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THE MILKY WAY AND ME, JOEL TONYAN, CC BY-NC-ND 2.0
TRYING TO FIND THE ANSWERS
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TEST-TUBES-COLOUR-FLUID, R.NIAL BRADSHAW, CC BY 2.0
THE WEEKLY
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CONTENTS 4
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WILL WE EVER BE ABLE TO BRING CRYOGENICALLY FROZEN CORPSES BACK TO LIFE? JUNO IS DELIVERING SPECTACULAR INSIGHTS INTOÂ JUPITER
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CREATURES THAT DEFY WHAT WE THINK WE KNOW
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GRAVITATIONAL WAVES FOUND: AN INSIDE STORY 3
CRYONICS WILL WE EVER BE ABLE TO BRING CRYOGENICALLY FROZEN CORPSES BACK TO LIFE? A CRYOBIOLOGIST EXPLAINS
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teenager who tragically died of cancer recently has become the latest among a tiny but growing number of people to be cryogenically frozen after death. These individuals were hoping that advances in science will one day allow them to be woken up and cured of the conditions that killed them. But how likely is it that such a day will ever come? Nature has shown us that it is possible to cryopreserve animals like reptiles, amphibians, worms and insects. Nematode worms trained to recognise certain smells retain this memory after being frozen. The wood frog (Rana sylvatica) freezes during winter into a block of ice and hops around the following spring. However, in human tissue each freeze-thaw process causes significant damage. Understanding and minimising this damage is one of the aims of cryobiology. At the cellular level, these damages are still poorly understood, but can be controlled. Each innovation in the field relies on two aspects: improving preservation during freezing and advancing recovery after thawing. During freezing, damage can be avoided by carefully modulating temperatures and by relying on various types of cryoprotectants. One of the main objectives is to inhibit ice formation which can destroy cells and tissues by displacing and rupturing them. For that reason, a smooth transition to a “glassy stage” (vitrification) by rapid cooling, rather than “freezing”, is the aim. For this, simple substances such as sugars and starches have been used to change viscosity and protect cell membranes. Chemicals like dimethyl
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sulfoxide (DMSO), ethylene glycol, glycerol and propandiol are used to prevent intracellular ice formation and anti-freeze proteins inhibit ice crystal growth and re-crystallisation during thawing. But it’s not just the individual cells we have to worry about. In a frozen state, tissues are generally biologically stable. Biochemical reactions, including degeneration, are slowed at ultra-low temperatures to a point where they are effectively halted. Nonetheless, there is a risk that frozen structures can experience physical disruption, such as hairline cracks. Then, upon thawing, temperature fluctuation causes a series
Ice cubes, Brain Rogers, CC BY-NC-ND 2.0
of problems. Tissues and cells can be damaged at this state. But it also has an effect on our overall “epigenetics” – how environmental factors and lifestyle choices influence our genes – by causing epigenetic reprogramming. However, antioxidants and other substances can help aid post-thaw recovery and prevent damage. Reviving whole bodies also poses its own challenges as organs need to commence function homogeneously. The challenges of restoring the flow of blood to organs and tissues are already well-known in emergency medicine. But it is perhaps encouraging that cooling itself does not only have negative effects – it can actually
Long Term Care, Anders Sandberg, CC BY-NC 2.0
THE BIGGEST HURDLES
Cryopreservation of whole brains is a niche interest at best. Experiments with frozen whole animal brains have not been reported since the 1970s. While factors like a good blood supply and high tolerance to mechanical distortion may facilitate brain freezing, particular technical and scientific challenges exist, especially where the goal is to preserve regulatory function and memory. Without huge breakthroughs in such research, it is likely to remain the one factor holding back therapeutic applications of whole-body cryopreservation. But there’s another huge hurdle for cryonics: to not only repair the damage incurred due to the freezing process but also to reverse the damage that led to death – and in such a manner that the individual resumes conscious existence. From a purely technical point of view, this added complication might be worth avoiding. For example, someone who suffers from dementia will have already lost his or her memory by the time they die and will therefore no longer be the same if woken up after being cryogenically frozen. Faced with this, patients with neuro-degenerative disorders who do not wish to live with the condition any longer may therefore seek to be frozen before death, in the
hope that they will retain some memory if revived in the distant future. This clearly raises both legal and ethical questions. As explained, success will depend on the quality of the cryopreservation as well as the quality of the revival technology. Where the former is flawed, as it would
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mitigate trauma. In fact, drowning victims who have been revived seem to have been protected by the cold water – something that has led to longstanding research into using low-temperature approaches during surgery. The pacemakers of scientific innovation in cryobiology are both medical and economic. Many advances in cell preservation are driven by the infertility sector and an emerging regenerative medicine sector. Cryopreserved and vitrified cells and simple tissues (eggs, sperm, bone marrow, stem cells, cornea, skin) are already regularly thawed and transplanted. Work has also started on cryopreservation of “simple” body parts such as fingers and legs. Some complex organs (kidney, liver, intestines) have been cryopreserved, thawed, and successfully re-transplanted into an animal. While transplantation of human organs currently relies on chilled, not frozen, organs, there is a strengthening case for developing cryopreservation of whole organs for therapeutic purposes.
SO WILL IT ONE DAY BE POSSIBLE TO CRYOPRESERVE A HUMAN BRAIN IN SUCH A MANNER THAT IT CAN BE REVIVED INTACT?
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be with current technologies, the demands on the latter increase. This has led to the suggestion that effective repair must inevitably rely on highly advanced nanotechnology – a field once considered science fiction. The idea is that tiny, artificial molecular machines could one day repair all sorts of damage to our cells and tissues caused by cryonics extremely quickly, making revival possible. Given the rapid advances in this field, it may seem hasty to dismiss the entire scientific aim behind cryonics. By Alexandra Stolzing The Conversation CC BY-ND 4.0
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Juno Arrives On Orbit, Robert Couse-Baker, CC BY 2.0
JUNO
IT’S BEEN A TURBULENT START, BUT JUNO IS NOW DELIVERING SPECTACULAR INSIGHTS INTO JUPITER
Now, 150 days into the mission, Juno should have made six or seven close fly-bys of Jupiter, which means flying through the point of its orbit that is closest to the giant planet. It is at this point that the spacecraft makes most of its important scientific observations. But in reality, we have had just one scienceintensive fly-by so far (in August), with another planned this month (December 11). So what happened? Juno was originally injected into a 53-day orbit around Jupiter. The plan was to complete two of these long orbits while all the instruments were being checked, before firing the engine again in October to move the spacecraft closer to the planet in a 14-day orbit. However, shortly before the burn, the Juno team reported that two helium valves – which play a vital role in firing the main engine – weren’t operating properly. So instead of risking the spacecraft by firing the engine, the team decided to wait and analyse the issue in more depth. It’s always better having a healthy, working spacecraft than an uncontrollable one. That’s not to say that Juno will never reach the 14-day orbit, but we now expect to stay in this 53-day orbit for at least the first half of 2017. But if we can’t figure out what’s going on with the valves, we could stay in this orbit indefinitely, as Juno doesn’t get any extra radiation exposure by doing this. From a science perspective, this change just means we’ll be taking data more slowly – with 53 days between each fly-by rather than 14. Juno will still achieve its full scientific potential, but we scientists will have to be more patient than we’d originally planned, as well as reworking all our carefully laid
plans for Earth-based support. With the engine burn postponed, Juno’s science instruments were scheduled to provide complete coverage during the close flyby on October 19. But Juno unexpectedly went into “safe mode” just 13 hours before the fly-by. Safe modes are designed into software in case the computer encounters any glitches. If this happens, everything non-essential is turned off, the computer reboots, the spacecraft makes sure its solar panels are pointed at the sun to maximise its power, and it awaits further instructions from Earth. Unfortunately, this meant that no science data were obtained. It came out of safe mode five days later, and mission managers are now being cautious about the next close approaches to avoid it happening again.
about the polar atmosphere over time. This is rather different to Saturn, where we see banding all the way to the poles and that bizarre northern hexagon.
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here was much excitement when the Juno spacecraft successfully arrived at Jupiter in July, after a five-year journey through the solar system. A perfect engine firing placed the solar-powered spacecraft into just the right orbit around the gas giant, with the promise of great discoveries to come.
SCIENCE SO FAR Despite these setbacks, Juno has already provided unprecedented views of Jupiter that have only served to whet our appetite for what’s still to come when the spacecraft gets into its groove. During the first orbit, Juno was collecting a whole series of colour images that citizen scientists have assembled into a three-month “marble movie” – allowing us to ride along with this robotic explorer, watching the dance of the Galilean moons and the spinning of Jupiter’s dynamic globe. For me, the incredible thing about these images is the vantage point: from Earth, we only ever see Jupiter in full illumination, but Juno can provide a view that currently only this robot can: a crescent Jupiter. Then, on August 27, Juno swooped to within 2,500 miles of Jupiter’s cloud tops, revealing humankind’s best ever views of Jupiter’s north and south poles. Rather than the striped appearance that we’re all familiar with, the poles look completely different. There are no belts and zones up here, but a multitude of small-scale storm systems – giant swirling cyclones with pinwheel structures that presumably wander
ICEBERGS, JUPITER’S STRIPEY CLOUDS ARE JUST THE VERY TOP OF A FASCINATING, VARIABLE LAYER THAT WE’LL EXPLORE IN GREAT DEPTH AS JUNO CONTINUES ITS MISSION IN 2017.
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It’s quite clear from these early images that there’s no such hexagon at either of Jupiter’s poles. The images have also shown nightside clouds towering high over the horizon in the terminator regions, rather like clouds catching the last rays of sun before night. But Juno can do much more than take visible images. The JIRAM instrument from Italy has mapped the entire planet in the infrared, allowing us to see Jupiter’s glowing internal heat and silhouetted clouds in more detail than we’ve ever been able to from Earth. The unique vantage point allows JIRAM to see Jupiter’s aurora, glowing hot due to emissions from excited hydrogen ions in the upper atmosphere as they’re bombarded by electrons moving along the magnetic field lines. Not only can Juno see the aurora, but it can also listen to it. A radio wave detector can hear the emissions of the energetic particles that form the aurora, some of the strongest emissions in the solar system – giving us an impression of the structure of the plasma environment as Juno hurtles through the Jovian system. Among the most hotly-anticipated results are those from the Microwave Radiometer, which is able to peer deeper inside Jupiter than ever before, probing hundreds of miles below the topmost cloud decks to reveal the inner workings of the giant planet’s atmosphere. Even from a single fly-by in August. Leigh Fletcher The Conversation CC BY-ND 4.0ING ONLY THETIPS OF
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BIZARRE CREATURES THAT DEFY WHAT WE THINK WE KNOW ABOUT PLANTS AND ANIMALS
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ou might have played the game called “animal, vegetable, mineral”. One player thinks of an object or organism and the other players ask questions to try to guess what it is – starting with this simple classification. But nature isn’t this simple. There are dozens of groups of living species that are neither plants nor animals. We tend to think of plants as organisms that stand still and use photosynthesis to produce energy from sunlight and make their own organic molecules from the soil. And we see animals as creatures that move and feed on other organisms to obtain the energy and molecules they need. But many organisms challenge those descriptions. The Venus flytrap, despite being a plant, feeds on other organisms – and some of its parts move faster than its unfortunate animal prey. Many groups of animals do not move and live attached to a surface for most of their life, including sponges, corals, mussels and barnacles to name a few. It’s still relatively easy to say whether these creatures are plants or animals. But there are other organisms whose nature is more mystifying.
HERE ARE A FEW OF THE MOST INTRIGUING CREATURES WHO DEFY OUR SIMPLE CATEGORIES.
HUNGRY SEA ANEMONES
Sea anemones are technically animals, but they look so much like plants that they are named after a group of flowers. Even Aristotle, the ancient Greek who produced one of the world’s first systems for categorising life, was puzzled by them. He classified anemones as “zoophytes”, organisms bearing traits of both groups. The truth is that they are animals because they can (very slowly) move and feed on other unsuspecting organisms that get trapped in their tentacles. In fact, sea anemones belong to a group of animals called cnidarians, which also includes jellyfish. Interestingly, there are even components of their nervous system that are the same as humans’, although their anatomy is very different. To make things even more confusing, there is a cnidarian called the “Venus flytrap sea anemone” that completely looks the part. It is a brilliant example of convergent evolution, where unrelated organisms independently evolve similar adaptations (for example, the wings of birds and bats). In this case, it is an animal that looks like a plant that imitates a carnivorous plant that feeds like an animal.
Sea Anemone, Bernard Spragg, Public Domain
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LEAFY SEA SLUGS
Chlorophyll is the green pigment in plant cells that enables photosynthesis to happen, and is one of the defining traits of plants. But some animals use a very clever trick: they steal those solar-powered factories and use them to their benefit, a process aptly named kleptoplasty. The gorgeous sea slug Elysia chlorotica was once described as “a leaf that crawls”. They can borrow chloroplasts from its algal snacks, sucking them with a structure that pretty much looks like a straw, pushing the concept of veganism to the limit. These sea slugs have specialised cells that can keep those chloroplasts for months. What’s more, they also use the stolen chlorophyll for camouflage. The blue dragon slug, Pteraeolidia ianthina, can go a step further. Instead of keeping chloroplasts from is food, is able to enslave whole algal cells. Creatures that are not animals or plants are often informally called protists. Many in this category are in the habit of robbing plastids from algae or subjugating other single-celled organisms. These include dinoflagellates, ciliates and foraminiferans. In this way, all these organisms are able to use an animal-like behaviour (eating other organisms) to acquire plant-like traits (photosynthesis), getting a higher return from their sunbathing sessions than their peers.
Elysia Chlorotica, Patrick Krug, CC BY 2.0
ALGAE FORESTS
Kelp Forest, NOAA, CC BY 2.0
Algae are mostly aquatic organisms that we often think of as single-celled lifeforms that appear as a kind of growth or slime on top of bodies of water in a range of colours. But there are also multicellular types of algae that look far more like plants – even though they often don’t have roots or leaves as we traditionally think about them. Even though they have evolved separately, algae are like plants in that they don’t move and can photosynthesise. If you have been to a beach, you most likely have run or swam into the sea lettuce Ulva, which despite its name is not a vegetable but a green alga. Nori seaweed is commonly used in Japanese cuisine to wrap delicious bits of sushi and rice – and red dulse is a snack in Ireland and Iceland that some claim tastes like bacon when fried. But in spite of their plantlike appearances and animal-like tastes, nori and dulse are scrumptious red algae. Another example is kelp, which forms astonishing massive underwater forests – some specimens reach the impressive length of 80 metres – and is also a key ingredient in many Asian meals. Despite its size, kelp belongs to the brown algae, and is unrelated to plants.
TOWN-SIZED MUSHROOMS
Mushrooms are often treated like vegetables but fungi (which includes yeast and mould) are actually closer to animals than plants, and form an entirely separate kingdom. Like plants, they do not move, but they also don’t perform photosynthesis. Instead their source of molecules and energy are other organisms. But instead of “hunting” them like animals, they either grow on top of them (soil, trees, human feet) or on top of decaying dead organisms (dead bark, dead animals, your bread). Due to their close evolutionary relationship to animals, eating a portabello mushroom in a bun is much closer to eating a hamburger than other veggie substitutes. What’s more, they can grow much bigger than any plant (or animal, for that matter), with the individual heads all part of one giant organism spread out underground. The humungous honey fungus, Armillaria, is allegedly able to cover up to nine square kilometres of forest, weigh up to 35,000 tons and live up to 2,400 years. These fungi are agents of a major forest pest, the “white rot” root disease, which slowly kills numerous trees. Nature is diverse, beautiful and complicated, always defying simple definitions. Human perception can be easily deceived by the intricacy of live beings. But none of this complexity impedes us from making delicious food out of almost every organism we encounter.
Honey Fungus, J.e.mcgowan, CC BY 2.0
Jordi Paps The Conversation CC BY-ND 4.0
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GRAVITY GRAVITATIONAL WAVES FOUND: THE INSIDE STORY
Astronomers have used light to study the universe with optical telescopes for hundreds of years. We have expanded that view hugely since the middle of the 20th century, by building detectors and instruments sensitive to all the forms of what physicists mean by light: the electromagnetic spectrum, from gamma rays to radio. Yet the discovery of gravitational waves represents our first steps into studying the universe through the gravitational-wave spectrum, which
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exists independently from light, probing directly the effects of gravity as it spreads across the cosmos. It is the first page in a whole new chapter for astronomy, and science. How we made the discovery The discovery dates back to last September, when two giant measuring devices in different parts of the US called LIGO (Laser Interferometer Gravitational-Wave Observatory) caught a passing gravitational wave from the collision of two massive black holes in a faraway galaxy.
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One hundred years ago Albert Einstein in his general theory of relativity predicted the existence of a dark side to the cosmos. He thought there were invisible “gravitational waves”, ripples in spacetime produced by some of the most violent events in the cosmos – exploding stars, colliding black holes, perhaps even the Big Bang itself. For decades, astronomers have gathered strong corroborative evidence of the existence of these waves, but they have never been detected directly – until now. They were the last part of the general theory still to be verified.
LIGO IS WHAT WE CALL AN INTERFEROMETER, CONSISTING OF TWO 4KM “ARMS” SET AT RIGHT ANGLES TO EACH OTHER, PROTECTED BY CONCRETE TUBES, AND A LASER BEAM WHICH IS SHONE AND REFLECTED BACK AND FORTH BY MIRRORS AT EACH END.
When a gravitational wave passes by, the stretching and squashing of space
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causes these arms alternately to lengthen and shrink, one getting longer while the other gets shorter and then vice versa. As the arms change lengths, the laser beams take a different time to travel through them. This means that the two beams are no longer “in step” and what we call an interference pattern is produced – hence the name interferometer. The changes in the length of the arms are actually tiny – roughly one million millionth the width of a human hair. This is because the signal from a gravitational wave from far out in the cosmos is mindbogglingly small by the time it reaches us. As if detecting this were not difficult enough, all manner of local disturbances on Earth make it worse, from the ground shaking to power-grid fluctuations; and instrumental “noises” that could mimic or indeed completely swamp a real signal from the cosmos. To achieve the astounding sensitivity required, almost every aspect of the LIGO detectors’ design has been upgraded over the past few years. We at the University of Glasgow led a consortium of UK
Artist Impression of gravitational waves, Penn State, CC BY-NC-ND 2.0
institutions that played a key role – developing, constructing and installing the sensitive mirror suspensions at the heart of the LIGO detectors that were crucial to this first detection. The technology was based on our work on the earlier UK/German GEO600 detector. This turned LIGO into Advanced LIGO, arguably the most sensitive scientific instrument ever, to give us our first direct glimpse of the dark universe. A long time ago …
the first direct evidence that black holes exist, can exist in a pair, and can collide and merge. Comparing our data with Einstein’s predictions allowed us to test whether general relativity correctly describes such a collision – they passed with flying colours.
What a glimpse it was. The two black holes that collided were respectively about 29 times and 36 times the mass of our sun (shown in the computer visualisation below). It is incidentally
The merger occurred more than one billion light years from Earth, converting three times the mass of the sun into gravitational wave energy. In a fraction of a second, the power radiated through
THE BLACK-HOLE COLLISION
ARTIST IMPRESSION OF GRAVITATIONAL WAVES, PENN STATE, CC BY-NC-ND 2.0
these waves was more than ten times greater than the combined luminosity of every star and galaxy in the observable universe. This was a truly cataclysmic event a long time ago in a galaxy far, far away. In Star Wars Darth Vader tells us not to “underestimate the power of the dark side”. This amazing discovery shows how right he was. Of course our discovery isn’t just about checking if Einstein was right. Detecting gravitational waves will help us to probe the most extreme corners of the cosmos – the event horizon of a black hole, the innermost heart of a supernova, the internal structure of a neutron star: regions that are completely inaccessible to electromagnetic telescopes. Could we ever harness gravitational waves for practical applications here on Earth? Could new insights about the dark universe help us, perhaps in the far future, not just to measure gravitational fields but to manipulate them, as imagined in the space colonies and wormholes of Christopher Nolan’s Interstellar? That is much harder to predict, but the lesson of history is that new phenomena we discover and explore frequently lead to disruptive technologies that come to underpin our everyday lives. It might take a few centuries, but I am confident the same will be true with gravitational waves. Martin Hendry The Conversation CC BY-ND 4.0
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