Exoplanets

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.

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."

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• 'Most Earth-like planet yet' spotted by Kepler

  17 April 2014
• Kepler telescope bags huge haul of planets

Could we one day hook our brains to the internet?

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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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