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Today, the greatest mysteries facing astronomers and cosmologists are the roles gravitational attraction and cosmic expansion play in the evolution of the Universe. To resolve these mysteries, astronomers and cosmologists are taking a two-pronged approach. These consist of directly observing the cosmos to observe these forces at work while attempting to find theoretical resolutions for observed behaviors – such as Dark Matter and Dark Energy.

In between these two approaches, scientists model cosmic evolution with computer simulations to see if observations align with theoretical predictions. The latest of which is AbacusSummit, a simulation suite created by the Flatiron Institute’s Center for Computational Astrophysics (CCA) and the Harvard-Smithsonian Center for Astrophysics (CfA). Capable of processing nearly 60 trillion particles, this suite is the largest cosmological simulation ever produced.

The creators of AbacusSummit announced the simulation suite in a series of papers that appeared in the Monthly Notices of the Royal Astronomical Society (MNRAS). Made up of more than 160 simulations, it models how particles behave in a box-shaped environment due to gravitational attraction. These models are known as N-body simulations and are intrinsic to modeling how dark matter interacts with baryonic (aka. “visible”) matter.

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The simulated distribution of dark matter in galaxies. Credit: Brinckmann et al.

The development of the AbacusSummit simulation suite was led by Lehman Garrison (a CCA research fellow) and Nina Maksimova and Daniel Eisenstein, a graduate student and professor of astronomy with the CfA (respectively). The simulations were run on the Summit supercomputer at the Oak Ridge Leadership Computing Facility (ORLCF) in Tennessee – overseen by the U.S. Department of Energy (DoE).

N-body calculations, which consist of computing the gravitational interaction of planets and other objects, are among the greatest challenges facing astrophysicists today. Part of what makes it daunting is that each object interacts with every other object, regardless of how far apart they are – the more objects under study, the more interactions that need to be accounted for.

To date, there is still no solution for N-body problems where three or more massive bodies are involved, and the calculations available are mere approximations. For example, the mathematics for calculating the interaction of three bodies, such as a binary star system and a planet (known as the “Three-Body Problem”), is yet to be resolved. A common approach with cosmological simulations is stopping the clock, calculating the total force acting on each object, moving time ahead slowly, and repeating.

For the sake of their research (which was led by Maksimova), the team designed their codebase (called Abacus) to take advantage of Summit’s parallel processing power – whereby multiple calculations can run simultaneously. They also relied on machine learning algorithms and a new numerical method, which allowed them to calculate 70 million particles per node/s at early times and 45 million particle updates per node/s at late times.

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A snapshot of one of the AbacusSummit simulations, shown at various zoom scales: 10 billion light-years across, 1.2 billion light-years across, and 100 million light-years across. Credit: The AbacusSummit Team/ layout by Lucy Reading-Ikkanda/Simons Foundation

As Garrison explained in a recent CCA press release:

“This suite is so big that it probably has more particles than all the other N-body simulations that have ever been run combined – though that’s a hard statement to be
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The 10 Best Backpacking Packs of 2024

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By Michael Lanza

Backpacks come in many sizes and designs for a reason: so do backpackers. Some of us need a pack for moderate loads, some for heavy loads, and others, increasingly, for lightweight or ultralight backpacking. Some prefer a minimalist pack, others a range of features and access. Everyone wants the best possible fit and comfort, and almost everyone has a budget. But no matter which type of backpacker you are, this review covers the best packs in each of those categories.

Each of my picks for the 10 best backpacking packs stands out for different reasons. I also point out two excellent packs for kids and small adults (at the bottom of the Gregory Paragon/Maven review). My judgments draw from many thousands of miles and more than three decades of backpacking and a quarter-century of testing and reviewing gear—including the 10 years I spent as the lead gear reviewer for Backpacker magazine and even longer running this blog. Few reviewers have lugged as many packs around the backcountry as me.

Tet19 047 Me on Teton Crest Trail copy cropped 3 jpg
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-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.

The Granite Gear Blaze 60 in the Grand Canyon.
” data-image-caption=”Testing the Granite Gear Blaze 60 in the Grand Canyon. Click photo to read about “the best backpacking trip in the Grand Canyon.”
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?resize=900%2C600&ssl=1″ alt=”The Granite Gear Blaze 60 in the Grand Canyon.” class=”wp-image-33676″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?resize=1024%2C683&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?resize=300%2C200&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?resize=768%2C512&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?resize=1080%2C720&ssl=1 1080w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/05/Granite-Gear-Blaze-60-lead-2.jpg?w=1200&ssl=1 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Testing the Granite Gear Blaze 60 in the Grand Canyon. Click photo to read about “the best backpacking trip in the Grand Canyon.”

I’m confident at least one of these packs will be perfect for you—plus you’ll find the best prices for them through the affiliate links to online retailers below. Purchasing gear through my affiliate links supports my work on this blog. Thanks for doing that.

I’ve listed the pack reviews below in order by weight because that’s the metric that most defines and influences a pack’s design and functionality. The ratings admittedly tend to favor more-featured packs, which are heavier, and that may not meet your needs; use the ratings as a comparison with packs of similar weight. The pack you ultimately choose may depend partly on weight, but also on design and on your budget. Each pack review in this article links to that pack’s complete review at The Big Outside.

A backpacker above Toxaway Lake, Sawtooth Mountains, Idaho.
” data-image-caption=”Testing the Osprey Aura AG 65 in Idaho’s Sawtooth Mountains. Click photo to read about the best backpacking trip in the Sawtooths.
” data-medium-file=”https://i0.wp.com/thebigoutside
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Hike the World’s Most Beautiful Trail: The Alta Via 2

Tet19 047 Me on Teton Crest Trail copy cropped jpg

By Michael Lanza

Hiking toward a mountain pass named Furcela dia Roa, on the first day of my family’s weeklong, hut-to-hut trek on the Alta Via 2 in northern Italy’s Dolomite Mountains, we stopped in an open meadow of grass and wildflowers overlooking a deep, verdant valley in Puez-Odle Natural Park. Across the valley loomed a wall of cliffs topped by jagged spires, like a castle a thousand feet tall. I looked at our map and back up at the stone wall before us, puzzled. After a moment, I realized: We have to get over that wall.

Scanning the vertiginous earth before us, I eventually picked out the trail snaking across the head of the valley and making dozens of switchbacks up a finger of scree, talus, and snow leading to the lowest notch in that wall: the Furcela dia Roa, the pass we had to cross.

Tet19 047 Me on Teton Crest Trail copy cropped 1 jpg
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 family trekking the Alta Via 2 in Parco Naturale Puez-Odle, Dolomite Mountains, Italy.
” data-image-caption=”My family trekking to Furcela dia Roa on the Alta Via 2 in Parco Naturale Puez-Odle, Dolomite Mountains, Italy.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?fit=300%2C199&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?fit=900%2C598&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=900%2C598&ssl=1″ alt=”A family trekking the Alta Via 2 in Parco Naturale Puez-Odle, Dolomite Mountains, Italy.” class=”wp-image-26784″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=1024%2C680&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=300%2C199&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=768%2C510&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=1080%2C717&ssl=1 1080w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=200%2C133&ssl=1 200w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?resize=670%2C445&ssl=1 670w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2018/02/Dolo1-019-Hiking-to-Furcela-dia-Roa-Alta-Via-2-Parco-Naturale-Puez-Odle-Dolomites-Italy-copy.jpg?w=1200&ssl=1 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />My family trekking to Furcela dia Roa on the Alta Via 2 in Parco Naturale Puez-Odle, Dolomite Mountains, Italy.

It was our first encounter with a lesson that would repeat itself many times over the course of our week of hiking on the Alta Via 2: These mountains are so steep and rocky that the trail often traverses ground that, from a distance, looks impassable without ropes and climbing gear.

But in reality, my family, including our young kids, were perfectly comfortable with the exposure, we never
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An AI Simulated Interactions Between Different Kinds of Advanced Civilizations

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The possibility for life beyond the Earth has captivated us for hundreds of years. It has been on the mind of science fiction writers too as our imaginations have explored the myriad possibilities of extraterrestrial life. But what would it really be like if/when we finally meet one; would it lead to war or peace? Researchers have used a complex language model to simulate the first conversations with civilisations from pacifists to militarists and the outcomes revealed interesting challenges.

The first radio transmissions were made in 1895 and since then the signals, however weak have been leaking out into space. The first intentional transmission out into space was the Arecibo message of 1974 that was sent toward the globular cluster M13 22,180 light years away. That means the signal won’t arrive there for about another 22,131 years! During this time of course, all the signals have been leaking out but the further they travel, the weaker they get. Its likely then that any signals out to a distance of about 100 light years is likely to be so weak as to not be detectable. 

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The Arecibo Radio Telescope Credit: UCF

It would be so easy to be dragged into other areas of debate about aliens but it feels useful to set the scene of how difficult it will be to make contact or rather, how likely it may be. Assume then, that in some way, we do find ourselves making communication with an alien civilisation. Just how that conversation goes has been modelled by a team led by Mingyu Jin from Northwestern University.

The team used a new artificial intelligence framework known as CosmoAgent to simulate the interaction based upon the unique Large Language Model (LLM). The system uses a Multi-Agent System to enable modelling among a diverse range of civilisations. The civilisations have the ability to choose their own character traits from hiding, fighting or collaborating. This dynamic environment allows for a plethora of outcomes from alliances forming, adherence to rules to rivalries to how a civilisation might respond to an unforeseen event.

Diversity and conditions for life were also inherent in the modelling using transition matrices to analyse how civilisations might grow and change over time. This natural progression of an intelligent life form would inevitably mean ethics, morals, beliefs and sciences would develop along a varied path. These different frameworks would hugely effect just how such a civilisation might respond to alien contact.

There are limitations to the research though, largely from an Earth-centric bias developing the language model. The use of mathematics and algorithms to compute responses and outcomes may not cover the full spectrum of inter-civilisation responses. After all, we cannot even distill our own emotional responses down to a set of algorithms. Add in a speculative set of principles of an alien civilisation, of which, we have no evidence or experience to draw upon.

It is hoped that future research can address these obstacles and develop better models of inter-civilisational interaction. Taking into account a broader range of ethical paradigms and decision making processes to provide a more realistic simulation of just how first contact may just play out.

Source : What if LLMs Have Different World Views: Simulating Alien Civilizations with LLM-based Agents

The post An AI Simulated Interactions Between Different Kinds of Advanced Civilizations appeared first on Universe Today.

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