понедельник, 22 октября 2018 г.

Block Patterns At the earliest stage of our lives, genes…

Block Patterns

At the earliest stage of our lives, genes switch on and off inside stem cells, guiding them towards different destinies in future tissues and organs. Here a technique called CRISPR interference blocks specific genes inside groups of human pluripotent stem cells, mimicking some of the early decisions made inside embryos. A high-powered microscope watches how artificially-coloured cell clumps develop differently over one, three and five days (across each row). The red-coloured cells have a switched-off ROCK1 gene (middle) and move towards the edge, while blocking CDH1 (bottom, blue) directs cells into little islands, compared to the white cells with normal genes (top). This technique may be used to study the effects of other developmental genes, creating realistic models for delicate embryonic stages. These may reveal insights into miscarriage or perhaps developmental disorders, as well as morphogenesis – the unseen patterns that shape early life.

Written by John Ankers

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Concrete Cast of Bronze Age Cup and Ring Marks found in the Kirkcudbright Stewarty,...

Concrete Cast of Bronze Age Cup and Ring Marks found in the Kirkcudbright Stewarty, Kirkcudbright Stewarty Museum, Dumfries and Galloway, Scotland, 22.10.18.

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Willow Sculpture Stag, Kirkcudbright Stewarty Museum, Kirkcudbright, Dumfries and...

Willow Sculpture Stag, Kirkcudbright Stewarty Museum, Kirkcudbright, Dumfries and Galloway, Scotland, 22.10.18.

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New study sets a size limit for undiscovered subatomic particles

A new study suggests that many theorized heavy particles, if they exist at all, do not have the properties needed to explain the predominance of matter over antimatter in the universe.

New study sets a size limit for undiscovered subatomic particles
In this artist’s representation, an electron travels between two lasers in an experiment. The electron is spinning
about its axis as a cloud of other subatomic particles are constantly emitted and reabsorbed. Some theories
 in particle physics predict particles, as yet undetected, that would cause the cloud to appear very slightly pear
 shaped when seen from a distance. With the support of the National Science Foundation, ACME researchers
created an experiment setup look at that shape with extreme precision. To the limits of their experiment,
they saw a perfectly round sphere, implying that certain types of new particles, if they exist at all,
have properties different from those theorists expected [Credit: Nicolle R. Fuller, NSF]

If confirmed, the findings would force significant revisions to several prominent theories posed as alternatives to the Standard Model of particle physics, which was developed in the early 1970s. Researchers from Yale, Harvard, and Northwestern University conducted the study, which was published in the journal Nature.

The discovery is a window into the mind-bending nature of particles, energy, and forces at infinitesimal scales, specifically in the quantum realm, where even a perfect vacuum is not truly empty. Whether that emptiness is located between stars or between molecules, numerous experiments have shown that any vacuum is filled with every type of subatomic particle — and their antimatter counterparts — constantly popping in and out of existence.

One approach to identifying them is to take a closer look at the shape of electrons, which are surrounded by subatomic particles. Researchers examine tiny distortions in the vacuum around electrons as a way to characterize the particles.

The new study reports work done with the Advanced Cold Molecule Electron Dipole Moment (ACME) experiment, a collaborative effort to detect the electric dipole moment (EDM) of the electron. An electron EDM corresponds to a small bulge on one end of the electron, and a dent on the opposite end.

The Standard Model predicts an extremely small electron EDM, but there are a number of cosmological questions — such as the preponderance of matter over antimatter in the aftermath of the Big Bang — that have pointed scientists in the direction of heavier particles, outside the parameters of the Standard Model, that would be associated with a much larger electron EDM. “The Standard Model makes predictions that differ radically from its alternatives and ACME can distinguish those,” said David DeMille, who leads the ACME group at Yale. “Our result tells the scientific community that we need to seriously rethink those alternative theories.”

Indeed, the Standard Model predicts that particles surrounding an electron will squash its charge ever so slightly, but this effect would only be noticeable at a resolution 1 billion times more precise than ACME observed. However, in models predicting new types of particles — such as supersymmetry and grand unified theories — a deformation in the shape at ACME’s level of precision was broadly expected.

“An electron always carries with it a cloud of fleeting particles, distortions in the vacuum around it,” said John Gillaspy, program director for atomic, molecular, and optical physics for the National Science Foundation (NSF), which has funded the ACME research for nearly a decade. “The distortions cannot be separated from the particle itself, and their interactions lead to the ultimate shape of the electron’s charge.”

ACME uses a unique process that involves firing a beam of cold thorium-oxide (ThO) molecules — a million of them per pulse, 50 times per second — into a chamber the size of a large desk.

Within that chamber, lasers orient the molecules and the electrons within, as they soar between two charged glass plates inside a carefully controlled magnetic field. ACME researchers watch for the light the molecules emit when targeted by a carefully tuned set of readout lasers. The light provides information to determine the shape of the electron’s charge.

By controlling some three dozen parameters, from the tuning of the lasers to the timing of experimental steps, ACME achieved a 10-fold detection improvement over the previous record holder: ACME’s 2014 experiment. The ACME researchers said they expect to reach another 10-fold improvement on precision in future versions of the experiment.

Author: Jim Shelton | Source: Yale University [October 17, 2018]



Astronomers find a cosmic Titan in the early universe

An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive structure yet found at such a remote time and distance.

Astronomers find a cosmic Titan in the early universe
An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years
 after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive structure
 yet found at such a remote time and distance. It has a mass estimated at a million billion Suns
[Credit: Luis Calcada & Olga Cucciati/ESO]

The team that made the discovery was led by Olga Cucciati of Istituto Nazionale di Astrofisica (INAF) Bologna, Italy and project scientist Brian Lemaux in the Department of Physics, College of Letters and Science at the University of California, Davis, and included Lori Lubin, professor of physics at UC Davis. They used the VIMOSinstrument on ESO’s Very Large Telescope in Paranal, Chile to identify a gigantic proto-supercluster of galaxies forming in the early Universe, just 2.3 billion years after the Big Bang.
Hyperion is the largest and most massive structure to be found so early in the formation of the Universe, with a calculated mass more than one million billion times that of the Sun. This enormous mass is similar to that of the largest structures observed in the Universe today, but finding such a massive object in the early Universe surprised astronomers.

“This is the first time that such a large structure has been identified at such a high redshift, just over 2 billion years after the Big Bang,” Cucciati said. “Normally these kinds of structures are known at lower redshifts, which means when the Universe has had much more time to evolve and construct such huge things. It was a surprise to see something this evolved when the Universe was relatively young.”

Supercluster mapped in three dimensions

Located in the constellation of Sextans (The Sextant), Hyperion was identified by a novel technique developed at UC Davis to analyze the vast amount of data obtained from the VIMOS Ultra-Deep Survey led by Olivier Le Fèvre from Laboratoire d’Astrophysique de Marseille, Centre National de la Recherche Scientifique and Centre National d’Etudes Spatiales. The VIMOS instrument can measure the distance to hundreds of galaxies at the same time, making it possible to map the position of galaxies within the forming supercluster in three dimensions.

The team found that Hyperion has a very complex structure, containing at least seven high-density regions connected by filaments of galaxies, and its size is comparable to superclusters closer to Earth, though it has a very different structure.

“Superclusters closer to Earth tend to a much more concentrated distribution of mass with clear structural features,” Lemaux said. “But in Hyperion, the mass is distributed much more uniformly in a series of connected blobs, populated by loose associations of galaxies.”

The researchers are comparing the Hyperion findings with results from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey, led by Lubin. The ORELSE survey uses telescopes at the W.M. Keck Observatory in Hawaii to study superclusters closer to Earth. Lubin and Lemaux are also using the Keck observatory to map out Hyperion and similar structures more completely.

The contrast between Hyperion and less distant superclusters is most likely due to the fact that nearby superclusters have had billions of years for gravity to gather matter together into denser regions — a process that has been acting for far less time in the much younger Hyperion.

Given its size so early in the history of the Universe, Hyperion is expected to evolve into something similar to the immense structures in the local Universe such as the superclusters making up the Sloan Great Wall or the Virgo Supercluster that contains our own galaxy, the Milky Way.

“Understanding Hyperion and how it compares to similar recent structures can give insights into how the Universe developed in the past and will evolve into the future, and allows us the opportunity to challenge some models of supercluster formation,” Cucciati said. “Unearthing this cosmic titan helps uncover the history of these large-scale structures.”

This research will be published in an upcoming issue of the journal Astronomy & Astrophysics.

Author: Andy Fell | Source: University of California – Davis [October 17, 2018]



Arctic ice sets speed limit for major ocean current

The Beaufort Gyre is an enormous, 600-mile-wide pool of swirling cold, fresh water in the Arctic Ocean, just north of Alaska and Canada. In the winter, this current is covered by a thick cap of ice. Each summer, as the ice melts away, the exposed gyre gathers up sea ice and river runoff, and draws it down to create a huge reservoir of frigid fresh water, equal to the volume of all the Great Lakes combined.

Arctic ice sets speed limit for major ocean current
A large pool of meltwater over sea ice in the Beaufort Sea 
[Credit: NASA/Operation IceBridge]

Scientists at MIT have now identified a key mechanism, which they call the “ice-ocean governor,” that controls how fast the Beaufort Gyre spins and how much fresh water it stores. In a paper published in Geophysical Research Letters, the researchers report that the Arctic’s ice cover essentially sets a speed limit on the gyre’s spin.

In the past two decades, as temperatures have risen globally, the Arctic’s summer ice has progressively shrunk in size. The team has observed that, with less ice available to control the Beaufort Gyre’s spin, the current has sped up in recent years, gathering up more sea ice and expanding in both volume and depth.

If global temperatures continue to climb, the researchers expect that the mechanism governing the gyre’s spin will diminish. With no governor to limit its speed, the researchers say the gyre will likely transition into “a new regime” and eventually spill over, like an overflowing bathtub, releasing huge volumes of cold, fresh water into the North Atlantic, which could affect the global climate and ocean circulation.

“This changing ice cover in the Arctic is changing the system which is driving the Beaufort Gyre, and changing its stability and intensity,” says Gianluca Meneghello, a research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “If all this fresh water is released, it will affect the circulation of the Atlantic.”

Meneghello is a co-author of the paper, along with John Marshall, the Cecil and Ida Green Professor of Oceanography, Jean-Michel Campin and Edward Doddridge of MIT, and Mary-Louise Timmermans of Yale University.

A “new Arctic ocean”

There have been a handful of times in the recorded past when the Beaufort Gyre has spilled over, beginning with the Great Salinity Anomaly in the late 1960s, when the gyre sent a surge of cold, fresh water southward. Fresh water has the potential to dampen the ocean’s overturning circulation, affecting surface temperatures and perhaps storminess and climate.

Similar events could transpire if the Arctic ice controlling the Beaufort Gyre’s spin continues to recede each year.

“If this ice-ocean governor goes away, then we will end up with basically a new Arctic ocean,” Marshall says.

“Nature has a natural governor”

The researchers began looking into the dynamics of the Beaufort Gyre several years ago. At that time, they used measurements taken by satellites between 2003 and 2014, to track the movement of the Arctic ice cover, along with the speed of the Arctic wind. They used these measurements of ice and wind speed to estimate how fast the Beaufort Gyre must be downwelling, or spinning down beneath the ice. But the number they came up with was much smaller than what they expected.

Arctic ice sets speed limit for major ocean current
The evolution of sea ice over the Beaufort Gyre: In springtime, as ice thaws and melts into the sea,
the gyre is exposed to the Arctic winds [Credit: Courtesy of the researchers]

“We thought there was a coding error,” Marshall recalls. “But it turns out there was something else kicking back.” In other words, there must be some other mechanism that was limiting, or slowing down, the gyre’s spin.

The team recalculated the gyre’s speed, this time by including estimates of ocean current activity in and around the gyre, which they inferred from satellite measurements of sea surface heights. The new estimate, Meneghello says, was “much more reasonable.”

In this new paper, the researchers studied the interplay of ice, wind, and ocean currents in more depth, using a high-resolution, idealized representation of ocean circulation based on the MIT General Circulation Model, built by Marshall’s group. They used this model to simulate the seasonal activity of the Beaufort Gyre as the Arctic ice expands and recedes each year.

They found that in the spring, as the Arctic ice melts away, the gyre is exposed to the wind, which acts to whip up the ocean current, causing it to spin faster and draw down more fresh water from the Arctic’s river runoff and melting ice. In the winter, as the Arctic ice sheet expands, the ice acts as a lid, shielding the gyre from the fast-moving winds. As a result, the gyre spins against the underside of the ice and eventually slows down.

“The ice moves much slower than wind, and when the gyre reaches the velocity of the ice, at this point, there is no friction — they’re rotating together, and there’s nothing applying a stress [to speed up the gyre],” Meneghello says. “This is the mechanism that governs the gyre’s speed.”

“In mechanical systems, the governor, or limiter, kicks in when things are going too fast,” Marshall adds. “We found nature has a natural governor in the Arctic.”

“In a warming world”

Marshall and Meneghello note that, as Arctic temperatures have risen in the last two decades, and summertime ice has shrunk with each year, the speed of the Beaufort Gyre has increased. Its currents have become more variable and unpredictable, and are only slightly slowed by the return of ice in the winter.

“At some point, if this trend continues, the gyre can’t swallow all this fresh water that it’s drawing down,” Marshall says. Eventually, the levee will likely break and the gyre will burst, releasing hundreds of billions of gallons of cold, fresh water into the North Atlantic.

An increasingly unstable Beaufort Gyre could also disrupt the Arctic’s halocline — the layer of ocean water underlying the gyre’s cold freshwater, that insulates it from much deeper, warmer, and saltier water. If the halocline is somehow weakened by a more instable gyre, this could encourage warmer waters to rise up, further melting the Arctic ice.

“This is part of what we’re seeing in a warming world,” Marshall says. “We know the global mean temperatures are going up, but the Arctic tempertures are going up even more. So the Arctic is very vulnerable to climate change. And we’re going to live through a period where the governor goes away, essentially.”

Author: Jennifer Chu | Source: Massachusetts Institute of Technology [October 17, 2018]



Arctic greening thaws permafrost, boosts runoff

A new collaborative study has investigated Arctic shrub-snow interactions to obtain a better understanding of the far north’s tundra and vast permafrost system. Incorporating extensive in situ observations, Los Alamos National Laboratory scientists tested their theories with a novel 3D computer model and confirmed that shrubs can lead to significant degradation of the permafrost layer that has remained frozen for tens of thousands of years. These interactions are driving increases in discharges of fresh water into rivers, lakes and oceans.

Arctic greening thaws permafrost, boosts runoff
NGEE-Arctic researchers from Los Alamos, University of Alaska Fairbanks and Oak Ridge National Laboratory dig deep
snow pits in tall shrub patches to understand the warming effect of snow-shrub interactions on underlying permafrost
 [Credit: Los Alamos National Laboratory]

“The Arctic is actively greening, and shrubs are flourishing across the tundra. As insulating snow accumulates atop tall shrubs, it boosts significant ground warming,” said Cathy Wilson, Los Alamos scientist on the project. “If the trend of increasing vegetation across the Arctic continues, we’re likely to see a strong increase in permafrost degradation.”

The team investigated interactions among shrubs, permafrost, and subsurface areas called taliks. Taliks are unfrozen ground near permafrost caused by a thermal or hydrological anomaly. Some tunnel-like taliks called “through taliks” extend over thick permafrost layers.

Results of the Los Alamos study published in Environmental Research Letters this week revealed that through taliks developed where snow was trapped, warmed the ground and created a pathway for water to flow through deep permafrost, significantly driving thawing and likely increasing water and dissolved carbon flow to rivers, lakes and the ocean. Computer simulations also demonstrated that the thawed active layer was abnormally deeper near these through taliks, and that increased shrub growth exacerbates these impacts. Notably, the team subtracted warming trends from the weather data used to drive simulations, thereby confirming that the shrub-snow interactions were causing degradation even in the absence of warming.

The Los Alamos team and collaborators from the Department of Energy (DOE) Office of Science’s Next-Generation Ecosystem Experiments Arctic program, which funds this project, used a new Los Alamos-developed fine-scale model, the Advanced Terrestrial Simulator (ATS). It incorporates soil physics and captures permafrost dynamics. The team repeatedly tested results against experimental data from Alaska’s Seward Peninsula.

“These simulations of through talik formation provide clues as to why we’re seeing an increase in winter discharge in the Arctic,” said Los Alamos postdoctoral research associate Elchin Jafarov, first author on the paper.

This model is the first to show how snow and vegetation interact to impact permafrost hydrology with through talik formation on a slope — prevalent across Alaskan terrain. The team, including collaborators from Oak Ridge National Laboratory and the University of Alaska, investigated how quickly through taliks developed at different permafrost depths, their impact on hydrology and how they interrupted and altered continuous permafrost.

Source: DOE/Los Alamos National Laboratory [October 17, 2018]



Evidence of earliest life on Earth disputed

When Australian scientists presented evidence in 2016 of life on Earth 3.7 billon years ago—pushing the record back 220 million years—it was a big deal, influencing even the search for life on Mars.

Evidence of earliest life on Earth disputed
This photograph shows putative stromatolitic structures in an outcrop (arrows). A new study says some structure
point down and some point up: Evidence that these are not relics of microbial mats growing
up from a sea floor but are formed through geological processes, the authors say
 [Credit: Abigail Allwood/California Institute of Technology/Nature]

But that discovery, based on an analysis of primordial rocks in Greenland, has now been challenged, with another team of researchers arguing that the structures presented as proof of microbial activity were, in fact, geologically forged by underground heat and pressure.

The truth hinges on whether the cone-shaped formations in question are genuine stromatolites, layered structures left in the wake of water-dwelling microorganisms.

Previously, the earliest confirmed stromatolites were found in 3.45-billion year old rocks in Australia.

Being able to accurately date the first stirrings of life on our young planet—roughly a billion years old at the time—has important implications for understanding how it emerged and evolved.

Writing in the journal Nature, Abigail Allwood of the California Institute of Technology and colleagues analysed the three-dimensional shape of the disputed formations, along with their orientation in space and chemical composition.

The 3-D view led them to conclude that the alleged fossils lacked internal layers, a signature trait of stromatolites. Upon closer examination, the cone-like shapes were shown to be ridges that typically arise over millions of years through a natural deforming process called metamorphism.

Also missing, they said, were the chemical traces of microbe activity.

“We believe that the current evidence does not support the interpretation of these structures as 3.7 billion-year-old stromatolites,” Allwood’s team concluded.

Their analysis, the study continued, should also serve as a “cautionary tale” in interpreting rock formations in the search for life on Mars.

Mark Van Zuilen, a geomicrobiologist at the Institut de Physique du Globe in Paris, said the reassessment is convincing, and suggests the Australian stromatolites should regain their status as the earliest confirmed proof of life on Earth.

“These observations provide strong evidence for physical rock deformation and therefore offer a non-biological explanation for the observed structures,” he commented in Nature.

Allen Nutman, a professor at the University of Wollongong in Australia and lead researcher on the 2016 study, was not available for comment.

Source: AFP [October 17, 2018]



Dry conditions in East Africa half a million years ago possibly shaped human evolution,...

Samples of ancient sediments from a lake basin in East Africa have revealed that arid conditions developed in the area around half a million years ago, an environmental change that could have played a major role in human evolution and influenced advances in stone technology, according to an international research team that includes geologists from Georgia State University.

Dry conditions in East Africa half a million years ago possibly shaped human evolution, study finds
Lake Magadi in Kenya [Credit: Georgia State University]

The team of geologists and anthropologists drilled deep cores in Lake Magadi in Kenya to obtain ancient sediment samples that date back a million years ago to the present. Georgia State researchers conducted mineral analysis on thousands of samples, and their collaborators performed other types of analyses.

Lake Magadi is one of five sites across the East African Rift that is being studied as part of the Hominin Sites and Paleolakes Drilling Project. Two additional sites are also being studied in collaboration with the Smithsonian Institution and Indiana University.

The findings, published in the Proceedings of the National Academy of Sciences, provide clues into how environmental and climate change may have played a role in human evolution and how early humans developed early stone technologies.

“The sediments that accumulated over the last million years show us that Lake Magadi used to be fresh water and gradually over the last million years has gotten more and more saline. That tells us that arid conditions developed in East Africa about half a million years ago,” said Dr. Daniel Deocampo, collaborating author of the study and professor of geosciences at Georgia State. “On top of that long-term increase in aridity in East Africa, there were also higher frequency environmental changes. There were shorter-term fluctuations where you might have some wet centuries and some dry centuries.

“The reason why this is important is that when you see these fluctuations really kicking in, that’s right about the time when the Middle Stone Age technologies were being developed by early human ancestors, about a half million years ago. These are really more meticulously made artifacts, not the crude, stone tools of a million years ago.”

While the researchers can’t directly link climate change to human evolution and advanced technology with evidence at this point, they’re using geological data to understand the details of how the environment changed.

“I think everyone in the community agrees that environmental change plays a role in evolution, including human evolution and the development of technology,” Deocampo said. “The problem that we’re trying to address is the details. In some ways, this is kind of the first step because by drilling these sediments we can better understand how the environment changed, and that’s the first step to understanding how that environmental change affected human evolution. Those are questions that will be addressed by evolutionary biologists and anthropologists. As geologists, we’re providing data on how the environment itself changed.”

Source: Georgia State University [October 17, 2018]



2018 October 22 Apollo 12 Visits Surveyor 3 Image Credit:…

2018 October 22

Apollo 12 Visits Surveyor 3
Image Credit: Apollo 12 Crew, NASA

Explanation: Apollo 12 was the second mission to land humans on the Moon. The landing site was picked to be near the location of Surveyor 3, a robot spacecraft that had landed on the Moon three years earlier. In the featured photograph, taken by lunar module pilot Alan Bean, mission commander Pete Conrad jiggles the Surveyor spacecraft to see how firmly it is situated. The lunar module is visible in the distance. Apollo 12 brought back many photographs and moon rocks. Among the milestones achieved by Apollo 12 was the deployment of the Apollo Lunar Surface Experiments Package, which carried out many experiments including one that measured the solar wind.

∞ Source: apod.nasa.gov/apod/ap181022.html

Zooming in on Mexico’s landscape

ESA – Sentinel 2 Mission logo.

22 October 2018

As part of a scientific collaboration with the Mexican Space Agency and other Mexican scientific public entities, ESA has combined images from the Copernicus Sentinel-2 mission to produce a detailed view of the different types of vegetation growing across the entire country.


The high-resolution land-cover map combines images captured by Copernicus Sentinel-2 between 2016 and 2018.

Sentinel-2 is a two-satellite constellation built for the EU’s Copernicus environmental monitoring programme. Each identical satellite carries a multispectral imager that can distinguish different types of vegetation and crops. It can also be used to determine numerous plant indices such as the amount of chlorophyll and water in leaves to monitor changes in plant health and growth.

Mapping Mexico’s land cover

The mission has a myriad of uses, one of which is to provide information to map land cover so that changes in the way land is being used can be monitored.

Thanks to this Copernicus mission and to ESA’s Climate Change Initiative Land Cover project, Mexico’s land cover has been mapped at a resolution of 10 m.

Land-cover mapping breaks down the different types of material on Earth’s surface, such as water bodies, different forms of agriculture, forests, grasslands and artificial surfaces.

This information is important for understanding changes in land use, modelling climate change, conserving biodiversity and managing natural resources.

This is a valuable source for scientific studies and practical applications alike.

Central America land cover

Daniela Jurado from Mexico’s National Commission for the Knowledge and Use of Biodiversity said, “Having access to such a detailed map is not only useful for scientific research such as understanding fluxes associated with the carbon cycle, but also for managing our natural resources and for conserving biodiversity.”

“It is also important for land-use management and for monitoring urban expansion.”

Alejandra Aurelia López Caloca, from the Center for Research in Geospatial Information Sciences added, “Indeed, this new map reveals a lot about our country. It is very helpful for studying the growth of cities and how rural areas are transitioned into urban environments. In addition, it is going to be a real help to understand where bodies of water are highly dependent on precipitation and to pinpoint those areas that are at risk of flooding.

“The new map allows us to identify the status land cover, specifically the agricultural kind so this will really help us understand how our land is being farmed.”

ESA has been coordinating global land cover maps since 2002 through its GlobCover and Climate Change Initiative Land Cover projects at a resolution of 300 m. But with the Copernicus Sentinel-2 pair now in orbit, land cover can be mapped at a resolution of 10 m.

In the same vein, a land-cover map of Central America is also now available.

Related links:

Sentinel-2: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-2

Copernicus: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus

ESA’s Climate Change Initiative: http://cci.esa.int/

Climate Change Initiative 10 m viewer:

Mexico land cover: http://2018mexicolandcover10m.esa.int/

Mexican Space Agency: https://www.gob.mx/aem

Commission for the Knowledge and Use of Biodiversity: https://www.gob.mx/conabio

Center for Research in Geospatial Information Sciences: https://www.centrogeo.org.mx/

National Council on Science and Technology: https://www.conacyt.gob.mx/

UC Louvain: https://uclouvain.be/en/index.html

Brockmann Consult: http://www.brockmann-consult.de/

ESA Earth observation science for society: https://eo4society.esa.int/

Images, Text, Credits: ESA/Contains modified Copernicus Sentinel data (2016–18) processed by ESA–CCI Land Cover Project/UC Louvain/Brockmann Consult/ATG medialab.

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South Stack Prehistoric Hut Circles and Enclosures Photoset 2, South Stack, Holy Island,...

South Stack Prehistoric Hut Circles and Enclosures Photoset 2, South Stack, Holy Island, Anglesey, 20.10.18.

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The Darkness that Followed Hurricane Michael

Earlier this month, the southeastern United States was struck by Hurricane Michael. After the category 4 storm made landfall on Oct. 10, 2018, Hurricane Michael proceeded to knock out power for at least 2.5 million customers across Florida, Georgia, North Carolina, and Virginia. 


In this data visualization, you can clearly see where the lights were taken out in Panama City, Florida. A team of our scientists from Goddard Space Flight Center processed and corrected the raw data to filter out stray light from the Moon, fires, airglow, and any other sources that are not electric lights. They also removed atmosphere interference from dust, haze, and clouds. 


In the visualization above, you can see a natural view of the night lights—and a step of the filtering process in an effort to clean up some of the cloud cover. The line through the middle is the path Hurricane Michael took. 


Although the damage was severe, tens of thousands of electric power industry workers from all over the country—and even Canada—worked together to restore power to the affected areas. Most of the power was restored by Oct. 15, but some people still need to wait a little longer for the power grids to be rebuilt. Read more here. 

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South Stack Prehistoric Hut Circles and Enclosures Photoset 1, South Stack, Holy Island,...

South Stack Prehistoric Hut Circles and Enclosures Photoset 1, South Stack, Holy Island, Anglesey, 20.10.18.

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HiPOD (21 October 2018): Eroded Bedrock    – Time. It just seems…

HiPOD (21 October 2018): Eroded Bedrock

   – Time. It just seems to overcome *everything.* (264 km above the surface. Black and white is less than 5 km across; enhanced color less than 1 km.)

NASA/JPL/University of Arizona

Measuring the Age of the Universe

An artist’s visualization of the merger of a binary neutron star. Gravitational waves from the mergers of binary neutron stars and binary black holes have recently been detected by the LIGO and Virgo facilities. These measurements can be used to calculate the age of the universe in a way that is independent of the two conventional methods previously used. Astronomers have calculated that in the next five years it is probable that fifty such events will be detected; their statistics will enable able an age determination with a precision of 2%, enough to also resolve the current incompatibility between the other two estimates. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet. Low Resolution (jpg)

Cambridge, MA – The single most important puzzle in today’s cosmology (the study of the universe as a whole) can be summarized in one question: How old is it? For nearly a century — since the discoveries by Einstein, Hubble, LeMaitre and others led to the big bang model of creation — we have known the answer. It is about 13.8 billion years old (using current data). But in just the past decade the two alternative measurement methods have narrowed the uncertainties in their results to a few percent to reach a stunning conclusion: The two do not agree with each other. Since both methods are based on exactly the same model and equations, our understanding of the universe is somehow wrong — perhaps fundamentally so.

Enter the most exciting technical achievement in astronomy for decades, the detection of gravitational waves (GW) caused by the mergers of black holes or neutron stars with each other by LIGO-Virgo, soon to be joined by other similar GW detection facilities in other countries. The solution to the cosmological dilemma is likely to be settled soon by these instruments according to a new Nature paper by Hsin-Yu Chen of Harvard’s Black Hole Initiative, Maya Fishbach and Daniel E. Holz of the University of Chicago. The authors describe how upcoming detections of GW will have enough statistics to settle the question of age, forcing either one or the other (or perhaps even both) methods to re-think their basic understanding, or possibly even forcing a new variation of the When and How of the creation.

The two currently conflicting methods rely on observations of vastly different parts of the cosmic order. The first method measures and models the cosmic microwave background radiation (the CMBR method) produced by the universe when, after about 380,000 years, it cooled down and allowed neutral hydrogen atoms to form and light to propagate without scattering. The second method, the one used by Hubble and interpreted by LeMaitre, measures galaxies. This method takes advantage of the expansion of the universe to correlate a galaxy’s distance with its recession velocity, the so-called Hubble-LeMaitre Law, and to derive the Hubble-LeMaitre parameter which describes how long these galaxies have been in motion, related to the age of the universe. All astronomers today rely on this expression to obtain the distances to galaxies too far away to measure directly but whose velocities are easily seen in the Doppler shifts (the redshift) of their spectral lines. While the most familiar use of the parameter is to obtain the age of the universe, its value influences all the other parameters in the cosmological model (about nine of them) which together also explain the shape and expansion character of the universe.

Hubble calibrated his set of distances with nearby galaxies, but today we are capable of seeing galaxies so remote their light has been traveling to us for over ten billion years. Supernovae (SN), or at least those whose brightness is thought to be well understood, can be seen at great distances and so have been used to bootstrap the distance scale calibration outward from Hubble’s original neighborhood. There are subtle complexities in SN that are not well understood, however, resulting in an uncertainty that has been getting smaller as our understanding of them has improved. Today those uncertainties are small enough to exclude the comparable result from CMBR measurements.

The GW method of distance measurement is completely independent of both galaxy and CMBR methods. General relativity alone provides the intrinsic strength of the GW signal from its peculiar ringing signal, and its observed strength provides a direct measure of its distance. (The velocity information is obtained from the redshift of atomic lines in the host galaxy). Dr. Chen and her colleagues simulated 90,000 merger events in binary black hole or binary neutron star systems, including the host galaxy properties, and included likely selection effects and other complexities. The GW strength, for example, depends on our viewing angle of inclination of the merger, while the number of events to expect is only roughly constrained by the detections so far. Including these and similar uncertainties, the astronomers conclude that within the next five years it is likely that the GW method will fix the Hubble-LeMaitre parameter (that is, the age of the universe) to a precision of 2%, and to 1% in a decade, good enough to exclude one or even both of the other methods. The new paper’s conclusions are bolstered by the fact that one paper using the GW method to estimate an age has already appeared. It had an uncertainty of between 11.9 billion years to 15.7 billion years, spanning both the current CMBR and galaxy values. But the new paper shows that in five years another roughly fifty GW events will be detected and these should be enough to settle the matter … and usher in a new era in precision cosmology.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

Tyler Jump
Public Affairs
Harvard-Smithsonian Center for Astrophysics
+1 617-495-7462

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Bodowyr Burial Chamber, Anglesey, North Wales, 20.10.18.

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