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Windows to the Soul: Pupils Reveal ‘Aphantasia’ – The Absence of Visual Imagination

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Summary: People who experience visual imagination have pupillary responses that optimize the amount of light hitting the retina and change in response to imagined items. This pupillary response does not occur in those with aphantasia.

Source: University of New South Wales

The study, led by researchers from UNSW Sydney and published in eLife, found that the pupils of people with aphantasia did not respond when asked to imagine dark and light objects, while those without aphantasia did.

To first gauge the pupillary reflex of non-aphantasic people, the researchers sought 42 study participants, self-reported as having a visual imagination, and fitted them with glasses to track their eye movements and pupil sizes.

Participants were then exposed to bright or dark shapes against a grey background, which predictably evoked pupillary constriction in response to bright shapes (comparable to looking up at a bright sky) and pupillary dilation in response to dark shapes (after switching a light off).

Next, to test visual imagery – the mind’s capacity to visualise objects – participants were asked to simply imagine those same light or dark shapes (with their eyes open, for their pupils to be tracked) and subsequently report the ‘vividness’ of that imagery.

The researchers found that even in response to imagined bright and dark shapes, the participants’ pupils still constricted and dilated appropriately, a pupillary response that was larger in those reporting greater imagery vividness.

“The pupillary reflex is an adaption that optimises the amount of light hitting the retina,” says Professor Joel Pearson, senior author on the paper.

“And while it was already known that imagined objects can evoke so-called ‘endogenous’ changes in pupil size, we were surprised to see more dramatic changes in those reporting more vivid imagery. This really is the first biological, objective test for imagery vividness.”

Testing for a lack of imagination

Finally, with the link between visual imagery and pupillary response established, the researchers sought to test the effect in aphantasic individuals. The researchers repeated the study with 18 participants self-reporting aphantasia.

Exposing participants to bright and dark shapes, the researchers found that aphantasic individuals exhibited the same pupillary response as the general population: constriction to bright, dilation to dark.

However, during the study’s second component where participants were asked to visualise those same shapes, the pupillary response of aphantasic individuals did not significantly differ in response to imagined dark versus imagined bright objects.

“One of the problems with many existing methods to measure imagery is that they are subjective, that is to say they rely on people being able to accurately assess their own imagery. Our results show an exciting new objective method to measure visual imagery,” says Prof Pearson, “and the first physiological evidence of aphantasia. With over 1.3 million Australians thought to have aphantasia, and 400 million more internationally, we are now close to an objective physiological test, like a blood test, to see if someone truly has it.”

To ensure the aphantasic participants were really attempting imagery, the researchers included a further experimental condition, requesting aphantasic individuals to visualise four shapes, instead of one.

While the pupils of those with aphantasia showed no difference when imagining light versus dark objects, they did show a difference imagining one versus four objects, suggesting more mental effort, thereby negating an explanation of non-participation by aphantasic individuals.

“Our pupils are known to get larger when we are doing a more difficult task,” says Lachlan Kay, PhD candidate in the Future Minds Lab, UNSW.

“Imagining four objects simultaneously is more difficult than imagining just one. The pupils of those with aphantasia dilated when they imagined four shapes compared to one, but did not change based on the whether the shapes were bright or dark. This indicated that the participants with aphantasia were indeed trying to imagine in this experiment, just not in a visual way”.

“The aphantasic pupil response to the four objects condition is also a really exciting finding,” adds Prof Pearson, “because for the first time we have strong biological evidence that those with aphantasia are really trying to create a mental image, putting to rest claims that they may simply not be attempting to create a mental image.”

The pupillary reflex is an adaption that optimises the amount of light hitting the retina, changing, even, in response to imagined objects – not so for aphantasic individuals. Image is in the public domain

“These findings are also really interesting in regard to memory and aphantasia,” said Dr Rebecca Keogh, Postdoctoral research fellow based at Macquarie University and another author of the study. “Our previous work has shown that aphantasic individuals are able to perform visual working memory tasks, remembering many images for a short period of time, without using visual imagery.

“These findings further highlight the wide variability of the human mind that can often remain hidden until we ask someone about their internal experiences or invent new ways to measure the mind. It reminds us that just because I remember or visualise something one way, doesn’t mean everyone does.”

What’s next for aphantasia research? A look into the future…

Next, Prof Pearson and his team at the Future Minds Lab plan to investigate how this new method could be scaled up and run online to allow a global, efficient and objective measurement of imagery and aphantasia.

See also

“This really is an exciting time. We are very close to having objective, reliable tests for extreme imagery, aphantasia and hyperphantasia (extremely strong visual imagery) that could be scaled up to run online for millions of people everywhere,” says Prof Pearson.

“We know that thinking in pictures or not affects the number of details in lifelong memories, how emotional we get when reading, and how we hold things in short term memory. This new method will allow us to understand the brain mechanisms of extreme imagery and the global implications for how we think, make decisions and feel.”

About this aphantasia research news

Author: Jesse Hawley
Source: University of New South Wales
Contact: Jesse Hawley – University of New South Wales
Image: The image is in the public domain

Original Research: Open access.
“The pupillary light response as a physiological index of aphantasia, sensory and phenomenological imagery strength” by Joel Pearson et al. eLife

Abstract

The pupillary light response as a physiological index of aphantasia, sensory and phenomenological imagery strength

The pupillary light response is an important automatic physiological response which optimizes light reaching the retina.

Recent work has shown that the pupil also adjusts in response to illusory brightness and a range of cognitive functions, however, it remains unclear what exactly drives these endogenous changes.

Here, we show that the imagery pupillary light response correlates with objective measures of sensory imagery strength. Further, the trial-by-trial phenomenological vividness of visual imagery is tracked by the imagery pupillary light response.

We also demonstrated that a group of individuals without visual imagery (aphantasia) do not show any significant evidence of an imagery pupillary light response, however they do show perceptual pupil light responses and pupil dilation with larger cognitive load.

Our results provide evidence that the pupillary light response indexes the sensory strength of visual imagery. This work also provides the first physiological validation of aphantasia.

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Science

Astrobotic unveils private robotic lunar lander it aims to launch to the Moon this year

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This afternoon, commercial space company Astrobotic unveiled its nearly complete robotic lunar lander, designed to take payloads for paying customers like NASA to the surface of the Moon. It marks the first time the company has shown the mostly finished flight hardware for the lander ahead of its launch, tentatively scheduled for late this year.

Called the Peregrine Lunar Lander, the spacecraft is roughly the size of a squat refrigerator, standing just over six feet tall. Five main engines mounted on the lander’s base will help navigate the vehicle through space and eventually allow the vehicle to touch down on the surface of the Moon. The vehicle has various locations it can store mounted payloads for experiments designed to take advantage of the lunar environment and customers who just want their products on the lunar surface.

Astrobotic, based in Pittsburgh, is one of two private companies aiming to become the first to send a commercial robotic lander to the Moon — and have it land in one piece. The other is Intuitive Machines, based out of Houston, which is building its own robotic lunar lander called Nova-C. Both companies have received multimillion-dollar contracts from NASA to help spur the development of their landers, which, in turn, provide the space agency with a way to get scientific experiments to the Moon. It’s a small part of NASA’s flagship Artemis program, a major effort by the agency to eventually return humans to the lunar surface.

By funding multiple companies, NASA also hoped to spur some friendly competition. Originally, the agency had funded three companies in its first round of contracts, known as the CLPS program, but one of the awardees dropped out. Now, it’s down to Astrobotic and Intuitive Machines, both of which are aiming to fly their landers sometime this year.

“Our first priority is mission success, and if it happens to be the first, great,” John Thornton, CEO of Astrobotic, tells The Verge. “And if it’s not, that’s fine too. Really, success is the most important, but it is the first commercial lander that is unveiled. We haven’t seen any hardware or pictures of [Intuitive Machines’] spacecraft yet.” (Another privately built lunar lander, made by Israeli nonprofit SpaceIL, attempted to reach the Moon in 2019, but didn’t quite stick the landing.)

Members of NASA’s leadership team, including administrator Bill Nelson and Thomas Zurbuchen, NASA’s associate administrator for science, were on hand at Astrobotic’s facility today for the unveiling. “This is an exciting time and our commercial partners are very much a part of this,” Nelson said during brief remarks at Astrobotic.

An artistic rendering of Astrobotic’s Peregrine lander on the Moon.
Image: Astrobotic

The lander’s flight structure was presented today, but some tanks, solar panels, propulsion, and other attributes still need to be added to the vehicle. “Obviously the lander is still being built, but it’s far enough along that we can unveil it for what it looks like now,” says Thornton. “And it’s so exciting. It’s 15 years in the making.” Astrobotic declined to provide specifics about the cost of Peregrine or how much it charges customers for a spot on the lander.

For its first launch, the Peregrine lander will carry 24 payloads to the Moon, according to the company. A little less than half are scientific instruments from NASA while the others come from a diverse group of commercial customers. One payload includes a rover crafted by students at Carnegie Mellon, and there is also a micro-rover from the Mexican Space Agency. The lander will house a few rather unique payloads — like a lunar dream capsule from Japan and a physical Bitcoin coin, “loaded” with one Bitcoin. The lander’s target destination is a region called Lacus Mortis — which eerily translates to “Lake of Death.” Once it lands, the Peregrine will attempt to last an entire lunar day, about two weeks, before the extra cold, two-week-long lunar night kicks in.

Astrobotic’s ride to the Moon is still an open question, though. The Peregrine lander is slated to be the very first spacecraft to fly on the United Launch Alliance’s (ULA) Vulcan rocket, a brand new vehicle that’s been under development since 2014. However, the Vulcan is a few years late getting to the launchpad, and it’s still not ready. The rocket is designed to fly on a new engine being built by Jeff Bezos’ space company Blue Origin, called the BE-4 — but those engines are also years behind schedule.

Thornton says he’s received assurances from ULA that Vulcan will launch in the fourth quarter of this year, and that the BE-4 engines will be ready in the middle of this year. He says Astrobotic has “no reason to doubt” ULA. “ULA is a storied, successful company,” says Thornton. “So we feel very confident in the launch, and that’s why we booked with them.”

One thing rival Intuitive Machines does have is a contract to fly on a functioning rocket. The company is supposed to fly its Nova-C lander on a SpaceX Falcon 9 rocket sometime later this year, though Intuitive Machines does not have a date for the flight. As for differences between the two landers, Thornton points to the fact that the Peregrine lander is much more squat than the rather tall Nova-C lander. He also mentions that the Peregrine will fly on “proven” hydrazine fuel, while Intuitive Machines is experimenting with a new cryogenic propulsion system.

“At the end of the day, we’re both in the business of lunar delivery,” says Thornton. “And obviously we think our lander is best suited for our customers, and so far, our customers have overwhelmingly picked us versus the competition.”

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Astronomers discover immense swarms of sunspots that could lead to solar flares

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A pair of massive sunspot swarms, some large enough to devour the Earth whole, have appeared on the surface of the Sun, increasing the chance of an intense solar storm.

Sunspots are dark regions of the Sun where it is cooler than other parts of the surface. Solar flares originate close to these dark areas of the star.

Recently, space weather forecasters spotted two ‘active regions’ known as AR2993 and AR2994 – swarms made up of a number of sunspots – in the past few days.

Solar flares and coronal mass ejections come from these regions, and when they explode in the direction of Earth, they can result in geomagnetic storms that produce beautiful auroras, as well as pose a danger to power grids and satellites.

It isn’t yet clear whether these new dark spot swarms will result in solar flares that hit the Earth, but astronomers predict it is possible in the coming weeks. 

A pair of massive sunspot swarms, some large enough to devour the Earth hole, have appeared on the surface of the Sun, increasing the chance of an intense solar storm

Sunspots are caused by magnetic disruptions in the photosphere of the Sun, exposing the cooler layers underneath – appearing as a black spot.

Solar flares can erupt in these regions, sending plasma and charged particles out into space – some of which head towards the Earth.

When they reach the planet, they run down the magnetic field, creating aurora such as the northern lights, but can also result in power outages and internet issues.

Earlier this month the Earth narrowly missed a plasma ejection, linked to a sunspot group that had appeared earlier on the star. If it had hit the planet, it could have resulted in risks to astronauts in space, as well as satellites and power grids. 

The recent increase in activity from the Sun is the result of it coming towards the most active phase in its 11-year solar cycle – hitting peak activity in 2024.  

‘I’m sure we shall see larger active regions over the next few years,’ according to solar physicist Dean Pesnell from NASA, speaking to Live Science.

‘Active regions 2993 and 2994 are middling in size and don’t represent the best that Solar Cycle 25 can produce.’

Sunspots are dark regions of the Sun where it is cooler than other parts of the surface. Solar flares originate close to these dark areas of the star

WHAT ARE AURORAS AND WHAT TRIGGERS THE STUNNING NATURAL DISPLAYS? 

The Northern and Southern Lights are natural light spectacles triggered in our atmosphere that are also known as the ‘Auroras’.

There are two types of Aurora — Aurora Borealis, which means ‘dawn of the north’, and Aurora Australis, ‘dawn of the south.’

The displays light up when electrically charged particles from the sun enter the Earth’s atmosphere. 

Usually the particles, sometimes referred to as a solar storm, are deflected by Earth’s magnetic field.

But during stronger storms they enter the atmosphere and collide with gas particles, including hydrogen and helium.

These collisions emit light. Auroral displays appear in many colours although pale green and pink are common.

Jan Janssens from the Solar-Terrestrial Centre of Excellence in Brussels, told Live Science multiple solar flares and coronal mass ejections are ‘typical at this stage of the solar cycle,’ with some heading towards, but missing the Earth.

‘As the solar cycle is heading for its maximum, more and more complex sunspot regions become visible, which can then produce solar flares.’

Studies have shown that the level of solar activity currently happening, is about the same as it was 11 years ago, during the same point in the last cycle.

Pesnell told Live Science there appears to be a third swarm, hidden from view, that is rotating behind AR2993 and AR2994, that produced a class X1.1 flare on Sunday.

Solar flares have letter classes, with A-class the weakest, then B, C, and M-class, with X-class the strongest of the categories. They are then given a size – small numbers represent smaller flares within the class. 

An X1 flare is ten times less powerful than the most intense solar flare possible, and the most powerful on record, from 2003, overwhelmed sensors as an X28.

The Space Weather Prediction Center of the National Oceanic and Atmospheric Administration (NOAA) found that Sunday’s flare caused a blackout at certain radio frequencies below 30 MHz in Southeast Asia and Australia.

Despite the flare causing a radio blackout, the plasma from the flare won’t hit Earth. 

‘Flares and coronal mass ejections will become more frequent over the next few years, raising the hazard level of solar activity,’ Pesnell told Live Science.

There hasn’t been an extreme CME or Solar Flare in the modern world – the last was the Carrington Event in 1859 – creating a geomagnetic storm with aurora appearing globally, as well as fires at telegraph stations.  

SOLAR STORMS PRESENT A CLEAR DANGER TO ASTRONAUTS AND CAN DAMAGE SATELLITES

Solar storms, or solar activity, can be divided into four main components that can have impacts on Earth:  

  • Solar flares: A large explosion in the sun’s atmosphere. These flares are made of photons that travel out directly from the flare site. Solar flares impact Earth only when they occur on the side of the sun facing Earth.  
  • Coronal Mass Ejections (CME’s): Large clouds of plasma and magnetic field that erupt from the sun. These clouds can erupt in any direction, and then continue on in that direction, plowing through solar wind. These clouds only cause impacts to Earth when they’re aimed at Earth. 
  • High-speed solar wind streams: These come from coronal holes on the sun, which form anywhere on the sun and usually only when they are closer to the solar equator do the winds impact Earth. 
  • Solar energetic particles: High-energy charged particles thought to be released primarily by shocks formed at the front of coronal mass ejections and solar flares. When a CME cloud plows through solar wind, solar energetic particles can be produced and because they are charged, they follow the magnetic field lines between the Sun and Earth. Only charged particles that follow magnetic field lines that intersect Earth will have an impact. 

While these may seem dangerous, astronauts are not in immediate danger of these phenomena because of the relatively low orbit of manned missions.

However, they do have to be concerned about cumulative exposure during space walks.

This photo shows the sun’s coronal holes in an x-ray image. The outer solar atmosphere, the corona, is structured by strong magnetic fields, which when closed can cause the atmosphere to suddenly and violently release bubbles or tongues of gas and magnetic fields called coronal mass ejections

The damage caused by solar storms 

Solar flares can damage satellites and have an enormous financial cost.

The charged particles can also threaten airlines by disturbing Earth’s magnetic field.

Very large flares can even create currents within electricity grids and knock out energy supplies.

When Coronal Mass Ejections strike Earth they cause geomagnetic storms and enhanced aurora.

They can disrupt radio waves, GPS coordinates and overload electrical systems.

A large influx of energy could flow into high voltage power grids and permanently damage transformers.

This could shut off businesses and homes around the world. 

Source: NASA – Solar Storm and Space Weather 

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Wow! Perseverance rover captures gorgeous video of solar eclipse on Mars

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The tiny Mars moon Phobos looms large on the sun’s face in dramatic eclipse footage captured by NASA’s Perseverance rover.

The life-seeking Perseverance took a break April 2 from its quest to reach an ancient Red Planet river delta (its successful arrival there was announced yesterday) to observe the minuscule moon passing across the sun.

“These observations can help scientists better understand the moon’s orbit and how its gravity pulls on the Martian surface, ultimately shaping the Red Planet’s crust and mantle,” officials with NASA’s Jet Propulsion Laboratory (JPL) in Southern California, which manages Perseverance’s mission, said in a statement about the new eclipse video.

Other Mars rovers, such as NASA’s Curiosity, have observed solar eclipses. But the new shots from Perseverance’s Mastcam-Z camera provide the most powerful view yet of such an event, featuring a high frame rate not used before on the Martian surface, mission team members said.

“I knew it was going to be good, but I didn’t expect it to be this amazing,” Rachel Howson of Malin Space Science Systems in San Diego, one of the Mastcam-Z team members, said in the same statement.

Related: 12 amazing photos from the Perseverance rover’s 1st year on Mars

Phobos, which is about 157 times smaller than Earth’s moon, is one of Mars’ two natural satellites. The other, Deimos, is even smaller than Phobos. Scientists think the two lumpy bodies may be former asteroids that were captured by Mars’ gravity. 

Phobos is in a death spiral over Mars and will likely crash into the Red Planet’s surface in a few tens of millions of years, researchers say.

Roughly 20 years of eclipse observations like this, taken from rovers on Mars, have refined the understanding of that moon’s slowly collapsing orbit.

We’re also learning more about the structure of Mars from such observations. “As Phobos circles Mars, its gravity exerts small tidal forces on the Red Planet’s interior, slightly deforming rock in the planet’s crust and mantle. These forces also slowly change Phobos’ orbit,” JPL officials said in the statement. 

“As a result,” they added, “geophysicists can use those changes to better understand how pliable the interior of Mars is, revealing more about the materials within the crust and mantle.”

Solar eclipse guide 2022: When, where & how to see them

Past rover missions have caught Phobos and/or Deimos in action across the sun’s face. JPL officials pointed to observations of Phobos from NASA’s twin Spirit and Opportunity rovers in 2004, which mission team members stitched into a time-lapse video. 

Curiosity’s upgraded capabilities allowed the rover to capture solar eclipse videos, and its eclipse observations now number in the dozens. As of 2019, Curiosity, Opportunity and Spirit had collectively observed 40 eclipses by Phobos and eight solar transits by Deimos. 

Perseverance’s Mastcam-Z has a further upgrade compared to the camera systems of its predecessor rovers: a sunglasses-like filter that reduces the intensity of the sun’s light, allowing scientists to see bumps and ridges in the outline of Phobos as well as a group of sunspots on the sun. (The sun has been active all month as a result of sunspots like those.)

Perseverance is on a years-long quest to hunt for signs of ancient life on Mars, and to collect and cache dozens of samples that may hold evidence of Red Planet organisms. NASA and the European Space Agency plan to return those samples to Earth via a sample-return campaign over the next decade or so.

Accompanying Perseverance on its journeys is an intrepid helicopter, Ingenuity. The little chopper has exceeded its planned flight manifest fivefold, achieving 25 airborne sorties to date.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom or Facebook. 



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Stop the Clocks: Brisk Walking May Slow Biological Aging Process

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Summary: A new study found a causal link between brisk walking and telomere length. Researchers found that 10 minutes of brisk walking per day was associated with longer life expectancy, and brisk walkers have up to 20 years’ greater life expectancy than those who walk slowly.

Source: University of Leicester

A new study of genetic data published today (Wednesday) of more than 400,000 UK adults has revealed a clear link between walking pace and a genetic marker of biological age.

Confirming a causal link between walking pace and leucocyte telomere length (LTL) – an indicator of biological age – the Leicester-based team of researchers estimate that a lifetime of brisk walking could lead to the equivalent of 16 years younger biological age by midlife.

Researchers from the University of Leicester at the National Institute for Health Research (NIHR) Leicester Biomedical Research Centre studied genetic data from 405,981 middle-aged UK Biobank participants and found that a faster walking pace, independent of the amount of physical activity, was associated with longer telomere.

Telomeres are the ‘caps’ at the end of each chromosome, and hold repetitive sequences of non-coding DNA that protect the chromosome from damage, similar to the way the cap at the end of a shoelace stops it from unravelling.

Each time a cell divides, these telomeres become shorter – until a point where they become so short that the cell can no longer divide, known as ‘replicative senescence’. Therefore, scientists consider LTL a strong marker for ‘biological age’, independent from when an individual was born.

Although the relationship between telomere length and disease is not fully understood, the build-up of these senescent cells is believed to contribute to a range of symptoms we associate with aging, such as frailty and age-related diseases.

While the physical, mental, social and health benefits of walking are well-documented, this study is one of the first of its kind to compare genetic data with both self-reported walking speeds, as well as actual measurements of movement intensity from wearable activity tracking devices worn by participants.

Dr Paddy Dempsey is a Lecturer and Research Fellow at the University of Leicester and within the NIHR Leicester Biomedical Research Centre, part of the University Hospitals of Leicester (UHL) NHS Trust, and lead author on the study published in Communications Biology. He said:

“Previous research on associations between walking pace, physical activity and telomere length has been limited by inconsistent findings and a lack of high-quality data.

“This research uses genetic data to provide stronger evidence for a causal link between faster walking pace and longer telomere length. Data from wrist-worn wearable activity tracking devices used to measure habitual physical activity also supported a stronger role of habitual activity intensity (e.g. faster walking) in relation to telomere length.

“This suggests measures such as a habitually slower walking speed are a simple way of identifying people at greater risk of chronic disease or unhealthy ageing, and that activity intensity may play an important role in optimising interventions.

For example, in addition to increasing overall walking, those who are able could aim to increase the number of steps completed in a given time (e.g. by walking faster to the bus stop). However, this requires further investigation.”

Although the relationship between telomere length and disease is not fully understood, the build-up of these senescent cells is believed to contribute to a range of symptoms we associate with aging, such as frailty and age-related diseases. Image is in the public domain

Researchers from the University of Leicester have previously shown using UK Biobank that as little as 10 minutes of brisk walking a day is associated with longer life expectancy, and that brisk walkers have up to 20 years’ greater life expectancy compared to slow walkers.

This new study demonstrates a causal link between brisk walking and telomere length and, significantly, not the other way round.

Tom Yates, senior author and Professor of Physical Activity, Sedentary Behaviour and Health at the University of Leicester and NIHR Leicester Biomedical Research Centre, added:

“Whilst we have previously shown that walking pace is a very strong predictor of health status, we have not been able to confirm that adopting a brisk walking pace actually causes better health. In this study we used information contained in people’s genetic profile to show that a faster walking pace is indeed likely to lead to a younger biological age as measured by telomeres.”

Funding: The study was funded by the UK Medical Research Council, Biotechnology and Biological Sciences Research Council, British Heart Foundation, and supported by the NIHR Leicester BRC – a partnership between Leicester’s Hospitals, the University of Leicester and Loughborough University.

About this aging research news

Author: Jonathan Whitney
Source: University of Leicester
Contact: Jonathan Whitney – University of Leicester
Image: The image is in the public domain

Original Research: Open access.
“Investigation of a UK biobank cohort reveals causal associations of self-reported walking pace with telomere length” by Paddy Dempsey et al. Communications Biology

Abstract

See also

Investigation of a UK biobank cohort reveals causal associations of self-reported walking pace with telomere length

Walking pace is a simple and functional form of movement and a strong predictor of health status, but the nature of its association with leucocyte telomere length (LTL) is unclear.

Here we investigate whether walking pace is associated with LTL, which is causally associated with several chronic diseases and has been proposed as a marker of biological age. Analyses were conducted in 405,981 UK Biobank participants.

We show that steady/average and brisk walkers had significantly longer LTL compared with slow walkers, with accelerometer-assessed measures of physical activity further supporting this through an association between LTL and habitual activity intensity, but not with total amount of activity. Bi-directional mendelian randomisation analyses suggest a causal link between walking pace and LTL, but not the other way around.

A faster walking pace may be causally associated with longer LTL, which could help explain some of the beneficial effects of brisk walking on health status.

Given its simple measurement and low heritability, self-reported walking pace may be a pragmatic target for interventions.

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This 40-second solar eclipse seen from the surface of Mars is sublime

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April 2, 2021, solar eclipse on Mars.

When NASA’s Perseverance rover landed on Mars in February 2021, it carried a high-definition video camera, complete with a powerful zoom capability. This camera has since provided all sorts of amazing views of the red planet during the last 14 months.

However, earlier this month operators of rover turned its powerful Mastcam-Z camera toward the sky to capture Mars’ potato-shaped moon Phobos transiting across the surface of the Sun. And the result, well, the result is spectacular.

Phobos is much smaller than Earth’s Moon, measuring only about 20 km across, so it does not plunge Mars into darkness. However, with the moon etched against the Sun, the video reveals the lumpy nature of Phobos’ terrain, complete with ridges and small hills. It also showcases sunspots on the surface of our star.

NASA has been capturing planet-bound views of Phobos, and Mars’ even smaller moon Deimos, ever since the landing of the agency’s twin rovers Spirit and Opportunity in 2004. For example, Curiosity captured this transit of Phobos in 2019. But the full-color video of the new solar eclipse is on another level—it is, if you will excuse us, night-and-day different—in terms of detail and color.

“I knew it was going to be good, but I didn’t expect it to be this amazing,” said Rachel Howson of Malin Space Science Systems in San Diego, one of the Mastcam-Z team members who operates the camera, in a news release. Amazing seems like an understatement.

Listing image by NASA

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A Magnificent View of an Unusual Collection of Five Galaxies

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NASA is commemorating the Hubble Space Telescope’s 32nd birthday with a breathtaking view of five galaxies known as the Hickson Compact Group 40. This amazing assembly includes a giant elliptical galaxy, glowing with blended light from billions of stars. Several spiral galaxies show prominent dusty lanes that outline their winding spiral arms, regions where star formation is active. We see one galaxy oriented edge-on, showing off its prominent dust along its flattened starry disk. Credit: NASA’s Goddard Space Flight Center

One possible explanation is that there’s a lot of dark matter (an unknown and invisible form of matter) associated with these galaxies. If they come close together, then the dark matter can form a big cloud within which the galaxies are orbiting. As the galaxies plow through the dark matter they feel a resistive force due to its gravitational effects. This slows their motion and makes the galaxies lose energy, so they fall together.

Therefore, this snapshot catches the galaxies at a very special moment in their lifetimes. In about 1 billion years they will eventually collide and merge to form a giant elliptical galaxy.

The NASA/ESA Hubble Space Telescope is celebrating its 32nd birthday with a stunning look at an unusual close-knit collection of five galaxies, called the Hickson Compact Group 40. This snapshot reflects a special moment in their lifetimes as they fall together before they merge. Credit: NASA, ESA and STScI

Astronomers have studied this compact galaxy group not only in visible light, but also in radio, infrared, and X-ray wavelengths. Almost all of them have a compact radio source in their cores, which could be evidence for the presence of supermassive black holes. X-ray observations show that the galaxies have been gravitationally interacting due to the presence of a lot of hot gas among the galaxies. Infrared observations reveal clues to the rate of new star formation.

Though over 100 such compact galaxy groups have been cataloged in sky surveys going back several decades, Hickson Compact Group 40 is one of the most densely packed. Observations suggest that such tight groups may have been more abundant in the early universe and provided fuel for powering black holes, known as quasars, whose light from superheated infalling material blazed across space. Studying the details of galaxies in nearby groups like this helps astronomers sort out when and where galaxies assembled themselves, and what they are assembled from.

This image shows a wide-field view centred on the Hickson Compact Group 40. Credit: ESA/Hubble, Digitized Sky Survey 2. Acknowledgement: D. De Martin

“I remember seeing this on a sky survey and saying, ‘wow look at that!’” said Paul Hickson of the University of British Columbia, Vancouver, Canada. “All that I was using at the time was a big plastic ruler and a magnifying glass while looking over sky survey prints.” He re-discovered the group by browsing through a collection of peculiar galaxies first published by Halton Arp in 1966.

Hubble was deployed into orbit around Earth by NASA astronauts aboard the space shuttle Discovery, on April 25, 1990. The telescope has taken 1.5 million observations of approximately 50,000 celestial targets to date. This treasure trove of knowledge about the universe is stored for public access in the Mikulski Archive for Space Telescopes, at the Space Telescope Science Institute in Baltimore, Maryland.

Hubble’s unique capabilities in observing visible and ultraviolet light are a critical scientific complement to the infrared-light observations of the recently launched Webb Space Telescope, which will begin science observations this summer.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.



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Pterosaurs were covered with colorful feathers, study says

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Now we know. Not only did these flying reptiles have feathers, but they could actually control the color of those feathers on a cellular level to create multicolor plumage in a way similar to modern birds, new research has revealed.

These color patterns, determined by melanin pigments, may have been used as a way for pterosaur species to communicate with each other. A study detailing these findings published Wednesday in the journal Nature.

Researchers analyzed the fossilized headcrest of Tupandactylus imperator, a pterosaur that lived 115 million years ago in Brazil. Upon closer inspection, the paleontologists realized that the bottom of this huge headcrest was rimmed with two kinds of feathers: short, wiry ones that were more similar to hair, as well as fluffier ones that branch like bird feathers.

“We didn’t expect to see this at all,” said lead study author Aude Cincotta, a paleontologist and postdoctoral researcher at the University College Cork in Ireland, in a statement.

“For decades, palaeontologists have argued about whether pterosaurs had feathers,” Cincotta said. “The feathers in our specimen close off that debate for good as they are very clearly branched all the way along their length, just like birds today.”

The research team studied the feathers with electron microscopes and were surprised to find preserved melanosomes, or granules of melanin. These granules had different shapes, depending on the types of feathers they were associated with on the pterosaur fossil. Patchy color was also found in the preserved soft tissue.

“In birds today, feather colour is strongly linked to melanosome shape,” said study coauthor Maria McNamara, professor of paleontology in the University College Cork’s School of Biological, Earth and Environmental Sciences, in a statement.

“Since the pterosaur feather types had different melanosome shapes, these animals must have had the genetic machinery to control the colours of their feathers. This feature is essential for colour patterning and shows that coloration was a critical feature of even the very earliest feathers.”

Previously, scientists understood that pterosaurs had some kind of whisker-like fluffy covering to help keep them insulated. The new research confirms that this fuzz was actually made from different types of feathers. These feathers and the surrounding skin had different colors, like black, brown, ginger, gray and other tones associated with the different melanin granules.

“This strongly suggests that the pterosaur feathers had different colours,” McNamara said. “The presence of this feature in both dinosaurs (including birds) and pterosaurs indicates shared ancestry, where this feature derives from a common ancestor that lived in the Early Triassic (250 million years ago). Colouration was therefore probably an important driving force in the evolution of feathers even in the earliest days of their evolutionary history.”

Some of these colors helped the pterosaurs to share visual signals with one another, but the team isn’t quite sure what those signals would have meant.

“We would need to know the precise hue and pattern to work this out,” McNamara said. “Unfortunately we can’t do either at the moment, with current data. We need to look at melanosomes in feathers across the body to work out whether they were patterned, and we need to figure out whether traces of non-melanin pigments can be detected.”

Tupandactylus was an odd-looking creature, with a wingspan of 16 feet (5 meters) and a huge (albeit lightweight) head with toothless jaws. Its giant crest had irregular blooms of color.

“Perhaps they were used in pre-mating rituals, just as certain birds use colourful tail fans, wings and head crests to attract mates,” wrote Michael Benton, a professor of vertebrate paleontology at the University of Bristol’s School of Earth Sciences, in a News and Views article that published with the study. Benton was not involved in the research.

“Modern birds are renowned for the diversity and complexity of their colourful displays, and for the role of these aspects of sexual selection in bird evolution, and the same might be true for a wide array of extinct animals, including dinosaurs and pterosaurs,” Benton wrote.

The discovery could allow for a better understanding of pterosaurs, which first appeared about 230 million years ago and went extinct along with the dinosaurs 66 million years ago.

“This finding opens up opportunities to explore new aspects of pterosaur behaviour, and to revisit previously described specimens for further insights into feather structure and functional evolution,” McNamara said.

The fossil, originally recovered from northeastern Brazil, has been repatriated to its home country thanks to efforts by the scientists and a private donor.

“It is so important that scientifically important fossils such as this are returned to their countries of origin and safely conserved for posterity” said study coauthor Pascal Godefroit, paleontologist at the Royal Belgian Institute of Natural Sciences, in a statement. “These fossils can then be made available to scientists for further study and can inspire future generations of scientists through public exhibitions that celebrate our natural heritage”.

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What’s in Store for the Next Decade of Planetary Science – Sky & Telescope

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A planetary vision for the coming decade.
The National Academies of Sciences

It’s out. The planetary science community has released a report outlining a vision for the next decade. This decadal survey, the result of years of steering committees, white papers, advisory groups, and conferences, represents the marching orders for NASA’s (and to some extent, NSF’s) next 10+ years of planetary — and exoplanetary — exploration.

The National Academies of Sciences’ Planetary Sciences and Astrobiology Decadal Survey, titled Origins, Worlds and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032, is the third prioritized wish list of its kind. As always, any mission concepts will still need to go through rounds of funding, design, and development before reaching the launch pad.

The Last Decadal

A look at the last decadal survey, entitled Visions and Voyages, shows the influence of these efforts can have. That report listed as top priority a Mars astrobiology explorer and sample-caching mission, which became the Perseverance rover that’s currently exploring Jezero Crater on the Red Planet. Perseverance is setting aside samples as the first step of the Mars Sample Return initiative, for which the return vehicle will launch in the 2026 launch window. The decadal’s second priority, a Europa orbiter mission now named the Europa Clipper, is set to launch in 2024.

Visions and Voyages also set themes for smaller missions, categorized by NASA as New Frontiers and Discovery-class missions. Those themes ultimately led to the selection of Dragonfly, a nuclear-powered helicopter that will head to Saturn’s moon Titan in 2027, the Lucy and Psyche asteroid missions, as well as the DAVINCI and VERITAS Venus missions set to fly later this decade.

This Year’s Champions

Besides continuing development and support of these projects, the newest decadal survey prioritizes a few large exciting mission concepts.

As the top-priority new flagship mission, which by definition has a budget more than $1 billion, the report recommends the Uranus Orbiter and Probe. This would be a large, Cassini-style mission to the ice giant and its moons and will include a probe that will enter the atmosphere. To date, we’ve only seen Uranus up close once, during the brief Voyager 2 flyby in 1986. Uranus won out over Neptune due to the flexibility of existing launch vehicles and technology for a 2031 to 2038 launch window, with a Jupiter-flyby assist.

An early 2011 concept design proposal for a possible Uranus mission.
NASA / NRC Decadal Survey

The second-highest priority among flagships is a combination orbiter-and-lander that would head to Saturn’s moon Enceladus, referred to in the report as the Enceladus Orbilander. This moon is a dynamic world with a subsurface ocean that that may contain the complex processes needed to host life. Cassini caught sight of plumes emanating from ice geysers during several flybys, and Enceladus Orbilander could sample these and study the moon’s surface up close.

Four other flagship concepts that were in the running were a Europa lander, a Mercury lander, a Neptune/Triton mission, and a large mission to Venus.

An artist’s concept of Orbilander on the surface of Enceladus.
NASA

As guiding principles, the survey identifies 12 top scientific questions under three key themes: origins, worlds and processes, and life and habitability. These questions, which cover everything from how giant planets form to the whether we’ll find life beyond Earth, will help shepherd mission selection.

“I think [the decadal] is a very compelling vision for space exploration for the next decade and beyond,” says Jonathan Fortney (University of California, Santa Cruz). “I think it is a great mix of getting new data from some of the hottest areas, and essentially new exploration and reconnaissance.”

The Role of Smaller Missions

NASA has two classes of smaller missions, of which New Frontiers offers roughly double the budget as for Discovery-class missions but at a slower launch cadence. The New Frontiers 5 selection, covered in the last decadal and originally slated for October 2022, has been delayed to October 2024.

The new decadal survey covers the next two rounds, New Frontiers 6 and 7, which will take us through 2032. Rather than recommending specific missions for these competitive selections, the report sets detailed themes for consideration:

  • Centaur Asteroid Orbiter and Lander
  • Ceres Sample Return
  • Comet Surface Sample Return mission
  • Enceladus mission with multiple flybys
  • Lunar Geophysical Network
  • Saturn Probe
  • Titan Orbiter
  • Triton Ocean World Surveyor (to be added for New Frontiers 7 only)
  • Venus In Situ Explorer

The report doesn’t lay out any specific themes for the Discovery program, though it does recommend that NASA should continue to select two Discovery-class missions per round. The report also recommends the cost cap for Discovery-class missions be raised from $500 to $800 million.

In addition, the decadal also recommends a cap increase, from $55 million to $80 million, for NASA’s Small Innovative Missions for Planetary Exploration (SIMPLEx), very small, low-cost, and higher-risk projects.

For our next step on Mars, the report prioritizes a Mars Life Explorer as the next mission to be developed after the Mars Sample Return is completed.

For lunar exploration, the survey recommends the development of Endurance A, a large sample-return mission that will visit the lunar south pole. It would collect about 100 kilograms of samples (220 pounds), to be returned to Earth by astronauts as part of the Artemis initiative. The report notes that planetary exploration goals should be primary to Artemis rather than a side objective.

The report also cites a need for NASA to address shortfalls in funding of technology for planetary science missions, which has dropped in recent years to just 4%. To correct this and achieve the goals stated in the report, the panel recommends that NASA’s Planetary Science Division increase funding to match previous levels, 6–8% of the total budget.

Costs of the projects in the Decadal Survey over time.
National Academies of Sciences

Planetary Defense

NASA’s goals in planetary defense are guided by the Brown Act, which called for NASA to identify 90% of near-Earth asteroids more than 140 meters across by 2020. As of 2021, scientists have only cataloged a third of that population. The mid-infrared NEO Surveyor space telescope, already under development, will be crucial to finding more of these potentially threatening space rocks. While the forthcoming Vera C. Rubin Observatory is complementary to NEO Surveyor, it’s not a substitute.

The report also calls for NASA’s Orbital Debris Program Office to work with U.S. Space Command in detecting asteroids that come very near Earth. Ground-based radar and other tracking offers a chance to characterize small near-Earth asteroids, including the upcoming close pass of 99942 Apophis on April 13, 2029. The recent loss of Arecibo makes the need to upgrade tracking and the Deep Space Network especially urgent.

Diversity and Equity

In a first, this decadal survey highlights the urgent need to promote diversity and equity in the field of planetary science. “Ensuring the broadest level of participation is necessary to produce high-quality science in an environment of fierce competition for limited human resources,” the report states. “The rich and unparalleled diversity of the people in the United States is NASA’s strongest advantage, but only if such diversity is tapped by robust procedures for identification and recruitment . . . and equitable reward structures.”

To this end, the report recommends that NASA’s Planetary Science Directorate should adopt a view that bias can be often both pervasive and unintentional, and the agency should work to “eliminate bias from its procedures, wherever it is found to exist.”

The Need for Plutonium

The report also highlights the production of plutonium-238, restarted in 2013, as crucial to the future of deep-space exploration. The radioactive energy source will be needed for the Uranus and Enceladus missions, which venture too far from the Sun to use solar panels. The report recommends that NASA review the plutonium needs for a coming generation of missions and increase production if needed.

Cassini spies ice geysers erupting on Enceladus.
NASA/JPL/Space Science Institute

Satellites vs. Near-Earth Asteroids

Finally, the report cites the impact that the rise of satellite constellations, such as SpaceX’s Starlink, UK’s OneWeb, and Amazon’s Project Kuiper, will have on the effort to effectively search for near-Earth asteroids. The report thus calls for NASA, the National Science Foundation, and the astronomical community to continue to monitor the satellite swarms and investigate ways to mitigate their impacts on observations.

The next decade promises exciting years of planetary space exploration. I, for one, can’t wait to see a crescent Saturn above the icy horizon of Enceladus, not to mention new images of Uranus and its moons. Let’s see, by 2042 I’ll be . . .

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Astronomers discover small but mighty ‘micronova’ star explosion

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Each micronova can burn through “around 3.5 billion Great Pyramids of Giza” of material (or 20,000,000 trillion kilograms) in just a few hours, according to the researchers.

These extremely powerful outbursts can occur on the surface of white dwarfs, or dead stars about as small as our planet, based on observations made by a team of astronomers using the European Southern Observatory’s Very Large Telescope in Chile’s Atacama Desert.

“We have discovered and identified for the first time what we are calling a micronova,” said lead study author Simone Scaringi, an astronomer and assistant professor at Durham University in the United Kingdom, in a statement. “The phenomenon challenges our understanding of how thermonuclear explosions in stars occur. We thought we knew this, but this discovery proposes a totally new way to achieve them.”

A study detailing the findings published Wednesday in the journal Nature.

Strong magnetic fields

White dwarf stars that are found paired with other stars draw hydrogen from their companions, like zombies feeding on their fellow stars. When the gas encounters the piping hot surface of the white dwarf, the hydrogen atoms fuse into helium, triggering an explosion. These events are known as novae.

“Such detonations make the entire surface of the white dwarf burn and shine brightly for several weeks,” said study coauthor Nathalie Degenaar, an astronomer and assistant professor at the University of Amsterdam, in a statement.

Micronovae are smaller than typical novae and only last for a few hours.

Micronovae explosions occur on white dwarfs that have strong magnetic fields, which send material toward the star’s poles. This trajectory causes the hydrogen fusion reactions to occur in more localized spots at the magnetic poles.

“This leads to micro-fusion bombs going off, which have about one millionth of the strength of a nova explosion, hence the name micronova,” said study coauthor Paul Groot, an astronomer and professor at Radboud University in the Netherlands, in a statement.

Tracking intense but brief events

The research team spotted the microexplosions after going through data collected by NASA’s planet-hunting Transiting Exoplanet Survey Satellite, or TESS mission. The satellite is used to search for exoplanets, but it also surveys nearby stars to search for planets located around them.

“Looking through astronomical data collected by NASA’s TESS, we discovered something unusual: a bright flash of optical light lasting for a few hours. Searching further, we found several similar signals,” Degenaar said.

Two of the micronovae occurred on white dwarfs, and the astronomers followed up on the third using the Very Large Telescope to confirm it was also a white dwarf. This allowed the researchers to declare their observations were the discovery of something new.

Now that micronovae are their own class of stellar explosion, the research team hopes to observe more of them to see how common they are — especially since they challenge the current understanding of star explosions.

“It just goes to show how dynamic the universe is. These events may actually be quite common, but because they are so fast they are difficult to catch in action,” Scaringi said.

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