Astronomy

Hubble data confirms galaxies lacking dark matter

By ScientifiCult 20 June 2021

Hubble data confirms galaxies lacking dark matter

NGC1052-DF2 Hubble galaxies dark matter — Hubble data confirms galaxies lacking dark matter: NGC1052-DF2. Credits: NASA, ESA, Z. Shen and P. van Dokkum (Yale University), and S. Danieli (Institute for Advanced Study)

The most accurate distance measurement yet of ultra-diffuse galaxy (UDG) NGC1052-DF2 (DF2) confirms beyond any shadow of a doubt that it is lacking in dark matter. The newly measured distance of 22.1 +/-1.2 megaparsecs was obtained by an international team of researchers led by Zili Shen and Pieter van Dokkum of Yale University and Shany Danieli, a NASA Hubble Fellow at the Institute for Advanced Study.

“Determining an accurate distance to DF2 has been key in supporting our earlier results,” stated Danieli. “The new measurement reported in this study has crucial implications for estimating the physical properties of the galaxy, thus confirming its lack of dark matter.”

The results, published in Astrophysical Journal Letters on June 9, 2021, are based on 40 orbits of NASA’s Hubble Space Telescope, with imaging by the Advanced Camera for Surveys and a “tip of the red giant branch” (TRGB) analysis, the gold standard for such refined measurements. In 2019, the team published results measuring the distance to neighboring UDG NGC1052-DF4 (DF4) based on 12 Hubble orbits and TRGB analysis, which provided compelling evidence of missing dark matter. This preferred method expands on the team’s 2018 studies that relied on “surface brightness fluctuations” to gauge distance. Both galaxies were discovered with the Dragonfly Telephoto Array at the New Mexico Skies observatory.

“We went out on a limb with our initial Hubble observations of this galaxy in 2018,” van Dokkum said. “I think people were right to question it because it’s such an unusual result. It would be nice if there were a simple explanation, like a wrong distance. But I think it’s more fun and more interesting if it actually is a weird galaxy.”

In addition to confirming earlier distance findings, the Hubble results indicated that the galaxies were located slightly farther away than previously thought, strengthening the case that they contain little to no dark matter. If DF2 were closer to Earth, as some astronomers claim, it would be intrinsically fainter and less massive, and the galaxy would need dark matter to account for the observed effects of the total mass.

Dark matter is widely considered to be an essential ingredient of galaxies, but this study lends further evidence that its presence may not be inevitable. While dark matter has yet to be directly observed, its gravitational influence is like a glue that holds galaxies together and governs the motion of visible matter. In the case of DF2 and DF4, researchers were able to account for the motion of stars based on stellar mass alone, suggesting a lack or absence of dark matter. Ironically, the detection of galaxies deficient in dark matter will likely help to reveal its puzzling nature and provide new insights into galactic evolution.

While DF2 and DF4 are both comparable in size to the Milky Way galaxy, their total masses are only about one percent of the Milky Way’s mass. These ultra-diffuse galaxies were also found to have a large population of especially luminous globular clusters.

This research has generated a great deal of scholarly interest, as well as energetic debate among proponents of alternative theories to dark matter, such as Modified Newtonian dynamics (MOND). However, with the team’s most recent findings–including the relative distances of the two UDGs to NGC1052–such alternative theories seem less likely. Additionally, there is now little uncertainty in the team’s distance measurements given the use of the TRGB method. Based on fundamental physics, this method depends on the observation of red giant stars that emit a flash after burning through their helium supply that always happens at the same brightness.

“There’s a saying that extraordinary claims require extraordinary evidence, and the new distance measurement strongly supports our previous finding that DF2 is missing dark matter,” stated Shen. “Now it’s time to move beyond the distance debate and focus on how such galaxies came to exist.”

Moving forward, researchers will continue to hunt for more of these oddball galaxies, while considering a number of questions such as: How are UDGs formed? What do they tell us about standard cosmological models? How common are these galaxies, and what other unique properties do they have? It will take uncovering many more dark matter-less galaxies to resolve these mysteries and the ultimate question of what dark matter really is.

###

The published ApJL article is available here: https://iopscience.iop.org/article/10.3847/2041-8213/ac0335

A pre-publication is available at: https://arxiv.org/abs/2104.03319

About the Institute

The Institute for Advanced Study is one of the world’s foremost centers for theoretical research and intellectual inquiry. Located in Princeton, N.J., the IAS is dedicated to independent study across the sciences and humanities. Founded in 1930, the Institute is devoted to advancing the frontiers of knowledge without concern for immediate application. From founding IAS Professor Albert Einstein to the foremost thinkers of today, the IAS enables bold, curiosity-driven innovation to enrich society in unexpected ways.

Each year, the Institute welcomes more than 200 of the world’s most promising post-doctoral researchers and scholars who are selected and mentored by a permanent Faculty, each of whom are preeminent leaders in their fields. Among present and past Faculty and Members there have been 35 Nobel Laureates, 42 of the 60 Fields Medalists, and 21 of the 24 Abel Prize Laureates, as well as many MacArthur Fellows and Wolf Prize winners.

Press release from the Institute for Advanced Study

Keep Reading

Astronomy

NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus

By ScientifiCult 2 June 2021

NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus

NASA has selected two new missions to Venus, Earth’s nearest planetary neighbor. Part of NASA’s Discovery Program, the missions aim to understand how Venus became an inferno-like world when it has so many other characteristics similar to ours – and may have been the first habitable world in the solar system, complete with an ocean and Earth-like climate.

These investigations are the final selections from four mission concepts NASA picked in February 2020 as part of the agency’s Discovery 2019 competition. Following a competitive, peer-review process, the two missions were chosen based on their potential scientific value and the feasibility of their development plans. The project teams will now work to finalize their requirements, designs, and development plans.

NASA is awarding approximately $500 million per mission for development. Each is expected to launch in the 2028-2030 timeframe.

Venus 2 missions NASA — **NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus.** Venus hides a wealth of information that could help us better understand Earth and exoplanets. NASA’s JPL is designing mission concepts to survive the planet’s extreme temperatures and atmospheric pressure. This image is a composite of data from NASA’s Magellan spacecraft and Pioneer Venus Orbiter. Credits: NASA/JPL-Caltech

The selected missions are:

DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging)

DAVINCI+ will measure the composition of Venus’ atmosphere to understand how it formed and evolved, as well as determine whether the planet ever had an ocean. The mission consists of a descent sphere that will plunge through the planet’s thick atmosphere, making precise measurements of noble gases and other elements to understand why Venus’ atmosphere is a runaway hothouse compared the Earth’s.

In addition, DAVINCI+ will return the first high resolution pictures of the unique geological features on Venus known as “tesserae,” which may be comparable to Earth’s continents, suggesting that Venus has plate tectonics. This would be the first U.S.-led mission to Venus’ atmosphere since 1978, and the results from DAVINCI+ could reshape our understanding of terrestrial planet formation in our solar system and beyond. James Garvin of Goddard Space Flight Center in Greenbelt, Maryland, is the principal investigator. Goddard provides project management.

VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy)

VERITAS will map Venus’ surface to determine the planet’s geologic history and understand why it developed so differently than Earth. Orbiting Venus with a synthetic aperture radar, VERITAS will chart surface elevations over nearly the entire planet to create 3D reconstructions of topography and confirm whether processes such as plate tectonics and volcanism are still active on Venus.

VERITAS also will map infrared emissions from Venus’ surface to map its rock type, which is largely unknown, and determine whether active volcanoes are releasing water vapor into the atmosphere. Suzanne Smrekar of NASA’s Jet Propulsion Laboratory in Southern California, is the principal investigator. JPL provides project management. The German Aerospace Center will provide the infrared mapper with the Italian Space Agency and France’s Centre National d’Études Spatiales contributing to the radar and other parts of the mission.

“We’re revving up our planetary science program with intense exploration of a world that NASA hasn’t visited in over 30 years,” said Thomas Zurbuchen, NASA’s associate administrator for science. “Using cutting-edge technologies that NASA has developed and refined over many years of missions and technology programs, we’re ushering in a new decade of Venus to understand how an Earth-like planet can become a hothouse. Our goals are profound. It is not just understanding the evolution of planets and habitability in our own solar system, but extending beyond these boundaries to exoplanets, an exciting and emerging area of research for NASA.”

Zurbuchen added that he expects powerful synergies across NASA’s science programs, including the James Webb Space Telescope. He anticipates data from these missions will be used by the broadest possible cross section of the scientific community.

“It is astounding how little we know about Venus, but the combined results of these missions will tell us about the planet from the clouds in its sky through the volcanoes on its surface all the way down to its very core,” said Tom Wagner, NASA’s Discovery Program scientist. “It will be as if we have rediscovered the planet.”

In addition to the two missions, NASA selected a pair of technology demonstrations to fly along with them. VERITAS will host the Deep Space Atomic Clock-2, built by JPL and funded by NASA’s Space Technology Mission Directorate. The ultra-precise clock signal generated with this technology will ultimately help enable autonomous spacecraft maneuvers and enhance radio science observations.

DAVINCI+ will host the Compact Ultraviolet to Visible Imaging Spectrometer (CUVIS) built by Goddard. CUVIS will make high resolution measurements of ultraviolet light using a new instrument based on freeform optics. These observations will be used to determine the nature of the unknown ultraviolet absorber in Venus’ atmosphere that absorbs up to half the incoming solar energy.

Established in 1992, NASA’s Discovery Program has supported the development and implementation of over 20 missions and instruments. These selections are part of the ninth Discovery Program competition.

The concepts were chosen from proposals submitted in 2019 under NASA Announcement of Opportunity NNH19ZDA010O. The selected investigations will be managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, as part of the Discovery Program. The Discovery Program conducts space science investigations in the Planetary Science Division of NASA’s Science Mission Directorate. The goals of the program are to provide frequent opportunities for principal investigator-led investigations in planetary sciences that can be accomplished under a not-to-exceed cost cap.

For more information about NASA’s planetary science, visit: https://www.nasa.gov/solarsystem

Press release from NASA on the 2 new missions to Venus.

Keep Reading

Physics

First results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics

By ScientifiCult 7 April 2021

First results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics

The long-awaited first results from the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists’ best theory, the Standard Model of particle physics. This landmark result, made with unprecedented precision, confirms a discrepancy that has been gnawing at researchers for decades.

The strong evidence that muons deviate from the Standard Model calculation might hint at exciting new physics. Muons act as a window into the subatomic world and could be interacting with yet undiscovered particles or forces.

“Today is an extraordinary day, long awaited not only by us but by the whole international physics community,” said Graziano Venanzoni, co-spokesperson of the Muon g-2 experiment and physicist at the Italian National Institute for Nuclear Physics. “A large amount of credit goes to our young researchers who, with their talent, ideas and enthusiasm, have allowed us to achieve this incredible result.”

muon new physics — First results from the Muon g-2 experiment at Fermilab have strengthened evidence of new physics. The centerpiece of the experiment is a 50-foot-diameter superconducting magnetic storage ring, which sits in its detector hall amidst electronics racks, the muon beamline, and other equipment. This impressive experiment operates at negative 450 degrees Fahrenheit and studies the precession (or wobble) of muons as they travel through the magnetic field. Photo: Reidar Hahn, Fermilab

A muon is about 200 times as massive as its cousin, the electron. Muons occur naturally when cosmic rays strike Earth’s atmosphere, and particle accelerators at Fermilab can produce them in large numbers. Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon’s magnet precesses, or wobbles, much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision.

As the muons circulate in the Muon g-2 magnet, they also interact with a quantum foam of subatomic particles popping in and out of existence. Interactions with these short-lived particles affect the value of the g-factor, causing the muons’ precession to speed up or slow down very slightly. The Standard Model predicts this so-called anomalous magnetic moment extremely precisely. But if the quantum foam contains additional forces or particles not accounted for by the Standard Model, that would tweak the muon g-factor further.

“This quantity we measure reflects the interactions of the muon with everything else in the universe. But when the theorists calculate the same quantity, using all of the known forces and particles in the Standard Model, we don’t get the same answer,” said Renee Fatemi, a physicist at the University of Kentucky and the simulations manager for the Muon g-2 experiment. “This is strong evidence that the muon is sensitive to something that is not in our best theory.”

The predecessor experiment at DOE’s Brookhaven National Laboratory, which concluded in 2001, offered hints that the muon’s behavior disagreed with the Standard Model. The new measurement from the Muon g-2 experiment at Fermilab strongly agrees with the value found at Brookhaven and diverges from theory with the most precise measurement to date.

The first result from the Muon g-2 experiment at Fermilab confirms the result from the experiment performed at Brookhaven National Lab two decades ago. Together, the two results show strong evidence that muons diverge from the Standard Model prediction. Image: Ryan Postel, Fermilab/Muon g-2 collaboration

The accepted theoretical values for the muon are:
g-factor: 2.00233183620(86)
anomalous magnetic moment: 0.00116591810(43)
[uncertainty in parentheses]

The new experimental world-average results announced by the Muon g-2 collaboration today are:
g-factor: 2.00233184122(82)
anomalous magnetic moment: 0.00116592061(41)

The combined results from Fermilab and Brookhaven show a difference with theory at a significance of 4.2 sigma, a little shy of the 5 sigma (or standard deviations) that scientists require to claim a discovery but still compelling evidence of new physics. The chance that the results are a statistical fluctuation is about 1 in 40,000.

The Fermilab experiment reuses the main component from the Brookhaven experiment, a 50-foot-diameter superconducting magnetic storage ring. In 2013, it was transported 3,200 miles by land and sea from Long Island to the Chicago suburbs, where scientists could take advantage of Fermilab’s particle accelerator and produce the most intense beam of muons in the United States. Over the next four years, researchers assembled the experiment; tuned and calibrated an incredibly uniform magnetic field; developed new techniques, instrumentation, and simulations; and thoroughly tested the entire system.

The Muon g-2 experiment sends a beam of muons into the storage ring, where they circulate thousands of times at nearly the speed of light. Detectors lining the ring allow scientists to determine how fast the muons are precessing.

In its first year of operation, in 2018, the Fermilab experiment collected more data than all prior muon g-factor experiments combined. With more than 200 scientists from 35 institutions in seven countries, the Muon g-2 collaboration has now finished analyzing the motion of more than 8 billion muons from that first run.

“After the 20 years that have passed since the Brookhaven experiment ended, it is so gratifying to finally be resolving this mystery,” said Fermilab scientist Chris Polly, who is a co-spokesperson for the current experiment and was a lead graduate student on the Brookhaven experiment.

Data analysis on the second and third runs of the experiment is under way, the fourth run is ongoing, and a fifth run is planned. Combining the results from all five runs will give scientists an even more precise measurement of the muon’s wobble, revealing with greater certainty whether new physics is hiding within the quantum foam.

“So far we have analyzed less than 6% of the data that the experiment will eventually collect. Although these first results are telling us that there is an intriguing difference with the Standard Model, we will learn much more in the next couple of years,” Polly said.

“Pinning down the subtle behavior of muons is a remarkable achievement that will guide the search for physics beyond the Standard Model for years to come,” said Fermilab Deputy Director of Research Joe Lykken. “This is an exciting time for particle physics research, and Fermilab is at the forefront.”

Press release from the Fermilab; first results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics.

Keep Reading

Geology

Pompeii: the duration of pyroclastic currents generated by the eruption of Vesuvius in 79 AD has been determined

By ScientifiCult 23 March 2021

Pompeii: the duration of pyroclastic currents generated by the eruption of Vesuvius in 79 AD has been determined

A research on the effects of the pyroclastic flows of the 79 AD eruption on Pompeii highlighted how their duration had a tragic impact on the population

About fifteen minutes was the duration of the pyroclastic currents that hit Pompeii during the eruption of Vesuvius in 79 AD: the volcanic ashes, inhaled by the inhabitants, were fatal, causing asphyxiation.
This is what reveals the study “The impact of pyroclastic density currents duration on humans: the case of the AD 79 eruption of Vesuvius”, conducted by the University of Bari – Department of Earth and Geo-environmental Sciences, in collaboration with the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and the British Geological Survey of Edinburgh. The study has just been published ‘Scientific Reports’.
“The aim of the work”, says Roberto Isaia, senior researcher of the Vesuvian Observatory of the INGV “was to develop a model to try to understand and quantify the impact of pyroclastic flows on the inhabited area of Pompeii”.

The inhabited area around Vesuvius volcano in a 3D perspective view from West; DTM overlaid with digital color orthophoto (Laboratory of Geomatics and Cartography, INGV-OV)

Pyroclastic flows, in fact, are the most devastating phenomenon of the so-called explosive eruptions. Comparable to avalanches, they are generated by the collapse of the eruptive column. The resulting dense pyroclastic flows flow along the slopes of the volcano at speeds of hundreds of kilometers per hour, at high temperatures and with a high particles concentration.
“During our research”, continues Isaia, “we carried out filed and laboratory studies of the pyroclastic deposits recognized within the archaeological excavations of Pompeii which led to the measurement and definition of the physical-mechanical parameters of the rocks. The obtained data have been used as input parameters for a mathematical model that has allowed us to carry out numerical simulations. From these we obtained the physical parameters of the pyroclastic currents and, therefore, the effects on the territory, including people, have been estimated. The main result is that the persistence of the flow of pyroclastic currents took place over a period of time between 10 and 20 minutes”.

Pyroclastic deposits within the Pompeii inhabited area including stratified layer with tractional structures formed by the Pyroclastic Density Currents

“The developed model” adds the researcher, “can also be applied to other active volcanoes around the world,. The example of Pompeii in fact, about 10 km far from Vesuvius, suggests how the use of this model could be very valuable for understanding the duration of pyroclastic flows and, therefore, the damage deriving from an eruption even at distances where the temperature and the pressure of the pyroclastic currents no longer causes harmful effects on humans and the environment. The applied methodology can therefore provide new elements of knowledge in the context of the hazard assessment of an active volcanic structure “, concludes Roberto Isaia.
“It is very important to be able to reconstruct what happened in the past eruptions of Vesuvius starting from the geological record, in order to trace the characteristics of the pyroclastic currents and the impact on population” declares Professor Pierfrancesco Dellino of the University of Bari, referent for the sector volcanic activity of the Commissione Grandi Rischi nazionale. “The adopted scientific approach in this study reveals information that are contained by the pyroclastic deposits and that clarifies new aspects of the eruption of Pompeii and provides valuable insights for interpreting the behavior of Vesuvius also in terms of civil protection”.

Briefly

Who: Università degli Studi di Bari, Istituto Nazionale di Geofisica e Vulcanologia (INGV) e British Geological Survey, Edinburgh (UK)
What: A model was developed that allowed to calculate that in Pompeii the persistence of the passage of pyroclastic currents occurred in a period of time between 10 and 20 minutes, causing lethal effects on its inhabitants.
Where: The research The impact of pyroclastic density currents duration on humans: the case of the AD 79 eruption of Vesuvius in ‘Scientific Reports’.
Link: https://www.nature.com/articles/s41598-021-84456-7

——–
Abstract
Pyroclastic density currents are ground hugging gas-particle flows that originate from the collapse of an eruption column or lava dome. They move away from the volcano at high speed, causing devastation. The impact is generally associated with flow dynamic pressure and temperature. Little emphasis has yet been given to flow duration, although it is emerging that the survival of people engulfed in a current strongly depends on the exposure time. The AD 79 event of Somma-Vesuvius is used here to demonstrate the impact of pyroclastic density currents on humans during an historical eruption. At Herculaneum, at the foot of the volcano, the temperature and strength of the flow were so high that survival was impossible. At Pompeii, in the distal area, we use a new model indicating that the current had low strength and low temperature, which is confirmed by the absence of signs of trauma on corpses. Under such conditions, survival should have been possible if the current lasted a few minutes or less. Instead, our calculations demonstrate a flow duration of 17 min, long enough to make lethal the breathing of ash suspended in the current. We conclude that in distal areas where the mechanical and thermal effects of a pyroclastic density currents are diminished, flow duration is the key for survival.

Press release from the Istituto Nazionale di Geofisica e Vulcanologia (INGV)

Keep Reading

Biology

Dwarf lemurs are coming out of winter’s slumber; here’s why scientists are excited

By ScientifiCult 16 March 2021

An unusual creature is coming out of winter’s slumber; here’s why scientists are excited

Duke Lemur Center recreates the seasonal swings of native habitat, helping to unlock the secrets of hibernation

The fat-tailed dwarf lemurs are our closest hibernating relative. Researchers at the Duke Lemur Center have been changing up their care to more closely match the seasonal fluctuations they experience in the wild. Researchers at the Duke Lemur Center have been changing up their care to more closely match the seasonal fluctuations they experience in the wild. Photo by David Haring, Duke Lemur Center

DURHAM, N.C. — If you binged on high-calorie snacks and then spent the winter crashed on the couch in a months-long food coma, you’d likely wake up worse for wear. Unless you happen to be a fat-tailed dwarf lemur.

This squirrel-sized primate lives in the forests of Madagascar, where it spends up to seven months each year mostly motionless and chilling, using the minimum energy necessary to withstand the winter. While zonked, it lives off of fat stored in its tail.

Animals that hibernate in the wild rarely do so in zoos and sanctuaries, with their climate controls and year-round access to food. But now our closest hibernating relative has gone into true, deep hibernation in captivity for the first time at the Duke Lemur Center.

“They did not disappoint,” said research scientist Marina Blanco, who led the project. “Indeed, our dwarf lemurs hibernated just like their wild kin do in western Madagascar.”

The researchers say recreating some of the seasonal fluctuations of the lemurs’ native habitat might be good for the well-being of a species hardwired for hibernation, and also may yield insights into metabolic disorders in humans.

“Hibernation is literally in their DNA,” Blanco said.

Blanco has studied dwarf lemurs for 15 years in Madagascar, fitting them with tracking collars to locate them when they are hibernating in their tree holes or underground burrows. But what she and others observed in the wild didn’t square with how the animals behaved when cared for in captivity.

Captive dwarf lemurs are fed extra during the summer so they can bulk up like they do in the wild, and then they’ll hunker down and let their heart rate and temperature drop for short bouts — a physiological condition known as torpor. But they rarely stay in this suspended state for longer than 24 hours. Which got Blanco to wondering: After years in captivity, do dwarf lemurs still have what it takes to survive seasonal swings like their wild counterparts do? And what can these animals teach us about how to safely put the human body on pause too, slowing the body’s processes long enough for, say, life-saving surgery or even space travel?

To find out, Duke Lemur Center staff teamed up to build fake tree hollows out of wooden boxes and placed them in the dwarf lemurs’ indoor enclosures, as a haven for them to wait out the winter. To mimic the seasonal changes the lemurs experience over the course of the year in Madagascar, the team also gradually adjusted the lights from 12 hours a day to a more “winter-like” 9.5 hours, and lowered the thermostat from 77 degrees Fahrenheit to the low 50s.

The animals were offered food if they were awake and active, and weighed every two weeks, but otherwise they were left to lie.

It worked. In the March 11 issue of the journal Scientific Reports, the researchers show for the first time that fat-tailed dwarf lemurs can hibernate quite well in captivity.

For four months, the eight lemurs in the study spent some 70% of their time in metabolic slow-motion: curled up, cool to the touch, barely moving or breathing for up to 11 days at a stretch, showing little interest in food — akin to their wild counterparts.

Now that spring is afoot in North Carolina and the temperatures are warming, the lemurs are waking up. Their first physical exams after they emerged showed them to be 22% to 35% lighter than they were at the start but otherwise healthy. Their heart rates are back up from just eight beats per minute to about 200, and their appetites have returned.

“We’ve been able to replicate their wild conditions well enough to get them to replicate their natural patterns,” said Erin Ehmke, who directs research at the center.

Females were the hibernation champs, out-stuporing the males and maintaining more of their winter weight. They need what’s left of their fat stores for the months of pregnancy and lactation that typically follow after they wake up, Blanco said.

Study co-author Lydia Greene says the next step is to use non-invasive research techniques such as metabolite analysis and sensors in their enclosures to better understand what dwarf lemurs do to prepare their bodies and eventually bounce back from months of standby mode — work that could lead to new treatments for heart attacks, strokes, and other life-threatening conditions in humans.

Blanco suspects the impressive energy-saving capabilities of these lemurs may also relate to another trait they possess: longevity. The oldest dwarf lemur on record, Jonas, died at the Duke Lemur Center at the age of 29. The fact that dwarf lemurs live longer than non-hibernating species their size suggests that something intrinsic to their biological machinery may protect against aging.

“But until now, if you wanted to study hibernation in these primates, you needed to go to Madagascar to find them in the act,” Blanco said. “Now we can study hibernation here and do more close monitoring.”

This research was supported by the Duke Lemur Center.

CITATION: “On the Modulation and Maintenance of Hibernation in Captive Dwarf Lemurs,” Marina B. Blanco, Lydia K. Greene, Robert Schopler, Cathy V. Williams, Danielle Lynch, Jenna Browning, Kay Welser, Melanie Simmons, Peter H. Klopfer, Erin E. Ehmke. Scientific Reports, March 11, 2021. DOI: 10.1038/s41598-021-84727-3.

Press release from Duke University, by Robin A. Smith.

Keep Reading

Astronomy

GJ 1132 b: Hubble sees new atmosphere forming on the rocky exoplanet

By ScientifiCult 13 March 2021

Hubble sees new atmosphere forming on a rocky exoplanet, GJ 1132 b

The planet GJ 1132 b appears to have begun life as a gaseous world with a thick blanket of atmosphere. Starting out at several times the radius of Earth, this so-called “sub-Neptune” quickly lost its primordial hydrogen and helium atmosphere, which was stripped away by the intense radiation from its hot, young star. In a short period of time, it was reduced to a bare core about the size of Earth.

To the surprise of astronomers, new observations from Hubble [1] have uncovered a secondary atmosphere that has replaced the planet’s first atmosphere. It is rich in hydrogen, hydrogen cyanide, methane and ammonia, and also has a hydrocarbon haze. Astronomers theorise that hydrogen from the original atmosphere was absorbed into the planet’s molten magma mantle and is now being slowly released by volcanism to form a new atmosphere. This second atmosphere, which continues to leak away into space, is continually being replenished from the reservoir of hydrogen in the mantle’s magma.

“This second atmosphere comes from the surface and interior of the planet, and so it is a window onto the geology of another world,” explained team member Paul Rimmer of the University of Cambridge, UK. “A lot more work needs to be done to properly look through it, but the discovery of this window is of great importance.”

Pictured here is the region around the host star of the exoplanet GJ 1132 b. Credit:
ESA/Hubble, Digitized Sky Survey 2, CC BY 4.0.
Acknowledgement: Davide De Martin

“We first thought that these highly radiated planets would be pretty boring because we believed that they lost their atmospheres,” said team member Raissa Estrela of the Jet Propulsion Laboratory at the California Institute of Technology in Pasadena, California, USA. But we looked at existing observations of this planet with Hubble and realised that there is an atmosphere there.”

“How many terrestrial planets don’t begin as terrestrials? Some may start as sub-Neptunes, and they become terrestrials through a mechanism whereby light evaporates the primordial atmosphere. This process works early in a planet’s life, when the star is hotter,” said team leader Mark Swain of the Jet Propulsion Laboratory. “Then the star cools down and the planet’s just sitting there. So you’ve got this mechanism that can cook off the atmosphere in the first 100 million years, and then things settle down. And if you can regenerate the atmosphere, maybe you can keep it.”

In some ways, GJ 1132 b has various parallels to Earth, but in some ways it is also very different. Both have similar densities, similar sizes, and similar ages, being about 4.5 billion years old. Both started with a hydrogen-dominated atmosphere, and both were hot before they cooled down. The team’s work even suggests that GJ 1132 b and Earth have similar atmospheric pressure at the surface.

This plot shows the spectrum of the atmosphere of an Earth sized rocky exoplanet, GJ 1132 b, which is overlaid on an artist’s impression of the planet. The orange line represents the model spectrum. In comparison, the observed spectrum is shown as blue dots representing averaged data points, along with their error bars. This analysis is consistent with GJ 1132 b being predominantly a hydrogen atmosphere with a mix of methane and hydrogen cyanide. The planet also has aerosols which cause scattering of light. This is the first time a so-called “secondary atmosphere,” which was replenished after the planet lost its primordial atmosphere, has been detected on a world outside of our solar system. Credit:
NASA, ESA, and P. Jeffries (STScI)

However, the planets’ formation histories are profoundly different. Earth is not believed to be the surviving core of a sub-Neptune. And Earth orbits at a comfortable distance from our yellow dwarf Sun. GJ 1132 b is so close to its host red dwarf star that it completes an orbit the star once every day and a half. This extremely close proximity keeps GJ 1132 b tidally locked, showing the same face to its star at all times — just as our moon keeps one hemisphere permanently facing Earth.

“The question is, what is keeping the mantle hot enough to remain liquid and power volcanism?” asked Swain. “This system is special because it has the opportunity for quite a lot of tidal heating.”

The phenomenon of tidal heating occurs through friction, when energy from a planet’s orbit and rotation is dispersed as heat inside the planet. GJ 1132 b is in an elliptical orbit, and the tidal forces acting on it are strongest when it is closest to or farthest from its host star. At least one other planet in the host star’s system also exerts a gravitational pull on the planet. The consequences are that the planet is squeezed or stretched by this gravitational “pumping.” That tidal heating keeps the mantle liquid for a long time. A nearby example in our own Solar System is the Jovian moon, Io, which has continuous volcanism as a result of a tidal tug-of-war between Jupiter and the neighbouring Jovian moons.

The team believes the crust of GJ 1132 b is extremely thin, perhaps only hundreds of feet thick. That’s much too feeble to support anything resembling volcanic mountains. Its flat terrain may also be cracked like an eggshell by tidal flexing. Hydrogen and other gases could be released through such cracks.

“This atmosphere, if it’s thin — meaning if it has a surface pressure similar to Earth — probably means you can see right down to the ground at infrared wavelengths. That means that if astronomers use the James Webb Space Telescope to observe this planet, there’s a possibility that they will see not the spectrum of the atmosphere, but rather the spectrum of the surface,” explained Swain. “And if there are magma pools or volcanism going on, those areas will be hotter. That will generate more emission, and so they’ll potentially be looking at the actual geological activity — which is exciting!”

This result is significant because it gives exoplanet scientists a way to figure out something about a planet’s geology from its atmosphere,” added Rimmer. “It is also important for understanding where the rocky planets in our own Solar System — Mercury, Venus, Earth and Mars, fit into the bigger picture of comparative planetology, in terms of the availability of hydrogen versus oxygen in the atmosphere.”

###

Notes:

[1] The observations were conducted as part of the Hubble observing program #14758 (PI: Zach Berta-Thomson).

Keep Reading

Astronomy

NASA’s Perseverance Drives on Mars’ Terrain for First Time

By ScientifiCult 5 March 2021

NASA Mars Perseverance — This image was captured while NASA’s Perseverance rover drove on Mars for the first time on March 4, 2021. One of Perseverance’s Hazard Avoidance Cameras (Hazcams) captured this image as the rover completed a short traverse and turn from its landing site in Jezero Crater.
Credits: NASA/JPL-Caltech

NASA’s Mars 2020 Perseverance rover performed its first drive on Mars March 4, covering 21.3 feet (6.5 meters) across the Martian landscape. The drive served as a mobility test that marks just one of many milestones as team members check out and calibrate every system, subsystem, and instrument on Perseverance. Once the rover begins pursuing its science goals, regular commutes extending 656 feet (200 meters) or more are expected.

“When it comes to wheeled vehicles on other planets, there are few first-time events that measure up in significance to that of the first drive,” said Anais Zarifian, Mars 2020 Perseverance rover mobility test bed engineer at NASA’s Jet Propulsion Laboratory in Southern California. “This was our first chance to ‘kick the tires’ and take Perseverance out for a spin. The rover’s six-wheel drive responded superbly. We are now confident our drive system is good to go, capable of taking us wherever the science leads us over the next two years.”

The drive, which lasted about 33 minutes, propelled the rover forward 13 feet (4 meters), where it then turned in place 150 degrees to the left and backed up 8 feet (2.5 meters) into its new temporary parking space. To help better understand the dynamics of a retrorocket landing on the Red Planet, engineers used Perseverance’s Navigation and Hazard Avoidance Cameras to image the spot where Perseverance touched down, dispersing Martian dust with plumes from its engines.

More Than Roving

The rover’s mobility system is not the only thing getting a test drive during this period of initial checkouts. On Feb. 26 – Perseverance’s eighth Martian day, or sol, since landing – mission controllers completed a software update, replacing the computer program that helped land Perseverance with one they will rely on to investigate the planet.

More recently, the controllers checked out Perseverance’s Radar Imager for Mars’ Subsurface Experiment (RIMFAX) and Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) instruments, and deployed the Mars Environmental Dynamics Analyzer (MEDA) instrument’s two wind sensors, which extend out from the rover’s mast. Another significant milestone occurred on March 2, or sol 12, when engineers unstowed the rover’s 7-foot-long (2-meter-long) robotic arm for the first time, flexing each of its five joints over the course of two hours.

“Tuesday’s first test of the robotic arm was a big moment for us,” said Robert Hogg, Mars 2020 Perseverance rover deputy mission manager. “That’s the main tool the science team will use to do close-up examination of the geologic features of Jezero Crater, and then we’ll drill and sample the ones they find the most interesting. When we got confirmation of the robotic arm flexing its muscles, including images of it working beautifully after its long trip to Mars – well, it made my day.”

Upcoming events and evaluations include more detailed testing and calibration of science instruments, sending the rover on longer drives, and jettisoning covers that shield both the adaptive caching assembly (part of the rover’s Sample Caching System) and the Ingenuity Mars Helicopter during landing. The experimental flight test program for the Ingenuity Mars Helicopter will also take place during the rover’s commissioning.

Through it all, the rover is sending down images from the most advanced suite of cameras ever to travel to Mars. The mission’s cameras have already sent about 7,000 images. On Earth, Perseverance’s imagery flows through the powerful Deep Space Network (DSN), managed by NASA’s Space Communications and Navigation (SCaN) program. In space, several Mars orbiters play an equally important role.

“Orbiter support for downlink of data has been a real gamechanger,” said Justin Maki, chief engineer for imaging and the imaging scientist for the Mars 2020 Perseverance rover mission at JPL. “When you see a beautiful image from Jezero, consider that it took a whole team of Martians to get it to you. Every picture from Perseverance is relayed by either the European Space Agency’s Trace Gas Orbiter, or NASA’s MAVEN, Mars Odyssey, or Mars Reconnaissance Orbiter. They are important partners in our explorations and our discoveries.”

The sheer volume of imagery and data already coming down on this mission has been a welcome bounty for Matt Wallace, who recalls waiting anxiously for the first images to trickle in during NASA’s first Mars rover mission, Sojourner, which explored Mars in 1997. On March 3, Wallace became the mission’s new project manager. He replaced John McNamee, who is stepping down as he intended, after helming the project for nearly a decade.

“John has provided unwavering support to me and every member of the project for over a decade,” said Wallace. “He has left his mark on this mission and team, and it has been my privilege to not only call him boss but also my friend.”

Touchdown Site Named

With Perseverance departing from its touchdown site, mission team scientists have memorialized the spot, informally naming it for the late science fiction author Octavia E. Butler. The groundbreaking author and Pasadena, California, native was the first African American woman to win both the Hugo Award and Nebula Award, and she was the first science fiction writer honored with a MacArthur Fellowship. The location where Perseverance began its mission on Mars now bears the name “Octavia E. Butler Landing.”

Official scientific names for places and objects throughout the solar system – including asteroids, comets, and locations on planets – are designated by the International Astronomical Union. Scientists working with NASA’s Mars rovers have traditionally given unofficial nicknames to various geological features, which they can use as references in scientific papers.

“Butler’s protagonists embody determination and inventiveness, making her a perfect fit for the Perseverance rover mission and its theme of overcoming challenges,” said Kathryn Stack Morgan, deputy project scientist for Perseverance. “Butler inspired and influenced the planetary science community and many beyond, including those typically under-represented in STEM fields.”

“I can think of no better person to mark this historic landing site than Octavia E. Butler, who not only grew up next door to JPL in Pasadena, but she also inspired millions with her visions of a science-based future,” said Thomas Zurbuchen, NASA associate administrator for science. “Her guiding principle, ‘When using science, do so accurately,’ is what the science team at NASA is all about. Her work continues to inspire today’s scientists and engineers across the globe – all in the name of a bolder, more equitable future for all.”

Butler, who died in 2006, authored such notable works as “Kindred,” “Bloodchild,” “Speech Sounds,” “Parable of the Sower,” “Parable of the Talents,” and the “Patternist” series. Her writing explores themes of race, gender, equality, and humanity, and her works are as relevant today as they were when originally written and published.

More About the Mission

A key objective of Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.

Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

JPL, which is managed for NASA by Caltech in Pasadena, built and manages operations of the Perseverance rover.

Press release from NASA.

Keep Reading

Biology

Oahu marine protected areas offer limited protection of coral reef herbivorous fishes

By ScientifiCult 1 March 2021

Marine protected areas (MPAs) around Oʻahu do not adequately protect populations of herbivorous reef fishes that eat algae on coral reefs. That is the primary conclusion of a study published in Coral Reefs by researchers from the University of Hawaiʻi at Mānoa School of Ocean and Earth Science and Technology (SOEST).

A large parrotfish scrapes algae from a Hawaiian reef. Credits: Noam Altman-Kurosaki

There are over 20 species of herbivorous fishes and ten species of herbivorous urchins commonly observed on Hawaiian reefs. These species eat algae that grows on reefs, a process called herbivory, that contributes to the resilience of coral reefs by preventing algae dominance that can lead to overgrowth of corals.

The team of researchers found that of the four marine protected areas around Oʻahu they assessed in the study, three did not provide biologically significant benefits for herbivorous fish populations compared to reefs outside the areas.

“Marine protected areas are a fishery management tool to limit or prevent fishing to help the recovery and maintenance of fish abundance and biomass inside the MPA,” said senior author Erik Franklin, Associate Research Professor at the Hawaiʻi Institute of Marine Biology in SOEST. “An effective MPA should lead to a considerably higher abundance and biomass of fishes inside the MPA boundaries that would otherwise be caught by fishers but that wasn’t what our study found.”

Other factors influencing the biomass of herbivorous fishes included habitat complexity and depth, suggesting that environmental characteristics of coral reefs may have had a greater impact on herbivorous fish populations than MPA protection.

coral reef fishes protected marine areas — A large school of surgeonfishes swims over a shallow Hawaiian reef. Credits: Noam Altman-Kurosaki

Importance for Hawaiʻi

As part of the Sustainable Hawaiʻi Initiative, the State of Hawaiʻi’s Division of Aquatic Resources leads the Marine 30×30 Initiative, which committed to effectively manage Hawaii’s nearshore waters with 30 percent established as marine management areas by 2030. Currently, five percent of waters within state jurisdiction, which is within three nautical miles of shore, have some form of marine management, but no-take MPAs that ban fishing only make up less than one-half of one percent of the nearshore waters. To attain the stated goal of the 30×30 Initiative would require an expansion of marine managed areas to include an additional 25 percent of Hawaiʻi state waters.

“Our results suggest that prior to an expansion of MPAs in Hawaiian waters, more effort should be directed to effectively manage the existing MPAs to see if they meet the desired management objectives,” said lead author and UH Mānoa’s Marine Biology Graduate Program graduate student Noam Altman-Kurosaki. “The addition of more MPAs throughout the state that have similar performance to the Oʻahu MPAs would just lead to a series of paper parks that don’t provide biologically significant conservation benefits while decreasing fishing opportunities.”

Study details

Franklin said the research resulted in a comparative analysis of herbivorous fish and urchin populations inside and outside of Oʻahu MPAs that demonstrated biologically insignificant differences in fish biomass between the MPAs and reference areas, except for one site, Hanauma Bay. The analyses used statistical methods to assess the effects of protecting population within MPAs and the influence that differences in benthic habitats contributed to the results.

The research team, including Franklin, Altman-Kurosaki, and Professor Celia Smith from the UH Mānoa School of Life Sciences, performed dive surveys, analyzed the data, and identified algae specimens, with assistance from several field assistants.

Press release from the School of Ocean and Earth Science and Technology (SOEST) on the limited protection offered by Oahu marine protected areas to coral reef herbivorous fishes

Keep Reading

Astronomy

Sensing suns: Astronomers accurately measure the temperature of red supergiant stars

By ScientifiCult 1 March 2021

Sensing suns

Astronomers accurately measure the temperature of red supergiant stars

red supergiant stars temperature — For the first time, astronomers develop an accurate method to determine the surface temperatures of red supergiants. Credits: © 2021 Daisuke Taniguchi/The University of Tokyo

Red supergiants are a class of star that end their lives in supernova explosions. Their lifecycles are not fully understood, partly due to difficulties in measuring their temperatures. For the first time, astronomers develop an accurate method to determine the surface temperatures of red supergiants.

Stars come in a wide range of sizes, masses and compositions. Our sun is considered a relatively small specimen, especially when compared to something like Betelgeuse which is known as a red supergiant. Red supergiants are stars over nine times the mass of our sun, and all this mass means that when they die they do so with extreme ferocity in an enormous explosion known as a supernova, in particular what is known as a Type-II supernova.

Type II supernovae seed the cosmos with elements essential for life; therefore, researchers are keen to know more about them. At present there is no way to accurately predict supernova explosions. One piece of this puzzle lies in understanding the nature of the red supergiants that precede supernovae.

Despite the fact red supergiants are extremely bright and visible at great distances, it is difficult to ascertain important properties about them, including their temperatures. This is due to the complicated structures of their upper atmospheres which leads to inconsistencies of temperature measurements that might work with other kinds of stars.

“In order to measure the temperature of red supergiants, we needed to find a visible, or spectral, property that was not affected by their complex upper atmospheres,” said graduate student Daisuke Taniguchi from the Department of Astronomy at the University of Tokyo. “Chemical signatures known as absorption lines were the ideal candidates, but there was no single line that revealed the temperature alone. However, by looking at the ratio of two different but related lines — those of iron — we found the ratio itself related to temperature. And it did so in a consistent and predictable way.”

Astronomers accurately measure the temperature of red supergiant stars: the WINERED spectrograph mounted on the Araki telescope. Credits: © 2021 Kyoto Sangyo University

Taniguchi and his team observed candidate stars with an instrument called WINERED which attaches to telescopes in order to measure spectral properties of distant objects. They measured the iron absorption lines and calculated the ratios to estimate the stars’ respective temperatures. By combining these temperatures with accurate distance measurements obtained by the European Space Agency’s Gaia space observatory, the researchers calculated the stars luminosity, or power, and found their results consistent with theory.

“We still have much to learn about supernovae and related objects and phenomena, but I think this research will help astronomers fill in some of the blanks,” said Taniguchi. “The giant star Betelgeuse (on Orion’s shoulder) could go supernova in our lifetimes; in 2019 and 2020 it dimmed unexpectedly. It would be fascinating if we were able to predict if and when it might go supernova. I hope our new technique contributes to this endeavor and more.”

###

Journal article

Daisuke Taniguchi, Noriyuki Matsunaga, Mingjie Jian, Naoto Kobayashi, Kei Fukue, Satoshi Hamano, Yuji Ikeda, Hideyo Kawakita, Sohei Kondo, Shogo Otsubo, Hiroaki Sameshima, Keiichi Takenaka and Chikako Yasui. Effective temperatures of red supergiants estimated from line-depth ratios of iron lines in the YJ bands, 0.97-1.32 μm. Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/staa3855.
http://doi.org/10.1093/mnras/staa3855

Keep Reading

Biology

New flower from 100 million years ago brings fresh holiday beauty to 2020

By ScientifiCult 27 December 2020

Valviloculus pleristaminis: a new flower from 100 million years ago brings fresh holiday beauty to 2020

flower Cretaceous Valviloculus pleristaminis — Valviloculus pleristaminis. Credits: George Poinar Jr., OSU

CORVALLIS, Ore. – Oregon State University researchers have identified a spectacular new genus and species of flower from the mid-Cretaceous period, a male specimen whose sunburst-like reach for the heavens was frozen in time by Burmese amber.

“This isn’t quite a Christmas flower but it is a beauty, especially considering it was part of a forest that existed 100 million years ago,” said George Poinar Jr., professor emeritus in the OSU College of Science.

Findings were published in the Journal of the Botanical Research Institute of Texas.

“The male flower is tiny, about 2 millimeters across, but it has some 50 stamens arranged like a spiral, with anthers pointing toward the sky,” said Poinar, an international expert in using plant and animal life forms preserved in amber to learn more about the biology and ecology of the distant past.

A stamen consists of an anther – the pollen-producing head – and a filament, the stalk that connects the anther to the flower.

“Despite being so small, the detail still remaining is amazing,” Poinar said. “Our specimen was probably part of a cluster on the plant that contained many similar flowers, some possibly female.”

The new discovery has an egg-shaped, hollow floral cup – the part of the flower from which the stamens emanate; an outer layer consisting of six petal-like components known as tepals; and two-chamber anthers, with pollen sacs that split open via laterally hinged valves.

Poinar and collaborators at OSU and the U.S. Department of Agriculture named the new flower Valviloculus pleristaminis. Valva is the Latin term for the leaf on a folding door, loculus means compartment, plerus refers to many, and staminis reflects the flower’s dozens of male sex organs.

The flower became encased in amber on the ancient supercontinent of Gondwana and rafted on a continental plate some 4,000 miles across the ocean from Australia to Southeast Asia, Poinar said.

Geologists have been debating just when this chunk of land – known as the West Burma Block – broke away from Gondwana. Some believe it was 200 million years ago; others claim it was more like 500 million years ago.

Numerous angiosperm flowers have been discovered in Burmese amber, the majority of which have been described by Poinar and a colleague at Oregon State, Kenton Chambers, who also collaborated on this research.

Angiosperms are vascular plants with stems, roots and leaves, with eggs that are fertilized and develop inside the flower.

Since angiosperms only evolved and diversified about 100 million years ago, the West Burma Block could not have broken off from Gondwana before then, Poinar said, which is much later than dates that have been suggested by geologists.

Joining Poinar and Chambers, a botany and plant pathology researcher in the OSU College of Agricultural Sciences, on the paper were Oregon State’s Urszula Iwaniec and the USDA’s Fernando Vega. Iwaniec is a researcher in the Skeletal Biology Laboratory in the College of Public Health and Human Sciences and Vega works in the Sustainable Perennial Crops Laboratory in Beltsville, Maryland.

About the OSU College of Science: As one of the largest academic units at OSU, the College of Science has seven departments and 12 pre-professional programs. It provides the basic science courses essential to the education of every OSU student, builds future leaders in science, and its faculty are international leaders in scientific research.

Press release from the Oregon State University.

Keep Reading