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"Not my King": Second coronation marred by protestors

<p>King Charles has celebrated his coronation a second time during a ceremony in the Scottish capital of Edinburgh, just two months after being crowned King in London. </p> <p>The monarch was joined by Queen Camilla, and Prince and Princess of Wales, who are known as the Duke and Duchess of Rothesay in Scotland, for a Service of Thanksgiving and Dedication held in his honour. </p> <p>During the service inside St Giles Cathedral, the monarch was presented with the symbols of his authority in Scotland – the Crown, the Sceptre and the Sword of State.</p> <p>The new Elizabeth Sword, named in honour of the late monarch, was commissioned to replace the previous Sword of State as it had become too fragile, having been given to James IV by Pope Julius in 1507.</p> <p>The sword was carried into the cathedral by Olympic rower Dame Katherine Grainger.</p> <p>Despite the grand and emotional service, the ceremony was slightly marred by anti-monarch protestors outside.</p> <p>The protestors stood chanting "not my King" for hours on end so loudly, that the voices could be heard from inside the church during the quieter moments of the ceremony. </p> <p>Four protestors were later arrested for their disruption. </p> <p>Prior to the ceremony, Grant McKenzie from the Republic anti-monarchy pressure group, told the BBC's <em>Good Morning Scotland</em> programme that his group would be vocal at the event.</p> <p>"It's being forced upon us," McKenzie said. "We've got an unprecedented cost of living crisis. I don't think the public in the UK are particularly interested in their tax payer money being put towards a parade up and down the Royal Mile in Edinburgh - it's tone deaf.</p> <p>"Of course people are going to be able to enjoy it if that's what they want to do. Protests by their very nature are disruptive, we will be making ourselves visible and heard."</p> <p>The King and Queen didn't let the demonstrators get in the way of the proceedings, which was strengthened by the thousands of crowds who lined the streets of Edinburgh in support of the royal family. </p> <p>The tradition of a second coronation taking place in Scotland dates back over 400 years, with the late Queen Elizabeth also celebrating the event just weeks after her coronation in 1953. </p> <p><em>Image credits: Getty Images</em></p>

Travel Trouble

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Humans are still hunting for aliens. Here’s how astronomers are looking for life beyond Earth

<p>We have long been fascinated with the idea of alien life. The earliest written record presenting the idea of “aliens” is seen in the satiric work of Assyrian writer <a href="https://blogs.scientificamerican.com/life-unbounded/the-first-alien/">Lucian of Samosata</a> dated to 200 AD.</p> <p>In one novel, Lucian <a href="https://www.yorku.ca/inpar/lucian_true_tale.pdf">writes of a journey to the Moon</a> and the bizarre life he imagines living there – everything from three-headed vultures to fleas the size of elephants.</p> <p>Now, 2,000 years later, we still write stories of epic adventures beyond Earth to meet otherworldly beings (<a href="https://www.britannica.com/topic/The-Hitchhikers-Guide-to-the-Galaxy-novel-by-Adams">Hitchhiker’s Guide</a>, anyone?). Stories like these entertain and inspire, and we are forever trying to find out if science fiction will become science fact.</p> <h2>Not all alien life is the same</h2> <p>When looking for life beyond Earth, we are faced with two possibilities. We might find basic microbial life hiding somewhere in our Solar System; or we will identify signals from intelligent life somewhere far away.</p> <div data-id="17"> </div> <p>Unlike in <a href="https://www.britannica.com/topic/Star-Wars-film-series">Star Wars</a>, we’re not talking far, far away in another galaxy, but rather around other nearby stars. It is this second possibility which really excites me, and should excite you too. A detection of intelligent life would fundamentally change how we see ourselves in the Universe.</p> <p>In the last 80 years, programs dedicated to the search for extraterrestrial intelligence (SETI) have worked tirelessly searching for cosmic “hellos” in the form of radio signals.</p> <p>The reason we think any intelligent life would communicate via radio waves is due to the waves’ ability to travel vast distances through space, rarely interacting with the dust and gas in between stars. If anything out there is trying to communicate, it’s a pretty fair bet they would do it through radio waves.</p> <h2>Listening to the stars</h2> <p>One of the most exciting searches to date is <a href="https://breakthroughinitiatives.org/initiative/1">Breakthrough Listen</a>, the largest scientific research program dedicated to looking for evidence of intelligent life beyond Earth.</p> <p>This is one of many projects funded by US-based Israeli entrepreneurs Julia and Yuri Milner, with some serious dollars attached. Over a ten-year period a total amount of <a href="https://breakthroughinitiatives.org/initiative/1">US$100 million</a> will be invested in this effort, and they have a mighty big task at hand.</p> <p>Breakthrough Listen is currently targeting the closest one million stars in the hope of identifying any unnatural, alien-made radio signals. Using telescopes around the globe, from the 64-metre Murriyang Dish (Parkes) here in Australia, to the 64-antenna MeerKAT array in South Africa, the search is one of epic proportions. But it isn’t the only one.</p> <p>Hiding away in the Cascade Mountains north of San Francisco sits the <a href="https://www.seti.org/ata">Allen Telescope Array</a>, the first radio telescope built from the ground up specifically for SETI use.</p> <p>This unique facility is another exciting project, able to search for signals every day of the year. This project is currently upgrading the hardware and software on the original dish, including the ability to target several stars at once. This is a part of the non-profit research organisation, the SETI Institute.</p> <h2>Space lasers!</h2> <p>The SETI Institute is also looking for signals that would be best explained as “space lasers”.</p> <p>Some astronomers hypothesise that intelligent beings might use massive lasers to communicate or even to propel spacecraft. This is because even here on Earth we’re investigating <a href="https://www.nasa.gov/feature/goddard/2022/the-future-of-laser-communications/">laser communication</a> and laser-propelled <a href="https://www.insidescience.org/news/new-light-sail-design-would-use-laser-beam-ride-space">light sails</a>.</p> <p>To search for these mysterious flashes in the night sky, we need speciality instruments in locations around the globe, which are currently being developed and deployed. This is a research area I’m excited to watch progress and eagerly await results.</p> <p>As of writing this article, sadly no alien laser signals have been found yet.</p> <h2>Out there, somewhere</h2> <p>It’s always interesting to ponder who or what might be living out in the Universe, but there is one problem we must overcome to meet or communicate with aliens. It’s the speed of light.</p> <p>Everything we rely on to communicate via space requires light, and it can only travel so fast. This is where my optimism for finding intelligent life begins to fade. The Universe is big – really big.</p> <p>To put it in perspective, humans started using radio waves to communicate across large distances in 1901. That <a href="https://ethw.org/Milestones:Reception_of_Transatlantic_Radio_Signals,_1901">first transatlantic signal</a> has only travelled 122 light years, reaching just 0.0000015% of the stars in our Milky Way.</p> <p>Did your optimism just fade too? That is okay, because here is the wonderful thing… we don’t have to find life to know it is out there, somewhere.</p> <p>When we consider the <a href="https://theconversation.com/how-many-stars-are-there-in-space-165370">trillions of galaxies</a>, septillion of stars, and likely many more planets just in the observable Universe, it feels near impossible that we are alone.</p> <p>We can’t fully constrain the parameters we need to estimate how many other lifeforms might be out there, as famously proposed by Frank Drake, but using our best estimates and <a href="https://www.cambridge.org/core/journals/international-journal-of-astrobiology/article/numerical-testbed-for-hypotheses-of-extraterrestrial-life-and-intelligence/0C97E7803EEB69323C3728F02BA31AFA">simulations</a> the current best answer to this is tens of thousands of possible civilisations out there.</p> <p>The Universe <a href="https://theconversation.com/is-space-infinite-we-asked-5-experts-165742">might even be infinite</a>, but that is too much for my brain to comprehend on a weekday.</p> <h2>Don’t forget the tiny aliens</h2> <p>So, despite keenly listening for signals, we might not find intelligent life in our lifetimes. But there is hope for aliens yet.</p> <p>The ones hiding in plain sight, on the planetary bodies of our Solar System. In the coming decades we’ll explore the moons of Jupiter and Saturn like never before, with missions hunting to find traces of basic life.</p> <p>Mars will continue to be explored – eventually by humans – which could allow us to uncover and retrieve samples from new and unexplored regions.</p> <p>Even if our future aliens are only tiny microbes, it would still be nice to know we have company in this Universe.</p> <p><em>Images: Getty</em></p> <p><em style="box-sizing: border-box; color: #212529; font-family: -apple-system, 'system-ui', 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji'; font-size: 16px; background-color: #ffffff;">This article originally appeared on <a href="https://theconversation.com/humans-are-still-hunting-for-aliens-heres-how-astronomers-are-looking-for-life-beyond-earth-197621" target="_blank" rel="noopener">The Conversation</a>. </em></p>

Technology

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NASA’s Perseverance rover sends back Mars soundscape playlist

<p>Nearly two years after its <a href="https://cosmosmagazine.com/space/mars-is-the-place-in-space-to-be/" target="_blank" rel="noreferrer noopener">launch</a>, and almost 18 months after <a href="https://cosmosmagazine.com/science/mars-news-all-good/" target="_blank" rel="noreferrer noopener">landing on Mars</a>, NASA’s Perseverance rover has hours of audio recordings from the red planet’s atmosphere.</p> <p>So, what does Mars sound like? On the whole, it’s quiet. Very quiet. But the recordings did pick up interesting weather events and changes which give us a better overall picture of Mars’s clime.</p> <p>Perseverance’s primary mission is to explore sediments in a dormant river delta on the edge of the 45 kilometre-wide <a href="https://cosmosmagazine.com/weekly-edition/one-year-mars-perseverance-rover/" target="_blank" rel="noreferrer noopener">Jezero Crater</a>, to learn about the crater’s formation and hopefully find signs of ancient life. But microphones are light and cheap, so it made sense to add a couple to the rover’s instruments.</p> <p>The <a href="https://cosmosmagazine.com/science/engineering/the-bizarre-acoustics-of-mars/" target="_blank" rel="noreferrer noopener">first audio from Mars</a> was sent by Perseverance earlier this year. Now, a year’s worth of recording from the Martian atmosphere has been condensed into about five hours of sound.</p> <p>The findings are due to be presented by Baptiste Chide of the Los Alamos National Lab during a seminar, “Mars soundscape: Review of the first sounds recorded by the Perseverance microphones,” at the <a href="https://acoustics.org/world-wide-press-room/" target="_blank" rel="noopener">182nd Meeting of the Acoustical Society of America</a> tomorrow, May 25, in Denver  in the US.</p> <p>With no large dynamical natural phenomena, extant animal species (that we know of), industrial civilisation, or extreme weather events, you’d expect Mars to be pretty silent. And it is. Under the same conditions on Earth, sounds are 20 decibels louder than on Mars.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p192195-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> </div> </div> <p>“It is so quiet that, at some point, we thought the microphone was broken!” says Chide.</p> <p>But, like giving a new music album a second run-through, closer listening revealed some fascinating phenomena. The group heard much variability in the wind and abrupt changes in the atmosphere, see-sawing from calm to intense gusts.</p> <p>The team noticed that the red planet’s soundscape is seasonal. During winter, carbon dioxide freezes in the polar caps. This causes changes in atmospheric density, and environmental volume fluctuates by about 20%. Atmospheric CO<sub>2</sub> also causes high-pitched sounds in the distance to become fainter.</p> <p>The rover also used laser sparks to calculate the speed of sound’s dispersion, confirming a theory that high-frequency sounds travel faster than low frequencies.</p> <p>“Mars is the only place in the solar system where that happens in the audible bandwidth because of the unique properties of the carbon dioxide molecule that composes the atmosphere,” notes Chide. While the rover will continue to record audio as it travels across Mars’s surface, Chide believes that the technique could be applied to studies of other celestial bodies. Planets and moons with denser and more volatile atmospheres, such as Venus and Titan, may yield even more information as sound waves interact more strongly and travel further.</p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=192195&amp;title=NASA%E2%80%99s+Perseverance+rover+sends+back+Mars+soundscape+playlist" width="1" height="1" /></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/space/nasa-perseverance-rover-soundscape/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/evrim-yazgin" target="_blank" rel="noopener">Evrim Yazgin</a>. Evrim Yazgin has a Bachelor of Science majoring in mathematical physics and a Master of Science in physics, both from the University of Melbourne.</em></p> <p><em>Image: NASA</em></p> </div>

Technology

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The bizarre acoustics of Mars

<p>Shortly after NASA’s Mars Perseverance rover <a href="https://cosmosmagazine.com/space/perseverance-pays-off/" target="_blank" rel="noreferrer noopener">landed</a> and unlimbered its instruments, scientists turned on one of the more unusual of them – a microphone system – and for the first time listened in on an alien world: first to the wind, then to the sounds of the rover driving, and later yet to the <a href="https://cosmosmagazine.com/space/exploration/ingenuity-helicopter/" target="_blank" rel="noreferrer noopener">Ingenuity helicopter</a> on one of its early flights.</p> <p>It was captivating. But it also seemed to be of limited scientific value – the type of thing you’d do because today’s microphones are so lightweight that there’s no real cost to including a couple on the rover (and being able to listen to it might help diagnose mechanical problems if they arose).</p> <p>But it turns out there are a lot of other things you can do with microphones, once you have them.</p> <p>The simplest is to measure the speed of sound. On Earth, says Baptiste Chide, a postdoctoral researcher at Los Alamos National Laboratory, New Mexico, US, that’s about 340 metres per second. In the thin Martian air, it was expected to be more like 240 m/s.</p> <p><a href="https://mars.nasa.gov/mars2020/multimedia/audio/" target="_blank" rel="noreferrer noopener">Sounds on Mars</a> were also expected to be about 20 decibels lower than on Earth, Chide said at this year’s Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas. The Red Planet, he says, is also the “quiet planet.”</p> <p>The difference, he adds, is particularly pronounced at higher frequencies – something borne out by the muted sounds first released by NASA.</p> <figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"> <div class="wp-block-embed__wrapper"> <div class="entry-content-asset"> <div class="embed-wrapper"> <div class="inner"><iframe title="NASA's Perseverance Rover Captures the Sounds of Mars" src="https://www.youtube.com/embed/GHenFGnixzU?feature=oembed" width="500" height="281" frameborder="0" allowfullscreen="allowfullscreen"></iframe></div> </div> </div> </div> </figure> <p>To a large extent, Chide says, “you can only hear bass sounds on Mars”.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p185282-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> </div> </div> <p>Weirder yet, due to strange properties of its thin carbon dioxide atmosphere, sounds on Mars travel at different speeds depending on their frequency, with those above 400 hertz (about that of the G above middle C) travelling 4% faster than those of lower pitch.</p> <p>“Let’s imagine that we have this <a href="https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf" target="_blank" rel="noreferrer noopener">talk</a> on Mars,” Chide said at the LPSC meeting. “My voice is between 200 hertz and 1000 hertz. You would receive all of the high-frequency tones before the low-frequency tones, so it might [be] distort[ed], not understandable.”</p> <p>But things like that are mere curiosities. The true scientific value of the microphones came into play when Chide’s team realised they could use them to measure rapid fluctuations in the air temperature in the vicinity of the rover.</p> <p>It works, he says, because air temperature is another factor that affects the speed of sound. And one way the rover produces sound is by firing its mast-mounted laser at nearby rocks.</p> <p>The primary purpose of the laser is to vaporise tiny puffs of rock so that other instruments can determine their composition from spectroscopic analysis of the escaping vapor.</p> <p>But the vaporisation process produces an audible pop when the laser hits the rock, and by timing how quickly that is heard after the laser is fired, Chide says, it’s possible to determine the temperature of the intervening air.</p> <p>That makes the microphone a useful complement to the rover’s onboard weather station, because it gives much more rapid readings, repeating each time a laser pulse is fired, which can be as often as three times a second.</p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=185282&amp;title=The+bizarre+acoustics+of+Mars" width="1" height="1" data-spai-target="src" data-spai-orig="" data-spai-exclude="nocdn" /></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/science/engineering/the-bizarre-acoustics-of-mars/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/richard-a-lovett" target="_blank" rel="noopener">Richard A Lovett</a>. Richard A Lovett is a Portland, Oregon-based science writer and science fiction author. He is a frequent contributor to Cosmos.</em></p> <p><em>Image: NASA</em></p> </div>

Technology

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False fossils could hamper search for life on Mars

<div> <div class="copy"> <p>If you’re an interplanetary alien hunter scouring the red expanses of Mars for signs of life, you’re more likely to come across <a rel="noreferrer noopener" href="https://cosmosmagazine.com/space/looking-for-microbes-on-mars/" target="_blank">microbes</a> than little green men. You’re even more likely to come across fossils of ancient critters that lived billions of years ago.</p> <p>But new research warns that chemical processes can create “pseudofossils”, potentially fooling future exo-palaeontologists.</p> <p>“At some stage a Mars rover will almost certainly find something that looks a lot like a fossil, so being able to confidently distinguish these from structures and substances made by chemical reactions is vital,” says astrobiologist Sean McMahon from the University of Edinburgh, UK.</p> <p>“For every type of fossil out there, there is at least one non-biological process that creates very similar things, so there is a real need to improve our understanding of how these form.”</p> <p>In a study published in the <em>Journal of the Geological Society</em>, McMahon and colleagues from the Universities of Edinburgh and Oxford assessed dozens of known processes that could have created life-like traces in Martian rocks.</p> <p>Many chemical processes can mimic the structures created by microscopic lifeforms, like bacterial cells or carbon-based molecules that make up the building blocks of life as we know it.</p> <p>Stromatolites are one example of fossils that could be impersonated. These rock-like structures formed from layers deposited by communities of blue-green algae. Called “living fossils”, they are still <a rel="noreferrer noopener" href="https://cosmosmagazine.com/history/palaeontology/extremely-ancient-lifeform-discovered-in-tasmania/" target="_blank">found</a> in shallow aquatic environments today, and at more than 3.5 billion years old they’re among the <a rel="noreferrer noopener" href="https://cosmosmagazine.com/earth/earth-sciences/earliest-life-found-in-ancient-aussie-rocks/" target="_blank">oldest evidence</a> for life on Earth.</p> <p>But non-biological processes can produce pseudofossils that mimic the domes and columns of stromatolites. Surprisingly, similar deposits can build up in places like factory floors, where cars are spray-painted, as well as more natural processes like the deposition of silica around hot springs, some of which <a rel="noreferrer noopener" href="https://doi.org/10.1038/ncomms13554" target="_blank">have recently been found</a> on Mars.</p> <p>Another example of ambiguous fossils can be found in sandstone beds from the Ediacaran period, 550 million years ago. Animal and plant-like imprints are embedded in “textured” rocks, where the texture actually represents fossilised microbial mats that once covered the ancient sea floor.</p> <p>A joint Australian-US team has <a rel="noreferrer noopener" href="https://cosmosmagazine.com/earth/earth-sciences/studying-fossils-with-ai-tech/" target="_blank">recently been awarded</a> NASA funding to see if AI can distinguish between rocks that are formed from biological signatures (like these microbial mats) or from purely abiotic chemical processes.</p> <p>The team’s ultimate goal is to apply similar machine learning techniques to geological images taken by Mars rovers.</p> <p>This new paper by UK astrobiologists says that research like this may be key to the success of current and future exobiology missions.</p> <p>“We have been fooled by life-mimicking processes in the past,” says co-author Julie Cosmidis, a geobiologist from the University of Oxford. “On many occasions, objects that looked like fossil microbes were described in ancient rocks on Earth and even in meteorites from Mars, but after deeper examination they turned out to have non-biological origins.</p> <p>“This article is a cautionary tale in which we call for further research on life-mimicking processes in the context of Mars, so that we avoid falling into the same traps over and over again.”</p> <!-- Start of tracking content syndication. Please do not remove this section as it allows us to keep track of republished articles --> <img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=172969&amp;title=False+fossils+could+hamper+search+for+life+on+Mars" alt="" width="1" height="1" /> <!-- End of tracking content syndication --></div> <div id="contributors"> <p><a href="https://cosmosmagazine.com/space/astrobiology/false-fossils-on-mars-could-hamper-search-for-life/">This article</a> was originally published on <a href="https://cosmosmagazine.com">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/lauren-fuge">Lauren Fuge</a>. Lauren Fuge is a science journalist at Cosmos. She holds a BSc in physics from the University of Adelaide and a BA in English and creative writing from Flinders University.</p> <p><em>Image: gremlin/Getty Images</em></p> </div> </div>

International Travel

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Is a trip to Mars ethical?

<div class="copy"> <p>For the 21st century explorer Mars would have to be the number one travel destination. If that’s you, you might try your luck with Mars One, a privately funded mission to colonise Mars led by Dutch entrepreneur Bars Landsorp.</p> <p>If you’re selected, it’s a seventh-month one-way only trip. The first four human volunteers are scheduled to blast off in 2026 in the hope of setting up a colony. Scientists, engineers and others in the space industry say the mission is not feasible. But it is the ethics of the enterprise that concern me here.</p> <p>Some years ago I was among a group of bioethicists asked to ponder the morality of sending humans into space for several months or years.</p> <p>At the time NASA was considering the idea of sending astronauts to Mars – with no real way of organising a flight home. (Since then NASA has developed plans for a three-year return trip to Mars in 2035.)</p> <p>I told NASA that exploration in situations of terrifying and serious risk was not new.</p> <p>Asking if human long-duration space flight is ethical means asking the same questions that Englishman Robert Falcon Scott <em>should</em> have asked before setting out on his doomed mission to the South Pole. What are the technical constraints and what needs to be invented? What preparedness is needed and what is the cost? What information is needed for the crew to consent?</p> <p>History tells us that Scott arrived at the Pole a month after Roald Amundsen claimed it for Norway. Scott died along with his entire company on the way home. They were hopelessly unprepared  – taking French olives and raspberry jam and inadequate  gloves. Amundsen by contrast learned survival skills from peoples who lived in the Arctic before setting out. Scott’s example teaches us that bravery is not enough: realistic preparation is crucial.</p> <p>The risks of long-haul human space flight have been known for years. In 2002 a NASA committee wrote a list. These included the health hazards posed by space radiation; the possibility that the crew could sabotage the mission – based on studies of isolated communities and the psycho-social issues that can arise; physiological risk, including bone and muscle loss in microgravity; and medical risk – including the difficulties of treating injuries and illness in space. Several years later, all these factors remain.</p> <p>The Canadians, the European Union and the Japanese conducted studies of their own and reached the same conclusion. Space is the harshest possible human environment, exceeding conditions anywhere on the planet. Crucially, more is unknown about the physical and mental challenges of space travel than is known.</p> <p>Assessing risk in a situation of utter unknowability is complicated. In the face of this uncertainty risk analysts have put forward the RABA concept (Risk Associated with the Best Alternative). A bad outcome of the best considered alternative might be easier  to accept than charging in like Scott without adequately considering the risks. But there are limits to rational arguments about the risks of space colonisation: we don’t know what we don’t know.</p> <p>So what makes risk ethical? Historically it has been one thing: consent. The ethical considerations change if we think of the crew as military personnel.<br />We expect soldiers to face considerable risk. And think of the pioneers who travelled to remote and desolate places with no thought of return.</p> <p>So what did I advise NASA? Exploring space is an awesome enterprise – but it has to be done at awesome cost. The process has to protect the astronauts as much as possible. The mission must be done publicly for peaceful purposes, by free people, with the results considered common stock.</p> <p>But before we set out we need a far-reaching public discussion of what space travel means to us – and what we are prepared to sacrifice for it.</p> <em>Image credits: Shutterstock         </em></div> <div id="contributors"> <p><em>This article was originally published on <a rel="noopener" href="https://cosmosmagazine.com/space/is-a-trip-to-mars-ethical/" target="_blank">cosmosmagazine.com</a> and was written by Laurie Zoloth. </em></p> </div>

Travel Tips

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Elon Musk selling final Earth home so he can "focus on Mars"

<p>Tesla CEO Elon Musk has listed the last home he owns of his $100 million real estate portfolio, in a quest to “own no house” and focus solely on his mission to Mars.</p> <p>It’s been no easy feat letting go of his beloved properties, however this San Francisco mansion has been a little harder to let go of for Musk.</p> <p>Deemed his “special place,” the nine-bedder has proven to be a difficult property to shift.</p> <p>After initially listing the home last year, it failed to receive any substantial offers so the 49-year-old took it off the market.</p> <p>However, this week Musk announced he would be selling the 47-acre lot for an eye-watering $48.6 million (US$37.5 million).</p> <p>“Decided to sell my last remaining house. Just needs to go to a large family who will live there. It’s a special place,” the Tesla and SpaceX CEO wrote.</p> <p>Musk, who has an estimated net worth of $185 billion, initially purchased the home in 2017 for US$23.4 million.</p> <p>The incredible Hillsborough retreat is over 100-years-old and has every feature possible including Bay views, a pool, hiking trails and mesmerising canyons.</p> <p>Not only that, but the incredible mansion even features a ballroom, banquet dining room and a well-preserved but completely updated professional kitchen.</p> <p>Musk vowed to get rid of his homes and belongings in order to devote his life “to Mars and Earth.”</p> <p>“Don’t need the cash,” the eccentric billionaire tweeted in May 2020.</p> <p>“Possession just weighs you down.”</p>

Real Estate