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As of this month, astronomers have discovered 5,506 exoplanets orbiting other stars. That number is growing daily, and astronomers are hoping, among other things, to find Earth-like worlds. But will we know one when we see it? How might we be able to tell an Earth-like garden from a Venus-like pressure cooker from upwards of 40 light years away? Is JWST up to the challenge?

In a paper released in preprint earlier this week, four researchers used a simulation to put the space telescope to the test. They found that there are indeed telltale signatures that should help us parse the exoVenuses from exoEarths – but there is a catch (we’ll come back to that).

This simulation worked like this: The researchers placed six Earth-like planets and six Venus-like planets 40 light years away, each with varying levels of carbon dioxide (CO2), cloud cover, and haze in their atmospheres. The simulated planets orbited around a star identical to TRAPPIST-1.

In the real world, TRAPPIST-1 is one of the most promising systems discovered so far in which astronomers hope to find an exoEarth. It features a dim red dwarf star (making observing its planets an easier task than it would be around a bright yellow star like our Sun). The system has seven rocky worlds, three or four of which might lie within the star’s habitable zone. JWST has already observed the innermost two planets, and found them to be barren rocks more akin to Mercury than to Earth or Venus.

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NASA/JPL-Caltech.

In the simulation, the orbits of the test planets were placed right on the ‘runaway greenhouse boundary’: the distance from the star where it’s possible for the same planetary catastrophe that turned Venus into a hellscape to occur.

The authors aimed a simulated JWST at the planets, matching the capabilities of the real telescope’s NIRCSpec instrument, which observes the wavelengths of light coming from distant worlds. Different compounds in the atmosphere show up as peaks, patterns, and spikes in the spectra, allowing researchers to see what chemical compounds are present.

But the data isn’t always clear-cut. Spectral signatures for some molecules hide the signatures of others, or mimic them, making it difficult to know for sure what we’re looking at.

“Venus-like clouds and hazes may prevent the detection of molecular species, or an atmosphere at all,” the authors write.

But that doesn’t mean impossible, and the model was intended to help determine what astronomers should be looking for. Here’s what they found:

First, if you want to determine whether a planet has an atmosphere at all, regardless of whether it is Earth-like or Venus-like, the best bet is to look for Carbon Dioxide (CO2). It has an easily detectible signal, and remains visible for both planets with clear skies and those with haze and clouds.

But CO2 is less useful for distinguishing between Earths and Venuses, because the signature of CO2 overlaps with both water and methane, confusing the data.

There is only one spectral feature that clearly shows up on a Venus-like planet and not on an Earth-like one: Sulfur Dioxide (SO2). SO2 reacts with water vapor, so if it is present, it would rule out a wet Earth-like planet and confirm a dry Venus-like one.

Here’s the catch. In the real world, Venus actually doesn’t have much SO2. UV radiation from the Sun has stripped it away.

But there’s still hope. Around a TRAPPIST-1-like red dwarf, SO2 would last much longer, making the detection of SO2 possible in that scenario.

“The reduced UV output from TRAPPIST-1 allows SO2 to have an extended lifetime in the exoVenus atmosphere, which enhances the possibility of the SO2 being detectable,” the authors claim.

As for an Earth-like planet, the best signature to look for is methane. There are absorption features of methane that don’t show up on Venus, and can be clearly distinguished from CO2. Furthermore, if methane is accompanied by oxygen, it may be evidence of life.

The
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New Simulation Explains how Supermassive Black Holes Grew so Quickly

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One of the main scientific objectives of next-generation observatories (like the James Webb Space Telescope) has been to observe the first galaxies in the Universe – those that existed at Cosmic Dawn. This period is when the first stars, galaxies, and black holes in our Universe formed, roughly 50 million to 1 billion years after the Big Bang. By examining how these galaxies formed and evolved during the earliest cosmological periods, astronomers will have a complete picture of how the Universe has changed with time.

As addressed in previous articles, the results of Webb‘s most distant observations have turned up a few surprises. In addition to revealing that galaxies formed rapidly in the early Universe, astronomers also noticed these galaxies had particularly massive supermassive black holes (SMBH) at their centers. This was particularly confounding since, according to conventional models, these galaxies and black holes didn’t have enough time to form. In a recent study, a team led by Penn State astronomers has developed a model that could explain how SMBHs grew so quickly in the early Universe.

The research team was led by W. Niel Brandt, the Eberly Family Chair Professor of Astronomy and Astrophysics at Penn State’s Eberly College of Science. Their research is described in two papers presented at the 244th meeting of the American Astronomical Society (AAS224), which took place from June 9th to June 13th in Madison, Wisconsin. Their first paper, “Mapping the Growth of Supermassive Black Holes as a Function of Galaxy Stellar Mass and Redshift,” appeared on March 29th in The Astrophysical Journal, while the second is pending publication. Fan Zou, an Eberly College graduate student, was the lead author of both papers.

Illustration of an active quasar. What role does its dark matter halo play in activating the quasar? Credit: ESO/M. Kornmesser
Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

As they note in their papers, SMBHs grow through two main channels: by accreting cold gas from their host galaxy or merging with the SMBHs of other galaxies. When it comes to accretion, previous research has shown that a black hole’s accretion rate (BHAR) is strongly linked to its galaxy’s stellar mass and the redshift of its general stellar population. “Supermassive black holes in galaxy centers have millions-to-billions of times the mass of the Sun,” explained Zhou in a recent NASA press release. How do they become such monsters? This is a question that astronomers have been studying for decades, but it has been difficult to track all the ways black holes can grow reliably.”

For their research, the team relied on forefront X-ray sky survey data obtained by NASA’s Chandra X-ray Observatory, the ESA’s X-ray Multi-Mirror Mission-Newton (XMM-Newton), and the Max Planck Institute for Extraterrestrial Physics’ eROSITA telescope. They measured the accretion-driven growth in a sample of 8000 active galactic nuclei (AGNs) located in 1.3 million galaxies. This was combined with IllustrisTNG, a suite of state-of-the-art cosmological simulations that model galaxy formation, evolution, and mergers from Cosmic Dawn to the present. This combined approach has provided the best modeling to date of SMBH growth over the past 12 billion years. Said Brandt:

“During the process of consuming gas from their hosting galaxies, black holes radiate strong X-rays, and this is the key to tracking their growth by accretion. We measured the accretion-driven growth using X-ray sky survey data accumulated over more than 20 years from three of the most powerful X-ray facilities ever launched into space.

“In our hybrid approach, we combine the observed growth by accretion with the simulated growth through mergers to reproduce the growth history of supermassive black holes. With this new approach, we believe we have produced the most realistic picture of the growth of supermassive black holes up to the present day.”

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This still image shows the timeline running from the Big
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10 Tips for Taking Kids on Their First Backpacking Trip

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By Michael Lanza

Whether you’re a family of novices planning your first backpacking trip or an experienced backpacker ready to take your kids on their first multi-day hike, heed this friendly advice: You’re in for some surprises. And I speak from experience. I’d been backpacking for years—in fact, I was already working as a professional backpacker—when my wife (also a longtime backpacker) and I first dove into the grand new adventure of taking our young kids into the wilderness.

We learned a lot. But the biggest lesson was this: Our backcountry adventures brought us closer together as a family and helped mold our children into eager and skilled backpackers and confident young adults with a passion and appreciation for the outdoors—and who seize every chance to spend time with us (their parents!) outdoors (and indoors!).

This article shares lessons I learned while taking our kids on countless backpacking trips since they were quite little and over the course of the 10 years I spent as Northwest Editor of Backpacker magazine and even longer running this blog.

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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 young girl backpacking the High Sierra Trail above Hamilton Lakes, Sequoia National Park.
” data-image-caption=”My daughter, Alex, backpacking the High Sierra Trail above Hamilton Lakes, Sequoia National Park, which is also the lead photo at the top of this story.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg?fit=300%2C199&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg?fit=900%2C598&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2-1024×680.jpg?resize=900%2C598&ssl=1″ alt=”A young girl backpacking the High Sierra Trail above Hamilton Lakes, Sequoia National Park.” class=”wp-image-45459″ srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg 1024w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg 300w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg 150w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2020/05/06230302/Sierra3-040-High-Sierra-Trail-above-Hamilton-Lakes-Sequoia-N.P.-CA-2.jpg 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />My daughter, Alex, backpacking the High Sierra Trail above Hamilton Lakes, Sequoia National Park.

Follow the tips below to make your family backpacking trips a success and ensure that your kids want to go again and again. Like many stories at The Big Outside, much of this one is free for anyone to read but reading the entire story requires a paid subscription. If you’re already a subscriber, thank you for supporting my blog.

Please share your thoughts, questions, or your own tips in the comments section at the bottom of this story. I try to
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A Survival Guide For the Outdoors Lover Who’s a New Parent

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By Michael Lanza

So, you’ve been an avid [circle all appropriate terms: hiker/backpacker/climber/trail runner/skier/kayaker] for years, and now you’re spending big chunks of your days changing diapers and your nights wondering when you’ll sleep again. You’ve never gone this long without getting out into the mountains, and you see no remedy for that shortfall in the foreseeable future. Your new baby is more wonderful than you’d ever imagined—and yet, you’re feeling a little despair over what’s missing from your life lately.

I know where your head is right now. And I have good news for you: I’ve reached the bright light at the end of the tunnel, and you can get there faster than you might think. Here’s how.

A family on a hike in Idaho’s City of Rocks National Reserve.
” data-image-caption=”My family on a hike in Idaho’s City of Rocks National Reserve. Click photo to read my “10 Tips for Raising Outdoors-Loving Kids.”
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2017/06/06235050/Us-4-at-COR-June04.jpg?fit=244%2C300&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2017/06/06235050/Us-4-at-COR-June04.jpg?fit=521%2C640&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2017/06/06235050/Us-4-at-COR-June04.jpg?resize=521%2C640&ssl=1″ alt=”My family on a hike in Idaho’s City of Rocks National Reserve.” class=”wp-image-23944″ srcset=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2017/06/06235050/Us-4-at-COR-June04.jpg?resize=521%2C640&ssl=1 521w, https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2017/06/06235050/Us-4-at-COR-June04.jpg?resize=521%2C640&ssl=1 244w, https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2017/06/06235050/Us-4-at-COR-June04.jpg?resize=521%2C640&ssl=1 200w” sizes=”(max-width: 521px) 100vw, 521px” data-recalc-dims=”1″ />My family on a hike in Idaho’s City of Rocks National Reserve.

First of all, I know it’s hard to take a long view when you’re so deeply buried in the day-to-day management of a hectic life. But as a father of two young adults, I can tell you that growing children race through development stages—each one very different—with blinding speed. While in many respects the infant and toddler years are the most demanding (and cutest), and can seem eternal at times, they do pass. In my experience, parenting keeps getting better.

But for now, you need some strategies for surviving the early years of parenting, when you face the greatest demands on your personal time—and your sanity.

The following tips reflect what I’ve learned from more than 20 years as a parent who has always strived to get outside as much as possible—dayhiking, backpacking, climbing, running, paddling, skiing—with my family whenever I can, but also, at times without them.

Please share your questions or tips in the comments section at the bottom of this story. I try to respond to all comments. Click on any photo to read about that trip.

Tet19 047 Me on Teton Crest Trail copy cropped 31
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 baby girl in Skillern Hot Springs, Smoky Mountains, Idaho.
” data-image-caption=”My daughter, Alex, at Skillern Hot Springs, Smoky Mountains, Idaho. Click photo to read my “10 Tips for Raising Outdoors-Loving Kids.”
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2014/05/07010457/Alex-at-Skillern-Hot-Springs-Smoky-Mtns-ID-2.jpg
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