Friday, February 20, 2015

Alien star system buzzed the Sun

18 February 2015 Last updated at 08:06 ET

Alien star system buzzed the Sun

By Paul RinconScience editor, BBC News website

An alien star passed through our Solar System just 70,000 years ago, astronomers have discovered.

No other star is known to have approached this close to us.

An international team of researchers says it came five times closer than our current nearest neighbour - Proxima Centauri.

The object, a red dwarf known as Scholz's star, cruised through the outer reaches of the Solar System - a region known as the Oort Cloud.

Scholz's star was not alone; it was accompanied on its travels by an object known as a brown dwarf. These are essentially failed stars that lacked the necessary mass to get fusion going in their cores.

The findings are published in Astrophysical Journal Letters.

Observations of the dim star's trajectory suggest that 70,000 years ago this cosmic infiltrator passed within 0.8 light years of the Sun. By comparison, Proxima Centauri is 4.2 light years away.

Close encounter

In the paper, astronomers led by Eric Mamajek at the University of Rochester, New York, say they are 98% certain that Scholz's star travelled through what is known as the "outer Oort Cloud" - a region at the edge of the Solar System filled with trillions of comets a mile or more across.

This region is like a spherical shell around the Solar System and may extend out to as much as 100,000 Astronomical Units, or AU (one AU is the distance between the Earth and the Sun).

The Oort Cloud is thought to give rise to long-period comets that can swing past the Sun when their orbits are disturbed.

To determine the trajectory of the star, the researchers needed two pieces of information: the change in distance from the Sun to the star (its radial velocity) and the star's motion across the sky (its tangential velocity).

Scholz's star currently lies 20 light years away - making it a fairly nearby system. But it showed very slow tangential motion for a star this close. This indicated that it was either moving away from us or towards a future close encounter with the Solar System.

The radial velocity measurements confirmed that the binary star system was actually speeding away from us. By tracing its movements back in time, they found its close shave with the Sun occurred some 70,000 years ago.

Grand theft Oort-o?

A star passing through the Oort Cloud could potentially play gravitational havoc with the orbits of comets there, sending them on trajectories into the inner Solar System. But Dr Mamajek believes the effects of Scholz's star on our cosmic neighbourhood were "negligible".

"There are trillions of comets in the Oort cloud and likely some of them were perturbed by this object," he told BBC News.

"But so far it seems unlikely that this star actually triggered a significant 'comet shower'."

The effect of a passing star on the Oort Cloud is a function of the star's mass, speed and proximity. The worst case scenario for stirring up comets would be a slow-moving, massive star that came close to the Sun.

Scholz's star came relatively close, but the binary system (the red dwarf and its brown dwarf companion) has a low mass and it was speeding by. These factors conspired to make its effect on the Oort Cloud very small.

While this is the closest flyby detected so far, Dr Mamajek thinks it's not uncommon for alien stars to buzz the Sun. He says a star probably passes through the Oort Cloud every 100,000 years, or so.

But he suggests an approach as close - or closer - than that made by Scholz's star is somewhat rarer. Dr Mamajek said mathematical simulations show such an event occurs on average about once every nine million years.

"So it is a bit of a strange coincidence that we happen to have caught one that passed so close within the past 100,000 years or so," he said.

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Wednesday, January 7, 2015

Exoplanets

Artist's impression of exoplanet — Artist's impression: Kepler has identified many exoplanets but few are within their star's "Goldilocks zone"

One of eight new planets spied in distant solar systems has usurped the title of "most Earth-like alien world", astronomers have said.

All eight were picked out by Nasa's Kepler space telescope, taking its tally of such "exoplanets" past 1,000.

But only three sit safely within the "habitable zone" of their host star - and one in particular is rocky, like Earth, as well as only slightly warmer.

The find was revealed at a meeting of theAmerican Astronomical Society.

Red sky

The three potentially habitable planets joinKepler's "hall of fame", which now boasts eight fascinating planetary prospects.

And researchers say the most Earth-like of the new arrivals, known as Kepler 438b, is probably even more similar to our home than Kepler 186f - which previously looked to be our most likely twin.

At 12% larger than Earth, the new claimant is bigger than 186f but it is closer to our temperature, probably receiving just 40% more heat from its sun than we do from ours.

So if we could stand on the surface of 438b it may well be warmer than here, according to Dr Doug Caldwell from the Seti (Search for Extra-Terrestrial Intelligence) Institute in California.

"And it's around a cooler [red dwarf] star... so your sky would look redder than ours does to us," Dr Caldwell said.

With the three new arrivals, Kepler's 'hall of fame' expands to eight small, habitable-zone exoplanets

That first-person encounter, however, is unlikely - both because the planet is 475 light-years away and because we still have essentially no idea what it's made of.

Images from the Kepler telescope, which trails behind the Earth and peers far into the distance as we orbit our own sun, are used to identify far-off planets by observing "transits".

This refers to the dimming of a star's light when a planet passes in front of it.

A large team of researchers then uses additional data from Earth-bound telescopes to further explore these unfamiliar solar systems.

They try to calculate how big the planets are, and how closely they orbit their host stars.

Not everything that causes such a dimming eventually turns out to be a planet, however.

At the same time as the eight confirmed new exoplanets were announced by a 26-strong team spanning Nasa and multiple US institutions, the Kepler mission's own scientists released another tranche of more than 500 "candidate" planets.

"With further observation, some of these candidates may turn out not to be planets," said Kepler science officer, Fergal Mullally.

"Or as we understand their properties better, they may move around in, or even outside, the habitable zone."

'Star Trek' scenario

Even once scientists have anointed a candidate as a confirmed exoplanet, the question of whether or not it is "Earth-like" is a fraught one, with fuzzy boundaries.

The size of the habitable, or "Goldilocks" zone, where a planet is far enough from its sun to hold water but not so distant that it freezes, depends on how confident scientists want to be with their guess-work.

According to Dr Cardwell, just three of the eight new exoplanets can be confidently placed in that zone - and only two of those are probably rocky like the Earth.

More detailed description is very difficult.

Artist's view of Kepler 186f — An artist's view of Kepler 186f, which experts say has now been pipped as "most Earth-like" known exoplanet

"From the Kepler measurements and the other measurements we made, we don't know if these planets have oceans with fish and continents with trees," Dr Caldwell told BBC News.

"All we know is their size and the energy they're receiving from their star.

"So we can say: Well, they're of a size that they're likely to be rocky, and the energy they're getting is comparable to what the Earth is getting.

"As we fill in these gaps in our solar system that we don't have, we learn more about what it means to be Earth-like, in some sense."

Speaking at a related event at the conference, Prof Debra Fischer from Yale University said she remembered a time before the first exoplanet was discovered, more than two decades ago.

"I remember astronomers before that point being very worried," she said.

"We really had to step back and say: Maybe the Star Trek picture is wrong. That filled me with despair."

Prof Fischer said that sensitive telescopes like Kepler had ushered in an era of "amazing and impressive work".

"We're talking about a planet - and we can only see its star with a powerful telescope.

"And we can draw graphs and sketch its composition and have serious scientific discussions. This is incredible."

Follow Jonathan on Twitter.

Could we one day hook our brains to the internet?

Could we one day hook up our brains to the internet? Rose Eveleth investigates a claim for the ‘first’ online message sent between two minds.

As internet connections become faster and more of the devices we carry help keep us online, it can sometimes feel like we’re on the verge of spontaneous email communication. I send an email, you receive it, open it, and respond – all in a matter of seconds. Regardless of whether you think near-instant communication is a good thing or not, it’s certainly happening. Not long ago we routinely waited days or weeks for a letter – today even waiting hours for a reply can feel like an eternity.

Perhaps the ultimate way to speed up online communication would be to push towards direct brain-to-brain communication over the web. If brains were directly connected, there would be no more need for pesky typing – we could simply think of an idea and send it instantly to a friend, whether they are in the same room or half the world away. We’re not there yet, of course, but a recent study took a first step in that direction, claiming direct brain-to-brain communication over the internet between people thousands of miles from one another.

The work is simply a proof of concept, as Giulio Ruffini, one of the researchers on the project – and CEO of Starlab, based in Barcelona – is quick to explain. The team did not, as some reported, send words or thoughts or emotions from one brain to another. Instead they did something much simpler.

Technology to detect brainwaves can be used to broadcast simple messages (Thinkstock)

Here’s how it worked. One subject – in this case a man in Kerala, India – was fitted with a brain-computer interface that records brainwaves through the scalp. That person was then instructed to imagine they were moving either their hands, or their feet. If he imagined moving his feet, the computer recorded a zero. If he imagined moving his hands, it recorded a one.

This string of zeros and ones was then sent through the internet to a receiver: a man in Strasbourg, France. He was fitted with something called a TMS robot – a robot designed to deliver strong but short electrical pulses to the brain. When the sender thought about moving his hands, the TMS robot zapped the receiver’s brain in a way that made him see light – even though his eyes were closed. The receiver saw no light if the sender thought about moving his feet.

To make the message more meaningful, the researchers came up with a cipher: one string of zeros and ones (or hands and feet) meant “hola” and another meant “ciao”. The receiver – who had also been taught the cipher – could then decode the signal of lights to interpret which word the sender had sent.

Deep concentration

This might sound simple, but at each stage there are complications. The sender has to concentrate extremely hard to focus only on imagining moving their hands or feet. Any other activity in the brain can cloud the signal, and make it hard to pick up the message. In fact, the sender had to be trained in how to do this properly.

(Thinkstock)

The whole process isn’t fast, either. The researchers estimated that from brain to brain the transmission speed was about two bits (a zero and a one) per minute. So to get even a simple message from one brain to another would take a while. But when it happened, and it worked, Ruffini says it was exciting.

“I mean, you can look at this experiment in two ways,” he says. “On the one hand it’s quite technical and a very humble proof of concept. On the other hand, this was the first time it was done, so it was a little bit of a historical moment I suppose, and it was pretty exciting. After all the years thinking about it and finding the means to do it, it felt pretty good.”

Just a stunt?

There is actually some debate over whether the experiment really does represent a first. Last year, a team at Harvardhooked up a man’s brain to a rat’s tail, and he was able to make the tail twitch just by thinking. Also last year, a group at the University of Washington was able to create a brain-to-brain interface in which a sender gained some control over a receiver’s motor cortex, allowing him to send messages that caused the receiver’s hand to subconsciously strike a keyboard. Consequently, one scientist told IEEE Spectrum he thought Ruffini’s work was “pretty much a stunt”, and had “all been shown before”. But Ruffini’s experiment is certainly the first in which a brain-to-brain connection was attempted over such great a distance, and the first time the receiver was consciously interpreting the signal.

(SPL)

And Ruffini has bigger dreams. He wants to transmit feelings, sensations, and complete thoughts between brains. “The technology is very limited right now, but some day can be very powerful,” he says. “Some day we will transcend verbal communications.”

There are advantages to doing so, he says. Receiving another’s thoughts directly into your brain might allow people to more effectively put themselves in someone else’s shoes and understand how they feel, which could make the world a better place. “I think most of the world’s problems stem from the fact that we have different viewpoints and we don’t understand how other people see or feel about the world,” he says, “Being able to actually feel what other people are feeling, it would change a lot.” He even talks about applying the method to animals, to understand their world and feelings.

(SPL)

Before they can send fully formed concepts, the next step for the team is to try to transmit something more complicated than a one or a zero. This might involve stimulating the brain at multiple sites, and moving beyond using the perception of light as the signal. “The way we have encoded information in the brain, it’s distributed, there is not a single place where the word ‘hello’ is stored,” says Ruffini. To transmit language directly, he says, the researchers will have to figure out how to stimulate the networked brain in a new way. And if they want to send sensations, they’ll have to figure out how to stimulate those segments of the brain too. What makes the task even harder is the fact that the researchers want to do this stimulation externally, without invasive – but more precise – brain implants.

Of course, with this kind of power comes danger too. Anything sent over the internet can be hacked and tracked. The ability to send messages directly into a person’s brain is, to some, a terrifying concept. “It can potentially be some day used in a negative way – you could try to take control of [somebody’s] motor system,” says Ruffini. But he points out that researchers are a long way from being able to do anything even remotely so sophisticated.

Still, it remains an intriguing thought that one day, many decades from now, you might be digesting emails, messages or even an article like this one directly into your mind.

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Tuesday, December 2, 2014

Stephen Hawking warns artificial intelligence could end mankind

By Rory Cellan-JonesTechnology correspondent

Prof Stephen Hawking and Rory Cellan-Jones — Prof Hawking joins a growing list of leading thinkers who have cautioned about AI's risks

Prof Stephen Hawking, one of Britain's pre-eminent scientists, has said that efforts to create thinking machines pose a threat to our very existence.

He told the BBC:"The development of full artificial intelligence could spell the end of the human race."

His warning came in response to a question about a revamp of the technology he uses to communicate, which involves a basic form of AI.

But others are less gloomy about AI's prospects.

The theoretical physicist, who has the motor neurone disease amyotrophic lateral sclerosis (ALS), is using a new system developed by Intel to speak.

Machine learning experts from the British company Swiftkey were also involved in its creation. Their technology, already employed as a smartphone keyboard app, learns how the professor thinks and suggests the words he might want to use next.

Prof Hawking says the primitive forms of artificial intelligence developed so far have already proved very useful, but he fears the consequences of creating something that can match or surpass humans.

HAL 2001 — Stanley Kubrick's film 2001 and its murderous computer HAL encapsulate many people's fears of how AI could pose a threat to human life

"It would take off on its own, and re-design itself at an ever increasing rate," he said.

"Humans, who are limited by slow biological evolution, couldn't compete, and would be superseded."

Celverbot — Cleverbot is software that is designed to chat like a human would

But others are less pessimistic.

"I believe we will remain in charge of the technology for a decently long time and the potential of it to solve many of the world problems will be realised," said Rollo Carpenter, creator of Cleverbot.

Cleverbot's software learns from its past conversations, and has gained high scores in the Turing test, fooling a high proportion of people into believing they are talking to a human.

Rise of the robots

Mr Carpenter says we are a long way from having the computing power or developing the algorithms needed to achieve full artificial intelligence, but believes it will come in the next few decades.

"We cannot quite know what will happen if a machine exceeds our own intelligence, so we can't know if we'll be infinitely helped by it, or ignored by it and sidelined, or conceivably destroyed by it," he says.

But he is betting that AI is going to be a positive force.

Prof Hawking is not alone in fearing for the future.

In the short term, there are concerns that clever machines capable of undertaking tasks done by humans until now will swiftly destroy millions of jobs.

In the longer term, the technology entrepreneur Elon Musk has warned that AI is "our biggest existential threat".

Robotic voice

In his BBC interview, Prof Hawking also talks of the benefits and dangers of the internet.

He quotes the director of GCHQ's warning about the net becoming the command centre for terrorists: "More must be done by the internet companies to counter the threat, but the difficulty is to do this without sacrificing freedom and privacy."

He has, however, been an enthusiastic early adopter of all kinds of communication technologies and is looking forward to being able to write much faster with his new system.

But one aspect of his own tech - his computer generated voice - has not changed in the latest update.

Prof Hawking concedes that it's slightly robotic, but insists he didn't want a more natural voice.

"It has become my trademark, and I wouldn't change it for a more natural voice with a British accent," he said.

" I'm told that children who need a computer voice, want one like mine."

Monday, November 3, 2014

Fossil fuels should be phased out by 2100 says IPCC

SCIENCE & ENVIRONMENT

2 November 2014 Last updated at 11:34 ET
Fossil fuels should be phased out by 2100 says IPCC

COMMENTS (1762)

By Matt McGrathEnvironment correspondent, BBC News

The unrestricted use of fossil fuels should be phased out by 2100 if the world is to avoid dangerous climate change, a UN-backed expert panel says. The Intergovernmental Panel on Climate Change says in a stark report that most of the world's electricity can - and must - be produced from low-carbon sources by 2050. If not, the world faces "severe, pervasive and irreversible" damage. The UN said inaction would cost "much more" than taking the necessary action. The IPCC's Synthesis Report was published on Sunday in Copenhagen, after a week of intense debate between scientists and government officials. It is intended to inform politicians engaged in attempts to deliver a new global treaty on climate by the end of 2015. The report says that reducing emissions is crucial if global warming is to be limited to 2C - a target acknowledged in 2009 as the threshold of dangerous climate change. The report suggests renewables will have to grow from their current 30% share to 80% of the power sector by 2050. In the longer term, the report states that fossil fuel power generation without carbon capture and storage (CCS) technology would need to be "phased out almost entirely by 2100".
'Science has spoken'
The Synthesis Report summarises three previous reports from the IPCC, which outlined the causes, the impacts and the potential solutions to climate change. It re-states many familiar positions:
Warming is "unequivocal" and the human influence on climate is clear
The period from 1983 to 2012, it says, was likely the warmest 30 year period of the last 1,400 years
Warming impacts are already being seen around the globe, in the acidification of the oceans, the melting of arctic ice and poorer crop yields in many parts
Without concerted action on carbon, temperatures will increase over the coming decades and could be almost 5C above pre-industrial levels by the end of this century "Science has spoken," UN Secretary-General Ban Ki-moon said. "There is no ambiguity in their message. Leaders must act. Time is not on our side." "There is a myth that climate action will cost heavily," said Mr Ban, "but inaction will cost much more." The US Secretary of State, John Kerry, described the report as "another canary in the coal mine". "Those who choose to ignore or dispute the science so clearly laid out in this report do so at great risk for all of us and for our kids and grandkids," Mr Kerry said in a statement. The Secretary of State for Energy and Climate Change Ed Davey described the report as the "most comprehensive, thorough and robust assessment of climate change ever produced". "It sends a clear message that should be heard across the world - we must act on climate change now. It's now up to the politicians - we must safeguard the world for future generations by striking a new climate deal in Paris next year," he said. "The UK has been leading the world and bringing the world with us. The historic agreement to cut carbon emissions in Europe by at least 40 per cent by 2030 effectively means our Climate Change Act is being replicated across Europe, just as it's being copied in countries across the world as they seek to cap and cut their own emissions."
Blunt language
Prof Myles Allen from Oxford University, a member of the IPCC core writing team, said: "We can't afford to burn all the fossil fuels we have without dealing with the waste product which is CO2 and without dumping it in the atmosphere." "If we can't develop carbon capture we will have to stop using fossil fuels if we want to stop dangerous climate change."
Analysis: David Shukman, BBC science editor
The language in the UN's climate reports has been steadily ratcheted up over the years, but this publication lays out the options more bluntly than before. The conclusion that fossil fuels cannot continue to be burned in the usual way - and must be phased out by the end of the century - presents governments with an unusually stark choice. The IPCC has tried to make it more palatable by saying that fossil fuel use can continue if the carbon emissions are captured and stored. But so far the world only has one commercially-operating plant of that type, in Canada, and progress developing the technology is far slower than many had hoped. So this raises the difficult question of how key governments are likely to respond. Events in Copenhagen back in 2009, when a disastrous and dysfunctional summit failed to agree anything substantial, showed how easily rhetoric crumbles in the face of economic pressures or domestic realities. The report's clarity of language over the future of coal, oil, and gas was welcomed by campaigners. "What they have said is that we must get to zero emissions, and that's new," said Samantha Smith from World Wildlife Fund. "The second thing is they said that it is affordable, it is not going to cripple economies."
Fierce standoff
In the IPCC's discussions on fossil fuels, there was a fierce battle over a chart that showed how much the electricity sector needed to curb its carbon, the BBC's environment correspondent Matt McGrath reports from Copenhagen. According to one observer, "the Saudis went ballistic" over the chart's inclusion. Another significant fight was over the inclusion of text about Article 2 of the UN Framework Convention on Climate Change. It quickly became a standoff between those who want the focus to be on cutting emissions against those who think the right to develop economies must come first. An unlikely alliance between Bolivia and Saudi Arabia ultimately saw the section dropped entirely from the underlying report. Some of those attending the talks said that tackling climate change and sustainable development went hand in hand. "Different countries come to different perspectives" said Prof Jim Skea from Imperial College and a review editor of the report.
"But from the science perspective, we need them both. We need to walk and chew gum at the same time."

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lunar crater architecture

Friday, February 20, 2015