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The first stars were odd ducks. Nobody’s observed them yet (although astronomers are hopeful JWST might spot them someday) but their ghosts remain. Born more than 13.5 billion years ago, they were very different from most of those we know today. These were massive monsters made mostly of hydrogen and helium. And, when they exploded as supernovae, their “starstuff” got scattered to space. Astronomers have now found the chemical remains of those stars in three distant gas clouds observed by European Southern Observatory’s Very Large Telescope.

How can astronomers detect those remains? It’s a tough task because the succeeding generations of stars recycled the starstuff. When those “child” stars died, they scattered their own heavier elements throughout space, which, in turn, got used in the next generations of stars.

So, the very first stars and their remains are pretty much history. Or, are they? It turns out maybe not. “Primordial stars can be studied indirectly by detecting the chemical elements they dispersed in their environment after their death,” said Stefania Salvadori, Associate Professor at the University of Florence.

She and a colleague used data from the VLT to search for gas clouds with the chemical elements left over from the deaths of the first stars. Light from distant quasars passing through those clouds provided a way to look for those elements.

Astronomers analyze the chemical composition of distant clouds of gas using the light of a background object like a quasar as a beacon.  When the light of the quasar passes through the gas cloud, the chemical elements in it absorb different colors or wavelengths, leaving dark lines in the spectrum of the quasar. Each element leaves a different set of lines, so by studying the spectrum astronomers can work out the chemical composition of the intervening gas cloud. This is how astronomers found the chemical fingerprints of the first stars in three clouds of gas in the early Universe. Courtesy ESO.
 When the light of a quasar passes through a gas cloud, the chemical elements in it absorb different wavelengths. That leaves dark lines in the spectrum of the quasar. Each element leaves a different set of lines, so by studying the spectrum astronomers can work out the chemical composition of the intervening gas cloud. This is how astronomers found the chemical fingerprints of the first stars in three clouds of gas in the early Universe. Courtesy ESO.

Understanding Stellar Chemical Wreckage

The mass of these early stars and the strength of their explosions determined which elements were spread to space. The first ones may have been mainly hydrogen and helium, but they cooked up other elements inside their cores. That is, in fact, what stars do throughout their lives. They turn hydrogen into helium and other “heavy” elements in their cores. Typically, they form carbon, oxygen, silicon, and so on, all the way up to iron. When they die all that material gets scattered to interstellar space. Those like the Sun live fairly long lives and end up as white dwarfs. That’s after they go through a planetary nebula phase. Only the most massive ones die in supernova explosions.

An artist’s illustration of the first stars to appear in the universe.

Credit: N.R. Fuller, National Science Foundation

Those first massive stars died in really tremendous supernova explosions and those provided the chemical remains the astronomers found. However, some of those first explosions were not energetic enough to scatter elements like iron that existed in their cores.

The team had to take that into account, so they searched for gas clouds from stars that exploded as low-energy supernovae. The three they studied were in the early Universe and had very little iron but plenty of carbon and other elements.

Implications for Other Stars

Interestingly, the peculiar chemical composition in the clouds studied by Salvadori and her team shows up in many old stars in our own galaxy. These are second-generation stellar populations that formed directly from the “ashes” of the first ones. “Our discovery opens new avenues to indirectly study the nature of the first stars, fully complementing studies of stars in our galaxy,” explained Salvadori.

The second-generation ones had a much different, richer chemical composition than their “parents” from the early Universe. When they died, their “starstuff” became fodder for the third and subsequent generations.
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Fish Could Turn Regolith into Fertile Soil on Mars

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What a wonderful arguably simple solution. Here’s the problem, we travel to Mars but how do we feed ourselves? Sure we can take a load of food with us but for the return trip that’s a lot. If we plan to colonise the red planet we need even more. We have to grow or somehow create food while we are there. The solution is an already wonderfully simple ‘biosphere’ style system; a fish tank! New research suggests fish could be raised in an aquatic system and nutrient rich water can fertilise and grow plants in the regolith! A recent simulation showed vegetables could be grown in regolith fertilised by the fish tank water!

In the next few decades we may well see human beings colonise Mars. The red planet is 54.6 million km away which, even on board a rocket, takes about 7 months to get there! Future colonists could simply have supply ships drop all they need but that becomes ridiculously expensive to sustain and frankly, isn’t sustainable. The lucky people that colonise Mars will just have to find some way to grow what they need.

If you have watched ‘The Martian’ movie with Matt Damon you will know how unforgiving the Martian environment is. Ok the film was a little out on scientific accuracy in places but it certainly showed how inhospitable it really is there. Matt managed to cultivate a decent crop of potatoes in Martian regolith fertilised in human faeces.This may not be quite so practical in real life and there may be alternative, less smelly – and dangerous – alternatives. 

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NASA astronaut, Dr. Mark Watney played by Matt Damon, as he’s stranded on the Red Planet in ‘The Martian’. (Credit: 20th Century Fox)

Taking the assumption that colonists will have to grow fresh produce locally, a team of researchers decided to explore how feasible this might be. On first glance, it may seem not too great an idea after all, the atmosphere is toxic with 95% carbon dioxide (compared to just 0.04% on Earth). There is a similar length of day on Mars but being able to grow crops will require longer periods of lighting. It is possible at least water may be collected from the ice which forms on and in the Martian rocks. The rocks most certainly have water stored away but organic compounds that we know of.

The team wanted to see how fish could help and whether the water from the system could be used to impart nutrients into the Martian regolith. To test the idea, they setup an aquaponic system with fish in tanks to generate the nutrient rich liquid.

The results were very promising. They found that aquaponic systems not only facilitate growing plants within the system itself but the nutrient rich water performed as an excellent fertiliser. This took the organically deficient regolith and turned it into something akin to useable soil. The fish used in the study were tilapia (Oreochromis niloticus) and using them, the team managed to grow potatoes, tomatoes, beans, carrots and much more. To enable all this to happen, the fish received sufficient light and other environmental stimulus. The plants were grown and indeed thrived in a tent that simulated Mars in every way possible.

It’s an interesting aside that the study not only benefits future space travellers but those inhabitants of more environmentally hostile places on Earth.

Source : Fish and chips on Mars: our research shows how colonists could produce their own food

The post Fish Could Turn Regolith into Fertile Soil on Mars appeared first on Universe Today.

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How to Backpack the Teton Crest Trail Without a Permit

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By Michael Lanza

So you just got the inspired idea to backpack the Teton Crest Trail and discovered you’re months late to reserve a backcountry permit. You’ve probably also learned that it’s possible to get a walk-in backcountry permit for Grand Teton National Park—but competition for those is high, especially for the camping zones along the TCT.

So you’re wondering: Is it possible to backpack the Teton Crest Trail without a permit? In a word, the answer is: yes. It’s somewhat complicated and not easy, but this story explains how to do that.

The Teton Crest Trail deservedly sees sky-high demand for backcountry permits. It’s unquestionably one of the 10 best backpacking trips in America, incredibly scenic virtually every step from start to finish, featuring high passes with sweeping vistas, endless meadows bursting with wildflowers, beautiful lakes, creeks, and waterfalls, a good chance of seeing wildlife like elk and moose—and some of the best campsites you will ever pitch a tent in.

Tet19 047 Me on Teton Crest Trail copy cropped 37
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.

Backpackers on the Teton Crest Trail on Death Canyon Shelf, Grand Teton National Park.
” data-image-caption=”Backpackers on the Teton Crest Trail on Death Canyon Shelf, Grand Teton National Park. Click photo for my expert e-book to backpacking the Teton Crest Trail.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P.-1024×683.jpg?resize=900%2C600&ssl=1″ alt=”Backpackers on the Teton Crest Trail on Death Canyon Shelf, Grand Teton National Park.” class=”wp-image-38603″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg 1080w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231051/Tet19-018-Backpackers-on-the-Teton-Crest-Trail-Death-Canyon-Shelf-Grand-Teton-N.P..jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Backpackers on the Teton Crest Trail on Death Canyon Shelf, Grand Teton National Park. Click photo for my expert e-book to backpacking the Teton Crest Trail.

I’ve taken at least 20 trips in the Tetons and several on the Teton Crest Trail over the past three decades, including the 10 years I spent as Northwest Editor of Backpacker magazine and even longer running this blog.

See my story about my most-recent TCT trip, “A Wonderful Obsession: Backpacking the Teton Crest Trail,” which requires a paid subscription to

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Backpacking the Teton Crest Trail—A Photo Gallery

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By Michael Lanza

As we hiked up the North Fork of Cascade Canyon on the Teton Crest Trail in Grand Teton National Park, moments after the path emerged from the forest into a meadow strewn with boulders and still dappled with blooming wildflowers in late August, my friend David turned to look over his shoulder and blurted out, “Oh, wow, look at that view!” Behind us, the sheer north faces of the Grand Teton and Mount Owen towered a vertical mile above us, shooting straight up over the canyon like fireworks (photo above).

By that point on our trip, though, uncontrolled outbursts of awe were occurring several times a day. That’s what it’s like to backpack the Teton Crest Trail.

Tet19 047 Me on Teton Crest Trail copy cropped 35
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 backpacker on the Teton Crest Trail in Grand Teton National Park.
” data-image-caption=”Jeff Wilhelm backpacking the Teton Crest Trail in Grand Teton National Park. Click photo for my e-book “The Complete Guide to Backpacking the Teton Crest Trail.”
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg?fit=900%2C599&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401-1024×681.jpg?resize=900%2C599&ssl=1″ alt=”A backpacker on the Teton Crest Trail in Grand Teton National Park.” class=”wp-image-35224″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg 1080w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232037/DSC_2401.jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Jeff Wilhelm backpacking the Teton Crest Trail in Grand Teton National Park. Click photo for my e-book “The Complete Guide to Backpacking the Teton Crest Trail.”

Three friends and I backpacked a 36-mile traverse of Grand Teton National Park, mostly on the Teton Crest Trail, in late August—in many ways, an ideal time to hike there. While I’ve backpacked the TCT several times now, it was the first time for all three of them.

Seeing the reactions of these friends—every one of them very experienced backpackers who’ve taken numerous trips with me—to the scenery along this classic trek, reaffirmed my opinion that few multi-day hikes offer so much grandeur almost every step of way like the Teton Crest Trail. But I’ll let the photos in this story make that case.

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A backpacker on the Teton Crest Trail in Grand Teton National Park.
” data-image-caption=”David Gordon backpacking the Teton Crest Trail in Grand Teton National Park. Click photo to get my customized help planning your trip.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232029/DSC_2658.jpg?fit=300%2C175&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2019/09/06232029/DSC_2658.jpg?fit=900%2C525&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces
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