Space Sunday: water, water everywhere

NASA’s Mars Curiosity rover celebrated its two-thousandth Martian day, or Sol, on the Red Planet on March 22nd, 2018. In celebration, NASA issued a new photo-mosaic of images captured by the rover in January 2018, which have been processed to provide a offers a preview of what comes next.

Looming over the image is Mount Sharp, the mound Curiosity has been climbing since September 2014. In the centre of the image is the rover’s next big, scientific target: an area scientists have studied from orbit and have determined contains clay minerals.

Clay minerals requires water to form. Curiosity has already revealed that the lower layers of Mount Sharp formed within lakes that once spanned Gale Crater’s floor. The area the rover is about to survey could offer additional insight into the presence of water in the region, how long it may have persisted, and whether the ancient environment may have been suitable for life.

Key to examining the area will be the rover’s drill mechanism, which the science team hope will be able to draw samples pulled from the clay-bearing rocks so their composition can be determined. As I recently reported, a new process for obtaining samples via the drill and getting them to the rover’s on-board science suite was recently tested to overcome a long-term issue with the drill feed mechanism, and the approach is being refined on Earth in preparation for the excursion into the clay region.

The 2,000 Sol celebration mosaic, published on March 22nd. It is made up of dozens of images captured by the rover’s Mastcam on Sol 1931 back in January. The mount of “Mount Sharp” (Aeolis Mons) dominates the mosaic, while the area outlined in white marks the region of clay minerals the rover is going to explore in the weeks and months ahead. The image has been white-balanced to match Earth normal lighting. Credit: NASA/JPL / MSSS

In the meantime, a new study seeking to explain how Mars’ putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million years earlier than previously thought, and were not as deep as had been assumed. In particular, it links the existence of oceans early in Mars history to the rise of the massive Tharsis volcanoes on Mars and highlights the key role they may have played in the ancient oceans of the Red Planet.

A common objection to Mars ever having oceans of liquid water is that estimates of the size of the oceans doesn’t marry-up with estimates of how much water is retained within the planet’s polar caps, how much could be hidden today as permafrost underground, and how much could have escaped into space. In the new study, from the University of California, Berkeley, it is proposed that Mars’ oceans first formed before, or at the same time as, the massive volcanoes of the Tharsis bulge, 3.7 billion years ago, rather than after them.

“The assumption was that Tharsis formed quickly and early, rather than gradually, and that the oceans came later,” Michael Manga, professor of earth and planetary science and senior author of the study, said. “We’re saying that the oceans pre-date and accompany the lava outpourings that made Tharsis.”

This would mean that the plains that cover most of the northern hemisphere, which are the presumed to be an ancient seabed, would have extended into the area later deformed as the Tharsis Ridge expanded, and lava flows cut into the plains. Thus, the initial oceans on the planet would have been more widespread – but shallower – than originally thought, providing a smaller overall volume of water.

The early ocean known as Arabia (left, blue) would have looked like this when it formed 4 billion years ago on Mars, while the Deuteronilus ocean, about 3.6 billion years old, had a smaller shoreline. Both coexisted with the massive volcanic province Tharsis, located on the unseen side of the planet, which may have helped support the existence of liquid water. The water is now gone, perhaps frozen underground and partially lost to space, while the ancient seabed is known as the northern plains. Credit: Robert Citron images, UC Berkeley

The model also counters another argument against oceans: that the proposed shorelines are very irregular, varying in height by as much as a kilometre, when they should be level, like shorelines on Earth. However, this irregularity could be explained if the first ocean, called Arabia, started forming about 4 billion years ago and existed, if intermittently, during as much as the first 20% of Tharsis’s growth. The growing volcanoes would have depressed the land and deformed the shoreline over time, leading to the irregular heights seen today. This would also apply to the subsequent ocean, called Deuteronilus, if it formed during the last 17% of Tharsis’s growth, about 3.6 billion years ago.

Tharsis, now a 5,000-km-wide eruptive complex, contains some of the biggest volcanoes in the solar system and dominates the topography of Mars. Its bulk creates a bulge on the opposite side of the planet (the Elysium volcanic complex), and the canyon system of Valles Marineris in between. This explains why estimates of the volume of water the northern plains could hold based on today’s topography are twice what the new study estimates based on the topography 4 billion years ago.

This new theory has two further points in its favour. Firstly, it can account for the valley networks (cut by flowing water) that appeared around the same time.Secondly, both Arabia and Deuteronilus would have existed at a time when the Tharsis volcanoes and those of Elysium would have been active, throwing greenhouse gases into the Martian atmosphere, warming it and increasing its density.

The authors of the study admit it is just a hypothesis at this point in time, and Manga invites others to follow-up on it. “Scientists can do more precise dating of Tharsis and the shorelines to see if it holds up.”

Too Much Water To Be Habitable?

The latest study to be published concerning TRAPPIST-1, the 7-exoplanet star system 39 light-years from our Sun, suggests the exoplanets may be too wet to have ever supported life – which might sound a little surprising. It also suggests the planets have migrated closer to their planet red dwarf star since their formation.

The study was led by Cayman T. Unterborn, a geologist with the School of Earth and Space Exploration (SESE), and used data from prior surveys that attempted to place constraints on the mass and diameter of the TRAPPIST-1 planets in order to calculate their densities, one of which I mentioned in January 2018.

Artist’s concept showing what each of the TRAPPIST-1 planets may look like. Credit: NASA

Using this data as a starting point, the team constructed mass-radius-composition models to determine the volatile contents of each of the TRAPPIST-1 planets. They found the 7 planets are light for rocky bodies, suggesting a high content of volatile elements. On similar low-density worlds, this volatile component is usually thought to be atmospheric gases. However the TRAPPIST-1 planets are too small in mass to hold onto enough gas to make up the density deficit.

Because of this, Unterborn and his teams determined that the low-density component of the seven planets was most likely water. To determine just how much water, the team used ExoPlex, software for calculating interior structure and mineralogy and mass-radius relationships for exoplanets. This allowed the researchers to combine all of the available information about the TRAPPIST-1 system.

The results revealed that all of the TRAPPIST-1 planets have high percentages of water by mass: 15% for the two inner worlds, b and c, rising to more than 50% for the outer planets, f and g. To put this into context, Earth has just 0.02% water by mass. Thus, the TRAPPIST-1 planets have the equivalent of hundreds of Earth-sized oceans trapped within their volumes. Had this water been liquid at any point in the past, or simply frozen ice enveloping the surfaces of them, it would likely to have been far too much to support life, as Natalie R. Hinkel, an astrophysicists from Vanderbilt University, Nashville, explained:

We typically think having liquid water on a planet as a way to start life, since life, as we know it on Earth, is composed mostly of water and requires it to live. However, a planet that is a water world, or one that doesn’t have any surface above the water, does not have the important geochemical or elemental cycles that are absolutely necessary for life.

In addition, the study also suggests that all seven planets in the system most likely formed father away from their star and migrated inward over time – something which has been noted with other exoplanet systems. In the case of TRAPPIST-1, the planets are distributed either close to, or within, the star’s “ice line”. This is a boundary where, within which, ice on planets tends to melt and either form oceans (if sufficient atmosphere is present) or vaporise. Beyond this line, water will take the form of ice and can be accreted to form planets.

An artist’s impression of the sky from the outermost of the three TRAPPIST exoplanets in the star’s habitable zone.

Given the relative positions of the outer planets to their star’s ice line, the research team determined all seven of TRAPPIST-1’s planets must have formed beyond the ice line, but over the aeons migrated inwards, with the inner planets losing much of their water content through their surface ice vaporising – but leaving a high volume of water still being retained within their rocky crusts.

Working out how far – and when – the planets might have formed is made more complicated by the fact that M-type red dwarf stars like TRAPPIST-1 burn brighter and hotter early in their lives before cooling and dimming – so its “ice line” would have contracted inwards as well.  Based on how long it takes for rocky planets to form, the team estimated that the planets must have originally been twice as far from their star as they are now.

Overall, the study leans weight to the view that TRAPPIST-1 worlds are unlikely to be habitable. Early on, as Natalie Hinkel noted above, they may well have been ice or water covered, but lacking the geochemical and elemental cycles essential for life. Any period in which surface conditions might have been more favourable for life on the inner planets as their ice melted would likely have been comparatively short as a result of the star’s solar activity stripping most of their atmospheres away.

Kepler Observatory Nears End of Life

To date, around 3,743 exoplanets have been discovered in our galaxy – 2,649 of them by the Kepler Space Observatory, but we’re now approaching the end of life for this veritable planet hunter.

Launched in 2009, Kepler occupies an Earth-trailing heliocentric orbit, from which it has sought out exoplanets using the transit method – monitoring a star over a period of time for periodic dips in brightness caused by a planet transiting (passing in front of) the star.

In 2012 and 2013, the observatory suffered failures and issues with two of the observatory’s four reaction wheels used to hold it steady while observing distant stars. As a result, a new mission profile, K2 Second Light, was developed in order to compensate for the issues. Unfortunately this required the observatory to use small amounts of its propellant reserves to help hold it steady during operations – and those fuel reserves are almost expended.

Mission engineers are uncertain as to precisely when the observatory’s fuel will run out, other than it will likely happen in the next several months.  The hope is that there is still enough time to gather as much data a possible from the current observation campaign.

For the first four years of its primary mission, the space telescope observed a set star field located in the constellation Cygnus Since 2014, Kepler has been collecting data on its second mission, observing fields on the plane of the ecliptic of our galaxy. Credit: NASA / Wendy Stenzel

“Without a gas gauge, we have been monitoring the spacecraft for warning signs of low fuel— such as a drop in the fuel tank’s pressure and changes in the performance of the thrusters,” Charlie Sobeck, a system engineer for the Kepler space telescope mission, explained. “But in the end, we only have an estimate – not precise knowledge.”

The end of Kepler’s mission does not mark the end of the search for Exoplanets from space. April 2018 will see the launch of  the Transiting Exoplanet Survey Satellite (TESS), will conduct transit surveys on a large scale, and in 2019 the James Webb Space Telescope (JWST) will also have part of its mission devoted to the hunt for exoplanets. Both will help build on Kepler’s legacy.

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UWA Art of the Artists machinima challenge winners

Poster by Eliza Wierwright

On March 26th, 2018, the winners of the UWA Art of Artists machinima challenge, launched in July 2017, were announced. Initially sponsored by LaPiscean Liberty of SLArtist and Singh Albatros and The Writers Centre, Singapore, the challenge opened with a prize pool of L$350,00 which, thanks to additional sponsors such as Pooky Amsterdam of Pookymedia, topped-out at L$430,000 by the time the challenge closed to entries on December 31st, 2017.

Challenge entrants were asked to produce a machinima film focused on any of the art exhibits located on the UWA regions in Second Life. They were allowed to choose individual pieces of art or a collection around which to weave a story. However, the art had to be a relatively significant part of the story, and not merely something glimpsed in passing, and films to be considered for any of the prizes could not exceed 8 minutes in length (although longer films could be submitted if desired.

The award ceremony was held at the historic Winthrop Hall in the UWA virtual campus in Second Life. As well as a celebration of the competition and its winners, the event also marked an end of an era. “It’s a farewell from me,” Jayjay Zifanwe, who has been the powerhouse behind the UWA’s presence in Second Life and its patronage of digital arts, informed me ahead of the ceremony.

He continued, “Farewell in a sense that it’s the last of my major events, and the last speech in will do within SL.” During his opening address at the awards ceremony, Jayjay took time to thank all of those – especially Freewee Ling, curator of the UWA’s art exhibits, and to all those who have done so much to make the UWA’s presence in SL so rewarding for him. In doing so, he also paid tribute to artist Alizarin Goldflake, who passed away recently after a long illness.

The Awards

All of the entries can be viewed on the Slartist website.

Art of the Artists Awards

Sponsored by LaPiscean Liberty and Slartist.

Award Awarded To
Film title / link
1st – L$75,000 Glasz Decuir Adaptive Resonance Theory (ART) and Intrusion Detection System(IDS)
2nd – L$50,000 Tutsy Navarathna Serendipity
3rd – L$40,000 Natascha Randt & Karmia Hoisan The River of Forgetting
4th –  L$30,000 Isabelle Cheren Before the World was Made
5th – Award L$20,000 Bryn Oh Cerulean
Craft Awards (L$7,000 each)
Suzie Anderton; Amelie Marcoud; Diana Rose; Elle Thorkveld; Tantra Sangha & M1nn0taur; Veyot; Gerhard Helmut & Lila~R; Iono Allen; Joseph Nussbaum; Secret Rage; Lampithaler

 

The Pookymedia Awards

Sponsored by Pooky Amsterdam and Pookymedia.

Award Awarded To
Film title / link
1st – L$25,000 Bryn Oh Cerulean
2nd –  L$15,000 Tutsy Navarathna Serendipity
3rd –  L$10,000 Suzie Anderton Never Say Never
Honourable Mentions (L$1,000 each)
Amelie Marcoud; Iono Allen; Lampithaler; Isabelle Cheren; Chic Aeon

 

UWA Art of the Artists Special Awards

Totalling L$51,000, awarded by Jayjay Zifanwe on behalf of the University of Western Australia.

Award Awarded To
Film title / link
L$17,000 Amelie Marcoud For Love and Art
L$17,000 Suzie Anderton Never Say Never
L$17,000 Chic Aeon The Amalgamation of Objects

The Merlion Special Prizes

Awarded by Singh Albatros and Kaylee West on behalf of The Writer’s Centre, Singapore to the films which best represent the The Merlion,  the national personification of Singapore, and featured at the Merlion Portal in Second Life.

Award Awarded To
Film title / link
L$16,666 Amelie Marcoud For Love and Art
L$16,666 Suzie Anderton Art and Transformation – a dialogue at intervals
L$17,000 Diana Rose A Journey From the Past: Singapore

 

 

Congratulations to all those who received an award, and thanks to Jayjay, FreeWee and all those involved in this challenge.

A summer’s twirl in Second Life

La Virevolte; Inara Pey, March 2018, on FlickrLa Virevolte – click any image for full size

“Twirling like a butterfly, fluttering in the sky, choosing the most fragrant flowers, regardless of the end of summer.” So reads the introduction to the latest incarnation of La Virevolte (The Twirl), the highly photogenic Homestead region designed by Iska (sablina). When last we visited, the region was in the grip of winter. With this incarnation, the region has a new look caught in the Sun – as the description says – of late summer.

A visit starts on a terrace outside of a little café. It sits in the corner of a little hamlet built alongside a channel-like canal running east-to-west through the region, splitting it in two. A house also occupies the terrace, a vintage Citroen van serving as a mobile fresh produce stall, sitting between the two. Facing them sits another house, the barn alongside seemingly in the process of being converted into a home. House and barn sit on an island of grass surrounded by a loop of road.

La Virevolte; Inara Pey, March 2018, on FlickrLa Virevolte

The western end of this loop touches on a headland ending in a promontory of rock on which is perched a lighthouse keeping watch on things. North of the hamlet, beyond the road’s loop, the land offers rugged grassland rising to a rocky bluff. This open, rugged land continues around the east of the region, grassy slopes rising within the shoulders of a high v-shaped plateau. The grass between the slopes and the café are divided in part by an ancient stone wall, cupping a wild garden between it and the hamlet’s buildings.

Across the channel – which is spanned by a stone bridge – a road runs south before curling to wind its way up the stepped landscape, ending among tall pines trees, where a track points east to where an old farmhouse sits atop a rocky shelf, the land between track and building also falling in gentle steps, some of which are – like the terraces below – retained by ancient drystone walls.

La Virevolte; Inara Pey, March 2018, on FlickrLa Virevolte

These terraces are in part cultivated, presumably by whoever lives up in the farm-house. The lowest one is given over to root and vine vegetables, while grapes are ready for harvesting on the next terrace up. They and the vegetables point to the late summer setting for the region. Stone steps climb the terraces, offering a shorter route up to the track leading to the farm-house for those who don’t feel like walking the road.

This is another marvellous design by Iska, one made particularly attractive by the way things like the building have been brought together. Take the house across the road from the café, for example; part of the original wall seems to have collapsed at some point, and an effort has been made to replace it with a red brick wall. Elsewhere sit the carcasses of an old a car and van, the former turned into a little garden, the latter now serving as a snuggle spot. These and the children’s toy and tricycle in the grounds of the houses, a broken flower-pot on a doorstep, all give the feeling that this is a home to unseen locals.

La Virevolte; Inara Pey, March 2018, on FlickrLa Virevolte

Walking through the region, it is very easy to picture you’re deep in rural France. I was immediately put in mind of parts of the Massif Central (the open water and lighthouse notwithstanding), given the general style of the houses. I mentioned this to Iska as we talked about the design. “The southern foothills of Massif Central, yes!” she replied. “[With] a lot of fountains and rivers, I love the sound of water everywhere.”

To say this is once again a photogenic design would be an understatement; it is a painting in and of itself, the selected windlight and sound scape both complementing it perfectly. Throughout the region are places to sit and admire / cuddle, such as the aforementioned old van, a picnic blanket out on the banks of the channel, the tables of the café and more. 

La Virevolte; Inara Pey, March 2018, on FlickrLa Virevolte

Altogether, another fabulous design, kudos to Iska in building it and offering it to people to visit. and thanks to Shakespeare for the nudge concerning the redesign.

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