Tag: new (page 77 of 180)

Ancient ‘Blue’ Mars Lost an Entire Ocean to Space


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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Astronomers Find Massive Exoplanet With Four Parent Stars

Artist rendering of the system 30 Ari with its exoplanet and four stars. Excerpt from techtimes.com By Dianne Depra  Researchers seeking to study the complexities of exoplanets with multiple stars have found a new system with four. Cal...

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Could Saturn’s moon Titan host an alternate type of life?


Titan


Excerpt from mashable.com

In a world first, chemical engineers have taken a different look at a question astronomers and biologists have been pondering for decades: Does Saturn moon Titan host life?

Of course, Titan is way too hostile for life as we know it to eke out an existence — it is a frigid world awash with liquid methane and ethane and a noxious atmosphere devoid of any liquid water. But say if there is a different kind of biology, a life as we don't know it, thriving on the organic chemistry that is abundant on Titan's surface?

Normally, astrobiologists combine what we know about Earth's biosphere and astronomers zoom in on other stars containing exoplanets in the hope that some of those alien world have some similarities to Earth. By looking for small rocky exoplanets orbiting inside their star's habitable zones, we are basically looking for a "second Earth" where liquid water is at least possible. Where there's liquid water on Earth, there's inevitably life, so scientists seeking out alien life 'follow the water' in the hope of finding life with a similar terrestrial template on other planets.

Titan, however, does not fall into this category, it is about as un-Earth-like as you can get. So, chemical molecular dynamics expert Paulette Clancy and James Stevenson, a graduate student in chemical engineering, from Cornell University, Ithaca, New York, have looked at Titan in a different light and created a theoretical model of a methane-based, oxygen-free life form that could thrive in that environment.

There is no known template for this kind of life on Earth, but the researchers have studied what chemicals are in abundance on Titan and worked out how a very different kind of life could be sparked.

As a collaborator on the NASA/ESA Cassini-Huygens mission, Lunine, professor in the Physical Sciences in the College of Arts and Sciences’ Department of Astronomy, has been fascinated with the possibility of methane-based life existing on Titan for some time, so he joined forces with Clancy and Stevenson to see what this hypothetical life form might look like.

In their research published in the journal Science Advances on Feb. 27, Clancy and Stevenson focused on building a cell membrane "composed of small organic nitrogen compounds and capable of functioning in liquid methane temperatures of 292 degrees below zero (Fahrenheit; or 94 Kelvin)," writes a Cornell press release. On Earth, water-based molecules form phospholipid bilayer membranes that give cells structure, housing organic materials inside while remaining permeable. On Titan, liquid water isn't available to build these cell membranes.

"We're not biologists, and we're not astronomers, but we had the right tools," said Clancy, lead researcher of the study. "Perhaps it helped, because we didn't come in with any preconceptions about what should be in a membrane and what shouldn't. We just worked with the compounds that we knew were there and asked, 'If this was your palette, what can you make out of that?'"

The researchers were able to model the ideal cell that can do all the things that life can do (i.e. support metabolism and reproduction), but constructed it from nitrogen, carbon and hydrogen-based molecules that are known to exist in Titan's liquid methane seas. This chemical configuration gives this theoretical alien cell stability and flexibility in a similar manner to Earth life cells.
"The engineers named their theorized cell membrane an 'azotosome,' 'azote' being the French word for nitrogen. 'Liposome' comes from the Greek 'lipos' and 'soma' to mean 'lipid body;' by analogy, 'azotosome' means 'nitrogen body.'" — Cornell
"Ours is the first concrete blueprint of life not as we know it," said lead author Stevenson, who also said that he was inspired, in part, by Isaac Asimov, who wrote the 1962 essay "Not as We Know It" about non-water-based life.

Having identified a possible type of cell membrane chemistry that functions in the Titan environment as a cell on Earth might, the next step is to model how such a hypothetical type of biology would function on Titan. In the long run, we might also be able to model what kinds of observable indicators we should look for that might reveal that alien biology's presence.

That way, should a mission be eventually sent to Titan's seas, sampling the chemical compounds in the soup of organics may reveal a biology of a very alien nature.
Scientists have been trying to know if life could exist on Titan, the largest moon of Saturn. According to scientists, there are possibilities that life could survive amidst methane-based lakes of Titan. After conducting many studies, they have found signs of life on Titan, but the scientists also said that life will not be like life on earth.
As per some scientific reports, Titan is the only object other than earth which has clear evidence of stable bodies of surface liquid. Like earth, the moon has mountains, islands, lakes and storms, but it doesn’t have oxygen, which is a major element to support life. It means that only oxygen-free and methane-based can exist on Titan.
According to lead researcher Paulette Clancy, “We didn’t come in with any preconceptions about what should be in a membrane and what shouldn’t. We just worked with the compounds that, we knew were there and asked, ‘If this was your palette, what can you make out of that”.
Clancy said although they are not biologists or astronomers, they had the right tools to find life on Saturn’s largest moon. Adding to that, the researchers didn’t know what should be in a membrane and what should be not. They worked with compounds and found that life can exist on Titan, but would be very different from earth’s life, Clancy added.
According to reports, the researchers had used a molecular dynamics method to know about Titan. They screened for suitable candidate compounds from methane for self-assembly into membrane-like structures. As per the researchers, the most promising compound they discovered was an acrylonitrile azotosome, which is present in the atmosphere of Titan.
As per the researchers, acrylonitrile has shown good stability and flexibility similar to that of phospholipid membranes on Earth. It means that the Saturn largest has atmosphere and conditions to support life in a different way than earth.
- See more at: http://perfscience.com/content/2141391-life-titan-would-be-different-earth#sthash.2Kqc3Ewf.dpuf

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





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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Fresh fossil studies push the dawn of man back to 2.8 million years

(Reuters) - A 2.8-million-year-old jawbone fossil with five intact teeth unearthed in an Ethiopian desert is pushing back the dawn of humankind by about half a million years.Scientists said on Wednesday the fossil represents the oldest known repres...

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What happens to your body when you give up sugar?





Excerpt from independent.co.uk
By Jordan Gaines Lewis


In neuroscience, food is something we call a “natural reward.” In order for us to survive as a species, things like eating, having sex and nurturing others must be pleasurable to the brain so that these behaviours are reinforced and repeated.
Evolution has resulted in the mesolimbic pathway, a brain system that deciphers these natural rewards for us. When we do something pleasurable, a bundle of neurons called the ventral tegmental area uses the neurotransmitter dopamine to signal to a part of the brain called the nucleus accumbens. The connection between the nucleus accumbens and our prefrontal cortex dictates our motor movement, such as deciding whether or not to taking another bite of that delicious chocolate cake. The prefrontal cortex also activates hormones that tell our body: “Hey, this cake is really good. And I’m going to remember that for the future.”
Not all foods are equally rewarding, of course. Most of us prefer sweets over sour and bitter foods because, evolutionarily, our mesolimbic pathway reinforces that sweet things provide a healthy source of carbohydrates for our bodies. When our ancestors went scavenging for berries, for example, sour meant “not yet ripe,” while bitter meant “alert – poison!”
Fruit is one thing, but modern diets have taken on a life of their own. A decade ago, it was estimated that the average American consumed 22 teaspoons of added sugar per day, amounting to an extra 350 calories; it may well have risen since then. A few months ago, one expert suggested that the average Briton consumes 238 teaspoons of sugar each week.
Today, with convenience more important than ever in our food selections, it’s almost impossible to come across processed and prepared foods that don’t have added sugars for flavour, preservation, or both.
These added sugars are sneaky – and unbeknown to many of us, we’ve become hooked. In ways that drugs of abuse – such as nicotine, cocaine and heroin – hijack the brain’s reward pathway and make users dependent, increasing neuro-chemical and behavioural evidence suggests that sugar is addictive in the same way, too.

Sugar addiction is real

Anyone who knows me also knows that I have a huge sweet tooth. I always have. My friend and fellow graduate student Andrew is equally afflicted, and living in Hershey, Pennsylvania – the “Chocolate Capital of the World” – doesn’t help either of us. But Andrew is braver than I am. Last year, he gave up sweets for Lent. “The first few days are a little rough,” Andrew told me. “It almost feels like you’re detoxing from drugs. I found myself eating a lot of carbs to compensate for the lack of sugar.”
There are four major components of addiction: bingeing, withdrawal, craving, and cross-sensitisation (the notion that one addictive substance predisposes someone to becoming addicted to another). All of these components have been observed in animal models of addiction – for sugar, as well as drugs of abuse.
A typical experiment goes like this: rats are deprived of food for 12 hours each day, then given 12 hours of access to a sugary solution and regular chow. After a month of following this daily pattern, rats display behaviours similar to those on drugs of abuse. They’ll binge on the sugar solution in a short period of time, much more than their regular food. They also show signs of anxiety and depression during the food deprivation period. Many sugar-treated rats who are later exposed to drugs, such as cocaine and opiates, demonstrate dependent behaviours towards the drugs compared to rats who did not consume sugar beforehand.
Like drugs, sugar spikes dopamine release in the nucleus accumbens. Over the long term, regular sugar consumption actually changes the gene expression and availability of dopamine receptors in both the midbrain and frontal cortex. Specifically, sugar increases the concentration of a type of excitatory receptor called D1, but decreases another receptor type called D2, which is inhibitory. Regular sugar consumption also inhibits the action of the dopamine transporter, a protein which pumps dopamine out of the synapse and back into the neuron after firing.
In short, this means that repeated access to sugar over time leads to prolonged dopamine signalling, greater excitation of the brain’s reward pathways and a need for even more sugar to activate all of the midbrain dopamine receptors like before. The brain becomes tolerant to sugar – and more is needed to attain the same “sugar high.”

Sugar withdrawal is also real

Although these studies were conducted in rodents, it’s not far-fetched to say that the same primitive processes are occurring in the human brain, too. “The cravings never stopped, [but that was] probably psychological,” Andrew told me. “But it got easier after the first week or so.”
In a 2002 study by Carlo Colantuoni and colleagues of Princeton University, rats who had undergone a typical sugar dependence protocol then underwent “sugar withdrawal.” This was facilitated by either food deprivation or treatment with naloxone, a drug used for treating opiate addiction which binds to receptors in the brain’s reward system. Both withdrawal methods led to physical problems, including teeth chattering, paw tremors, and head shaking. Naloxone treatment also appeared to make the rats more anxious, as they spent less time on an elevated apparatus that lacked walls on either side.
Similar withdrawal experiments by others also report behaviour similar to depression in tasks such as the forced swim test. Rats in sugar withdrawal are more likely to show passive behaviours (like floating) than active behaviours (like trying to escape) when placed in water, suggesting feelings of helplessness.
A new study published by Victor Mangabeira and colleagues in this month’s Physiology & Behavior reports that sugar withdrawal is also linked to impulsive behaviour. Initially, rats were trained to receive water by pushing a lever. After training, the animals returned to their home cages and had access to a sugar solution and water, or just water alone. After 30 days, when rats were again given the opportunity to press a lever for water, those who had become dependent on sugar pressed the lever significantly more times than control animals, suggesting impulsive behaviour.
These are extreme experiments, of course. We humans aren’t depriving ourselves of food for 12 hours and then allowing ourselves to binge on soda and doughnuts at the end of the day. But these rodent studies certainly give us insight into the neuro-chemical underpinnings of sugar dependence, withdrawal, and behaviour.
Through decades of diet programmes and best-selling books, we’ve toyed with the notion of “sugar addiction” for a long time. There are accounts of those in “sugar withdrawal” describing food cravings, which can trigger relapse and impulsive eating. There are also countless articles and books about the boundless energy and new-found happiness in those who have sworn off sugar for good. But despite the ubiquity of sugar in our diets, the notion of sugar addiction is still a rather taboo topic.
Are you still motivated to give up sugar? You might wonder how long it will take until you’re free of cravings and side-effects, but there’s no answer – everyone is different and no human studies have been done on this. But after 40 days, it’s clear that Andrew had overcome the worst, likely even reversing some of his altered dopamine signalling. “I remember eating my first sweet and thinking it was too sweet,” he said. “I had to rebuild my tolerance.”
And as regulars of a local bakery in Hershey – I can assure you, readers, that he has done just that.
Jordan Gaines Lewis is a Neuroscience Doctoral Candidate at Penn State College of Medicine

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The Healing Of The Dream – Episode II

The Healing Of The DreamThe Picture Of Crucifixion - Beyond All SymbolsEpisode IIThe New Beginning Serieswww.themasterteacher.tv

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What Big Bang? Universe May Have Had No Beginning at All

Excerpt from spacedaily.com What we don't know about the Universe... could fill the Universe. Two theoretical physicists have suggested nothing like the Big Bang played a role in the start of our universe 13.8 billion years ago, refuting Edwin Hubb...

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