Space Sunday: Europa, a Starshade and ambitions

Arthur C. Clarke’s fictional warning from 2010: Odyssey Two, given with regards to Europa. Now we may have a further reason to send a mission to probe the ocean beneath the moon’s icy crust. Credit: NASA / I. Pey

The words in the image above form part of the conclusion to Arthur C. Clarke’s 2010: Odyssey Two, the sequel to Stanley Kubrick’s collaboration with Clarke, 2001: A Space Odyssey, and itself made into a film by Peter Hyams. They come as the alien force responsible for the strange monoliths that triggered the events of 2001: A Space Odyssey cause the gravitational collapse of Jupiter, generating sufficient compression to start nuclear fusion, turning it into a mini-sun.

The actions were taken due to primitive life being found in the waters under Europa’s crust of ice; life trapped in an evolutionary cul-de-sac unless Europa received greater sunlight to melt the ice, evaporate some of the sea to expose landmasses and allow its burgeoning life the opportunity to grow and evolve. The words were issued to prevent humanity interfering in this process.

While there is no sign of aliens, monoliths, or anything like it around Jupiter, we do know there is a vast salty ocean under Europa’s ice, potentially 100 km (62.5 mi) deep and kept liquid as a result of the gravitational forces of Jupiter and other Galilean moons causing Europa to “flex” and generate heat deep within itself – and that ocean could be the home of life.

Europa’s internal structure, showing the subsurface ocean which could be up to 100 km (62.5 mi) deep. Credit: NASA

It had generally been thought that the salt in Europa’s ocean was likely magnesium chloride. Now a new study indicates that the salt could well be sodium chloride – the same salt present in our own oceans.  This has important implications for the potential existence of life in Europa’s hidden depths.

Scientists believe that hydrothermal circulation within the ocean, mostly likely driven by hydrothermal vents created on the ocean floor as a result of Europa’s “flexing”, might naturally enrich the ocean in sodium chloride. On Earth, hydrothermal vents have been shown to support life around them, which utilises the minerals and heat from the vent. Much the same could be occurring on Europa.

NASA has had many plans for missions to explore Europa’s ocean. Thus far, none have got beyond the the planning phase. Credit: NASA

Identifying the presence of sodium chloride has been a long time coming. Europa is tidily-locked with Jupiter, meaning it always keeps the same side pointed toward the planet. As a result, studies of the moon have been focused on its far side relative to Jupiter, as this side of the moon reveals much of the complex and continuing interaction taking place between Jupiter, Europa, and Jupiter’s innermost moon, Io, which results in sulphur from Io to be deposited on Europa.

Mixed in with these sulphur deposits are traces of magnesium chloride, which led researchers to believe it had been ejected from the moon’s ocean through the cracks and breaks that occur in Europa’s icy shell as a result of the internal “flexing”. However, when reviewing recent data obtained from the Keck Observatory, the team responsible for the new study found something odd. The data – gathered in infra-red – included the “side” of Europa facing along the path of its orbit around Jupiter – a face largely free from sulphur deposits from Io, although it is still stained yellow.

It had been assumed that this discolouration was due to more magnesium chloride being ejected from within Europa. But magnesium chloride is visible in the infra-red – and the Keck data didn’t reveal any such infra-red signature associated with the discolouration. So what might be causing them?

One of the study’s authors, Kevin Hand of NASA’s Jet Propulsion Laboratory, realised that sodium chloride is “invisible” under infra-red – but it can change colour when irradiated. Carrying out tests on ocean salts, he found they did turn yellow under visible light when irradiated. He then analysed the yellow in the salt and the yellow on Europa imaged by Hubble – and found the two exhibited exactly the same absorption line in the visible spectrum.

A pair of composite images of Europa. On the left, as seen in natural light; on the right the same image that has been colour enhanced. They show, on the right, the “far side” of Europa relative to Jupiter, the rust colour the result of sulphur ejected from Jupiter’s inner moon Io being deposited on Europa by Jupiter’s radiation belts, and which show evidence of magnesium chloride. On the left, the yellow staining, originally thought to be the result of further magnesium chloride deposits from within the moon – but which now have been shown to be sodium chloride – the same salt as found in our own oceans. Credit: NASA/JPL / University of Arizona

We’ve had the capacity to do this analysis with the Hubble Space Telescope for the past 20 years. It’s just that nobody thought to look.

Mike Brown, Professor of Planetary Astronomy at Caltech, and study co-author

This is the clearest evidence yet as to the nature of Europa’s ocean and its similarity to our own, life-supporting ocean. However, it’s not absolute proof: the sodium chloride might be indicative of salt deposited in Europa’s icy crust from long ago, rather than evidence of it being contained with the moon’s oceans. However – and despite the fictional warning from Clarke’s novel – the study ups the need for us to send a mission to Europa that is capable of penetrating its icy surface and directly studying the ocean beneath ice, both for signs of possible life, and better understand the processes that might be occurring within its depths.

Starshade: The Quest to See Exoplanets

Over the last few decades, astronomers have discovered over 4,000 exoplanets orbiting other stars, leading to wide-ranging debates as to the suitability of such worlds supporting life. One of the ways we could better make such a determination would be through direct analysis of their atmospheres. The problem here is that given the distances involved, the atmospheres of exoplanets are effectively masked from observation from Earth by the glare of their parent star.

Plans are in hand to achieve this. When the WFIRST telescope is launched in the mid-2020s – assuming it continues to survive attempts by the White House to delay or cancel it – it will carry an instrument called the stellar coronagraph. This will effectively block the light of a star from reaching the telescope’s imaging systems, allowing it to see the atmospheres of planets roughly the size of Saturn or Jupiter or larger. But to see the atmospheres of smaller exoplanets  – the size of the majority so far discovered – an alternative its required. Enter Starshade.

Also called the New World Project, Starshade has been in development since 2005 – although it has yet to gain formal mission status. In essence, it proposes the deployment of a purpose-built space telescope and an “occulter” – a massive deployable, adjustable shade, 26 metres (85 ft) in diameter.

Starshade proposes using a large “occulter” (left) to block the light of distant stars so that a telescope (right) to study the atmospheres of planets orbiting the star. Note this image shows the shade unfurling following its deployment from its carrier vehicle, which also includes the originally-proposed telescope (seen at the right-hand end of the vehicle). once separated, the telescope vehicle would move away from the starshade before turning to align the telescope with it. Credit: NASA, 2014

The idea is that, placed between the telescope and a star with known exoplanets, the shade would block the star’s light – but allow the light from the planets be received by the telescope, allow it to be spectrographically analysed. This would allow scientists to understand the nature and composition of any atmospheres these planets might have, and thus determine their possible suitability for life.

One of the stumbling blocks for the proposal has been cost: developing and launching both a purpose-built telescope and occulter has been put at US $3 billion. However, were Starshade to be used with an already budgeted telescope – say WFIRST – that cost comes down to just US $750 million. Thus, the most recent studies related to the project have been focused on achieving this. In doing so, they’ve raised a significant technical issue: alignment.

Continue reading “Space Sunday: Europa, a Starshade and ambitions”

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Shakespeare, boys and badgers, and lunar tourists

Seanchai Library

It’s time to highlight another week of storytelling in Voice by the staff and volunteers at the Seanchai Library. As always, all times SLT, and events are held at the Library’s home at Holly Kai Park, unless otherwise indicated.

Sunday, June 16th, 13:00 A Midsummer’s Night Dream

Selected scenes presented live from the current A Midsummer Night’s Dream Project.

One of William Shakespeare’s most popular comedies, A Midsummer Night’s Dream is a four-stranded play set within a forest inhabited by the fairy folk under the rule of Titania and Oberon. There is the over-arching theme of the forthcoming wedding of Duke Theseus of Athens and Hippolyta, the Amazon queen, due to take place within the forest. This is to be in part celebrated by a group of six amateur actors staging a play, and who have also come to the forest to prepare. Then there are the four young Athenians who are to be among the guests at the wedding: Hermia, is in love with Lysander, but has been order by Egeus, her face to wed Demetrius, who is deeply loved by Helena, Hermia’s best friend – but whom he dumped to be free to wed Hermia.

Within the forest, Oberon and Titania are somewhat estranged over Titania’s refusal to accede to Oberon’s demand to hand him her Indian changeling. Angered by her actions, Oberon summon Robin “Puck” Goodfellow, his “shrewd and knavish sprite”, with the intent of putting into motion a plan to shame Titania into doing as he wishes through the use of a magical potion. However, as the plot is put into motion, Oberon witnesses assorted actions: the cruel words of Demetrius to Helena, the assery (a deliberately chosen term in the circumstances 🙂 ) of Nick Bottom, one of the amateur players, and the plot inevitably thickens – helped in no small part by a slight case of mistaken identities, until the fairies are forced to convince those with whom they have interacted have just experienced a dream – and Puck suggests that the dream might even extend to the audience.

A Midsummer’s Night Dream, LEA 2

Hosted by Elrik Merlin and Caledonia Skytower, with performances organised by Kayden Oconnell, the cast comprises Caledonia, Kayden, Da5id Abbot, Fayleen Belois, Ian Quintessa, and Aoife Lorefield, the project’s creator, who will also be interviewed after the performances.

If you cannot attend the event, then why not listen wherever you are, in-world or out, by tuning into fantasy.radioriel.org.

Monday, June 17th 19:00: Incident at Hawk’s Hill

Gyro Muggins reads naturalist and historian Allan W. Eckert’s popular novel.

In 1870, Manitoba became the fifth province of the (then) three-year-old Canadian Confederation. Over the previous 18 months, it had seen strife and rebellion, but for William MacDonald, his wife, Esther, and their family, the lands around what would eventually become the city of Winnipeg, are ideal for farming, and so they have settled and built Hawk’s Hill.

The open spaces are perfect for the MacDonald’s four children – or should have been; while the three elder children thrived, the youngest, six-year-old Ben, became increasingly introverted.

Small for his age, Ben was reserved and prefers being with animals, learning to imitate the sounds of many, and well as copying their movements and actions. In return, the local animals seem to respond well to him – although members of his family and the other locals consider him odd.

But then came the day when Ben, in seeking new animals to mimic, wandered further than was usual, venturing into unfamiliar territory – only to become hopelessly lost. When a storm breaks, he has no option but to hide in a badger hole – an occupied badger hole. And thus begins a relationship spanning several months between young boy and a female badger, to the benefit and comfort of both.

Tuesday, June 18th 19:00: The Penderwicks in Spring

Springtime is finally arriving on Gardam Street, and there are surprises in store for each member of the family. Some surprises are just wonderful, like neighbour Nick Geiger coming home from war. And some are ridiculous, like Batty’s new dog-walking business. Batty is saving up her dog-walking money for an extra-special surprise for her family, which she plans to present on her upcoming birthday. But when some unwelcome surprises make themselves known, the best-laid plans fall apart.

Filled with all the heart, hilarity, and charm that has come to define this beloved clan, The Penderwicks in Spring is about fun and family and friends (and dogs), and what happens when you bring what’s hidden into the bright light of the spring sun.

With Caledonia Skytower.

Wednesday, June 19th 19:00: The Menace from Earth

Young love is often hard on those experiencing it for the first time.

Take 15-year-old Holly, for example. A lunar colonist and aspiring starship designer, who has something of a crush on her closest male friend, Jeff, with whom she shares a particular passion: that of flying.

It’s a popular pastime on the Moon, thanks in part to the 1/6 gravity environment. Taking advantage of this in caverns within the cities where the air pressure can be kept high enough, locals can strap on sets of wings and take to the air. And Holly and Jeff are both fans of the activity.

Another element to life on the Moon is that of tourism: playing host to “groundhogs”, as the locals call them, who like to visit the Moon. One such tourist is Ariel, a glamorous woman to whom Holly is assigned to as a guide.

It all goes well to start with – until Holly introduces Ariel to Jeff. To her dismay, Holly find herself facing The Menace From Earth: Jeff is quite smitten with Ariel. As her jealousy grow, so Holly starts to resent Ariel more and more – but what to do?

Things take a sudden turn when Ariel asks to joins Holly and Jeff flying in the local cavern…

With Derry McMahon, Bear Silvershade, and Caledonia Skytower.

Thursday, June 20th 19:00: Monsters and Myths

Shandon Loring re-opens Bernard Evslin’s work of stories featuring the gods, heroes and monsters of Greek mythology, turning to Evslin’s words on Hecate, variously associated with crossroads, entrance-ways, light, magic, witchcraft, knowledge of herbs and poisonous plants, ghosts, necromancy, and sorcery.