It’s easy to think of Earth as a water world, with its vast oceans and beautiful lakes, but compared to many worlds, Earth is particularly wet. Even the icy moons of Jupiter and Saturn have far more liquid water than Earth. Earth is unusual not because it has liquid water, but because it has liquid water in the warm habitable zone of the Sun. And as a new study in Nature Communications shows, Earth could be even more unusual than we thought.
Water is one of the more common molecules in the universe. Hydrogen is the most abundant element in the cosmos, and oxygen is easily produced as part of the stellar CNO fusion cycle. So we would expect water-rich planets to be plentiful in stellar systems. But that isn’t to say liquid water will be plentiful. In our solar system, two kinds of worlds have liquid water. Earth and gas giant moons.
Like other warm terrestrial planets such as Venus and Mars, Earth had liquid water in its youth. Mars was too small to retain its water. Much of it evaporated into space, while some froze into its surface crust. Venus was large enough to retain water, but its extreme heat boiled much of it off into its thick atmosphere. We still aren’t entirely sure how Earth managed to retain its oceans, but it was likely a combination of a strong magnetic field and an extra helping of water from asteroids and comets during the heavy bombardment period.
The icy moons of Jupiter and Saturn are another story. They were far enough from the Sun that they retained the water of their formation. They quickly formed a thick layer of ice to prevent water from evaporating into space. But these moons are small worlds and would have very quickly frozen solid were it not for the tidal forces exerted by their gas giant.
Since cold gas planets are likely to have icy moons, the general thought we would be far more likely to find life on a Europa-like world than an Earth-like one. But this new study begs to differ. It argues that liquid water is much more likely to be found on super-Earths.
How icy super-Earths could have liquid water oceans. Credit: Ojha, Lujendra, et al
Super-Earths span a mass range from a couple of Earth masses to Neptune mass. On the large end, they are likely to be gassy worlds with thick atmospheres. On the small end, they are likely to be more Earth-like. Based on the exoplanets we’ve found so far, super-Earths are by far the most common. And a majority of them are likely to be outside their star’s habitable zone in the cold regions of the star system. So they are likely water-rich. But they also aren’t likely to be found orbiting a gas giant, so it’s generally been assumed that their ice layer would be mostly frozen solid over time.
The reason has to do with the various freezing and melting points of ice. The kind of ice we have on Earth melts at around 0 °C. But this is only true at around Earth’s atmospheric pressure. At higher pressures, there are several varieties of ice with differing melting points. Although it’s a bit complicated, generally at higher pressures ice can have a much higher melting point. So even if a super-Earth is geologically active, it might not be warm enough to melt ice.
Number of exoplanets discovered by the Kepler mission as of May, 2016. Credit: W. Stenzel/NASA Ames
This new study shows that super-Earths don’t have to be hot enough to create a deep ocean. Through geothermal and nuclear heating it can melt a thin layer of water at its surface, and thanks to fissures and various water phase transitions water can creep up to the layer just below the frozen surface.
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The Early Universe Had No Problem Making Barred Spiral Galaxies
Spiral galaxies like the Milky Way are like cosmic snowflakes—no two are exactly alike. For many years, astronomers thought spirals couldn’t exist until the universe was about half its present age. Now, a newly discovered galaxy in the early Universe is challenging that idea.
CEERS-2112 is an early “cosmic snowflake” with spiral arms and a bar across its middle. The amazing thing is that it’s showing this structure when the Universe was only 2 billion years old. That’s about five billion years earlier than astronomers expected something like that to exist. The fact that a perfectly formed spiral exists so early tells us that our ideas about galaxy formation in early cosmic history need some re-tuning.
Surveying the Early Universe
This galaxy showed up in a survey done by the JWST called “Cosmic Evolution Early Release Science” (CEERS). It uses JWST imaging and spectroscopy to do a survey of the early Universe to find the earliest galaxy. The analysis of the CEERS-2112 galaxy was done by an international team led by astronomer Luca Constantin of the Centro de Astrobiología in Spain.
CEERS results should show astronomers the early populations of galaxies at high redshifts (distances). They will also help them estimate related star-formation conditions and black hole growth. Finally, the work should give some insight into the formation of galaxy disks and bulges. Essentially, CEERS data should add to our store of knowledge about first light and reionization (which occurred after the Big Bang) and explain the formation and evolution of early galaxies.
Early deep-field images of very distant galaxies show shreds of galaxies and irregular clumps of stars in the early Universe. That was evident in some of the first Hubble Deep-Field images. The most distant ones in the images looked more blobby and indistinct. And, some of them appeared to be colliding, which fits into the collisional model of galaxy formation.
This view of nearly 10,000 galaxies is called the Hubble Ultra Deep Field. It shows some galaxies in the early Universe, (which appear as red blobs). Credit: NASA/ESA/HUDF
Forming Galaxies in the Early Universe
Prior to the Hubble and JWST eras, astronomers really felt that it would take a long time to form spiral galaxies. They often describe a hierarchical model of galaxy formation. That’s where smaller clumpy galaxies collide to form larger ones. Over time, those objects begin to develop structures like spiral arms and bars.
“In such galaxies, bars can form spontaneously due to instabilities in the spiral structure or gravitational effects from a neighboring galaxy,” according to astronomer and team member Alexander de la Vega. He is a post-doctoral researcher currently at the University of California Riverside. “In the past, when the Universe was very young, galaxies were unstable and chaotic. It was thought that bars could not form or last long in galaxies in the early universe.”
The spiral arms are likely the result of density waves moving through the galaxy. The bars also form from density waves radiating out from the center. That compresses material in the arms and bars, leading to bursts of star formation. That could explain why these regions in galaxies seem brighter, with their populations of hot young stars. All of this takes time to accomplish. That’s why astronomers suggested that it would take about half the age of the Universe to form spiral galaxies.
CEERS-2112 is Part of the Early Universe
CEERS-2112 upends the discussion about spiral formation, according to de la Vega. “Finding CEERS-2112 shows that galaxies in the early Universe could be as ordered as the Milky Way,” he said. “This is surprising because galaxies were much more chaotic in the early Universe and very few had similar structures to the Milky Way.”
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Apollo Samples Contain Hydrogen Hurled from the Sun
According to the U.S. National Academies of Sciences, Engineering, and Medicine, men should drink 3.7litres of water a day and women 2.7litres. Now imagine a crew of three heading to the Moon for a 3 week trip, that’s something of the order of 189 litres of water, that’s about 189 kilograms! Assuming you have to carry all the water rather than recycle some of it longer trips into space with more people are going to be logistically challenging for water carriage alone. Researchers from the U.S. Naval Research Laboratory (NRL) have discovered lunar rocks with hydrogen in them which, when combined with lunar oxygen provide a possibly supply for future explorers.
A total of 382 kilograms of rock was brought back from the Moon by the Apollo program (I weigh about 80kg so that’s almost five of me in weight – and its all muscle I promise!) Some of the samples were immediately studied while others were sealed for future research hoping that future instrumentation would be more sensitive.
A research team from NRL, led by Katherine D. Burgess and team members Brittany A. Cymes and Rhonda M. Stroud, have recently announced their findings whilst studying some of the lunar rock. They wanted to understand the source of water on the Moon and to understand its formation. Future lunar exploration especially permanent lunar bases will rely heavily upon existing lunar resources. The paper articulates “Effective use of the resource depends on developing an understanding of where and how within the regolith the water is formed and retained”.
Buzz Aldrin’s footprint in the lunar regolith – the soft powdery material found over the surface of the Moon (Credit – NASA)
Transmission electron microscopy was used as part of the study to explore lunar sample 79221. The technique utilises a particle beam of electrons to visualise specimens and generate a highly magnified image. In particular, the team looked at grains of the minerals apatite and merrillite and discovered signs of ‘space’ weathering due to the solar wind. The solar wind is a stream of charged particles that rush outward from the Sun at speeds of up to 1.6 million km per hour!
They found hydrogen signatures in samples in vesicles – small holes left behind after lava cools. The discovery confirms that solar wind is being trapped in detectable quantities proving a potential reservoir that could be accessible to future explorers.
Hydrogen itself is a tremendously useful resource and if that can be mined from the lunar surface material it can aide many aspects of exploration. The real buzz around the discovery is that it may finally resolve the mystery about the origins of lunar water and that it might well be the result of chemical interactions between the solar wind and lunar rocks. If we can understand the origins of the lunar water – and we may finally be close to that now – then we can be sure we use it effectively to reach out further into the Solar System.
Source : Hydrogen detected in lunar samples, points to resource availability for space exploration
The post Apollo Samples Contain Hydrogen Hurled from the Sun appeared first on Universe Today.
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The Best Clothing Layers for Winter in the Backcountry
By Michael Lanza
There’s one certainty about the clothing layers we use in winter: We get our money’s worth out of them. While a rain shell or puffy jacket may rarely come out of our pack on a summer hike or climb, we almost invariably wear every article of clothing we carry when backcountry, Nordic, or downhill skiing, snowshoeing, snowboarding, climbing, or trail running in winter. That’s money spent wisely to make us more comfortable and safer.
Every winter, I test out new clothing layers doing many of those activities frequently—something I’ve been doing for more than 25 years, previously as the lead gear reviewer for Backpacker magazine for 10 years and even longer running this blog. This review spotlights the best shell and insulated jackets, base layers, and pants I’ve found for high-exertion and moderate-exertion activities in winter.
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.
A backcountry skier in Idaho’s Boise Mountains.
” data-image-caption=”My son, Nate, backcountry skiing in Idaho’s Boise Mountains.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?resize=900%2C600&ssl=1″ alt=”A backcountry skier in Idaho’s Boise Mountains.” class=”wp-image-50099″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?resize=1024%2C683&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?resize=300%2C200&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?resize=768%2C512&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?resize=150%2C100&ssl=1 150w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/01/DSC_3743.jpg?w=1200&ssl=1 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />My son, Nate, backcountry skiing in Idaho’s Boise Mountains.
In my story “How to Dress in Layers for Winter in the Backcountry,” I offer advice—based on four decades of backcountry experience—on how to choose a specific, personalized layering system for different exertion levels and body types in temperatures near or below freezing. Use the tips in that story, along with this review, to make the best choices in winter outdoor apparel for your activities, your climate, and your body.
Please share your experiences with any of these products in the comments section at the bottom of this review. I try to respond to all comments. And if you make a purchase through any of the affiliate links to online retailers in this story or other reviews at The Big Outside, you support my work on this blog at no cost to you. Thanks for doing that.
Don’t go out in the cold without my “12 Pro Tips For Staying Warm Outdoors in Winter.”
Backcountry avalanche instructor Chago Rodriguez skiing in the shadow of Mount Heyburn in Idaho’s Sawtooth Mountains.
” data-image-caption=”Expert backcountry avalanche instructor Chago Rodriguez skiing in the shadow of Mount Heyburn in Idaho’s Sawtooth Mountains. Click photo to learn about his courses.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2015/01/Saw13-028-Pass-north-of-Mt.-Heyburn-Sawtooths-ID.jpg?fit=300%2C199&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2015/01/Saw13-028-Pass-north-of-Mt.-Heyburn-Sawtooths-ID.jpg?fit=900%2C598&ssl=1″ src=”https://i0.wp.com/thebigoutside
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