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By Michael Lanza

While sleeping bags have temperature ratings, with down jackets and other insulated jackets, there exists no easy way to determine how warm any specific garment will be without wearing it outside. But despite the absence of a precise metric for gauging the warmth of down and synthetic puffy jackets, there are ways to assess a specific jacket’s relative warmth before you even see it, using simple metrics. This article will explain how to do that.

Even though down and synthetic-insulation jackets don’t have ratings like sleeping bags (which, by the way, were not uniform for many years, though there is now a uniform bag-rating system; learn more in my “Pro Tips For Buying Sleeping Bags“), you can judge warmth using numbers easily available online. Over more than 25 years of testing and reviewing dozens of insulated jackets (and other gear and apparel), including the 10 years I spent as the lead gear reviewer for Backpacker magazine and even longer running this blog, I have found those indicators very reliable in helping me anticipate how warm at down jacket will be before I ever wear it.

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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.

The Himali Accelerator Down Jacket.
” data-image-caption=”The Himali Accelerator Down Jacket in the White Goat Wilderness, Canadian Rockies.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket-1024×683.jpg?resize=900%2C600&ssl=1″ alt=”The Himali Accelerator Down Jacket.” class=”wp-image-60110″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg 150w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/09/06224742/Himali-Accelerator-Down-Jacket.jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />The Himali Accelerator Down Jacket in the White Goat Wilderness, Canadian Rockies.

The down fill weight is one way to tell, though it’s not strictly a measure of a jacket’s warmth—it’s only a measure of the total weight (in ounces or grams) of the down in the jacket. How much insulation is in the garment is obviously an important factor in warmth, but not the only one, because down comes in a range of quality ratings. And of course, various types of synthetic insulation have different weights and warmth-per-weight ratios.

The down fill rating (not to be confused with the down fill weight) is basically a quality metric, not an indicator of warmth. The fill rating refers to the volume, in cubic inches, that one ounce of that down fills; in other words, an ounce of 800-fill down will occupy 800 cubic inches of volume. Down feathers and other insulation keep you warm through trapping heat from your body in tiny air pockets within the insulation, so higher fill ratings mean more trapped air,
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Astronomers See a Black Hole Wake Up from its Ancient Slumber

Four years ago, the supermassive black hole hidden in the heart of galaxy SDSS1335+0728 roared awake and announced its presence with a blast of radiation. It marks the first time astronomers witnessed a sudden activation of a supermassive black hole in real time.

“Imagine you’ve been observing a distant galaxy for years, and it always seemed calm and inactive,” said Paula Sánchez Sáez, an astronomer at ESO in Germany and lead author of the study of this object. “Suddenly, its [core] starts showing dramatic changes in brightness, unlike any typical events we’ve seen before.”

This is what happened to SDSS1335+0728, which is now officially classified as having an active galactic nucleus (AGN). It experienced what’s called a “nuclear transient.” Essentially, that means the galaxy now has a very bright compact region. However, it wasn’t always that bright and astronomers want to understand what caused it to wake up.

This artist’s impression shows two stages in the formation of a disc of gas and dust around the massive black hole at the center of the galaxy SDSS1335+0728. The core of this galaxy lit up in 2019 and keeps brightening today — the first time astronomers observed a massive black hole become active as it happened. Credit: ESO/M. Kornmesser

Looking for Transients in all the Right Places

The unusual brightness variations were detected by the Zwicky Transient Facility in California, which gives constant, real-time alerts about such things as transient flaring and brightening in the hearts of galaxies like SDSS1335+0728. In addition, several other facilities observed the variations, too, and brightness changes were found in archival data from several other observatories.

The sudden brightenings could be due to many things, including the cannibalization of stars and clouds of gas that stray too near supermassive black holes. How often they brighten and how a quiescent galaxy nucleus changes to an active one are topics that astronomers are using such surveys and observations to understand. They’re looking not just at distant galaxies, but activity within the neighborhood of our own galaxy’s supermassive black hole, too.

Galaxy and Its Supermassive Black Hole

Most galaxies have stupendously massive black holes at their hearts. They typically sequester away at least a hundred thousand times the mass of the Sun (sometimes more). It’s all trapped by gravity and nothing ever escapes, not even light. “These giant monsters usually are sleeping and not directly visible,” said study co-author Claudio Ricci, from Chile’s Diego Portales University. “In the case of SDSS1335+0728, we were able to observe the awakening of the massive black hole, [which] suddenly started to feast on gas available in its surroundings, becoming very bright.”

A black hole itself doesn’t emit any light at all. Instead, it sucks everything in, including light. However, the region around the black hole—called the accretion disk—is a pretty active place. It’s where material trapped by the intense gravitational pull of the black hole swirls around like water going down a drain. All that stuff—mostly gas, some dust—is threaded through with magnetic fields. Friction between accretions of the material heats it up. And, that act of heating gives off radiation. If there’s enough of it, we see light being given off. Intense active regions emit x-rays, which indicate the level of activity.

Gravity’s Slice-and-dice Activity

There’s also something called tidal disruption, which happens when something like a star or a cloud of gas gets trapped in the gravitational field. These things take time—on the order of years to occur. When they happen, the gravitational pull of the black hole eventually rips the star or cloud apart. That also gives off radiation. In fact, a very slow-motion tidal disruption event may be occurring at the heart of SDSS1335+0728. If so, it could be one of the longest and dimmest ones ever seen.

Regardless of what’s causing the brightening, the ultimate fate of some of the material is to end up inside the black hole. The rest of it gets superheated in the accretion disk and signals its fate through increased radiation.

Black Hole Growth and a Wake-up Call

The supermassive black holes in the hearts of galaxies grow from smaller ones to larger ones through mergers. We don’t see those growth patterns in real time, since they occur over millions of years. The merger scenario says that when galaxies come together, their central black holes (if they have them) do, too.

Simulation of merging supermassive black holes. Credit: NASA's Goddard Space Flight Center/Scott NobleDid you miss our previous article…
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Photo Gallery: 40 Gorgeous Backcountry Lakes

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By Michael Lanza

Water makes up about 60 percent of our bodies—and, I suspect, 100 percent of our hearts. We crave it not only physically, for survival, but emotionally, for spiritual rejuvenation. We love playing in it for hours as children and we paddle and swim in it as adults. We’re drawn by the calming effects of sitting beside a stream or lake in a beautiful natural setting, an experience that possesses a certain je ne sais quoi—a quality difficult to describe, but that we can all feel.

And nothing beats taking a swim in a gorgeous backcountry lake.

I’ve come across quite a few wonderful backcountry lakes over more than three decades of exploring wilderness—including about 10 years as the Northwest Editor of Backpacker magazine and even longer running this blog. I’ve just updated and expanded this list of my favorites—adding five new lakes from trips I took last year in two places that are crazy with gorgeous lakes, Glacier National Park and the Wind River Range—to give you some eye candy as well as ideas for future adventures, and perhaps compare against your list of favorite backcountry lakes.

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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.

Click on the links to my stories in these brief writeups to learn more about each of these trips. Much of this story is free for anyone to read, but reading the entire story requires a paid subscription, which is also needed to read the individual stories about numerous trips at The Big Outside, and those include my tips on planning these trips. See my Custom Trip Planning page to learn how I can help you plan a trip to any of these lakes.

If you know some gorgeous lakes that are not on my list, please suggest them in the comments section below this story. I try to respond to all comments.

Here’s to your next peaceful moment beside a gorgeous lake deep in the mountains somewhere.

Elizabeth Lake in Glacier National Park.
” data-image-caption=”Early morning at Elizabeth Lake in Glacier National Park. Click photo to learn how I can help you plan your Glacier trip.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2-1024×683.jpg?resize=900%2C600&ssl=1″ alt=”Elizabeth Lake in Glacier National Park.” class=”wp-image-38774″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg 1080w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/03/06231037/Gla6-018-Elizabeth-Lake-in-Glacier-National-Park.-2.jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Elizabeth Lake in Glacier National Park.

Elizabeth Lake, Glacier
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It’s Not Just Rocks, Scientists Want Samples Mars’s Atmosphere

Mars Percy parkingspot PIA26202

Mars holds a very special place in our hearts. Chiefly because of all the other planets in the Solar System Mars is probably the place we are going to find some tantalising clues or maybe even evidence of prehistoric life. NASA Perseverance Rover has been trundling around the Jezero Crater looking for evidence that it was once hospitable to life. To that end it has not only been collecting rock samples but air samples too and scientists can’t wait to get their hands on them. 

The Mars Perseverance Rover is part of NASA’s Mars 2020 mission. It launched on 30 July 2020 and landed in the Jezero Crater successfully on 18 February 2021. The site was picked because it’s a dried up river bed and if there is any evidence of ancient primitive life on Mars, it is a likely location. Perseverance is equipped with a host of instruments including a drone named Ingenuity to survey the planet. 

Mars Perseverence rover sent back this image of its parking spot during Mars Solar Conjunction. Courtesy NASA/JPL-Caltech
Mars Perseverence rover sent back this image of its parking spot during Mars Solar Conjunction. Courtesy NASA/JPL-Caltech

One exciting element of the mission is the collection of rock samples as part of the Mars Sample Return Campaign. Twenty four core samples have been collected to date and deposited on the surface ready for collection by a future mission. It’s not just rock samples that have been collected though. Known as ‘headspace’ there is air in the space around the rock samples and it is this that has got scientists excited.

Not only do the rocks hold secrets about Mars but the atmosphere does too. It’s an atmosphere rich in Carbon Dioxide but is expected to have trace amounts of other gasses  too. Information about the current climate can be gained from the trapped gasses but it’s also possible to learn about the evolution of the atmosphere through analysis of the rocks. There is one particularly important tube that has been filled entirely with gas from the atmosphere. 

Mars atmosphere 1 750
Image of the Martian atmosphere and surface obtained by the Viking 1 orbiter in June 1976. (Credit: NASA/Viking 1)

With the sample sat on the surface of Mars potentially for many years, the gas trapped will interact with the rock in the sample tube. It will only be when the tubes are opened up when they arrive back here on the Earth that the interaction will cease. It’s hoped to understand more about the levels of water vapour near the Martian surface.

It isn’t just the water vapour that is of interest but the levels of trace gas too are of interest. Through analysing the gas samples we can tell if there are gasses like neon, argon and xenon which are non reactive gasses. Because these gasses do not react then there presence in the tube samples may suggest that Mars stated with an atmosphere. We know that it had a much thicker atmosphere in the past but we don’t know whether it has always been there or whether it developed later.

There are many benefits that will come from analysing the samples even, the prevalence of dust that will help future human exploration. As Justin Simon from NASA’s Johnson Space Center in Houston said “The gas samples have a lot to offer Mars scientists, even those who don’t study Mars would be interested because it will shed light on how the planet forms and evolves.”

Source : Why Scientists Are Intrigued by Air in NASA’s Mars Sample Tubes

The post It’s Not Just Rocks, Scientists Want Samples Mars’s Atmosphere appeared first on Universe Today.

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