From New Scientist: “Free-fall experiment could test if gravity is a quantum force”

NewScientist

New Scientist

22 November 2017
Anil Ananthaswamy

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Free-falling. Manuela Schewe-Behnisch/EyeEm/Getty

Despite decades of effort, a theory of quantum gravity is still out of grasp. Now a group of physicists have proposed an experimental test of whether gravity is quantum or not, to settle questions about the force’s true nature.

The search for quantum gravity is an effort to reconcile Einstein’s general relativity with quantum mechanics, which is a theory of all the fundamental particles and the forces that act on them – except gravity. Both are needed to explain what happens inside black holes and what happened at the big bang. But the two theories are incompatible, leading to apparent paradoxes and things like singularities, where the theories break down.

If gravity is a quantum mechanical force, adjacent free-falling masses, each of which is in a superposition of being in two places at once, could get entangled by gravity such that measuring the properties of one mass could instantly influence the other. To test this, Sougato Bose of University College London and his colleagues have proposed an experiment.

Branching paths

It starts with a neutrally charged mass weighing about 10^-14 kilograms. Embedded within the mass is some material with a property called spin, which can be up or down. This mass falls through a continuously varying magnetic field, which changes the path of the mass depending on its spin. It is like the mass encounters a fork in the road and takes one path if its spin is up, and another if its spin is down.

As it falls, the mass is in a superposition of being on both paths. Next, a series of microwave pulses manipulate the spin at various stages of descent and thus the paths the mass takes. At the bottom, the paths then come together again and the mass is brought to its original state.

To use this set-up to test the quantum nature of gravity, two such masses would be dropped through the magnetic field. Each mass has two possible paths. This results in four possible states for the two masses combined. One of these states represents paths in which the masses come closest together.

This distance should be no less than 200 micrometres to avoid other interactions that can dominate gravity. Once the masses are back to their original state, a test to see if their spin components are entangled should tell us if gravity is indeed a quantum force. The assumption, of course, is that the experiment ensures there are no other ways in which the masses can get entangled – such as via electromagnetic interactions or the Casimir force.

Bose points out, however, that a null result – in which no entanglement is observed – wouldn’t constitute proof that gravity is classical, unless the experiment can definitively rule out all other interactions with the environment that can destroy entanglement, such as collisions with stray photons or molecules.

Quantum roots?

Antoine Tilloy at the Max Planck Institute of Quantum Optics in Germany is impressed. But he points out that a positive result will falsify only some classes of theories of classical gravity. “That said, the class is sufficiently large that I think the result would still be amazing,” he says.

Even a verifiable null result would be exciting because it would mean gravity doesn’t have quantum roots, says Maaneli Derakhshani of Utrecht University in the Netherlands. “This would then raise tough but interesting questions about how and when exactly gravity ‘turns on’ in the quantum-classical transition for ordinary matter,” says Derakhshani. “A null result would be the most surprising and interesting outcome.”

The biggest hurdle to carrying out the experiment for real would be putting such relatively large masses in a superposition. The most massive objects that have been observed to be in two places at once are still orders of magnitude smaller than what is required here. But efforts to go higher are ongoing.

This work is soon to be published in Physical Review Letters.

Reference: arxiv.org/abs/1707.06050

See the full article here .

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From New Scientist: “Half the universe’s missing matter has just been finally found”

NewScientist

New Scientist

9 October 2017
Leah Crane

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Discoveries seem to back up many of our ideas about how the universe got its large-scale structure
Andrey Kravtsov (The University of Chicago) and Anatoly Klypin (New Mexico State University). Visualisation by Andrey Kravtsov

The missing links between galaxies have finally been found. This is the first detection of the roughly half of the normal matter in our universe – protons, neutrons and electrons – unaccounted for by previous observations of stars, galaxies and other bright objects in space.

Two separate teams found the missing matter – made of particles called baryons rather than dark matter – linking galaxies together through filaments of hot, diffuse gas.

“The missing baryon problem is solved,” says Hideki Tanimura at the Institute of Space Astrophysics in Orsay, France, leader of one of the groups. The other team was led by Anna de Graaff at the University of Edinburgh, UK.

Because the gas is so tenuous and not quite hot enough for X-ray telescopes to pick up, nobody had been able to see it before.

“There’s no sweet spot – no sweet instrument that we’ve invented yet that can directly observe this gas,” says Richard Ellis at University College London. “It’s been purely speculation until now.”

So the two groups had to find another way to definitively show that these threads of gas are really there.

Both teams took advantage of a phenomenon called the Sunyaev-Zel’dovich effect that occurs when light left over from the big bang passes through hot gas. As the light travels, some of it scatters off the electrons in the gas, leaving a dim patch in the cosmic microwave background [CMB] – our snapshot of the remnants from the birth of the cosmos.

CMB per ESA/Planck

ESA/Planck

Stack ‘em up

In 2015, the Planck satellite created a map of this effect throughout the observable universe. Because the tendrils of gas between galaxies are so diffuse, the dim blotches they cause are far too slight to be seen directly on Planck’s map.

Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

Both teams selected pairs of galaxies from the Sloan Digital Sky Survey that were expected to be connected by a strand of baryons. They stacked the Planck signals for the areas between the galaxies, making the individually faint strands detectable en masse.

Tanimura’s team stacked data on 260,000 pairs of galaxies, and de Graaff’s group used over a million pairs. Both teams found definitive evidence of gas filaments between the galaxies. Tanimura’s group found they were almost three times denser than the mean for normal matter in the universe, and de Graaf’s group found they were six times denser – confirmation that the gas in these areas is dense enough to form filaments.

“We expect some differences because we are looking at filaments at different distances,” says Tanimura. “If this factor is included, our findings are very consistent with the other group.”

Finally finding the extra baryons that have been predicted by decades of simulations validates some of our assumptions about the universe.

“Everybody sort of knows that it has to be there, but this is the first time that somebody – two different groups, no less – has come up with a definitive detection,” says Ralph Kraft at the Harvard-Smithsonian Center for Astrophysics in Massachusetts.

“This goes a long way toward showing that many of our ideas of how galaxies form and how structures form over the history of the universe are pretty much correct,” he says.

Journal references: arXiv, 1709.05024
A Search for Warm/Hot Gas Filaments Between Pairs of SDSS Luminous Red Galaxies

and 1709.10378v1
Missing baryons in the cosmic web revealed by the Sunyaev-Zel’dovich effect

See the full article here .

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From New Scientist: “Lyme disease is set to explode and we still don’t have a vaccine”

NewScientist

New Scientist

29 March 2017 [Just found this in social media.]
Chelsea Whyte

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Tick tock. Mike Peres/Custom Medical Stock Photo/SPL

A new prediction says 2017 and 2018 will see major Lyme disease outbreaks in new areas. This could lead to lifelong health consequences, so where’s the vaccine?

BY THE time he had finished his walk through the woods in New York state, Rick Ostfeld was ready to declare a public health emergency. He could read the warning signs in the acorns that littered the forest floor – seeds of a chain of events that will culminate in an unprecedented outbreak of Lyme disease this year.

Since that day in 2015, Ostfeld has been publicising the coming outbreak. Thanks to a changing climate it could be one of the worst on record: the ticks that carry the disease have been found in places where it has never before been a problem – and where most people don’t know how to respond. The danger zone isn’t confined to the US: similar signs are flagging potential outbreaks in Europe. Polish researchers predict a major outbreak there in 2018.

In theory, Ostfeld’s early warning system gives public health officials a two-year window to prepare. In many other cases, this would be enough time to roll out a vaccination programme. But there is no human vaccine for Lyme disease. Why not? And what can you do to protect yourself in the meantime?

Lyme disease is the most common infection following a pest bite in the US: the Centers for Disease Control estimates that 300,000 Americans contract Lyme disease each year, calling it “a major US public health problem”. While it is easy enough to treat if caught early, we are still getting to grips with lifelong health problems that can stem from not catching it in time (see “Do I have Lyme disease?“).

This is less of a problem when Lyme is confined to a few small areas of the US, but thanks in part to warmer winters, the disease is spreading beyond its usual territory, extending across the US (see map) and into Europe and forested areas of Asia. In Europe in particular, confirmed cases have been steadily rising for 30 years – today, the World Health Organization estimates that 65,000 people get Lyme disease each year in the region. In the UK, 2000 to 3000 cases are diagnosed each year, up tenfold from 2001, estimates the UK’s National Health Service.

So how could a floor of acorns two years ago tell Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, New York, that 2017 would see an outbreak of Lyme disease? It’s all down to what happens next.

A bumper crop of the seeds – “like you were walking on ball bearings” – comes along every two to five years in Millbrook. Crucially, these nutrient-packed meals swell the mouse population: “2016 was a real mouse plague of a year,” he says. And mouse plagues bring tick plagues.

Soon after hatching, young ticks start “questing” – grasping onto grasses or leaves with their hind legs and waving their forelegs, ready to hitch a ride on whatever passes by, usually a mouse.

Gut reaction

Once on board, the feast begins. Just one mouse can carry hundreds of immature ticks in their post-larval nymph stage.

This is where the problems for us start. Mouse blood carries the Lyme-causing bacterium Borrelia burgdorferi, which passes to a tick’s gut as it feeds. The tick itself is unharmed, but each time it latches onto a new host to feed, the bacteria can move from its gut to the blood – including that of any human passers-by.

“We predict the mice population based on the acorns and we predict infected nymph ticks with the mice numbers. Each step has a one year lag,” Ostfeld says.

Ostfeld published his discovery of this chain of causation in 2006. Last year, researchers in Poland found the same trend there, with the same implications. “Last year we had a lot of oak acorns, so we might expect 2018 will pose a high risk of Lyme,” says Jakub Szymkowiak at Adam Mickiewicz University in Poznan, Poland.

Those who live in traditional Lyme disease zones are well versed in tick awareness – wear long trousers in the woods, check yourself thoroughly afterwards, and more. But this advice will be less familiar in places that used to sit outside Lyme zones – like Poland. “That’s sort of the perfect storm,” says Ostfeld. “The public is unaware, so they’re not looking for it and they don’t get treated.”

It’s not obvious when you have been bitten or infected: ticks are the size of a poppy seed, and not everyone gets the classic “bullseye” rash that is supposed to tip you off. The flu-like symptoms that follow are also easy to misdiagnose. And because antibodies to Lyme disease take a few weeks to develop, early tests can miss it. “That’s when you get late-stage, untreated, supremely problematic Lyme disease,” Ostfeld says.

The best approach would be to vaccinate people at risk – but there is currently no vaccine. We used to have one, but thanks to anti-vaccination activists, that is no longer the case.

In the late 1990s, a race was on to make the first Lyme disease vaccine. By December 1998, the US Food and Drug Administration approved the release of Lymerix, developed by SmithKline Beecham, now GSK. But the company voluntarily withdrew the drug after only four years.

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This followed a series of lawsuits – including one where recipients claimed Lymerix caused chronic arthritis. Influenced by now-discredited research purporting to show a link between the MMR vaccine and autism, activists raised the question of whether the Lyme disease vaccine could cause arthritis.

Media coverage and the anti-Lyme-vaccination groups gave a voice to those who believed their pain was due to the vaccine, and public support for the vaccine declined. “The chronic arthritis was not associated with Lyme,” says Stanley Plotkin, an adviser to pharmaceutical company Sanofi Pasteur. “When you’re dealing with adults, all kinds of things happen to them. They get arthritis, they get strokes, heart attacks. So unless you have a control group, you’re in la-la land.”

But there was a control group – the rest of the US population. And when the FDA reviewed the vaccine’s adverse event reports in a retrospective study, they found only 905 reports for 1.4 million doses. Still, the damage was done, and the vaccine was benched.

After that, “no one touched it”, says Thomas Lingelbach, CEO at Valneva, a biotech company based in France. Until now: Valneva has a vaccine in early human trials. It will improve on Lymerix, acting against all five strains of the disease instead of just the one most common in the US, and it will be suitable for children.

Lingelbach knows the battles his firm will face. “It will be hard to convince anti-vax lobbyists,” he says. That fight is still some way off: any public roll-out is at least six years away.

What makes this wait especially galling for some is that there is a vaccine for your pet. “It’s ironic that you can vaccinate your animal and you can’t vaccinate yourself,” Plotkin says.

In the animal vaccine, instead of exposing Fido to a weakened version of the antigen to trigger antibodies, it works within the tick, neutralising B. burgdorferi by altering the expression of a protein on the bacterium before it enters the bloodstream. This is how a human version would work. “The underlying scientific principle is not very far away from what it is in the veterinary environment,” says Lingelbach.

Some people have suggested taking the animal vaccine, but Plotkin doesn’t recommend this as it hasn’t been tested in people so there is insufficient safety data. “You just don’t have classical efficacy data in humans,” he says. It is also illegal in the US and UK for vets to practise medicine on humans.

While we wait for a human vaccine, you might start keeping track of your local acorn populations – but brush up on your anti-tick measures before you hit the woods.

_________________________________________________________

DO I HAVE LYME DISEASE?

The symptoms of Lyme disease, which you can get from a tick bite, aren’t always obvious. At the site of the bite, a red splotch will often start to grow into what looks like a bullseye target.

Not everyone gets this unmistakable sign, however. Over the next few weeks, flu-like symptoms, including aches and fever, can follow. Left untreated, Lyme disease can lead to a host of problems, chronic joint inflammation, facial palsy, issues with short-term memory, heart rhythm irregularities, and inflammation of the brain and spinal cord.

WHAT TO DO

IF YOU’VE BEEN AROUND TICKS

The best way to prevent Lyme disease is to do a thorough tick check. Nymph ticks are so tiny they can be hard to spot, so find a partner, strip down, and go over places that are hard to reach. Make sure you check your partner’s armpits, scalp and groin for ticks.

IF YOU FIND A TICK

If you know it has been on you for under 36 hours, use tweezers to pull it out correctly, and you will probably be fine. That’s because the Lyme-causing bacteria that live in a tick’s gut are slow, and it takes 36 to 48 hours for them to make it into your bloodstream. Always see a doctor if you are unsure.

IF YOU’VE MISSED THE WINDOW

It’s best to see a doctor for a Lyme disease test – but not right away. Your antibodies to Lyme disease take weeks to form, so an early test can give a false reassurance. Wait four to six weeks before requesting a blood test.

IF YOU TEST POSITIVE

If you do test positive for Lyme disease, a course of antibiotics will usually stop the infection in its tracks fairly quickly.

IF SYMPTOMS LINGER

A small percentage of people who are treated will continue to have symptoms like fatigue or sore joints and muscles. This condition is called post-treatment Lyme disease syndrome, sometimes referred to as chronic Lyme disease. It isn’t exactly clear what causes these symptoms, it could be a delayed immune response or even another illness altogether. Until this controversial area of medicine is clarified, it’s best to avoid getting Lyme disease in the first place, at least while a vaccine is still in development.
_________________________________________________________

Article amended on 5 April 2017

We have corrected how to pull out a tick, and recalled the correct classification of mites.

See the full article here .

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From New Scientist: “We still haven’t heard from aliens – here’s why we might never”

NewScientist

New Scientist

26 April 2017 [Where did this come from? Just found in social media.]
Leah Crane

CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

THE most ambitious search so far for extraterrestrial intelligence has released its first data – and there are no aliens yet. The lack of success could be explained by the result of a new approach to calculating the likelihood of detecting alien signals. This calculation suggests we might never make contact, even if extraterrestrial life is common.

The search for extraterrestrial intelligence (SETI) has been active for decades.

Drake Equation, Frank Drake, Seti Institute

SETI Institute

SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA

SETI@home, BOINC project at UC Berkeley Space Science Lab

Breakthrough Listen aims to be the largest, most comprehensive search ever. [Using only three telescopes? There are a lot more available.]

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Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



GBO radio telescope, Green Bank, West Virginia, USA


CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

The $100 million initiative uses three of the world’s most sensitive telescopes to look for alien signals from the 1 million closest stars to Earth and the 100 closest galaxies.

“It’s like finding a needle in a haystack,” says Seth Shostak at the SETI Institute in California. “But we don’t know how many needles are there.”

Breakthrough Listen team members have analysed the light from 692 stars so far. They have found 11 potential alien signals, none of which remained promising after further analysis.

“It’s the beginning of a very exciting time,” says Avi Loeb at Harvard University. “But while it’s exciting, it’s still very risky. We could find nothing.”

That’s exactly what an assessment by Claudio Grimaldi at the Swiss Federal Institute of Technology in Lausanne predicts.

Most methods for calculating the likelihood of detecting alien signals start with an expected number of sources. Instead, Grimaldi started with what volume of the galaxy could be reached by alien signals, a value that requires fewer assumptions about the nature and abundance of extraterrestrial life.

Grimaldi assumed that signals from an extraterrestrial emitter might get weaker or be blocked as they travel, so they would only cover a certain volume of space. It’s relatively simple to calculate the probability that Earth is within that space and so able to detect the signal. “Not all signals can be visible at the same time – only those that intersect with the Earth,” says Grimaldi.

He found that even if half of our galaxy was full of alien noise, the average number of signals that we would be able to detect from Earth is less than one (Scientific Reports, doi.org/b562).

This implies that, even if there are lots of aliens out there, we might never be able to hear from them. But some researchers take umbrage: Grimaldi’s method still requires you to plug in numbers for how far alien signals could be detectable and how long they last – neither of which is known.

“You have to make some assumptions about what the aliens are doing in all these calculations, unfortunately, and the data set that we have with alien activity is fairly sparse,” says Shostak. Our only example of intelligent life is on Earth, and there’s little reason to expect that ET resembles us.

But, says Loeb, extraterrestrial signals should be no harder to find than other astronomical events.

“The question of whether you can detect a signal has nothing to do with whether it’s artificial or natural, and astronomers routinely detect lots of kinds of signals,” he says.

“In SETI, theory is great, but observation is the gold standard,” says Douglas Vakoch, president of METI International, which aims to send messages to extraterrestrial intelligence.

METI (Messaging Extraterrestrial Intelligence) International has announced plans to start sending signals into space

It’s not difficult to think up a different signal that we would be able to detect, he says.

For example, if there were alien life at the TRAPPIST-1 planets, just 40 light years away, they wouldn’t need particularly advanced technology to contact us.

A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

It seems implausible that we would miss their call.

See the full article here .

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From New Scientist: “Gravity may be created by strange flashes in the quantum realm”

NewScientist

New Scientist

20 September 2017
Anil Ananthaswamy

1
Gravity comes about in a flash. Emma Johnson/Getty

HOW do you reconcile the two pillars of modern physics: quantum theory and gravity? One or both will have to give way. A new approach says gravity could emerge from random fluctuations at the quantum level, making quantum mechanics the more fundamental of the two theories.

Of our two main explanations of reality, quantum theory governs the interactions between the smallest bits of matter. And general relativity deals with gravity and the largest structures in the universe. Ever since Einstein, physicists have been trying to bridge the gap between the two, with little success.

Part of the problem is knowing which strands of each theory are fundamental to our understanding of reality.

One approach towards reconciling gravity with quantum mechanics has been to show that gravity at its most fundamental comes in indivisible parcels called quanta, much like the electromagnetic force comes in quanta called photons. But this road to a theory of quantum gravity has so far proved impassable.

Now Antoine Tilloy at the Max Planck Institute of Quantum Optics in Garching, Germany, has attempted to get at gravity by tweaking standard quantum mechanics.

In quantum theory, the state of a particle is described by its wave function. The wave function lets you calculate, for example, the probability of finding the particle in one place or another on measurement. Before the measurement, it is unclear whether the particle exists and if so, where. Reality, it seems, is created by the act of measurement, which “collapses” the wave function.

But quantum mechanics doesn’t really define what a measurement is. For instance, does it need a conscious human? The measurement problem leads to paradoxes like Schrödinger’s cat, in which a cat can be simultaneously dead and alive inside a box, until someone opens the box to look.

One solution to such paradoxes is a so-called GRW model that was developed in the late 1980s. It incorporates “flashes”, which are spontaneous random collapses of the wave function of quantum systems. The outcome is exactly as if there were measurements being made, but without explicit observers.

Tilloy has modified this model to show how it can lead to a theory of gravity. In his model, when a flash collapses a wave function and causes a particle to be in one place, it creates a gravitational field at that instant in space-time. A massive quantum system with a large number of particles is subject to numerous flashes, and the result is a fluctuating gravitational field.

It turns out that the average of these fluctuations is a gravitational field that one expects from Newton’s theory of gravity (arxiv.org/abs/1709.03809). This approach to unifying gravity with quantum mechanics is called semiclassical: gravity arises from quantum processes but remains a classical force. “There is no real reason to ignore this semiclassical approach, to having gravity being classical at the fundamental level,” says Tilloy.

“I like this idea in principle,” says Klaus Hornberger at the University of Duisburg-Essen in Germany. But he points out that other problems need to be tackled before this approach can be a serious contender for unifying all the fundamental forces underpinning the laws of physics on scales large and small. For example, Tilloy’s model can be used to get gravity as described by Newton’s theory, but the maths still has to be worked out to see if it is effective in describing gravity as governed by Einstein’s general relativity.

Tilloy agrees. “This is very hard to generalise to relativistic settings,” he says. He also cautions that no one knows which of the many tweaks to quantum mechanics is the correct one.

Nonetheless, his model makes predictions that can be tested. For example, it predicts that gravity will behave differently at the scale of atoms from how it does on larger scales. Should those tests find that Tilloy’s model reflects reality and gravity does indeed originate from collapsing quantum fluctuations, it would be a big clue that the path to a theory of everything would involve semiclassical gravity.

See the full article here .

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From New Scientist: “Weird energy beam seems to travel five times the speed of light”

NewScientist

New Scientist

22 May 2017
Joshua Sokol

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Trick of the light. NASA and The Hubble Heritage Team (STScI/AURA)

Please welcome to the stage a master illusionist. An energy beam that stabs out of galaxy Messier 87 like a toothpick in a cocktail olive is pulling off the ultimate magic trick: seeming to move faster than the speed of light [always means speed of light in a vacuum].

Almost five times faster, in fact, as measured by the Hubble Space Telescope.

NASA/ESA Hubble Telescope

This feat was first observed in 1995 in galaxy Messier 87, and has been seen in many other galaxies since. It might have you questioning your entire reality. Nothing can break the cosmic speed limit, right? You can’t just flaunt the laws of physics… can you?

If you want to just enjoy the illusion from your seat in the audience, stop reading. Otherwise, I welcome you backstage for a look at how the trick works – and how it’s helping astronomers to understand the fate of entire galaxies.

Blobs faster than light?

We’ve known about the jet of plasma shooting from the core of Messier 87 since 1918, when astronomer Heber Curtis saw a ray of light connected to the galaxy. To be visible from so far away, it had to be huge – about 6000 light years long.

As modern astronomers now know, pretty much all galaxies have a central black hole that periodically draws in stars and gas clouds.

Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

When gas begins to swirl down the drain, it heats up and magnetic fields focus some of it into jets of hot plasma. These jets shoot out at velocities near to – but not faster than – the speed of light.

If you were to aim a telescope into the sky towards Messier 87, you would see that this lance of plasma is askew. Instead of pointing exactly into our line of sight, it’s angled a bit to the right.

To understand the illusion, picture a single glowing blob of plasma starting at the base of this path and emitting a ray of light, both of which travel towards Earth. Now wait 10 years. In that time, the blob has moved closer at a sizeable fraction of the speed of light. That gives the rays emitted from that later position a few light years’ head start on the way to us.

If you compare the first and second images from Earth’s perspective, it looks like the blob has just moved across the sky to the right. But because the second position is also closer to us, its light has had less far to travel than it appears. That means it seems to have arrived there faster than it actually did – as if the blob spent those 10 years travelling at ludicrous speed.

One among many

The jet from Messier 87 is more than just a curiosity, says Eileen Meyer at the University of Maryland, Baltimore County.

All over the universe, outflows of energy from massive black holes can stop or start the formation of stars throughout galaxies. But it’s unclear how these outflows work and how much energy they contain.

By appearing to move faster than light, jets such as the Messier 87 one change visibly over just a few years, which is unusual for distant objects like galaxies. That allows astronomers to make precise estimates of how fast the plasma is moving and thus how powerful the process is.

Messier 87 is special because it is relatively close compared to other galaxies, making it easy to study. In 1999, astronomers used Hubble pictures of the jet taken over four years to see that plasma ripple outwards. In 2013, Meyer lengthened that to 13 years of images, which seemed to show that the plasma might also be moving in corkscrew-like spirals – as if it wasn’t complicated enough.

Fresh results from Meyer, now being prepared for publication, extend that baseline again to a total of more than two decades and may offer new surprises. “Over 20 years, you know, things go bump in the night,” she says.

And although the faster-than-light effect is old hat to her, she still stops to appreciate it sometimes. Most things we see travelling across the sky, such as planets and comets, are close to us. But Messier87 is tens of millions of light years away. “We can see, over a human lifetime, things moving,” she says. “Which is crazy.”

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From NS: “Lyme disease is set to explode, and you can’t protect yourself”

NewScientist

New Scientist

29 March 2017
Chelsea Whyte

A new prediction says 2017 and 2018 will see major Lyme disease outbreaks in new areas. This could lead to lifelong health consequences, so where’s the vaccine?

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Tick tock. Mike Peres/Custom Medical Stock Photo/SPL

BY THE time he had finished his walk through the woods in New York state, Rick Ostfeld was ready to declare a public health emergency. He could read the warning signs in the acorns that littered the forest floor – seeds of a chain of events that will culminate in an unprecedented outbreak of Lyme disease this year.

Since that day in 2015, Ostfeld has been publicising the coming outbreak. Thanks to a changing climate it could be one of the worst on record: the ticks that carry the disease have been found in places where it has never before been a problem – and where most people don’t know how to respond. The danger zone isn’t confined to the US: similar signs are flagging potential outbreaks in Europe. Polish researchers predict a major outbreak there in 2018.

In theory, Ostfeld’s early warning system gives public health officials a two-year window to prepare. In many other cases, this would be enough time to roll out a vaccination programme. But there is no human vaccine for Lyme disease. Why not? And what can you do to protect yourself in the meantime?

Lyme disease is the most common infection following an insect bite in the US: the Centers for Disease Control estimates that 300,000 Americans contract Lyme disease each year, calling it “a major US public health problem”. While it is easy enough to treat if caught early, we are still getting to grips with lifelong health problems that can stem from not catching it in time (see “Do I have Lyme disease?“).

This is less of a problem when Lyme is confined to a few small areas of the US, but thanks in part to warmer winters, the disease is spreading beyond its usual territory, extending across the US (see map) and into Europe and forested areas of Asia. In Europe in particular, confirmed cases have been steadily rising for 30 years – today, the World Health Organization estimates that 65,000 people get Lyme disease each year in the region. In the UK, 2000 to 3000 cases are diagnosed each year, up tenfold from 2001, estimates the UK’s National Health Service.

So how could a floor of acorns two years ago tell Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, New York, that 2017 would see an outbreak of Lyme disease? It’s all down to what happens next.

A bumper crop of the seeds – “like you were walking on ball bearings” – comes along every two to five years in Millbrook. Crucially, these nutrient-packed meals swell the mouse population: “2016 was a real mouse plague of a year,” he says. And mouse plagues bring tick plagues.

Soon after hatching, young ticks start “questing” – grasping onto grasses or leaves with their hind legs and waving their forelegs, ready to hitch a ride on whatever passes by, usually a mouse.

Gut reaction

Once on board, the feast begins. Just one mouse can carry hundreds of immature ticks in their post-larval nymph stage.

This is where the problems for us start. Mouse blood carries the Lyme-causing bacterium Borrelia burgdorferi, which passes to a tick’s gut as it feeds. The tick itself is unharmed, but each time it latches onto a new host to feed, the bacteria can move from its gut to the blood – including that of any human passers-by.

“We predict the mice population based on the acorns and we predict infected nymph ticks with the mice numbers. Each step has a one year lag,” Ostfeld says.

Ostfeld published his discovery of this chain of causation in 2006 [PLOS Biology]. Last year, researchers in Poland found the same trend there, with the same implications. “Last year we had a lot of oak acorns, so we might expect 2018 will pose a high risk of Lyme,” says Jakub Szymkowiak at Adam Mickiewicz University in Poznan, Poland.

Those who live in traditional Lyme disease zones are well versed in tick awareness – wear long trousers in the woods, check yourself thoroughly afterwards, and more. But this advice will be less familiar in places that used to sit outside Lyme zones – like Poland. “That’s sort of the perfect storm,” says Ostfeld. “The public is unaware, so they’re not looking for it and they don’t get treated.”

It’s not obvious when you have been bitten or infected: ticks are the size of a poppy seed, and not everyone gets the classic “bullseye” rash that is supposed to tip you off. The flu-like symptoms that follow are also easy to misdiagnose. And because antibodies to Lyme disease take a few weeks to develop, early tests can miss it. “That’s when you get late-stage, untreated, supremely problematic Lyme disease,” Ostfeld says.

The best approach would be to vaccinate people at risk – but there is currently no vaccine. We used to have one, but thanks to anti-vaccination activists, that is no longer the case.

In the late 1990s, a race was on to make the first Lyme disease vaccine. By December 1998, the US Food and Drug Administration approved the release of Lymerix, developed by SmithKline Beecham, now GSK. But the company voluntarily withdrew the drug after only four years.

This followed a series of lawsuits – including one where recipients claimed Lymerix caused chronic arthritis. Influenced by now-discredited research purporting to show a link between the MMR vaccine and autism, activists raised the question of whether the Lyme disease vaccine could cause arthritis.

Media coverage and the anti-Lyme-vaccination groups gave a voice to those who believed their pain was due to the vaccine, and public support for the vaccine declined. “The chronic arthritis was not associated with Lyme,” says Stanley Plotkin, an adviser to pharmaceutical company Sanofi Pasteur. “When you’re dealing with adults, all kinds of things happen to them. They get arthritis, they get strokes, heart attacks. So unless you have a control group, you’re in la-la land.”

But there was a control group – the rest of the US population. And when the FDA reviewed the vaccine’s adverse event reports in a retrospective study, they found only 905 reports for 1.4 million doses. Still, the damage was done, and the vaccine was benched.

After that, “no one touched it”, says Thomas Lingelbach, CEO at Valneva, a biotech company based in France. Until now: Valneva has a vaccine in early human trials. It will improve on Lymerix, acting against all five strains of the disease instead of just the one most common in the US, and it will be suitable for children.

Lingelbach knows the battles his firm will face. “It will be hard to convince anti-vax lobbyists,” he says. That fight is still some way off: any public roll-out is at least six years away.

What makes this wait especially galling for some is that there is a vaccine for your pet. “It’s ironic that you can vaccinate your animal and you can’t vaccinate yourself,” Plotkin says.

In the animal vaccine, instead of exposing Fido to a weakened version of the antigen to trigger antibodies, it works within the tick, neutralising B. burgdorferi by altering the expression of a protein on the bacterium before it enters the bloodstream. This is how a human version would work. “The underlying scientific principle is not very far away from what it is in the veterinary environment,” says Lingelbach.

Some people have suggested taking the animal vaccine, but Plotkin doesn’t recommend this as it hasn’t been tested in people so there is insufficient safety data. “You just don’t have classical efficacy data in humans,” he says. It is also illegal in the US and UK for vets to practise medicine on humans.

While we wait for a human vaccine, you might start keeping track of your local acorn populations – but brush up on your anti-tick measures before you hit the woods.

See the full article here .

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