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The early Universe is a puzzling and—in many ways—still-unknown place. The first billion years of cosmic history saw the explosive creation of stars and the growth of the first galaxies. It’s also a time when the earliest known black holes appeared to grow very massive quickly. Astronomers want to know how they grew and why they feed more like “normal” recent supermassive black holes (SMBH).

Today we see SMBH in galaxies that can have upwards of millions or billions of solar masses sequestered away. Astronomers naturally assumed that it took a long time for such monsters to build up. Like billions of years. So, when JWST observed the most distant quasar J1120+0641, they expected to see an active galactic nucleus as it looked some 770 million years after the Big Bang. That is, they expected a still-growing central supermassive black hole. They were intrigued to find that it had a mass of at least a billion suns.

This image of ULAS J1120+0641, a very distant quasar powered by a black hole, was created from images taken from surveys made by both the Sloan Digital Sky Survey and the UKIRT Infrared Deep Sky Survey. The quasar appears as a faint red dot close to the centre. This quasar is the most distant yet found and is seen as it was just 770 million years after the Big Bang.
This image of ULAS J1120+0641, a very distant quasar powered by a black hole, was created from images taken from surveys made by both the Sloan Digital Sky Survey and the UKIRT Infrared Deep Sky Survey. The quasar appears as a faint red dot close to the center. It’s the most distant yet found, seen as it was 770 million years after the Big Bang.

That raised a question: how could such an early SMBH get so big so fast? For something that young, having that much mass says something about its feeding mechanism. Astronomers already know that SMBH existed early in cosmic time. These structures at the hearts of those distant quasars apparently already existed when the Universe was very young—about 5% of its current age.

Theory vs Observation: How Do Supermassive Black Holes Form?

The growth of SMBH in the early Universe is a hot topic these days. The standard idea for a long time was that they grew slowly through mergers and acquisitions during galaxy formation. Since those mergers take a long time—millions of years, at least—it seemed that the black holes would go along for the long, slow ride. And, you can’t speed up black hole growth too much once one forms. As matter swirls into the black hole, it does so through the accretion disk that feeds it. The disk—the active galactic nucleus—is very bright due to the radiation emitted as the matter heats up through friction and magnetic field interactions. The light pressure pushes stuff away. That limits how quickly the black hole can eat. Still, astronomers found these early SMBH sporting 10 billion solar masses when, by conventional wisdom, they should have been less massive.

For J1120+0641, astronomers considered different scenarios for its growth, including a so-called “ultra-effective feeding mode”. That implies early SMBH had some very efficient way of accreting gas and dust and other material. So, astronomers looked at these active galactic nuclei at the hearts of distant quasars in more detail using JWST. It has the MIRI spectrograph that looks at the light from those quasars in great detail. The MIRI spectra of J1120+0641 revealed the presence of a large dust torus (a donut-shaped ring) surrounding the accretion disk of the SMBH. That disk is feeding the SMBH at a very “normal” rate similar to SMBH in the “modern” Universe. The quasar’s broad-line region, where clumps of gas orbit the black hole at speeds near the speed of light look normal, too.

Artist’s interpretation of ULAS J1120+0641, a very distant quasar with a supermassive black hole at its heart.
Credit: ESO/M. Kornmesser

In the Final Analysis

By almost all the properties that can be deduced from the spectrum, J1120+0641 turns out to be feeding no differently than quasars at later times. So, what does that mean for theories of SMBH formation in the early Universe? According to Sarah Bosman, who headed up the team that used JWST to study this and other quasars, the observations rule out fast feeding and other explanations for why the SMBH is so massive. “Overall, the new observations only add to the
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Galaxies Regulate their Own Growth so they Don’t Run Out of Star Forming Gas

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Look at most spiral or barred spiral galaxies and you will see multiple regions where stars are forming. These star forming regions are comprised of mostly hydrogen gas with a few other elements for good measure. The first galaxies in the Universe had huge supplies of this star forming gas. Left unchecked they could have burned through the gas quickly, generating enormous amounts of star formation. Life fast though and die young for such an energetic burst of star formation would soon fizzle out leaving behind dead and dying stars. In some way it seems, galaxies seem to regulate their star formation thanks to supermassive black holes at their centre. 

The first galaxies formed about 400 to 700 million years after the Big Bang, during the Epoch known as Reionization. These early galaxies were small and faint, mostly composed of hydrogen and helium, and contained dense clusters of massive, short-lived Population III stars (the first generation of stars.) The intense radiation from these stars ionised the surrounding gas, clearing the fog that permeated space making the universe transparent for the first time. These primordial galaxies began merging and interacting, laying the foundation for the galaxy types seen today.

A new study published in the Monthly Notices of the Royal Astronomical Society explores why galaxies are not as large as astronomers would expect. The research suggests that galaxies, even those that formed first, avoid an early death because they have mechanisms similar to “heart and lungs,” which regulate their “breathing”. Without these regulatory processes our bodies, and galaxies would have aged much faster, resulting in massive galaxies filled with dead and dying stars and devoid of new star formation.

Observations show that galaxies are not so big and full of dying stars having outgrown themselves. It seems something limits their ability to allow gas to form into stars. Astrophysicists at the University of Kent believe they may have the answer: galaxies could be controlling their growth rate through a process not too dissimilar to “breathing.” They compare the supermassive black hole at the centre of a galaxy to a heart and the supersonic jets emerging from the poles with the radiation and gas they emit to airways feeding a pair of lungs.

The supermassive black holes seem to pulse just like a heart. These pulses cause a shock front to oscillate along the jets like a diaphragm inflating and deflating the lungs. This process transmits energy along the jet slowly counteracting the pull of gravity and slowing gas accretion and star formation. The idea was developed by PhD student Carl Richards and his simulations showed a black hole pulsing like a heart. 

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Assisted by magnetic fields, a spiraling wind helps the supermassive black hole in galaxy ESO320-G030 grow. In this illustration, the core of the galaxy is dominated by a rotating wind of dense gas leading outwards from the (hidden) supermassive black hole at the galaxy’s center. The motions of the gas, traced by light from molecules of hydrogen cyanide, have been measured with the Atacama Large Millimeter/submillimeter Array. Image credit: M. D. Gorski/Aaron M. Geller, Northwestern University, CIERA, the Center for Interdisciplinary Exploration and Research in Astrophysics.

Richards explains “We realised that there would have to be some means for the jets to support the body – the galaxy’s surrounding ambient gas – and that is what we discovered in our computer simulations,” He continued “The unexpected behaviour was revealed when we analysed the computer simulations of high pressure and allowed the heart to pulse.”

Evidence of ripples just like those in Richards’ simulations, in extra-galactic media have been found in galaxy clusters like the Perseus cluster. These ripples are thought to sustain a galaxy’s environment, though their generation mechanism was unclear. Conventional simulations fail to explain gas flows into galaxies, but the work of the team from the University of Kent may well have answered the question.

Source : How the ‘heart and lungs’ of a galaxy extend its life.

The post Galaxies Regulate their Own Growth so they Don’t Run Out of Star Forming Gas appeared first on Universe Today.

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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=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg?fit=300%2C201&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg?fit=900%2C602&ssl=1″ tabindex=”0″ role=”button” src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2-1024×685.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=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg 1080w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/03/06232206/Olym6-070-Black-bear-Sol-Duc-River-Trail-Olympic-NP-WA-2.jpg 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

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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