Tag: atom (page 1 of 4)

The Science of the Dogon

May 19, 2015 / / 0 Comments

Excerpt from The Science of The Dogon, by Laird ScrantonThe information presented in the preceding chapters demonstrates a direct relationship between the symbols and themes of the Dogon creation story and known scientific facts relating to the formation of the universe, matter, and biological reproduction. This relationship is a broad and specific one that is couched in clear definitions and supported by priestly interpretations and cosmological drawings. The parallels between Dogon myth [...]

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Consciousness Does Not Compute (and Never Will), Says Korean Scientist

May 9, 2015 / / 0 Comments

Daegene Song's research into strong AI could be key to answering fundamental brain science questions Excerpt from prnewswire.com Within some circles in the scientific community, debate rages about whether computers will achieve technological singulari...

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Black Holes, the Large Hadron Collider, & Finding Parallel Universes

March 27, 2015 / / 0 Comments

Excerpt from huffingtonpost.comI am a huge science enthusiast and an unabashed science fiction fan. There are tons of really cool stories out there that fire the imagination and even inspire young people to go into science. (I know they did me.) ...

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How Quantum Physics will change your life and amaze the world!

March 20, 2015 / / 0 Comments

 Excerpt from educatinghumanity.com "Anyone not shocked by quantum mechanics has not yet understood it."Niels Bohr10 Ways Quantum Physics Will Change the WorldEver want to have a "life do over", teleport, time travel, have your computer wor...

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Ancient ‘Blue’ Mars Lost an Entire Ocean to Space

March 7, 2015 / / 0 Comments


Artist impression of Mars ocean

Excerpt from news.discovery.com

Mars was once a small, wet and blue world, but over the past 4 billion years, Mars dried up and became the red dust bowl we know today.

But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.

“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”

Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.

It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.

This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 meters deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere. 
The water in Earth’s oceans contains molecules of H2O, the familiar oxygen atom bound with 2 hydrogen atoms, and, in smaller quantities, the not-so-familiar HDO molecule. HDO is a type of water molecule that contains 1 hydrogen atom, 1 oxygen atom and 1 deuterium atom. The deuterium atom is an isotope of hydrogen; whereas hydrogen consists of 1 proton and an electron, deuterium consists of 1 proton, 1 neutron and 1 electron. Therefore, due to the extra neutron the deuterium contains, HDO molecules are slightly heavier than the regular H2O molecules.

Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.

By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.

Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.

Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.

Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.

“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.

This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.

Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO

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Mars Had an Ocean, Scientists Say, Pointing to a Treasure Trove of New Data

March 5, 2015 / / 0 Comments





Excerpt from nytimes.com

After six years of planetary observations, scientists at NASA say they have found convincing new evidence that ancient Mars had an ocean.

It was probably the size of the Arctic Ocean, larger than previously estimated, the researchers reported on Thursday. The body of water spread across the low-lying plain of the planet’s northern hemisphere for millions of years, they said.

If confirmed, the findings would add significantly to scientists’ understanding of the planet’s history and lend new weight to the view that ancient Mars had everything needed for life to emerge.
“The existence of a northern ocean has been debated for decades, but this is the first time we have such a strong collection of data from around the globe,” said Michael Mumma, principal investigator at NASA’s Goddard Center for Astrobiology and an author of the report, published in the journal Science. “Our results tell us there had to be a northern ocean.”
But other experts said the question was hardly resolved. The ocean remains “a hypothesis,” said Ashwin Vasavada, project scientist of the Curiosity rover mission at the Jet Propulsion Laboratory in Pasadena, Calif.

Dr. Mumma and Geronimo Villanueva, a planetary scientist at NASA, measured two slightly different forms of water in Mars’ atmosphere. One is the familiar H2O, which consists of two hydrogen atoms and one oxygen atom.

The other is a slightly “heavier” version of water, HDO, in which the nucleus of one hydrogen atom contains a neutron. The atom is called deuterium.

The two forms exist in predictable ratios on Earth, and both have been found in meteorites from Mars. A high level of heavier water today would indicate that there was once a lot more of the “lighter” water, somehow lost as the planet changed.

The scientists found eight times as much deuterium in the Martian atmosphere than is found in water on Earth. Dr. Villanueva said the findings “provide a solid estimate of how much water Mars once had by determining how much water was lost to space.”

He said the measurements pointed to an ancient Mars that had enough water to cover the planet to a depth of at least 137 meters, or about 450 feet. Except for assessments based on the size of the northern basin, this is the highest estimate of the amount of water on early Mars that scientists have ever made.

The water on Mars mostly would have pooled in the northern hemisphere, which lies one to three kilometers — 0.6 to 1.8 miles — below the bedrock surface of the south, the scientists said.
At one time, the researchers estimated, a northern ocean would have covered about 19 percent of the Martian surface. In comparison, the Atlantic Ocean covers about 17 percent of Earth’s surface.

The new findings come at a time when the possibility of a northern ocean on Mars has gained renewed attention.

The Curiosity rover measured lighter and heavier water molecules in the Gale Crater, and the data also indicated that Mars once had substantial amounts of water, although not as much as Dr. Mumma and Dr. Villanueva suggest.

“The more water was present — and especially if it was a large body of water that lasted for a longer period of time — the better the chances are for life to emerge and to be sustained,” said Paul Mahaffy, chief of the atmospheric experiments laboratory at the Goddard Space Flight Center.

Just last month, the science team running the Curiosity rover held its first formal discussion about the possibility of such an ocean and what it would have meant for the rest of Mars.

Scientists generally agree that lakes must have existed for millions of years in Gale Crater and elsewhere. But it is not clear how they were sustained and replenished.

“For open lakes to remain relatively stable for millions of years — it’s hard to figure how to do that without an ocean,” Dr. Vasavada said. “Unless there was a large body of water supplying humidity to the planet, the water in an open lake would quickly evaporate and be carried to the polar caps or frozen out.”

Yet climate modelers have had difficulty understanding how Mars could have been warm enough in its early days to keep water from freezing. Greenhouse gases could have made the planet much warmer at some point, but byproducts of those gases have yet to be found on the surface.

James Head, a professor of geological sciences at Brown University, said in an email that the new paper had “profound implications for the total volume of water” on ancient Mars.

But, he added, “climate models have great difficulty in reconstructing an early Mars with temperatures high enough to permit surface melting and liquid water.”

Also missing are clear signs of the topographic and geological features associated with large bodies of water on Earth, such as sea cliffs and shorelines.

Based on low-resolution images sent back by the Viking landers, the geologist Timothy Parker and his colleagues at the NASA Jet Propulsion Lab reported in 1989 the discovery of ancient shorelines. But later high-resolution images undermined their conclusions.

Still, Dr. Parker and his colleagues have kept looking for — and finding, they say — some visible signs of a northern ocean. The new data “certainly encourages me to do more,” he said in an interview.

Other researchers have also been looking for signs of an ancient ocean.

In 2013, Roman DiBiase, then a postdoctoral student at the California Institute of Technology, and Michael Lamb, an assistant professor of geology there, identified what might have been a system of channels on Mars that originated in the southern hemisphere and emptied steeply into the northern basin — perhaps, they said, water flowing through a delta to an ocean.

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Stephen Hawking warns that attempting to contact aliens could invite disaster

February 13, 2015 / / 0 Comments

Excerpt from cambridge-news.co.ukWhat is known as Active Seti will be under serious discussion this week at the annual meeting of the American Association for the Advancement of Science (AAAS) in San Jose, California. Seti spokesman Dr Seth...

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Every Black Hole Contains a New Universe

February 11, 2015 / / 0 Comments


At the center of spiral galaxy M81 is a supermassive black hole about 70 million times more massive than our sun.



Excerpt from insidescience.org
A physicist presents a solution to present-day cosmic mysteries.



By: 
Nikodem Poplawski, Inside Science Minds Guest Columnist


(ISM) -- Our universe may exist inside a black hole. This may sound strange, but it could actually be the best explanation of how the universe began, and what we observe today. It's a theory that has been explored over the past few decades by a small group of physicists including myself. 
Successful as it is, there are notable unsolved questions with the standard big bang theory, which suggests that the universe began as a seemingly impossible "singularity," an infinitely small point containing an infinitely high concentration of matter, expanding in size to what we observe today. The theory of inflation, a super-fast expansion of space proposed in recent decades, fills in many important details, such as why slight lumps in the concentration of matter in the early universe coalesced into large celestial bodies such as galaxies and clusters of galaxies.
But these theories leave major questions unresolved. For example: What started the big bang? What caused inflation to end? What is the source of the mysterious dark energy that is apparently causing the universe to speed up its expansion?
The idea that our universe is entirely contained within a black hole provides answers to these problems and many more. It eliminates the notion of physically impossible singularities in our universe. And it draws upon two central theories in physics.
Nikodem Poplawski displays a "tornado in a tube." The top bottle symbolizes a black hole, the connected necks represent a wormhole and the lower bottle symbolizes the growing universe on the just-formed other side of the wormhole. Credit: Indiana University
In this picture, spins in particles interact with spacetime and endow it with a property called "torsion." To understand torsion, imagine spacetime not as a two-dimensional canvas, but as a flexible, one-dimensional rod. Bending the rod corresponds to curving spacetime, and twisting the rod corresponds to spacetime torsion. If a rod is thin, you can bend it, but it's hard to see if it's twisted or not.

The first is general relativity, the modern theory of gravity. It describes the universe at the largest scales. Any event in the universe occurs as a point in space and time, or spacetime. A massive object such as the Sun distorts or "curves" spacetime, like a bowling ball sitting on a canvas. The Sun's gravitational dent alters the motion of Earth and the other planets orbiting it. The sun's pull of the planets appears to us as the force of gravity.

The second is quantum mechanics, which describes the universe at the smallest scales, such as the level of the atom. However, quantum mechanics and general relativity are currently separate theories; physicists have been striving to combine the two successfully into a single theory of "quantum gravity" to adequately describe important phenomena, including the behavior of subatomic particles in black holes.
A 1960s adaptation of general relativity, called the Einstein-Cartan-Sciama-Kibble theory of gravity, takes into account effects from quantum mechanics. It not only provides a step towards quantum gravity but also leads to an alternative picture of the universe. This variation of general relativity incorporates an important quantum property known as spin. Particles such as atoms and electrons possess spin, or the internal angular momentum that is analogous to a skater spinning on ice.

Spacetime torsion would only be significant, let alone noticeable, in the early universe or in black holes. In these extreme environments, spacetime torsion would manifest itself as a repulsive force that counters the attractive gravitational force coming from spacetime curvature. As in the standard version of general relativity, very massive stars end up collapsing into black holes: regions of space from which nothing, not even light, can escape.
Here is how torsion would play out in the beginning moments of our universe. Initially, the gravitational attraction from curved space would overcome torsion's repulsive forces, serving to collapse matter into smaller regions of space. But eventually torsion would become very strong and prevent matter from compressing into a point of infinite density; matter would reach a state of extremely large but finite density. As energy can be converted into mass, the immensely high gravitational energy in this extremely dense state would cause an intense production of particles, greatly increasing the mass inside the black hole.
The increasing numbers of particles with spin would result in higher levels of spacetime torsion. The repulsive torsion would stop the collapse and would create a "big bounce" like a compressed beach ball that snaps outward. The rapid recoil after such a big bounce could be what has led to our expanding universe. The result of this recoil matches observations of the universe's shape, geometry, and distribution of mass.
In turn, the torsion mechanism suggests an astonishing scenario: every black hole would produce a new, baby universe inside. If that is true, then the first matter in our universe came from somewhere else. So our own universe could be the interior of a black hole existing in another universe. Just as we cannot see what is going on inside black holes in the cosmos, any observers in the parent universe could not see what is going on in ours.
The motion of matter through the black hole's boundary, called an "event horizon," would only happen in one direction, providing a direction of time that we perceive as moving forward. The arrow of time in our universe would therefore be inherited, through torsion, from the parent universe.
Torsion could also explain the observed imbalance between matter and antimatter in the universe. Because of torsion, matter would decay into familiar electrons and quarks, and antimatter would decay into "dark matter," a mysterious invisible form of matter that appears to account for a majority of matter in the universe.
Finally, torsion could be the source of "dark energy," a mysterious form of energy that permeates all of space and increases the rate of expansion of the universe. Geometry with torsion naturally produces a "cosmological constant," a sort of added-on outward force which is the simplest way to explain dark energy. Thus, the observed accelerating expansion of the universe may end up being the strongest evidence for torsion.
Torsion therefore provides a theoretical foundation for a scenario in which the interior of every black hole becomes a new universe. It also appears as a remedy to several major problems of current theory of gravity and cosmology. Physicists still need to combine the Einstein-Cartan-Sciama-Kibble theory fully with quantum mechanics into a quantum theory of gravity. While resolving some major questions, it raises new ones of its own. For example, what do we know about the parent universe and the black hole inside which our own universe resides? How many layers of parent universes would we have? How can we test that our universe lives in a black hole?
The last question can potentially be investigated: since all stars and thus black holes rotate, our universe would have inherited the parent black hole’s axis of rotation as a "preferred direction." There is some recently reported evidence from surveys of over 15,000 galaxies that in one hemisphere of the universe more spiral galaxies are "left-handed", or rotating clockwise, while in the other hemisphere more are "right-handed", or rotating counterclockwise. In any case, I believe that including torsion in geometry of spacetime is a right step towards a successful theory of cosmology.

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6 Supermaterials That Could Change Our World

February 3, 2015 / / 0 Comments


Graphene

Excerpt from gizmodo.com

Graphene isn't the only game-changing material to come out of a lab. From aerogels nearly as light as air to metamaterials that manipulate light, here are six supermaterials that have the potential to transform the world of the future.

Self-healing Materials — Bioinspired Plastics

6 Supermaterials That Could Change Our World 
Self-healing plastic. Image credit: UIUC


The human body is very good at fixing itself. The built environment is not. Scott White at the University of Illinois at Urbana Champlain has been engineering bioinspired plastics that can self-heal. Last year, White's lab created a new polymer that oozes to repair a visible hole. The polymer is embedded with a vascular system of liquids that when broken and combined, clot just like blood. While other materials have been able to heal microscopic cracks, this new one repaired a hole 4 millimeter wide with cracks radiating all around it. Not big deal for a human skin, but a pretty big deal for plastic.

Engineers have also been envisioning concrete, asphalt, and metal that can heal themselves. (Imagine a city with no more potholes!) The rub, of course, lies in making them cheap enough to actually use, which is why the first applications for self-healing materials are most likely to be in space or in remote areas on Earth. 

Thermoelectric Materials — Heat Scavengers

6 Supermaterials That Could Change Our World 
Power blocks with thermoelectric material sued inside Alphabet Energy 's generator. Image credit: Alphabet Energy


If you've ever had a laptop burn up in your lap or touched the hot hood of car, then you've felt evidence of waste. Waste heat is the inevitable effect of running any that device that uses power. One estimate puts the amount of waste heat as two-thirds of all energy used. But what if there was a way to capture all that wasted energy? The answer to that "what if" is thermoelectric materials, which makes electricity from a temperature gradient.

Last year, California-based Alphabet Energy introduced a thermoelectric generator that plugs right into the exhaust pipe of ordinary generator, turning waste heat back into useful electricity. Alphabet Energy's generator uses a relatively cheap and naturally occurring thermoelectric material called tetrahedrite. Alphabet Energy says tetrahedrite can reach 5 to 10 percent efficiency.
Back in the lab, scientists have also been tinkering with another promising and possibly even more efficient thermoelectric material called skutterudite, which is a type of mineral that contains cobalt. Thermoelectric materials have already had niche applications—like on spacecraft—but skutterudite could get cheap and efficient enough to be wrapped around the exhaust pipes of cars or fridges or any other power-hogging machine you can think of. [Nature, MIT Technology Review, New Scientist]

Perovskites — Cheap Solar Cells

6 Supermaterials That Could Change Our World 
Solar cells made of perovskites. Image credit: University of Oxford


The biggest hurdle in moving toward renewable energy is, as these things always are, money. Solar power is getting ever cheaper, but making a plant's worth of solar cells from crystalline silicon is still an expensive, energy-intensive process. There's an alternative material that has the solar world buzzing though, and that's perovskites. 

Perovskites were first discovered over a century ago, but scientists are only just realizing its potential. In 2009, solar cells made from perovskites had a solar energy conversion efficiency of a measly 3.8 percent. In 2014, the number had leapt to 19.3 percent. That may not seem like much compared to traditional crystalline silicon cells with efficiencies hovering around 20 percent, but there's two other crucial points to consider: 1) perovskites have made such leaps and bounds in efficiency in just a few years that scientist think it can get even better and 2) perovskites are much, much cheaper. 

Perovskites are a class of materials defined by a particular crystalline structure. They can contain any number of elements, usually lead and tin for perovskites used in solar cells. These raw materials are cheap compared to crystalline silicon, and they can be sprayed onto glass rather than meticulously assembled in clean rooms. Oxford Photovoltaics is one of the leading companies trying to commercialize perovskites, which as wonderful as they have been in the lab, still do need to hold up in the real world. [WSJ, IEEE Spectrum, Chemical & Engineering News, Nature Materials]

Aerogels — Superlight and Strong

6 Supermaterials That Could Change Our World 
Image credit: NASA

Aerogels look like they should not be real. Although ghostly and ethereal, they can easily withstand the heat of a blowtorch and the weight of a car. The material is almost what exactly the name implies: gels where where the liquid has been replaced entirely by air. But you can see why it's also been called "frozen smoke" or "blue smoke." The actual matrix of an aerogel can be made of any number of substances, including silica, metal oxides, and, yes, also graphene. But the fact that aerogel is actually mostly made of air means that it's an excellent insulator (see: blowtorch). Its structure also makes it incredibly strong (see: car).

Aerogels do have one fatal flaw though: brittleness, especially when made from silica. But NASA scientists have been experimenting with flexible aerogels made of polymers to use insulators for spacecraft burning through the atmosphere. Mixing other compounds into even silica-based aerogels could make them more flexible. Add that to aerogel's lightness, strength, and insulating qualities, and that's one incredible material. [New Scientist, Gizmodo]

Metamaterials — Light Manipulators

If you've heard of metamaterials, you likely heard about it in a sentence that also mentioned "Harry Potter" and "invisibility cloak." And indeed, metamaterials, whose nanostructures are design to scatter light in specific ways, could possibly one day be used to render objects invisible—though it still probably wouldn't be as magical as Harry Potter's invisibility cloak. 

What's more interesting about metamaterials is that they don't just redirect visible light. Depending on how and what a particular metamaterial is made of, it can also scatter microwaves, radiowaves, or the little-known T-rays, which are between microwaves and infrared light on the electromagnetic spectrum. Any piece of electromagnetic spectrum could be manipulated by metamaterials. 

That could be, for example, new T-ray scanners in medicine or security or a compact radio antennae made of metamaterials whose properties change on the fly. Metamaterials are at the promising but frustrating cusp where the theoretical possibilities are endless, but commercialization is still a long, hard road. [Nature, Discover Magazine]

Stanene — 100 percent efficient conductor

6 Supermaterials That Could Change Our World 
The molecular structure of stanene. Image credit: SLAC


Like the much better known graphene, stanene is also made of a single layer of atoms. But instead of carbon, stanene is made of tin, and this makes all the difference in allowing stanene to possibly do what even wondermaterial extraordinaire graphene cannot: conduct electricity with 100 percent efficiency.

Stanene was first theorized in 2013 by Stanford professor Shoucheng Zhang, whose lab specializes in, along other things, predicting the electronic properties of materials like stanene. According to their models, stanene is a topological insulator, which means its edges are a conductor and its inside is an insulator. (Think of a chocolate-covered ice cream bar. Chocolate conductor, ice cream insulator.) 

This means stanene could conduct electricity with zero resistance even, crucially, at room temperature. Stanene's properties have yet to been tested experimentally—making a single-atom sheet tin is no easy task—but several of Zhang's predictions about other topological insulators have proven correct.

If the predictions about stanene bear out, it could revolutionize the microchips inside all your devices. Namely, the chips could get a lot more powerful. Silicon chips are limited by the heat created by electrons zipping around—work 'em too fast and they'll simply get too hot. Stanene, which conducts electricity 100 percent efficiency, would have no such problem. [SLAC, Physical Review Letters, Scientific American]

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Where does water actually come from? Comet evidence opening floodgates of mystery

December 11, 2014 / / 0 Comments





Excerpt from slate.com

WE CALL Earth a water world, and that’s pretty fair: Our planet’s surface is 70 per cent covered in it, it makes up a percentage of our air, and there’s even a substantial amount of it mixed in to the planet’s mantle, deep underground. 

But where the heck did it come from?

This is no idle question. We have a lot of water here, and it must have come from somewhere. There are two obvious source — it formed here along with the Earth, or it was brought to Earth from space. Which is the dominant source has been a topic of long and heated debate among astronomers.

The first big science results have just been announced by the European science team working with the Rosetta probe, and, in my opinion, they throw more gasoline on the fire. Measurements made by the probe show that comets like 67P/Churyumov — Gerasimenko — the one Rosetta is orbiting — couldn’t have been the source of our water.

But that hardly helps answer the underlying question! Why not? Ah, the details …

When the Earth formed 4.55 billion years ago (give or take), there was a lot of water in the disk of material swirling around the Sun. Close in to the Sun, where it was warm, that water was a gas, and farther out it formed ice. We see that latter part echoed down through time now in the form of icy moons around the outer planets.

You’d expect water collected on Earth along with everything else (metals, silicates, and so on). When the Earth cooled, a lot of that water bubbled up from the interior or was outgassed by volcanism.

Where does water come from?
Where does water come from? Source: Getty Images
But we have another big source, too: comets. These are dirty snowballs, rock and dust held together by water frozen as ice. They formed farther out in the solar system, where ice was more plentiful. Long ago, just a few hundred million years after Earth formed and started to cool, there was a tremendous flood of comets sent down into the inner solar system, disturbed by the gravitational dance of the outer planets as they slowly settled down into their orbits. This Late Heavy Bombardment, as it’s called, could have supplied all of Earth’s water.

How to tell? Well, it turns out that in this one case, hipsters are right: Locally sourced is measurably different than stuff trucked in.
Water is made up of one oxygen atom and two hydrogen atoms. Hydrogen atoms, it so happens, come in two flavours: The normal kind that has single proton in its nucleus, and a heavier kind called deuterium that has a proton and a neutron (there’s also tritium, with two neutrons, but that’s exceedingly rare). Deuterium is far more rare than the normal kind of hydrogen, but how rare depends on what you look at. The ratio of deuterium to hydrogen in Earth’s water can be different than, say, water in comets, or on Mars.
Note I said, “can be”. We know the ratio differs across the solar system. But suppose we find the same ratio in comets as we do on Earth. That would be powerful evidence that water here began out there. Astronomers have looked at a lot of comets trying to pin down the ratio, and what they’ve found is maddening: Some comets have a ratio very different from Earth’s, and only one (103P/Hartley 2) has a ratio similar to ours.

Jets of material — including water — emanate from comet 67P/Churyumov — Gerasimenko.
Jets of material — including water — emanate from comet 67P/Churyumov — Gerasimenko. Source: AP
Now that’s interesting: 103/P is a Jupiter-family comet, meaning it used to orbit the Sun far out, but dropped into the inner solar system, got its orbit modified by Jupiter, and now has a much shorter path that keeps it in the inner solar system.
Rosetta’s comet, 67/P, is also a Jupiter-family comet. You’d expect them to have roughly similar deuterium/hydrogen ratios.

They don’t. 67/P, according to Rosetta, has three times the deuterium per hydrogen atom as Earth (and 103/P).
What does that mean? It’s not clear, which is why this is maddening. It could be simply that not all Jupiter-family comets have the same ratio; they may all have different origins (born scattered across the solar system, so with different D/H ratios), but now belong to the same family. Or it could mean that 67/P is an oddball, with a much higher ratio than most other comets like it. That would seem unlikely, though, since we’ve studied so few you wouldn’t expect an oddball to be found so easily.

Making things more complicated, some asteroids in the main belt between Mars and Jupiter have water on them, and it appears to have an Earth-like D/H ratio. But we think they have so little water that it would take a lot more of them impacting the early Earth to give us our water than it would comets. That’s possible, but we know lots of comets hit us back then, so it’s still weird that the D/H ratios don’t seem to work out. Still, it’s nice that there could be another potential source to study, and this new Rosetta result does lend credence to the idea that asteroids did the wet work.

So what do comets have to do with it?
So what do comets have to do with it? Source: Getty Images
So if you ask where Earth’s water come from, the answer is: We still don’t know...

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How will the world end? From ‘demonic’ AI to nuclear war — seven scenarios that could end human race

December 8, 2014 / / 0 Comments




news.nationalpost.com 


Humanity may have already created its own nemesis, Professor Stephen Hawking warned last week. The Cambridge University physicist claimed that new developments in the field of artificial intelligence (AI) mean that within a few decades, computers thousands of times more powerful than in existence today may decide to usurp their creators and effectively end humanity’s 100,000-year dominance of Earth.
This Terminator scenario is taken seriously by many scientists and technologists. Before Prof. Hawking made his remarks, Elon Musk, the genius behind the Tesla electric car and PayPal, had stated that “with artificial intelligence, we are summoning the demon,” comparing it unfavourably with nuclear war as the most potent threat to humanity’s existence.
Aside from the rise of the machines, many potential threats have been identified to our species, our civilization, even our planet. To keep you awake at night, here are seven of the most plausible.
Getty Images / ThinkStock
Getty Images / ThinkStockAn artist's depiction of an asteroid approaching Earth.
1. ASTEROID STRIKE
Our solar system is littered with billions of pieces of debris, from the size of large boulders to objects hundreds of kilometres across. We know that, from time to time, these hit the Earth. Sixty-five-million years ago, an object – possibly a comet a few times larger than the one on which the Philae probe landed last month – hit the Mexican coast and triggered a global winter that wiped out the dinosaurs. In 1908, a smaller object hit a remote part of Siberia and devastated hundreds of square kilometres of forest. Last week, 100 scientists, including Lord Rees of Ludlow, the Astronomer Royal, called for the creation of a global warning system to alert us if a killer rock is on the way.
Probability: remote in our lifetime, but one day we will be hit.
Result: there has been no strike big enough to wipe out all life on Earth – an “extinction-level event” – for at least three billion years. But a dino-killer would certainly be the end of our civilization and possibly our species.
Warner Bros.
Warner Bros.When artificial intelligence becomes self-aware, there is a chance it will look something like this scene from Terminator 3.
2. ARTIFICIAL INTELLIGENCE
Prof. Hawking is not worried about armies of autonomous drones taking over the world, but something more subtle – and more sinister. Some technologists believe that an event they call the Singularity is only a few decades away. This is a point at which the combined networked computing power of the world’s AI systems begins a massive, runaway increase in capability – an explosion in machine intelligence. By then, we will probably have handed over control to most of our vital systems, from food distribution networks to power plants, sewage and water treatment works, and the global banking system. The machines could bring us to our knees without a shot being fired. And we cannot simply pull the plug, because they control the power supplies.

Probability: unknown, although computing power is doubling every 18 months. We do not know if machines can be conscious or “want” to do anything, and sceptics point out that the cleverest computers in existence are currently no brighter than cockroaches.
Result: if the web wakes up and wants to sweep us aside, we may have a fight on our hands (perhaps even something similar to the man vs. machines battle in the Terminator films). But it is unlikely that the machines will want to destroy the planet – they “live” here, too.
Handout/AFP/Getty Images
Handout/AFP/Getty ImagesLaboratory technicians and physicians work on samples during research on the evolving Ebola disease in bats, at the Center for Emerging and Zoonotic Diseases research Laboratory of the National Institute for Communicable Diseases in Pretoria on Nov. 21, 2011.
3. A GENETICALLY CREATED PLAGUE
This is possibly the most terrifying short-term threat because it is so plausible. The reason Ebola has not become a worldwide plague – and will not do so – is because it is so hard to transmit, and because it incapacitates and kills its victims so quickly. However, a modified version of the disease that can be transmitted through the air, or which allows its host to travel around for weeks, symptom-free, could kill many millions. It is unknown whether any terror group has the knowledge or facilities to do something like this, but it is chilling to realize that the main reason we understand Ebola so well is that its potential to be weaponized was quickly realized by defence experts.
Probability: someone will probably try it one day.
Result: potentially catastrophic. “Ordinary” infectious diseases such as avian-flu strains have the capability to wipe out hundreds of millions of people.
AP Photo/U.S. Army via Hiroshima Peace Memorial Museum
AP Photo/U.S. Army via Hiroshima Peace Memorial MuseumA mushroom cloud billows about one hour after a nuclear bomb was detonated above Hiroshima, Japan Aug. 6, 1945.
4. NUCLEAR WAR
This is still the most plausible “doomsday” scenario. Despite arms-limitations treaties, there are more than 15,000 nuclear warheads and bombs in existence – many more, in theory, than would be required to kill every human on Earth. Even a small nuclear war has the potential to cause widespread devastation. In 2011, a study by NASA scientists concluded that a limited atomic war between India and Pakistan involving just 100 Hiroshima-sized detonations would throw enough dust into the air to cause temperatures to drop more than 1.2C globally for a decade.
Probability: high. Nine states have nuclear weapons, and more want to join the club. The nuclear wannabes are not paragons of democracy.
Result: it is unlikely that even a global nuclear war between Russia and NATO would wipe us all out, but it would kill billions and wreck the world economy for a century. A regional war, we now know, could have effects far beyond the borders of the conflict.
CERN)/MCT
CERN)/MCTThis is one of the huge particle detectors in the Large Hadron Collider, a 17 mile-long tunnel under the French-Swiss border. Scientists are searching for evidence of what happened right after- and perhaps before- the Big Bang.
5. PARTICLE ACCELERATOR DISASTER
Before the Large Hadron Collider (LHC), the massive machine at CERN in Switzerland that detected the Higgs boson a couple of years ago, was switched on, there was a legal challenge from a German scientist called Otto Rossler, who claimed the atom-smasher could theoretically create a small black hole by mistake – which would then go on to eat the Earth.
The claim was absurd: the collisions in the LHC are far less energetic than those caused naturally by cosmic rays hitting the planet. But it is possible that, one day, a souped-up version of the LHC could create something that destroys the Earth – or even the universe – at the speed of light.
Probability: very low indeed.
Result: potentially devastating, but don’t bother cancelling the house insurance just yet.
AP Photo/Oculus Rift/Fox
AP Photo/Oculus Rift/FoxThis photo shows a scene fromX-Men: Days of Future Past virtual reality experience. Oxford University philosopher Nick Bostrom has speculated that our universe may be one of countless "simulations" running in some alien computer, much like a computer game.
6. ‘GOD’ REACHES FOR THE OFF-SWITCH
Many scientists have pointed out that there is something fishy about our universe. The physical constants – the numbers governing the fundamental forces and masses of nature – seem fine-tuned to allow life of some form to exist. The great physicist Sir Fred Hoyle once wondered if the universe might be a “put-up job”.
More recently, the Oxford University philosopher Nick Bostrom has speculated that our universe may be one of countless “simulations” running in some alien computer, much like a computer game. If so, we have to hope that the beings behind our fake universe are benign – and do not reach for the off-button should we start misbehaving.
Probability: according to Professor Bostrom’s calculations, if certain assumptions are made, there is a greater than 50% chance that our universe is not real. And the increasingly puzzling absence of any evidence of alien life may be indirect evidence that the universe is not what it seems.
Result: catastrophic, if the gamers turn against us. The only consolation is the knowledge that there is absolutely nothing we can do about it.
AP Photo/Charles Rex Arbogast
AP Photo/Charles Rex ArbogastFloodwaters from the Souris River surround homes near Minot State University in Minot, N.D. on June 27, 2011. Global warming is rapidly turning America the beautiful into America the stormy and dangerous, according to the National Climate Assessment report released Tuesday, May 6, 2014.
7. CLIMATE CATASTROPHE
Almost no serious scientists now doubt that human carbon emissions are having an effect on the planet’s climate. The latest report by the Intergovernmental Panel on Climate Change suggested that containing temperature rises to below 2C above the pre-industrial average is now unlikely, and that we face a future three or four degrees warmer than today.
This will not literally be the end of the world – but humanity will need all the resources at its disposal to cope with such a dramatic shift. Unfortunately, the effects of climate change will really start to kick in just at the point when the human population is expected to peak – at about nine billion by the middle of this century. Millions of people, mostly poor, face losing their homes to sea-level rises (by up to a metre or more by 2100) and shifting weather patterns may disrupt agriculture dramatically.
Probability: it is now almost certain that CO2 levels will keep rising to 600 parts per billion and beyond. It is equally certain that the climate will respond accordingly.
Result: catastrophic in some places, less so in others (including northern Europe, where temperature rises will be moderated by the Atlantic). The good news is that, unlike with most of the disasters here, we have a chance to do something about climate change now.

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Dark matter may be massive & collide with Earth every billion years

November 10, 2014 / / 0 Comments

 Excerpt from zeenews.india.com A new study has revealed that no evidence has been found that dark matter is made of tiny exotic particles, and it might be more massive.Researchers from Case Western Reserve University found that dark matter ...

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Time travel and teleporting ‘a reality for today’s children’

November 9, 2014 / / 0 Comments

Excerpt from telegraph.co.uk

By Rhiannon Williams


Travelling through time, invisibility cloaks and teleporting could all happen within today's children's lifetimes, experts have predicted



Children could be travelling between centuries as soon as the year 2100, while teleportation could become a regular occurence by around 2080, professors from Imperial College London and the University of Glasgow have said. 
"The good thing about teleportation is that there is no fundamental law telling us that it cannot be done and with technical advances I would estimate teleportation that we see in the films will be with us by 2080,” said Dr. Mary Jacquiline Romero from the School of Physics and Astronomy, University of Glasgow. 
“Teleporting a person, atom by atom, will be very difficult and is of course a physicist's way, but perhaps developments in chemistry or molecular biology will allow us to do it more quickly. The good thing about teleportation is that there is no fundamental law telling us that it cannot be done and with technical advances I would estimate teleportation that we see in the films will be with us by 2080,” she said. 
“Time travel to the future has already been achieved, but only in tiny amounts. The record is 0.02 seconds set by cosmonaut Sergei Krikalev. Whilst that doesn't sound too impressive, it does show that time travel to the future is possible and that the amount of time travel couldn't be far greater," he argued. 

“If you travelled through space on a big loop at 10 per cent the speed of light for what seemed to you like six months, approximately six months and one day would have passed on Earth. You'd have time travelled a day into the future. Travel at the same speed for 10 years and you'll time travel nearly three weeks into the future. I would say we are looking at 2100 as a very optimistic timescale for travelling weeks into the future.” 

Invisibility cloaks, as featured in Harry Potter, could be "entirely feasible" within the next 10 to 20 years, Professor Chris Phillips, Professor of Experimental Solid State Physics at Imperial College London said. 



Harry tests his invisibility cloak for the first time


“One way to create an ‘invisibility cloak’ is to use adaptive camouflage, which involves taking a film of the background of an object or person and projecting it onto the front to give the illusion of vanishing, " he added. 

"We’re actually not that far away from this becoming a reality – rudimentary technology versions of this have already been created – but the main problem is that the fibre-like structures in the adaptive camouflage need to be so tightly woven that it’s incredibly labour intensive. With developments such as 3D printing allowing us to create previously impossible materials, it’s entirely feasible that we could see a ‘Harry Potter’-like invisibility cloak within the next 10 to 20 years.” 

The research was conducted by the Big Bang UK Young Scientists and Engineers Fair, which compared the predictions of scientists to that of a panel of 11-16 year-olds. 

While their speculation was largely in line with the experts' expectations, the children thought time travel could be feasible by 2078. They also dramatically overestimated when they might be able to become space tourists - anticipating it might take another 30 years, when commercial space flights are due to launch in 2015.

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