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Black holes are more than just massive objects that swallow everything around them – they’re also one of the universe’s biggest and most stable energy sources.  That would make them invaluable to the type of civilization that needs huge amounts of power, such as a Type II Kardashev civilization.  But to harness all of that power, the civilization would have to encircle the entire black hole with something that could capture the power it is emitting. 

One potential solution would be a Dyson sphere – a type of stellar mega engineering project that encapsulates an entire star (or, in this case, a black hole) in an artificial sheath that captures all of the energy the object at its center emits.  But even if it was able to capture all of the energy the black hole emits, the sphere itself would still suffer from heat loss.  And that heat loss would make it visible to us, according to new research published by an international team led by researchers at the National Tsing Hua University in Taiwan. 

Obviously, no such structure has yet been detected. Still, the paper proves that it is possible to do so, despite no visible light making it past the sphere’s surface and a black hole’s reputation for being light sinks rather than light sources.  To understand how we would detect such a system, first, it would be helpful to understand what that system would be designed to do.

The authors study six different energy sources that a potential Dyson sphere could collect around a black hole.  They are the omnipresent Cosmic Microwave Background radiation (which would be washing over the sphere no matter where it was placed), the black hole’s Hawking radiation, its accretion disk, its Bondi accretion, its corona, and its relativistic jets. 

Quasar gamma rays
Composite image of Centaurus A, our galaxy’s central supermassive black hole, showing the jets emerging together with the associated gamma radiation.
© ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray), H.E.S.S. collaboration (Gamma)

Some of these energy sources are much more high-powered than others, with the energy from the black hole’s accretion disk leading the pack in terms of potential energy captures.  Other types of energy would require completely different engineering challenges, such as capturing the kinetic energy of the relativistic jets that shoot out from the black hole’s poles.  Size obviously plays a large factor in how much energy these black holes emit. The authors primarily focus on stellar-mass black holes as a good point of comparison against other potential energy sources.  At that size, the accretion disk alone would provide hundreds of times the energy output of a main-sequence star.

It would be impossible to build a Dyson sphere around any object that size with current known materials.  But the type of civilization that would be interested in taking on such an engineering challenge would most likely have much stronger materials than we do today.  Alternatively, they could work with known materials to create a Dyson Swarm or Dyson Bubble, which doesn’t require as much material strength but does lose some of the energy that a complete sphere would capture, and adds multiple layers of complexity when coordinating orbital paths and other factors.  Any such structure would have to be outside the accretion disk to get the full benefit from the energy the black hole emits.

UT video about detecting Dyson Swarms

Even a single sphere around a single stellar-mass black hole would be enough to push any civilization that created it into Type II territory, giving it a level of power output unimaginable with current technology. But even such a potent civilization most likely won’t be able to bend the laws of physics.  No matter the power level, some of it will be lost to heat.  

To astronomers, heat is simply another form of light – infrared, to be exact.  And according to the researchers, the heat emitted by a Dyson sphere around a black hole should be detectable by our current crop of telescopes, such as the Wide Field Infrared Survey Explorer and the Sloan Digital Sky Survey, to a distance of about 10kpc at least.  That’s about 1/3 of the distance across the entire Milky Way. No matter how close they were, they wouldn’t appear
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Does Betelgeuse Even Rotate? Maybe Not

Betelgeuse pulsating UV HST jpeg

Betelgeuse is the well known red giant star in the corner of Orion the hunter. The name translated in some languages means ‘armpit of the giant’ which I think of all the star names, is simply the best! Betelgeuse has been fascinating observers of late not only because it unexpectedly faded a few years ago but more recently a study shows it’s super fast rotational speed which is, when compared to other supergiants, is like nothing seen before. 

One of the brightest stars in the northern hemisphere sky, in fact the tenth brightest, Betelgeuse has a stunning red colour. It is a semi regular variable star which means there is some regularity to its varied light output but there are occasions, perhaps lasting between 20 and 2000 days where the variation is interrupted. If Betelgeuse were placed in the Sun’s position then its visible surface would more than likely extend beyond the orbit of Mars and swallow up everything in between. 

Image showing the variability of Betelgeuse
1998/9 UV HST images of Betelgeuse showing asymmetrical pulsations with corresponding spectral line profiles (Credit :  STScI, NASA, ESA)

Like all stars, Betelgeuse rotates but a recent study using the Atacama Large Milimeter Array (ALMA) has showed that Betelgeuse is rotating faster than expected. Cool stars like Betelgeuse expand as they evolve and to conserve momentum the rotation must slow.  It is possible that mass loss due to stellar winds decreases rotation speeds further. The current theory predicts that red giants rotate at around 1km per second while red supergiants a little less than 0.1km per second. 

Image showing two of the receivers of the ALMA array in the Atacama Desert.
Two of the Atacama Large Millimeter/submillimeter Array (ALMA) 12-metre antennas (Credit : Iztok Bon?ina/ESO)

Current theory aside it seems there have been a number of observations of at least a few hundred giant stars rotating faster. Betelgeuse in particular has shown faster than expected rotation. Somewhat usefully, it’s proximity to Earth has meant its surface can be resolved and accurate measurements taken. Measurements showed that half of the visible hemisphere was blue shifted and the the other half red shifted. We can use this information to accurately calculate a rotational velocity.

When it comes to Betelgeuse, the radial velocity with ALMA was measured to be around 5.47 km per second. This value was compared against previous observations using Hubble Space Telescope and thankfully this agreed. One leading theory takes binary star evolution as a possible cause and in particular a merger with a low mass companion star. This is not an unusual process with an expected one-third of red supergiants experience stellar merger before their core collapses marking the end of their life. When it comes to red giants the team considered the impact of merging with planetary systems on the rotational velocity.

There are complications however in attaining sufficient data but the team modelled 3D radiation hydrodynamic simulations of red supergiants with properties similar to Betelgeuse. Throwing a proverbial spanner in the works, the team suggest that it is possible that the observations could be wrong and false signals have been picked up from churning convective plasma at the surface rather than the rotation of the star itself!

In an attempt to ascertain if it is possible to accurately measure the rotational speed of red giants and supergiants they had to develop new processing techniques to establish predictions that they could compare with observations of Betelgeuse. The team finally conclude that to be able to establish without doubt that Betelgeuse and other red supergiants are rotating
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5 Reasons You Must Backpack the Teton Crest Trail

Wind4 016 jpg

By Michael Lanza

On my first backpacking trip on the Teton Crest Trail in Grand Teton National Park, camped on Death Canyon Shelf, a broad, boulder-strewn and wildflower-carpeted bench at 9,500 feet, I awoke to the sound of heavy clomping outside my tent. I unzipped the tent door to investigate—and saw a huge bull elk standing just outside my nylon walls.

As I’ve come to learn over more than 20 trips to the Tetons since that first one over three decades ago, that elk encounter symbolized just one of several compelling reasons why every backpacker should move the Teton Crest Trail to the top of their to-do list: the wildlife. Where it occurred illustrates another reason: After years of backpacking all over the United States—including the 10 years I spent as a field editor for Backpacker magazine and even longer running this blog—Death Canyon Shelf is still one of my all-time favorite backcountry campsites.

Wind4 016 1 jpg
Hi, I’m Michael Lanza, creator of The Big Outside, which has made several top outdoors blog lists. 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 to learn how I can help you plan your next trip.

Watching the sunset from a campsite in the North Fork Cascade Canyon, Grand Teton National Park.
” data-image-caption=”Watching the sunset from a campsite in the North Fork Cascade Canyon on the Teton Crest Trail in Grand Teton National Park.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?fit=200%2C300&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?fit=683%2C1024&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?resize=432%2C648&ssl=1″ alt=”Watching the sunset from a campsite in the North Fork Cascade Canyon, Grand Teton National Park.” class=”wp-image-36411″ style=”width:432px;height:648px” width=”432″ height=”648″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?w=800&ssl=1 800w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?resize=200%2C300&ssl=1 200w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?resize=768%2C1152&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-090-A-campsite-on-the-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P.jpg?resize=683%2C1024&ssl=1 683w” sizes=”(max-width: 432px) 100vw, 432px” data-recalc-dims=”1″ />Watching the sunset from a campsite in the North Fork Cascade Canyon, Grand Teton National Park.

And I certainly consider the Teton Crest Trail one of the 10 best backpacking trips in America. It’s the one I keep going back to again and again. (Read about my most recent trip.)

I think the five reasons I lay out below will give you insights into questions you might have about this classic hike—and inspire you to go do it.

But know this important planning detail: The

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How to Get a Permit to Backpack the Teton Crest Trail

Tet19 047 Me on Teton Crest Trail copy cropped jpg

By
Michael Lanza

For
backpackers, the Teton Crest Trail really delivers it all: beautiful lakes,
creeks, and waterfalls, high passes with sweeping vistas, endless meadows of
vibrant wildflowers, a good chance of seeing wildlife like elk and moose, some
of the best campsites you will ever pitch a tent in, and mind-boggling scenery
just about every step of the way. And it’s a relatively beginner-friendly trip
of 40 miles or less, which most people can hike in four to five days.

No wonder it’s so enormously popular—and there’s so much competition for backcountry permits.

In this story, I will offer tips on how to maximize your chances of getting a permit to backpack the Teton Crest Trail, sharing expertise I’ve acquired from more than 20 trips in the Tetons and several on the Teton Crest Trail over more than three decades, including the 10 years I spent as Northwest Editor of Backpacker magazine and even longer running this blog.

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-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.

Lake Solitude, North Fork Cascade Canyon, Grand Teton National Park.
” data-image-caption=”Lake Solitude in the North Fork of Cascade Canyon, Grand Teton National Park. Click photo for my e-guide “The Complete Guide to Backpacking the Teton Crest Trail.”
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?resize=900%2C600&ssl=1″ alt=”Lake Solitude, North Fork Cascade Canyon, Grand Teton National Park.” class=”wp-image-36414″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?resize=1024%2C683&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?resize=300%2C200&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?resize=768%2C512&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?resize=1080%2C720&ssl=1 1080w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2019/11/Tet19-095-Lake-Solitude-Teton-Crest-Trail-North-Fork-Cascade-Canyon-Grand-Teton-N.P..jpg?w=1200&ssl=1 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Lake Solitude in the North Fork of Cascade Canyon, Grand Teton National Park. Click photo for my e-guide “The Complete Guide to Backpacking the Teton Crest Trail.”

See my story from my most-recent trip on it, “A Wonderful Obsession: Backpacking the Teton Crest Trail,” which requires a paid subscription to The Big Outside to read in full, including basic information on planning a TCT backpacking trip. For much more information and expert tips on planning this trip, get my top-selling e-guide “The Complete Guide to Backpacking the Teton Crest Trail in Grand Teton National Park.”

I’ve also helped many readers plan a backpacking trip in the Tetons and elsewhere, answering all of their questions and customizing an itinerary ideal for them. See my Custom Trip Planning page to learn how
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