Connect with us

The Milky Way galaxy is our home, and yet in some ways, it is the least understood galaxy. One of the biggest challenges astronomers have is in understanding its large-scale structure. Because we’re in the midst of it all, mapping our galaxy is a bit like trying to map the size and shape of a wooded park while standing in the middle of it.

One of the ways astronomers can map our galaxy is to measure the position and distance of thousands upon thousands of stars. This is one of the main goals of the Gaia mission, which studies the location and motion of more than a billion stars. Gaia has already revealed details in the structure of the Milky Way, such as a wave pattern among some stars.

pia24577 1024x576 2
The Eagle, Omega, Triffid, and Lagoon Nebulae, imaged by NASA’s infrared Spitzer Space Telescope. Credit: NASA/JPL-Caltech

Another method is to look at specific objects in our galaxy, such as star-forming nebulae. Star-forming nebulae tend to be located within the spiral arms of a galaxy, where there is the most gas and dust. The Spitzer infrared space telescope has measured the distances to young stars within many nebulae, which helped us confirm that the Milky Way has four main spiral arms.

A new study combines data from Gaia and Spitzer, comparing the location of some nebulae with the overall spiral distribution of stars.[^1] The study focused on a main spiral arm within the galaxy known as the Sagittarius Arm. It is the spiral arm just inward from the Sun’s arm of Orion. The team hoped to measure an aspect of the spiral arm known as the pitch angle. It tells you how tightly wound a spiral arm is. The larger the pitch angle, the more open the spiral arms are. In the case of the Sagittarius Arm, the pitch angle is about 12 degrees. But pitch the angle of some nebulae are very different.

break 1024x574 1
Astronomers found a break in our galaxy’s Sagittarius Arm. Credit: NASA/JPL-Caltech

The team looked at four prominent nebulae in our night sky: the Eagle Nebula (which contains the Pillars of Creation), the Omega Nebula, the Trifid Nebula, and the Lagoon Nebula. These four nebulae are in the same general region and were used in the 1950s to confirm the existence of the Sagittarius Arm. This new study pinned down the location of these nebulae and other stars and found the region has a pitch angle of 60 degrees.

This doesn’t mean our original measure of the Sagittarius Arm is wrong, but it does point to a type of structure known as galactic spurs. Some spiral galaxies have very smooth spiral arms, where gas, dust, and star-forming regions are all along the same curve. Other spiral galaxies have more broken spiral arms, with small feathery offshoots called spurs. We don’t know for sure which type of galaxy the Milky Way is, but this new study points to it being the latter.

Reference: Kuhn, M. A., et al. “A high pitch angle structure in the Sagittarius Arm.” Astronomy & Astrophysics 651 (2021): L10.

The post The Milky Way Broke one of its Arms appeared first on Universe Today.

Did you miss our previous article…
https://www.mansbrand.com/james-webbs-upper-stage-is-off-to-the-launch-site/

Frontier Adventure

Stellar Winds Coming From Other Stars Measured for the First Time

interstellar jpg

An international research team led by the University of Vienna has made a major breakthrough. In a study recently published in Nature Astronomy, they describe how they conducted the first direct measurements of stellar wind in three Sun-like star systems. Using X-ray emission data obtained by the ESA’s X-ray Multi-Mirror-Newton (XMM-Newton) of these stars’ “astrospheres,” they measured the mass loss rate of these stars via stellar winds. The study of how stars and planets co-evolve could assist in the search for life while also helping astronomers predict the future evolution of our Solar System.

The research was led by Kristina G. Kislyakova, a Senior Scientist with the Department of Astrophysics at the University of Vienna, the deputy head of the Star and Planet Formation group, and the lead coordinator of the ERASMUS+ program. She was joined by other astrophysicists from the University of Vienna, the Laboratoire Atmosphères, Milieux, Observations Spatiales (LAMOS) at the Sorbonne University, the University of Leicester, and the Johns Hopkins University Applied Physics Laboratory (JHUAPL).

Astrospheres are the analogs of our Solar System’s heliosphere, the outermost atmospheric layer of our Sun, composed of hot plasma pushed by solar winds into the interstellar medium (ISM). These winds drive many processes that cause planetary atmospheres to be lost to space (aka. atmospheric mass loss). Assuming a planet’s atmosphere is regularly replenished and/or has a protective magnetosphere, these winds can be the deciding factor between a planet becoming habitable or a lifeless ball of rock.

interstellar 1 jpg
Logarithmic scale of the Solar System, Heliosphere, and Interstellar Medium (ISM). Credit: NASA-JPL

While stellar winds mainly comprise protons, electrons, and alpha particles, they also contain trace amounts of heavy ions and atomic nuclei, such as carbon, nitrogen, oxygen, silicon, and even iron. Despite their importance to stellar and planetary evolution, the winds of Sun-like stars are notoriously difficult to constrain. However, these heavier ions are known to capture electrons from neutral hydrogen that permeates the ISM, resulting in X-ray emissions. Using data from the XXM-Newton mission, Kislyakova and her team detected these emissions from other stars.

These were 70 Ophiuchi, Epsilon Eridani, and 61 Cygni, three main sequence Sun-like stars located 16.6, 10.475, and 11.4 light-years from Earth (respectively). Whereas 70 Ophiuchi and 61 Cygni are binary systems of two K-type (orange dwarf) stars, Epsilon Eridani is a single K-type star. By observing the spectral lines of oxygen ions, they could directly quantify the total mass of stellar wind emitted by all three stars. For the three stars surveyed, they estimated the mass loss rates to be 66.5±11.1, 15.6±4.4, and 9.6±4.1 times the solar mass loss rate, respectively.

In short, this means that the winds from these stars are much stronger than our Sun’s, which could result from the stronger magnetic activity of these stars. As Kislyakova related in a University of Vienna news release:

“In the solar system, solar wind charge exchange emission has been observed from planets, comets, and the heliosphere and provides a natural laboratory to study the solar wind’s composition. Observing this emission from distant stars is much more tricky due to the faintness of the signal. In addition to that, the distance to the stars makes it very difficult to disentangle the signal emitted by the astrosphere from the actual X-ray emission of the star itself, part of which is “spread” over the field-of-view of the telescope due to instrumental effects.”

608c8c49dc jpeg
XMM-Newton X-ray image of the star 70 Ophiuchi (left) and
Did you miss our previous article…
https://mansbrand.com/how-to-know-how-hard-a-hike-will-be-3/

Continue Reading

Frontier Adventure

How to Know How Hard a Hike Will Be

Tet19 047 Me on Teton Crest Trail copy cropped 16 jpg

By Michael Lanza

“How hard will that hike be?” That’s a question that
all dayhikers and backpackers, from beginners to experts, think about all the
time—and it’s not always easy to answer. But there are ways of evaluating the
difficulty of any hike, using readily available information, that can greatly
help you understand what to expect before you even leave home. Here’s
how.

No matter how relatively easy or arduous the hike you’re considering, or where you fall on the spectrum of hiking experience or personal fitness level, this article will tell you exactly how to answer that question—and which questions to ask and what information to seek to reach that answer. This article shares what I’ve learned over four decades of backpacking and dayhiking, including the 10 years I spent as a field editor for Backpacker magazine and even longer running this blog, and this knowledge can help ensure that you and your companions or your family don’t get in over your heads.

Whether you’re new to dayhiking or backpacking, a
parent planning a hike with young kids, or a fit and experienced dayhiker or
backpacker contemplating one of the toughest hikes you’ve ever attempted, it’s
important to have a good sense of what you’ll face on a new and unfamiliar hike
and whether it’s within your abilities.

Tet19 047 Me on Teton Crest Trail copy cropped 17 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 backpacker hiking the Dawson Pass Trail in Glacier National Park.
” data-image-caption=”Pam Solon backpacking the Dawson Pass Trail in Glacier National Park. Click photo to read about backpacking in Glacier.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park-1024×683.jpg?resize=900%2C600&ssl=1″ alt=”A backpacker hiking the Dawson Pass Trail in Glacier National Park.” class=”wp-image-61235″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg 150w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/12/06224534/Gla7-117-Pam-Solon-backpacking-the-Dawson-Pass-Trail-in-Glacier-National-Park.jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Pam Solon backpacking the Dawson Pass Trail in Glacier National Park. Click photo to read about backpacking in Glacier.

Exceeding your limits or those of someone with you can
invite unwanted consequences—and the person with the least stamina,
abilities, or experience often dictates any party’s pace, limits, and outcomes.
Those consequences
Did you miss our previous article…
https://mansbrand.com/the-12-best-down-jackets-of-2024/

Continue Reading

Frontier Adventure

The 12 Best Down Jackets of 2024

Tet19 047 Me on Teton Crest Trail copy cropped 14 jpg

By Michael Lanza

Whatever you need an insulated jacket for, there’s a down or synthetic puffy for your needs, within your budget. And whether you want a puffy jacket for outdoor activities like backpacking, camping, skiing, climbing, and hut treks, or just to keep you warm around town or at outdoor sporting events, this review will help you figure out how to choose the right jacket for your purposes, and it spotlights the best down and synthetic insulated jackets available today.

I selected the jackets covered in this review after extensive testing on backpacking, camping, backcountry ski touring, climbing and other backcountry trips. I’ve field-tested dozens of insulated jackets over nearly three decades of testing and reviewing gear, formerly as the lead gear reviewer for Backpacker magazine for 10 years and even longer running this blog.

Technology has blurred the traditional lines between down and synthetics, with water-resistant down that traps heat even when wet—all but eliminating the weakness that had long been the Achilles heel of down—and synthetic insulation materials that approach the warmth-to-weight ratio and compressibility of down.

If you’d prefer, scroll past my buying tips to dive immediately into the jacket reviews.

If you have a question for me or a comment on this review, please leave it in the comments section at the bottom of this story. I try to respond to all comments.

Tet19 047 Me on Teton Crest Trail copy cropped 15 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 Black Diamond Approach Down Hoody.
” data-image-caption=”The Black Diamond Approach Down Hoody in the Grand Canyon.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1-1024×683.jpg?resize=900%2C600&ssl=1″ alt=”The Black Diamond Approach Down Hoody.” class=”wp-image-52287″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg 150w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2022/04/06225653/Black-Diamond-Approach-Down-Hoody-hood-up-1.jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />The Black Diamond Approach Down Hoody in the Grand Canyon.

How to Choose a Synthetic or Down Jacket

Insulated jackets today differ not only in type and amount of insulation, but also in water resistance, breathability, and as always, design features like the hood and pockets. When choosing between down and synthetic models, consider the usual conditions and temperatures in which you’ll use it—in other words, how wet and cold you expect to get, and your body type (how easily you get cold)—as well as the seasonal and activity versatility you require. Some questions to
Did you miss our previous article…
https://mansbrand.com/finally-an-explanation-for-the-moons-radically-different-hemispheres/

Continue Reading

Trending