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Dark Matter is Nature’s poltergeist. We can see its effects, but we can’t see it, and we don’t know what it is. It’s as if Nature is playing tricks on us, hiding most of its mass and confounding our efforts to determine what it is.

It’s all part of the Universe’s “missing mass” problem. Actually, it’s our problem. The Universe is what it is. It’s our understanding of the Universe, mass, and gravity that’s the problem. And a solution is proving to be elusive.

Whatever the missing mass is or whatever causes the effects we observe, we have a placeholder name for it: dark matter. And it makes up 85% of the matter in the Universe.

Could dark matter be primordial black holes? Could it be axions? How about WIMPS? Are dark photons its force carrier? There’s lots of theoretical thought but no conclusion.

New research in the Monthly Notices of the Royal Astronomical Society says that our hunt for dark matter may be off-track. Instead of looking for a type of particle, the solution might lie in a type of topological defect found throughout the Universe that has its roots in the Universe’s early stages.

The new research is in a paper titled “The binding of cosmological structures by massless topological defects.” The author is Richard Lieu, a distinguished professor of physics and astronomy at the University of Alabama at Huntsville.

“There is then no need to perpetuate this seemingly endless search for dark matter.”

Dr. Richard Lieu, Professor, University of Alabama, Huntsville

As the paper’s title makes clear, dark matter has a binding effect on structures like galaxies. Astronomers know that galaxies don’t have enough measurable mass to hold themselves together. By measuring the mass of the stars and gas in galaxies, it became clear that the visible components of the galaxies don’t provide enough mass to hold themselves together. They should simply dissipate into their constituent stars and clouds of gas.

But galaxies don’t dissipate, and scientists have concluded that something is missing. Professor Lieu has another idea.

“My own inspiration came from my pursuit for another solution to the gravitational field equations of general relativity — the simplified version of which, applicable to the conditions of galaxies and clusters of galaxies, is known as the Poisson equation — which gives a finite gravitation force in the absence of any detectable mass,” said Lieu. “This initiative is in turn driven by my frustration with the status quo, namely the notion of dark matter’s existence despite the lack of any direct evidence for a whole century.”

An entire century is a long time in the age of modern science. It’s not surprising that Nature has the power to confound us, but it is somewhat surprising that very little progress has been made on the problem. Scientists have made great progress in understanding how dark matter influences the Universe’s large-scale structure, an impressive feat, but haven’t figured out what it is.

“The nature of dark matter (DM), defined specifically in this letter as an unknown component of the cosmic substratum responsible for the extra gravitational field that binds galaxies and clusters of galaxies, has been an enigma for more than a century,” Dr. Lieu writes in his paper.

Lieu’s work leans on phase transitions in the Universe. These are episodes when the state of matter in the Universe changes. Not locally but across the entire cosmos. One example is when the Universe cooled enough to allow the strong force to bind quarks into protons and neutrons.

Dr. Lieu contends that topological defects could have formed during one of these phase transitions. These defects can take the shape of shell-like compact regions where matter density is much higher. When arranged in concentric rings, these defects behave like gravity but don’t have mass.

“It is unclear presently what precise form of phase transition in the universe could give rise to topological defects of this sort,” Lieu says. “Topological effects are very compact regions of space with a very high density of matter, usually in the form of linear structures known as cosmic strings, although 2-D structures such as spherical shells are also possible. The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers — which is all one could measure, mass-wise — is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell.”

So, despite our inability to measure the mass, it’s there, and other objects respond to it. Mass warps space-time and affects even massless photons. That fact underlies our ability to use gravitational lensing. We use the mass of galaxy clusters in gravitational lensing. A set of spherical shells, as Lieu talks about,
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Frontier Adventure

Bear Essentials: How to Store Food When Backcountry Camping

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By Michael Lanza

On our first night in the backcountry of Yosemite National Park on one of my earliest backpacking trips, two friends and I—all complete novices—hung our food from a tree branch near our camp. Unfortunately, the conifer trees around us all had short branches: Our food stuff sacks hung close to the trunk.

During the night, the predictable happened: We awoke to the sound of a black bear clawing up the tree after our food.

Despite our nervousness and incompetence, we somehow managed to shoo that black bear off, though not before he (or she) departed with a respectable haul from our food supply. But by virtue of having started out with way more food than we needed—another rookie mistake that, ironically, compensated for this more-serious rookie mistake (read my tips on not overpacking)—we made it through that hike without going hungry and ultimately had a wonderful adventure.

And we went home with a valuable lesson learned.

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Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-books to classic backpacking trips. Click here to learn how I can help you plan your next trip.

A black bear along the Sol Duc River Trail in Olympic National Park.
” data-image-caption=”A black bear along the Sol Duc River Trail in Olympic National Park.
” data-medium-file=”″ data-large-file=”″ tabindex=”0″ role=”button” src=”×685.jpg?resize=900%2C602&ssl=1″ alt=”A black bear along the Sol Duc River Trail in Olympic National Park.” class=”wp-image-34782″ srcset=” 1024w, 300w, 768w, 1080w, 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />A black bear along the Sol Duc River Trail in Olympic National Park.

I’ve learned much more about storing food properly in the backcountry over the more than three decades since that early trip, including the 10 years I spent as the Northwest Editor of Backpacker magazine and even longer running this blog. This article shares what I’ve learned about protecting food from critters like bears and, more commonly, mice and other small animals and some birds like ravens.

Follow the tips below and you’ll not only save yourself and your party or family from going hungry, you might save a bear from developing a habit of seeing humans as sources of food, which too often leads to a bad outcome for that animal.

If you have any questions or tips of your own to share, please do so in the comments section at the bottom of this
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The Rugged Desert Moss Best Equipped to Survive on Mars


For decades, we have seen Mars as a desolate landscape devoid of any signs of life. Attempt to identify ways of growing plants and food on the red planet have focussed on greenhouse like structures to enable plants to survive, that is, until now! A desert moss called ‘Syntrichia caninervis’ has been identified and it can grown in extreme environments like Antarctica and the Mojave Desert. A new study revealed the moss can survive Mars-like environments too including low temperatures, high levels of radiation and drought. 

Mars has often be referred to as the “Red Planet” for its distinct red hue. It is the fourth planet from the Sun and to some extent resembles the Earth. Polar ice caps, seasonal weather patterns, extinct volcanoes, ancient riverbeds and flood plains are among the many surface features and. This cold world has fascinated us for centuries and its thin atmosphere, mostly made up of carbon dioxide, has been subjected to lots of studies. It has been thought for many years that it experiences some of the harshest weather conditions, including planet-wide dust storms but the recent study suggests there may just be a plant on Earth capable of surviving these conditions. 

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Mars, Credit NASA

Exploring and colonising planets like Mars can enhance human sustainability. Since no life forms have been found on Mars, introducing Earth organisms might be necessary for creating suitable conditions for human life in a process known as terraforming. This will involve selecting or engineering plants that can thrive in the harsh environments of an alien world. Few studies have tested organisms’ ability to withstand extreme environments of space or Mars, focusing mainly on microorganisms, algae, and lichens. However until recently, studies including mosses and whole plants have been lacking.

There have been many long term plans and even whimsical ideas to establish settlements on Mars. Pivotal to the success is the establishment of adapted crops that can grow in controlled, synthetic environments. However, to develop such a plant requires significant progress and development before plants are capable of growing in the soils and harsh conditions. In the report by lead author Xiaoshuang Li and team the incredible resilience of a moss called Syntrichia caninervis (S. caninervis) to survive a Mars-like environment even after having lost more than 98% of its water content.

Studies into the resilience of the plants have shown they can withstand extremely low temperatures and regenerate even after being stored in a freezer at -80°C for five years or in liquid nitrogen for one month. S. caninervis also demonstrates high resistance to gamma radiation and can survive in simulated Martian conditions.

The study concluded that S. caninervis is among the most stress-tolerant organisms known. It shows how it is a real potential species for the colonisation of alien worlds like Mars. The resilience to extreme conditions such as desiccation, low temperatures, and high radiation makes it an ideal for future terraforming efforts. It helps to understand the unique properties of this moss (in particular) and how it can form a foundational layer for biologically sustainable human habitats in space.

Source : The extremotolerant desert moss Syntrichia caninervis is a promising pioneer plant for colonizing extraterrestrial environments

The post The Rugged Desert Moss Best Equipped to Survive on Mars appeared first on Universe Today.

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Do Planets Have the Raw Ingredients for Life? The Answer is in their Stars

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Finding planets that already have, or have the ingredients for intelligent life is a real challenge. It is exciting that new telescopes and spacecraft are in development that will start to identify candidate planets. Undertaking these observations will take significant amounts of telescope time so we need to find some way to prioritise which ones to look at first. A new paper has been published that suggests we can study the host stars first for the necessary raw elements giving a more efficient way to hunt for similar worlds to Earth. 

Exoplanets are planets that orbit stars outside our solar system. They have been identified in the thousands since the first discovery in 1992, totalling currently 5,288. They vary widely in size, composition, and orbit, ranging from gas giants like Jupiter to rocky, potentially habitable planets similar to Earth. Advanced telescopes and detection methods like the transit and radial velocity techniques have enabled the discovery of Earth-sized exoplanets. Their study not only enhances our understanding of planetary formation and evolution but also the search for extraterrestrial life. 

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This illustration shows what the hot rocky exoplanet TRAPPIST-1 b could look like. A new method can help determine what rocky exoplanets might have large reservoirs of subsurface water. Credits: NASA, ESA, CSA, J. Olmsted (STScI)

The search for extraterrestrial life is no easy feat. Looking for aliens or at least environments where extraterrestrial life could one day evolve means knowing what to look for. To star with we can assume life has three basic requirements; I) building block elements (i.e., CHNOPS – carbon, hydrogen, nitrogen, oxygen, phosphorous and sulphur,) II) a solvent to life’s reactions (generally, liquid water) and III) a thermodynamic disequilibrium. It is assumed that similar requirements might be universal in the Cosmos. There is of course a chance of life based on a completely different set of needs but if we are going to start somewhere then we may as well start looking for life like that found on Earth, otherwise well, who knows what to look for!

Life on Earth can gain energy from a wide range of different thermodynamic disequilibria, a great example is life that thrives at the bottom of the ocean, taking energy and indeed nutrients from thermal vents. More widely it relies upon chemical reactions where the an electron is lost or gained changing its oxidation state. This is known as redox disequilibrium. Each reaction requires special proteins called oxidoreductases. The process requires metals as catalysts and without them, the process is unable to progress. 

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A black smoker hydrothermal vent discovered in the Atlantic Ocean in 1979. It’s fueled from deep beneath the surface by magma that superheats the water. The plume carries minerals and other materials out to the sea. Courtesy USGS.

The distribution of these metals (which are more accurately known as transition metals) in the Universe varies significantly over time and space. Despite this wide ranging distribution across the cosmos, the role of these metals in enabling life has been largely overlooked in identifying astrobiological targets. The paper published by Giovanni Covone and Donato Giovannelli propose that the presence of certain elements is essential for
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