Saturday, June 24, 2017

Stephen Hawking's new ship could reach the "second Earth" in the next 20 years

Stephen Hawking says humanity must find a new home Max Alexander/Starmus

The renowned physicist Stephen Hawking is working on a spacecraft that can travel at a fifth of the speed of light – meaning it could reach the nearest star and send back images of a suspected ‘Second Earth’ within 25 years – in a bid to save humanity.

In a speech at the Starmus Festival, Professor Hawking warned humans must soon colonise another planet if we are to survive.

One explanation for why Earth has not been contacted by an advanced civilisations from another part of the Universe is that every time ‘intelligent’ life evolves it annihilates itself with “war, disease and weapons of mass destruction”, he said.

And in addition to the chance that we will meet this fate, Professor Hawking said the planet had become too small for our burgeoning population with its “physical resources … being drained at an alarming rate”. Climate change, an asteroid strike or some other kind of cataclysmic cosmic event also pose significant threats.

The proposed spacecraft, called a Star Chip, would be just a few centimetres in size with a lightsail weighing a few grams. It would be powered by an array of lasers based on Earth that would drive the tiny probe “on a beam of light” at about 100 million miles an hour, a fifth of light speed.

Credit: duluthnewstribune

“Such a system could reach Mars in less than an hour, reach Pluto in days, pass Voyager [the space probe launched in 1977] in under a week, and reach Alpha Centauri in just over 20 years,” Professor Hawking said.

“Once there, the nano craft could image any planets discovered in the system, test for magnetic fields and organic molecules, and send the data back to Earth in another laser beam. 

“This tiny signal would be received by the same array of dishes that were used to transit the launch beam, and return is estimated to take about four light years.


“Importantly, the Star Chips’ trajectories may include a fly-by of Proxima b, the Earth-sized planet that is in the habitable zone of … Alpha Centauri.”

And he admitted: “Of course, this would not be human interstellar travel, even if it could be scaled up to a crewed vessel. It would be unable to stop. 

“But it would be the moment when human culture goes interstellar, when we finally reach out into the galaxy. And if Breakthrough Star Shot should send back images of a habitable planet orbiting our closest neighbour, it could be of immense importance to the future of humanity.”

Because it is travelling so fast any pictures taken by a camera on the Space Chip would be “slightly distorted” due to the effects of special relativity, as first described by Albert Einstein. This would be the first time anything has travelled fast enough to see such effects.

And extolling the virtues of the human attribution – “out most powerful attribute” – he said: “With this, we can roam anywhere in space and time. And I do. 

“We can witness nature’s most exotic phenomena while in a car, snoozing in bed, or pretending to listen to someone boring at a party. And I do.”

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The above post is reprinted from materials provided by Independent . Note: Materials may be edited for content and length.

Sunday, June 18, 2017

Another step in understanding the mysteries of the brain. The Human Brain Can Create Structures in Up to 11 Dimensions

Neuroscientists have used a classic branch of maths in a totally new way to peer into the structure of our brains. What they've discovered is that the brain is full of multi-dimensional geometrical structures operating in as many as 11 dimensions.

We're used to thinking of the world from a 3-D perspective, so this may sound a bit tricky, but the results of this new study could be the next major step in understanding the fabric of the human brain - the most complex structure we know of.
This latest brain model was produced by a team of researchers from the Blue Brain Project, a Swiss research initiative devoted to building a supercomputer-powered reconstruction of the human brain.

The team used algebraic topology, a branch of mathematics used to describe the properties of objects and spaces regardless of how they change shape. They found that groups of neurons connect into 'cliques', and that the number of neurons in a clique would lead to its size as a high-dimensional geometric object.

"We found a world that we had never imagined," says lead researcher, neuroscientist Henry Markram from the EPFL institute in Switzerland.

"There are tens of millions of these objects even in a small speck of the brain, up through seven dimensions. In some networks, we even found structures with up to 11 dimensions."

Just to be clear - this isn't how you'd think of spatial dimensions (our Universe has three spatial dimensions plus one time dimension), instead it refers to how the researchers have looked at the neuron cliques to determine how connected they are.

"Networks are often analysed in terms of groups of nodes that are all-to-all connected, known as cliques. The number of neurons in a clique determines its size, or more formally, its dimension," the researchers explain in the paper.

Human brains are estimated to have a staggering 86 billion neurons, with multiple connections from each cell webbing in every possible direction, forming the vast cellular network that somehow makes us capable of thought and consciousness.

With such a huge number of connections to work with, it's no wonder we still don't have a thorough understanding of how the brain's neural network operates. But the new mathematical framework built by the team takes us one step closer to one day having a digital brain model.

To perform the mathematical tests, the team used a detailed model of the neocortex the Blue Brain Project team published back in 2015. The neocortex is thought to be the most recently evolved part of our brains, and the one involved in some of our higher-order functions like cognition and sensory perception.

After developing their mathematical framework and testing it on some virtual stimuli, the team also confirmed their results on real brain tissue in rats.

According to the researchers, algebraic topology provides mathematical tools for discerning details of the neural network both in a close-up view at the level of individual neurons, and a grander scale of the brain structure as a whole.

By connecting these two levels, the researchers could discern high-dimensional geometric structures in the brain, formed by collections of tightly connected neurons (cliques) and the empty spaces (cavities) between them.


"We found a remarkably high number and variety of high-dimensional directed cliques and cavities, which had not been seen before in neural networks, either biological or artificial," the team writes in the study.

"Algebraic topology is like a telescope and microscope at the same time," says one of the team, mathematician Kathryn Hess from EPFL.

"It can zoom into networks to find hidden structures, the trees in the forest, and see the empty spaces, the clearings, all at the same time."

Those clearings or cavities seem to be critically important for brain function. When researchers gave their virtual brain tissue a stimulus, they saw that neurons were reacting to it in a highly organised manner.

"It is as if the brain reacts to a stimulus by building [and] then razing a tower of multi-dimensional blocks, starting with rods (1D), then planks (2D), then cubes (3D), and then more complex geometries with 4D, 5D, etc," says one of the team, mathematician Ran Levi from Aberdeen University in Scotland.

"The progression of activity through the brain resembles a multi-dimensional sandcastle that materialises out of the sand and then disintegrates."

These findings provide a tantalising new picture of how the brain processes information, but the researchers point out that it's not yet clear what makes the cliques and cavities form in their highly specific ways.

And more work will be needed to determine how the complexity of these multi-dimensional geometric shapes formed by our neurons correlates with the complexity of various cognitive tasks.

But this is definitely not the last we'll be hearing of insights that algebraic topology can give us on this most mysterious of human organs - the brain.

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The above post is reprinted from materials provided by Sciencealert . Note: Materials may be edited for content and length.

Friday, April 28, 2017

Astronomers have discovered a new planet named LHS 1140b with the greatest chances of sustaining life. '' It's the most exciting planet ''

This artist's impression shows the exoplanet LHS 1140b, which orbits a red dwarf star 40 light-years from Earth and may be the new holder of the title 'best place to look for signs of life beyond the Solar System'. Using ESO's HARPS instrument at La Silla, and other telescopes around the world, an international team of astronomers discovered this super-Earth orbiting in the habitable zone around the faint star LHS 1140. This world is a little larger and much more massive than the Earth and has likely retained most of its atmosphere. Credit: ESO/spaceengine.org
An exoplanet orbiting a red dwarf star 40 light-years from Earth may be the new holder of the title 'best place to look for signs of life beyond the solar system.' Using ESO's HARPS instrument, and other telescopes, astronomers discovered a 'super-Earth' orbiting in the habitable zone around the star LHS 1140. This world is larger and more massive than the Earth and has likely retained most of its atmosphere. This makes it one of the most exciting targets for atmospheric studies.

The newly discovered super-Earth LHS 1140b orbits in the habitable zone around a faint red dwarf star named LHS 1140, in the constellation of Cetus (The Sea Monster). Red dwarfs are much smaller and cooler than the Sun and, although LHS 1140b is ten times closer to its star than the Earth is to the Sun, it only receives about half as much sunlight from its star as the Earth and lies in the middle of the habitable zone. The orbit is seen almost edge-on from Earth and as the exoplanet passes in front of the star once per orbit it blocks a little of its light every 25 days.

"This is the most exciting exoplanet I've seen in the past decade," said lead author Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics (Cambridge, USA). "We could hardly hope for a better target to perform one of the biggest quests in science -- searching for evidence of life beyond Earth."

"The present conditions of the red dwarf are particularly favourable -- LHS 1140 spins more slowly and emits less high-energy radiation than other similar low-mass stars," explains team member Nicola Astudillo-Defru from Geneva Observatory, Switzerland.

For life as we know it to exist, a planet must have liquid surface water and retain an atmosphere. When red dwarf stars are young, they are known to emit radiation that can be damaging for the atmospheres of the planets that orbit them. In this case, the planet's large size means that a magma ocean could have existed on its surface for millions of years. This seething ocean of lava could feed steam into the atmosphere long after the star has calmed to its current, steady glow, replenishing the planet with water.

The discovery was initially made with the MEarth facility, which detected the first telltale, characteristic dips in light as the exoplanet passed in front of the star. ESO's HARPS instrument, the High Accuracy Radial velocity Planet Searcher, then made crucial follow-up observations which confirmed the presence of the super-Earth. HARPS also helped pin down the orbital period and allowed the exoplanet's mass and density to be deduced .

The astronomers estimate the age of the planet to be at least five billion years. They also deduced that it has a diameter 1.4 times larger than the Earth -- almost 18,000 kilometres. But with a mass around seven times greater than the Earth, and hence a much higher density, it implies that the exoplanet is probably made of rock with a dense iron core.

This super-Earth may be the best candidate yet for future observations to study and characterise its atmosphere, if one exists. Two of the European members of the team, Xavier Delfosse and Xavier Bonfils both at the CNRS and IPAG in Grenoble, France, conclude: "The LHS 1140 system might prove to be an even more important target for the future characterisation of planets in the habitable zone than Proxima b or TRAPPIST-1. This has been a remarkable year for exoplanet discoveries!" [4,5].

In particular, observations coming up soon with the NASA/ESA Hubble Space Telescope will be able to assess exactly how much high-energy radiation is showered upon LHS 1140b, so that its capacity to support life can be further constrained.

Further into the future -- when new telescopes like ESO's Extremely Large Telescope are operating -- it is likely that we will be able to make detailed observations of the atmospheres of exoplanets, and LHS 1140b is an exceptional candidate for such studies.

Notes

[1] The habitable zone is defined by the range of orbits around a star, for which a planet possesses the appropriate temperature needed for liquid water to exist on the planet's surface.

[2] Although the planet is located in the zone in which life as we know it could potentially exist, it probably did not enter this region until approximately forty million years after the formation of the red dwarf star. During this phase, the exoplanet would have been subjected to the active and volatile past of its host star. A young red dwarf can easily strip away the water from the atmosphere of a planet forming within its vicinity, leading to a runaway similar to that on Venus.

[3] This effort enabled other transit events to be detected by MEarth so that the astronomers could nail down the detection of the exoplanet once and for all.

[4] The planet around Proxima Centauri is much closer to Earth, but it probably does not transit its star, making it very difficult to determine whether it holds an atmosphere.

[5] Unlike the TRAPPIST-1 system, no other exoplanets around LHS 1140 have been found. Multi-planet systems are thought to be common around red dwarfs, so it is possible that additional exoplanets have gone undetected so far because they are too small.


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The above post is reprinted from materials provided by Sciencedaily . Note: Materials may be edited for content and length.

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Finally due to space,science and exploration throughout the Universe we got everyone to agree with the fact that we are not the only planet with life.  My blog is full of interesting articles about Creation of the Universe with all his laws,  NASA's Missions,  History,   Science,  Physics, Health, Nature, Ancient origins and Culture.