Pioneer Astronautics, it's possible to make a solar sail that could propel a craft to around 1 per cent of the speed of light. The key, they suggest, is to use a mesh of metal-coated carbon nanotubes. The ultra-lightweight sail this creates, just nanometres thick, could pass close to the sun after launch without melting. The intense illumination, as well as extra acceleration from the sun's gravity, could boost the sail to speeds of over 3000 kilometres per second. Now you would reach Gliese 581c in around 2000 years.

ref: http://space.newscientist.com/article/mg19526201.900-engage-the-antimatter-drive.html

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Did our galaxy's black hole eat its baby brother?

Did the colossal black hole at the centre of the Milky Way devour its baby brother 120 million years ago? Possibly, says a team led by Warren Brown of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, US.
The grisly suggestion comes from observations of 10 'hypervelocity' stars that are moving so fast they will eventually escape the galaxy altogether.

Since the first such star was discovered in December 2004, astronomers have suspected that the supermassive black hole at the heart of the Milky Way, which weighs 3.6 million times the Sun's mass, is responsible for catapulting the objects outwards at extreme speeds. In that scenario, a pair of stars wanders too close to a single, supermassive black hole, and one star gets captured while the other gets flung outwards at up to 4000 km/sec.
But alternative models have also been proposed, including a scenario in which a second, middleweight black hole lurks near the larger one and together, both black holes fling stars outwards.
It is too soon to say which scenario is correct. But Brown's team says the observations to date point to an intriguing possibility: that a middleweight black hole did exist near the galactic centre at one time, but was swallowed up by its larger neighbour about 120 million years ago.

Single burst
The researchers arrived at this possibility after studying the stars' distances and speeds and then calculating when they must have been ejected from the galactic centre. Interestingly, five of the stars seemed to have been evicted around the same time – about 120 million years ago.
"It's possible they came from a single burst," Brown told New Scientist. As the smaller black hole fell towards the larger one, the black holes would have gravitationally "kicked out a bunch of stars, and we happen to see five of them".

He stresses, however, that the small number of observations means this scenario is only a possibility, and that the stars may instead have been kicked out one at a time, in unrelated incidents.
The new study also estimates that about 100 hypervelocity stars lie within 330,000 light years of Earth, where many should be observable. Brown believes that as many as 50 may be found within the next five years by future sky surveys.

Those observations may settle the vexing issue of what is slinging the stars out of the galaxy, he says: "Is it a single massive black hole ejecting pairs of stars, is it a binary black hole, or is it something else? I think that's probably the biggest question."
Journal reference: Astrophysical Journal

ref: http://space.newscientist.com/article/dn12622-did-our-galaxys-black-hole-eat-its-baby-brother.html

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Invisibility cloak turns you into ray of light

While true invisibility cloaks may remain forever a dream, the ability to vanish into an ethereal ray of light is still on the cards.
A device that bends microwaves around an object has been shown to render it partially invisible (New Scientist, 28 October 2006, p 29), but Min Qiu of the Royal Institute of Technology in Kista, Sweden, and colleagues argue that total invisibility would require the value of some of the cloak's key electrical and magnetic properties to be infinitely large - something that is impossible.
A more realistic goal is to remove the part of the cloak where the values should be infinitely large. They have calculated that the resulting cloak renders someone entirely invisible and leaves only a thin line of light in the object's place. The results will be published in Physical Review Letters.

ref: http://technology.newscientist.com/article/dn12611-invisibility-cloak-turns-you-into-ray-of-light.html

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PARAMORE!!

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