[Video] The 7 Most Mysterious Lost Ancient Lands

Almost everyone is familiar with the legend of the lost city of Atlantis, which was a fictional island first imagined by Plato in his stories of “Ancient Athens.”  But there are many other stories of lost lands or cities across the cultures of the world, and some that were simply assumed to be myths turn out to have actually existed, or evidence has been found that shows the stories had an actual basis in reality.

Here’s an intriguing video that explores seven of the most mysterious of these ancient lost lands:

Our gratitude and thanks to the Hybrid Librarian YouTube channel for creating this interesting and entertaining video!

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Early-onset Alzheimer’s: should you worry?

By Troy Rohn, Boise State University.

You have forgotten where you put your car keys, or you can’t seem to remember the name of your colleague you saw in the grocery store the other day. You fear the worst, that maybe these are signs of Alzheimer’s disease.

You’re not alone: a recent study asking Americans age 60 or older the condition they were most afraid of getting indicated the number one fear was Alzheimer’s or dementia (35 percent), followed by cancer (23 percent), and stroke (15 percent).

And when we hear of someone like legendary basketball Coach Pat Summitt  (pictured with President Obama in this articles feature image) dying on June 28 from early-onset Alzheimer’s at age 64, fears are heightened.

Losing your keys every once in a while does not mean you have Alzheimer’s Disease.
From www.shutterstock.com

Memory loss is normal; Alzheimer’s is not

Alzheimer’s is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, leading to cognitive impairment that severely affects daily living. Often the terms Alzheimer’s and dementia are used interchangeably and although the two are related, they are not the same. Dementia is a general term for the loss of memory or other mental abilities that affect daily life. Alzheimer’s is a cause of dementia, with over 70 percent of all dementia cases occurring as a result of Alzheimer’s.

The majority of Alzheimer’s cases occur in people aged 65 years or older.

Slight memory loss is a normal consequence of aging, and people therefore should not be overly concerned if they lose their keys or forget the name of a neighbor at the grocery store. If these things happen infrequently, there is scant reason to worry. You most likely do not have Alzheimer’s if you simply forgot one time where you parked upon leaving Disneyland or the local mall during the holidays.

How do you know when forgetfulness is part of the normal aging process and when it could be a symptom of Alzheimer’s? Here are 10 early signs and symptoms of Alzheimer’s disease.

A key point to consider is whether these symptoms significantly affect daily living. If so, then Alzheimer’s disease might be the cause.

For every one of these 10 symptoms of Alzheimer’s, there is also a typical age-related change that is not indicative of Alzheimer’s disease. For example, an early symptom of Alzheimer’s is memory loss including forgetting important dates or events and asking for the same information numerous times over. A typical age-related change may be sometimes forgetting names and appointments, but remembering them later.

People frequently ask if they might be afflicted with the disease if a grandparent had Alzheimer’s. The majority of Alzheimer’s cases occur in people aged 65 years or older. These individuals are classified as having what is known as late-onset Alzheimer’s. In late-onset Alzheimer’s, the cause of the disease is unknown (e.g. sporadic), although advancing age and inheriting certain genes may play an important role. Importantly, although there are several known genetic risk factors associated with late-onset Alzheimer’s, inheriting any one of these genes does not assure a prognosis of Alzheimer’s as one advances in age.

Early-onset is rare – but heredity does play an important role

In fact less than 5 percent of the 5 million cases are a direct result of hereditary mutations (e.g. familial form of Alzheimer’s). Inheriting these rare, genetic mutations leads to what is known as early-onset Alzheimer’s, which is characterized by an earlier age of onset, often in the 40s and 50s, and is a more aggressive form of the disease that leads to a more rapid decline in memory impairment and cognition.

In general, most neurologists agree that early-onset and late-onset Alzheimer’s are essentially the same disease, apart from the differences in genetic cause and age of onset. The one exception is the prevalence of a condition called myoclonus (muscle twitching and spasm) that is more commonly observed in early-onset Alzheimer’s disease than in late-onset Alzheimer’s disease.

In addition, some studies suggest that people with early-onset Alzheimer’s decline at a faster rate than those with late-onset. Even though generally speaking the two forms of Alzheimer’s are medically equivalent, the large burden early-onset poses on the family is quite evident. Often these patients are still in the most productive phases of their life and yet the onset of the disease robs them of brain function at such a young age. These individuals may still be physically fit and active when diagnosed and more often than not still have family and career responsibilities. Therefore, a diagnosis of early-onset may have a greater negative, ripple effect on the patient as well as family members.

Although the genes giving rise to early-onset Alzheimer’s are extremely rare, these inherited mutations do run in families worldwide and the study of these mutations has provided critical knowledge to the molecular underpinnings of the disease. These familial forms of Alzheimer’s result from mutations in genes that are typically defined as being autosomal dominant, meaning that you only need to have one parent pass on the gene to their child. If this happens, there is no escape from an eventual Alzheimer’s diagnosis.

What scientists have learned from these rare mutations that cause early-onset Alzheimer’s is that in every case the gene mutation leads to the overproduction of a rogue, toxic, protein called beta-amyloid. The build up of beta-amyloid in the brain produces plaques that are one of the hallmarks of the disease. Just as plaques in arteries can harm the heart, plaques on the “brain” can have dire consequences for brain function.

By studying families with early-onset Alzheimer’s, scientists now realize that the build up of beta-amyloid can happen decades before the first symptoms of the disease manifest. This gives scientists tremendous hope in terms of a large therapeutic window to intervene and stop the beta-amyloid cascade.

Hope is high for large trial underway of 5,000

Indeed, one of the most anticipated clinical trials under way at this moment involves a large Colombian family of over 5,000 members who may carry an early-onset Alzheimer’s gene. Three hundred family members will participate in this trial in which half of those people who are young and years away from symptoms but who have the Alzheimer’s gene will receive a drug that has been shown to decrease the production of beta-amyloid. The other half will take a placebo and will comprise the control group.

Neither patient nor doctor will know whether they will be receiving the active drug, which helps eliminate any potential biases. The trial will last 5 years and although it will involve a small percentage of people with early-onset Alzheimer’s, the information from the trial could be applied to millions of people worldwide who will develop the more conventional, late-onset form of Alzheimer’s disease.

Currently there are no effective treatments or cure for Alzheimer’s and the only medications available are palliative in nature. What is critically needed are disease-modifying drugs: those drugs that actually stop the beta-amyloid in its tracks. Devastating as early-onset Alzheimer’s is, there is hope that prevention trials as described above could ultimately lead to effective treatments in the near future for this insidious disease.

The ConversationTroy Rohn, Professor of Biology, Boise State University

This article was originally published on The Conversation. Read the original article.

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How to 3D Print ‘Joint Patches’ with Ink Made of Cartilage [Video]

Strands of cow cartilage substitute for ink in a 3D bioprinting process that may one day create cartilage patches for worn-out joints.

“Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches,” says Ibrahim T. Ozbolat, associate professor of engineering science and mechanics at Penn State. “Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this.”

The 3D printer lays down rows of cartilage strands in any pattern the researchers choose.

Cartilage is a good tissue to target for scale-up bioprinting because it is made up of only one cell type and has no blood vessels within the tissue. It is also a tissue that cannot repair itself. Once cartilage is damaged, it remains damaged.

Previous attempts at growing cartilage began with cells embedded in a hydrogel—a substance composed of polymer chains and about 90 percent water—that is used as a scaffold to grow the tissue.

“Hydrogels don’t allow cells to grow as normal,” says Ozbolat. “The hydrogel confines the cells and doesn’t allow them to communicate as they do in native tissues.”This leads to tissues that do not have sufficient mechanical integrity. Degradation of the hydrogel also can produce toxic compounds that are detrimental to cell growth.

Ozbolat and his research team developed a method to produce larger scale tissues without using a scaffold.

How it works

They create a tiny—from 3 to 5 one hundredths of an inch in diameter—tube made of alginate, an algae extract. They inject cartilage cells into the tube and allow them to grow for about a week and adhere to each other.

Because cells do not stick to alginate, they can remove the tube and are left with a strand of cartilage. The cartilage strand substitutes for ink in the 3D printing process. Using a specially designed prototype nozzle that can hold and feed the cartilage strand, the 3D printer lays down rows of cartilage strands in any pattern the researchers choose.

After about half an hour, the cartilage patch self-adheres enough to move to a petri dish. The researchers put the patch in nutrient media to allow it to further integrate into a single piece of tissue. Eventually the strands fully attach and fuse together.

“We can manufacture the strands in any length we want,” says Ozbolat. “Because there is no scaffolding, the process of printing the cartilage is scalable, so the patches can be made bigger as well. We can mimic real articular cartilage by printing strands vertically and then horizontally to mimic the natural architecture.”

Supply your own cartilage?

The artificial cartilage produced by the team is very similar to native cow cartilage. However, the mechanical properties are inferior to those of natural cartilage, but better than the cartilage that is made using hydrogel scaffolding.

Natural cartilage forms with pressure from the joints, and Ozbolat thinks that mechanical pressure on the artificial cartilage will improve the mechanical properties.

If this process is eventually applied to human cartilage, each individual treated would probably have to supply their own source material to avoid tissue rejection. The source could be existing cartilage or stem cells differentiated into cartilage cells.

Researchers from Harvard University and the University of Iowa worked on the project, which was funded by the National Science Foundation, Grow Iowa Value Funds, and the China Scholarship Fund. The researchers report their results in the current issue of Scientific Reports.

Source: Republished from Futurity.org as a derivative work under the Attribution 4.0 International license. Original article posted to Futurity by A’ndrea Elyse Messer-Penn State.

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Bikini islanders still deal with fallout of US nuclear tests, 70 years later [Video]

By Timothy J. Jorgensen, Georgetown University.

In 1946, French fashion designer Jacques Heim released a woman’s swimsuit he called the “Atome” (French for “atom”) – a name selected to suggest its design would be as shocking to people that summer as the atomic bombings of Japan had been the summer before.

The scandalous ‘Bikini,’ small enough to fit in a matchbox like the one she’s holding.

Not to be outdone, competitor Louis Réard raised the stakes, quickly releasing an even more skimpy swimsuit. The Vatican found Réard’s swimsuit more than shocking, declaring it to actually be “sinful.” So what did Réard consider an appropriate name for his creation? He called it the “Bikini” – a name meant to shock people even more than “Atome.” But why was this name so shocking?

In the summer of 1946, “Bikini” was all over the news. It’s the name of a small atoll – a circular group of coral islands – within the remote mid-Pacific island chain called the Marshall Islands. The United States had assumed control of the former Japanese territory after the end of World War II, just a few months earlier.

The United States soon came up with some very big plans for the little atoll of Bikini. After forcing the 167 residents to relocate to another atoll, they started to prepare Bikini as an atomic bomb test site. Two test bombings scheduled for that summer were intended to be very visible demonstrations of the United States’ newly acquired nuclear might. Media coverage of the happenings at Bikini was extensive, and public interest ran very high. Who could have foreseen that even now – 70 years later – the Marshall Islanders would still be suffering the aftershocks from the nuclear bomb testing on Bikini Atoll?

The big plan for tiny Bikini

According to the testing schedule, the U.S. plan was to demolish a 95-vessel fleet of obsolete warships on June 30, 1946 with an airdropped atomic bomb. Reporters, U.S. politicians, and representatives from the major governments of the world would witness events from distant observation ships. On July 24, a second bomb, this time detonated underwater, would destroy any surviving naval vessels.

These two sequential tests were intended to allow comparison of air-detonated versus underwater-detonated atomic bombs in terms of destructive power to warships. The very future of naval warfare in the advent of the atomic bomb was in the balance. Many assumed the tests would clearly show that naval ships were now obsolete, and that air forces represented the future of global warfare.

Slow motion film of atomic bomb airdropped on Bikini Atoll.

But when June 30 arrived, the airdrop bombing didn’t go as planned. The bomber missed his target by more than a third of a mile, so the bomb caused much less ship damage than anticipated.

Color film of underwater atomic bomb near Marshall Islands.

The subsequent underwater bomb detonation didn’t go so well either. It unexpectedly produced a spray of highly radioactive water that extensively contaminated everything it landed on. Naval inspectors couldn’t even return to the area to assess ship damage because of the threat of deadly radiation doses from the bomb’s “fallout” – the radioactivity produced by the explosion. All future bomb testing was canceled until the military could evaluate what had gone wrong and come up with another testing strategy.

And even more bombings to follow

The United States did not, however, abandon little Bikini. It had even bigger plans with bigger bombs in mind. Ultimately, there would be 23 Bikini test bombings, spread over 12 years, comparing different bomb sizes, before the United States finally moved nuclear bomb testing to other locations, leaving Bikini to recover as best it could.

1956 Operation Redwing bombing at Enewetak Atoll.
National Nuclear Security Administration / Nevada Field Office

The most dramatic change in the testing at Bikini occurred in 1954, when the bomb designs switched from fission to fusion mechanisms. Fission bombs – the type dropped on Japan – explode when heavy elements like uranium split apart. Fusion bombs, in contrast, explode when light atoms like deuterium join together. Fusion bombs, often called “hydrogen” or “thermonuclear” bombs, can produce much larger explosions.

The United States military learned about the power of fusion energy the hard way, when they first tested a fusion bomb on Bikini. Based on the expected size of the explosion, a swath of the Pacific Ocean the size of Wisconsin was blockaded to protect ships from entering the fallout zone.

On March 1, 1954, the bomb detonated just as planned – but still there were a couple of problems. The bomb turned out to be 1,100 times larger than the Hiroshima bomb, rather than the expected 450 times. And the prevailing westerly winds turned out to be stronger than meteorologists had predicted. The result? Widespread fallout contamination to islands hundreds of miles downwind from the test site and, consequently, high radiation exposures to the Marshall Islanders who lived on them.

Dealing with the fallout, for decades

Three days after the detonation of the bomb, radioactive dust had settled on the ground of downwind islands to depths up to half an inch. Natives from badly contaminated islands were evacuated to Kwajalein – an upwind, uncontaminated atoll that was home to a large U.S. military base – where their health status was assessed.

Residents of the Rongelap Atoll – Bikini’s downwind neighbor – received particularly high radiation doses. They had burns on their skin and depressed blood counts. Islanders from other atolls did not receive doses high enough to induce such symptoms. However, as I explain in my book “Strange Glow: The Story of Radiation,” even those who didn’t have any radiation sickness at the time received doses high enough to put them at increased cancer risk, particularly for thyroid cancers and leukemia.

A Marshall Islands resident has his body levels of radioactivity checked in a U.S. government lab. Argonne National Laboratory, CC BY

What happened to the Marshall Islanders next is a sad story of their constant relocation from island to island, trying to avoid the radioactivity that lingered for decades. Over the years following the testing, the Marshall Islanders living on the fallout-contaminated islands ended up breathing, absorbing, drinking and eating considerable amounts of radioactivity.

In the 1960s, cancers started to appear among the islanders. For almost 50 years, the United States government studied their health and provided medical care. But the government study ended in 1998, and the islanders were then expected to find their own medical care and submit their radiation-related health bills to a Nuclear Claims Tribunal, in order to collect compensation.

Marshall Islanders still waiting for justice

By 2009, the Nuclear Claims Tribunal, funded by Congress and overseen by Marshall Islands judges to pay compensation for radiation-related health and property claims, exhausted its allocated funds with US$45.8 million in personal injury claims still owed the victims. At present, about half of the valid claimants have died waiting for their compensation. Congress shows no inclination to replenish the empty fund, so it’s unlikely the remaining survivors will ever see their money.

Ten years after bombing ended, the U.S. government assured Marshall Islanders a safe return.
Department of Energy

But if the Marshall Islanders cannot get financial compensation, perhaps they can still win a moral victory. They hope to force the United States and eight other nuclear weapons states into keeping another broken promise, this one made via the Treaty on the Non-Proliferation of Nuclear Weapons.

This international agreement between 191 sovereign nations entered into force in 1970 and was renewed indefinitely in 1995. It aims to prevent the spread of nuclear weapons and work toward disarmament.

In 2014, the Marshall Islands claimed that the nine nuclear-armed nations – China, Britain, France, India, Israel, North Korea, Pakistan, Russia and the United States – have not fulfilled their treaty obligations. The Marshall Islanders are seeking legal action in the United Nations International Court of Justice in The Hague. They’ve asked the court to require these countries to take substantive action toward nuclear disarmament. Despite the fact that India, North Korea, Israel and Pakistan are not among the 191 nations that are signatories of the treaty, the Marshall Islands’ suit still contends that these four nations “have the obligation under customary international law to pursue [disarmament] negotiations in good faith.”

The process is currently stalled due to jurisdictional squabbling. Regardless, experts in international law say the prospects for success through this David versus Goliath approach are slim.

But even if they don’t win in the courtroom, the Marshall Islands might shame these nations in the court of public opinion and draw new attention to the dire human consequences of nuclear weapons. That in itself can be counted as a small victory, for a people who have seldom been on the winning side of anything. Time will tell how this all turns out, but after 70 years since the first bomb test, the Marshall Islanders are well accustomed to waiting.

The ConversationTimothy J. Jorgensen, Director of the Health Physics and Radiation Protection Graduate Program and Associate Professor of Radiation Medicine, Georgetown University

This article was originally published on The Conversation. Read the original article.

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Why the GM food labeling debate is not over

By Jane Kolodinsky, University of Vermont.

The U.S. Senate this week reached a compromise to require food manufacturers to label foods that contain genetically modified (GM) ingredients, a bill that would preempt state-level laws. The deal comes only one week before Vermont’s law to require GM food labeling will go into effect. If the Senate compromise bill is voted on and passed by a supermajority and signed into law by President Obama, Vermont’s law will be superseded.

The Vermont law stipulates a positive declaration – that is, a label must indicate there are some ingredients are genetically modified organisms (GMOs). The Senate proposal, which backers said is meant to avoid a patchwork of state laws, gives food manufacturers a number of options for how to disclose which products have GM ingredients. Companies could place text on labels, offer a Quick Response (QR) code that would be read with a smartphone or provide a phone number or website with more information. Organic products can be labeled “non-GMO.”

Although the Vermont law and the Senate bill bring the question of labeling to the forefront, the debate over GM food and consumer education has been percolating for some 25 years.

I have studied the social science research about whether and how GM foods should be labeled. In my view, the proposed federal legislation, while consistent across the country, makes it very difficult for consumers to obtain the information they want to know – namely, whether a product has been produced using GM technology or ingredients.

What labels convey

In a 2013 study, Arizona State University professors Gary Marchant and Guy Cardineu identified five issues that are important to the decision of whether or not to label:

  • public opinion
  • consumer choice
  • the legality of labeling requirements
  • costs and benefits of labeling, and
  • risks and benefits of GM foods.

They concluded: “While the case for GM labeling seems compelling on first appearance, a closer examination of the scientific, legal, economic and policy arguments and evidence demonstrates that compulsory GM labeling is unwarranted, unnecessary and being manipulated by a cynical and self-serving campaign funded and organized by the organic food industry.”

But I have examined the current state of evidence and have come to the opposite conclusion, as have American courts and several major corporations.

For starters, for at least 15 years, research surveys have found that consumers desire labeling. This has been indicated by Consumer Reports, my own research and many others. Public opinion is on the side of labeling.

Labels play a significant role in facilitating consumer choice in the case of credence goods. These are goods for that consumers cannot determine, through search nor experience, whether a product contains an attribute or quality they prefer, such as the use of GM technology. Labels convey to consumers a desired or undesired attribute.

On the question of legality of labeling requirements, it is worth noting that legal arguments against labeling have failed. Challenged by the Grocery Manufacturer’s Association of America and several other trade groups, the Vermont law was upheld in April 2015. And, while bill HR 1599 passed the U.S. House of Representatives in July of 2015, which would have prohibited states from promulgating their own labeling laws, it failed to pass the U.S Senate in March 2016.

Also, there is no published evidence that GM labels will increase the cost of food. Reports, funded by industry, advocacy and consumer groups have estimated cost ranges between zero and US$500 per year for a family of four.

But the Campbell’s company has publicly stated the cost of labeling is negligible. If there are costs, they will not be passed on to consumers. Company spokesman Tom Hushen said, “To be clear, there will be no price increase as a result of Vermont or national GMO labeling for Campbell products.”

Changing corporate positions

That leaves only Marchant and Cardineu’s fifth point: the risks and benefits of GM foods. The National Academies of Sciences, Engineering and Medicine earlier this year released an exhaustive report on GM foods and found there is no evidence of health risks from genetically modified ingredients.

But pro-GM labeling advocates have not used the GM safety issue in their arguments. Instead, they focus on consumers’ right to know what is in their food and how it is produced.

Several major corporations, which have previously spent millions of dollars to defeat mandatory GM labels, have indicated they will label their products or have already. Campbell’s, General Mills, Kellogg’s, Mars and ConAgra had said they would label their products nationwide in order to be in compliance with Vermont’s anticipated law. PepsiCo and Frito Lay have quietly begun to label already without public fanfare.

Campbell’s President and CEO Denise Morrison said in a statement, “Our decision (to label) was guided by our Purpose; rooted in our consumer-first mindset; and driven by our commitment to transparency – to be open and honest about our food. I truly believe it is the right thing to do for consumers and for our business.”

However, the Senate proposal, if it comes into law, does not make it easy for consumers to actually find out whether a product has GM contents at the supermarket.

One food manufacturing company may choose a QR code, another a label, another a symbol and another a toll-free number. If consumers do not see a disclosure using words, as the Vermont law requires, they look for a symbol. If they don’t see a symbol, they scan the product with a smartphone or call a telephone number. If that doesn’t provide information, they go to a website. For a consumer purchasing multiple products, this will be a cumbersome process. While it has been said that Vermont’s law, in isolation, may cause chaos for industry, as proposed, the compromise bill will cause chaos for consumers seeking more transparency in the food system.

In the months ahead, we will see whether the Senate bill is turned into law and how food makers choose to comply with any disclosure requirements. But given the strong consumer support for labeling, it is unlikely that the debate over GM food labeling will die down.

The ConversationJane Kolodinsky, Professor and Chair Community Development and Applied Economics, University of Vermont

This article was originally published on The Conversation. Read the original article.

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Surprise! Mars Dunes Really are Alien

Some of the wind-sculpted sand ripples on Mars are a type not seen on Earth, and their relationship to the thin Martian atmosphere today provides new clues about the atmosphere’s history.

The determination that these mid-size ripples are a distinct type resulted from observations by NASA’s Curiosity Mars rover. Six months ago, Curiosity made the first up-close study of active sand dunes anywhere other than Earth, at the “Bagnold Dunes” on the northwestern flank of Mars’ Mount Sharp.

Two sizes of ripples are evident in this Dec. 13, 2015, view of a top of a Martian sand dune, from NASA's Curiosity Mars rover. Sand dunes and the smaller type of ripples also exist on Earth. The larger ripples are a type not seen on Earth nor previously recognized as a distinct type on Mars. Credits: NASA/JPL-Caltech/MSSS. Click/tap for larger image
Two sizes of ripples are evident in this Dec. 13, 2015, view of a top of a Martian sand dune, from NASA’s Curiosity Mars rover. Sand dunes and the smaller type of ripples also exist on Earth. The larger ripples are a type not seen on Earth nor previously recognized as a distinct type on Mars.
Credits: NASA/JPL-Caltech/MSSS. Click/tap for larger image

“Earth and Mars both have big sand dunes and small sand ripples, but on Mars, there’s something in between that we don’t have on Earth,” said Mathieu Lapotre, a graduate student at Caltech in Pasadena, California, and science team collaborator for the Curiosity mission. He is the lead author of a report about these mid-size ripples published in the July 1 issue of the journal Science.

Both planets have true dunes — typically larger than a football field — with downwind faces shaped by sand avalanches, making them steeper than the upwind faces.

Earth also has smaller ripples — appearing in rows typically less than a foot (less than 30 centimeters) apart — that are formed by wind-carried sand grains colliding with other sand grains along the ground. Some of these “impact ripples” corrugate the surfaces of sand dunes and beaches.

Images of Martian sand dunes taken from orbit have, for years, shown ripples about 10 feet (3 meters) apart on dunes’ surfaces. Until Curiosity studied the Bagnold Dunes, the interpretation was that impact ripples on Mars could be several times larger than impact ripples on Earth. Features the scale of Earth’s impact ripples would go unseen at the resolution of images taken from orbit imaging and would not be expected to be present if the meter-scale ripples were impact ripples.

“As Curiosity was approaching the Bagnold Dunes, we started seeing that the crest lines of the meter-scale ripples are sinuous,” Lapotre said. “That is not like impact ripples, but it is just like sand ripples that form under moving water on Earth. And we saw that superimposed on the surfaces of these larger ripples were ripples the same size and shape as impact ripples on Earth.”

Besides the sinuous crests, another similarity between the mid-size ripples on Mars and underwater ripples on Earth is that, in each case, one face of each ripple is steeper than the face on the other side and has sand flows, as in a dune. Researchers conclude that the meter-scale ripples are built by Martian wind dragging sand particles the way flowing water drags sand particles on Earth — a different mechanism than how either dunes or impact ripples form. Lapotre and co-authors call them “wind-drag ripples.”

“The size of these ripples is related to the density of the fluid moving the grains, and that fluid is the Martian atmosphere,” he said. “We think Mars had a thicker atmosphere in the past that might have formed smaller wind-drag ripples or even have prevented their formation altogether. Thus, the size of preserved wind-drag ripples, where found in Martian sandstones, may have recorded the thinning of the atmosphere.”

The researchers checked ripple textures preserved in sandstone more than 3 billion years old at sites investigated by Curiosity and by NASA’s Opportunity Mars rover. They found wind-drag ripples about the same size as modern ones on active dunes. That fits with other lines of evidence that Mars lost most of its original atmosphere early in the planet’s history.

Other findings from Curiosity’s work at the Bagnold Dunes point to similarities between how dunes behave on Mars and Earth.

“During our visit to the active Bagnold Dunes, you might almost forget you’re on Mars, given how similar the sand behaves in spite of the different gravity and atmosphere. But these mid-sized ripples are a reminder that those differences can surprise us,” said Curiosity Project Scientist Ashwin Vasavada, of NASA’s Jet Propulsion Laboratory in Pasadena.

After examining the dune field, Curiosity resumed climbing the lower portion of Mount Sharp. The mission is investigating evidence about how and when ancient environmental conditions in the area evolved from freshwater settings favorable for microbial life, if Mars has ever hosted life, into conditions drier and less habitable.

Source: Republished from NASA.gov under public domain rights and in observance of the NASA multimedia guidelines

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NASA’s Juno arrives at Jupiter to lift its cloudy veil – but first it must survive the hostile environment

By Leigh Fletcher, University of Leicester.

A burst of flame will streak across the skies of Jupiter in the early hours of July 5 as humankind’s newest robotic explorer arrives at the giant planet. NASA’s Juno spacecraft will be entering the unknown, penetrating deep into the radiation-filled heart of the Jupiter system in a bold attempt to unlock the secrets of the gas giant’s origins.

This ambitious mission could completely reshape our understanding of how the solar system’s largest world came to be – and how it influenced the evolution of other planets. But this is only if Juno survives the perils of exploring an environment that no spacecraft has dared venture into before.

So far, only the Galileo mission has orbited Jupiter, parachuting a probe into its churning, cloud-filled atmosphere in 1995. Despite its successes, there remain huge gaps in our knowledge of how Jupiter formed and whether it contains a planetary core, a remnant of our early solar system. Indeed, Jupiter’s powerful gravity has forever entrapped the original material from which it formed, making it an enormous time capsule that records the conditions that existed when our solar system was young.

The formation of this giant planet played a crucial role in shaping the architecture of the solar system as we see it today. With its immense gravity, Jupiter could have been both our destroyer and our saviour. That’s because its early motion through the young solar system could have destroyed the forming terrestrial worlds, leading to cataclysmic collisions that threatened Earth’s very existence.

Later on, Jupiter’s gravity is thought to have shepherded debris such as comets and asteroids that may have delivered the essential ingredients for life to our home planet. The story of Jupiter’s origins is therefore key to understanding our place in the solar system, and the tantalising possibility that similar events unfolded elsewhere.

Crucial measurements

Just like Jupiter’s mythological counterpart, who veiled himself in clouds to hide his mischief, the giant planet will not give up its secrets easily. Juno’s suite of sophisticated instruments must probe deeper than ever before, to regions beneath the churning cloud decks that are invisible to our Earth-bound telescopes. After a five-year journey, the solar-powered spacecraft will embark on a series of fortnightly orbits around the planet, taking it high above the planet’s poles and then skimming within 5,000 kilometres of the cloud tops.

The suite of science instruments and scale of the Juno spacecraft.
Credit: NASA/JPL

These close passes will permit precise measurements of Jupiter’s gravity and magnetic fields, probing its inner structure and its density. This will help examine the exotic interior of the gas giant, where simple hydrogen gas is compressed under immense, crushing pressures to become metallic and conducting (a state only glimpsed fleetingly in laboratories on Earth). These measurements could potentially provide the first glimpses of a core, if one exists at all.

If our theories of planetary formation are correct, then Jupiter’s heavier elements, such as carbon, nitrogen and sulphur, should have been delivered as molecules trapped in water ice cages, frozen in the cold outer reaches of our young solar system. That should have left behind a huge amount of water in Jupiter, but as water condenses in the frigid conditions of the planet’s atmosphere, we have never had a reliable estimate of how much is really down there. If there isn’t enough water present, then the prevailing theory of Jupiter’s formation would have to undergo a complete revision.

The exotic interior of Jupiter, hidden deep below the visible cloud layers. Does a dense core actually exist?

In the coming months, Juno will answer this question. It carries an instrument that can map Jupiter at microwave wavelengths, allowing it to reveal the distribution of water deep below the clouds for the first time. Combined with the gravity measurements, Juno will peel back the layers of Jupiter to finally test our theories of how giant planets form – is a heavy planetary embryo required, or can these enormous worlds form directly from the collapse of the gases surrounding a young star?

Juno’s unique orbit will also provide our first direct views of Jupiter’s poles, exploring the powerful auroras and dynamic atmosphere. The spinning spacecraft (three rotations per minute) will sweep the array of sensors through the radiation environment to explore the immense plasma and magnetic fields. Its camera will target atmospheric features, such as erupting storms and spinning vortices, at breathtaking resolutions. In addition to the scientific instruments, Juno also carries the first Jupiter camera to be aimed primarily at education and outreach, with the public invited to suggest the targets.

To add to this intense scrutiny, an army of professional and amateur observers, including those here at the University of Leicester, are engaged in an international campaign to support the mission. These observations will provide global views of the planet to support Juno’s up-close observations; reveal how Jupiter’s dynamic atmosphere changes throughout the mission, and observe it in wavelengths of light that Juno cannot access. An example of the incredible capabilities of Earth-based observers is shown by our recent images from the Very Large Telescope in Chile.

Ground-based observations of Jupiter to support Juno. The left hand image shows Jupiter’s infrared glow with dark clouds in silhouette against the bright background (Credit: ESO/L.N. Fletcher), the right hand image is an amateur observation acquired at nearly the same time (Credit: D. Peach).
ESO/L.N. Fletcher/D. Peach

But during all of these unique observations, the intrepid Juno spacecraft will be taking a pummelling from the high-energy particles within Jupiter’s harsh radiation belts, equivalent to 100m dental X-rays in the first year alone. No spacecraft has ever had to cope with such severe conditions. Even with the instrument components shielded in a vault with 1cm thick titanium walls, there will still be an accumulation of radiation damage and a degradation of equipment.

No one knows exactly how the instruments will fare as the long-suffering spacecraft heroically battles on to complete its 20-month mission. But one thing is certain – Jupiter’s cloak of clouds will no longer shroud its mischief, as Juno’s instruments gaze down into the heart of the giant for the first time.

The ConversationLeigh Fletcher, Royal Society Research Fellow, University of Leicester

This article was originally published on The Conversation. Read the original article.

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