On Icy Enceladus, Expansion Cracks Let Inner Ocean Boil Out

Saturn's tiny, frozen moon Enceladus is slashed by four straight, parallel fissures or "tiger stripes" from which water erupts. These features are unlike anything else in the solar system. Researchers now have an explanation for them.
NASA/JPL/Space Science Institute image

In 2006, the Cassini spacecraft recorded geyser curtains shooting forth from “tiger stripe” fissures near the south pole of Saturn’s moon Enceladus — sometimes as much as 200 kilograms of water per second. A new study suggests how expanding ice during millennia-long cooling cycles could sometimes crack the moon’s icy shell and let its inner ocean out, providing a possible explanation for the geysers.

Enceladus has a diameter of about 504 kilometers (313 miles) — roughly the length of the United Kingdom at its longest point. The moon is covered in ice 20-30 kilometers (12.4-18.6 miles) thick, and the surface temperature is about -201 Celsius (-330 Fahrenheit), but a decade of data from NASA’s Cassini–Huygens mission supplied evidence for a deep liquid ocean inside the icy shell, escaping into space through continuous “cryo-volcanism”. How such a small, cold world can sustain so much geological activity has been an enduring scientific puzzle.

“It captivated both the scientists’ and the general public’s attention,” said Max Rudolph, an assistant professor in geophysics at the University of California, Davis, and lead author of the new study, published in Geophysical Research Letters.

New study of Yellowstone National Park shines new light on once hidden details of the famous American landmark

The SkyTEM instrument being flown over Old Faithful in Yellowstone National Park.
Photo by Jeff Hungerford, Yellowstone National Park; supplied by Carol Finn of U.S. Geological Survey.

The geysers and fumaroles of Yellowstone National Park are among the most iconic and popular geological features on our planet. Each year, millions of visitors travel to the park to marvel at the towering eruptions of Old Faithful, the bubbling mud cauldrons of Artists Paint Pots, the crystal-clear water and iridescent colors of Grand Prismatic Spring, and the stacked travertine terraces of Mammoth Hot Springs.

Those who have visited the park may have asked themselves, “Where does all the hot water come from?” A study published this week in Nature, co-authored by Virginia Tech’s W. Steven Holbrook and colleagues from the U.S. Geological Survey and Aarhus University in Denmark, provides stunning subsurface images that begin to answer that question.

The research team used geophysical data collected from a helicopter to create images of Yellowstone’s subsurface “plumbing” system. The method detects features with unusual electrical and magnetic properties indicative of hydrothermal alteration.

Quan­tum sen­sors: Mea­suring even more preci­sely

Time could be determined even more precisely with sophisticated computational methods on entangled atoms. Physicists from Innsbruck, Austria, have developed such a technique.
Credit: Uni Innsbruck/Harald Ritsch

Two teams of physicists led by Peter Zoller and Thomas Monz have designed the first programmable quantum sensor, and tested it in the laboratory. To do so they applied techniques from quantum information processing to a measurement problem. The innovative method promises quantum sensors whose precision reaches close to the limit set by the laws of nature.

Atomic clocks are the best sensors mankind has ever built. Today, they can be found in national standards institutes or satellites of navigation systems. Scientists all over the world are working to further optimize the precision of these clocks. Now, a research group led by Peter Zoller, a theorist from Innsbruck, Austria, has developed a new concept that can be used to operate sensors with even greater precision irrespective of which technical platform is used to make the sensor. “We answer the question of how precise a sensor can be with existing control capabilities, and give a recipe for how this can be achieved,” explain Denis Vasilyev and Raphael Kaubrügger from Peter Zoller's group at the Institute of Quantum Optics and Quantum Information at the Austrian Academy of Sciences in Innsbruck.

Dense Bones Allowed Spinosaurus to Hunt Underwater

Dense bones in the skeleton of Spinosaurus strongly suggest it spent a substantial amount of time submerged in the water.
Artwork credit: Davide Bonadonna

Spinosaurus is the largest predatory dinosaur known – over two meters longer than the longest Tyrannosaurus rex – but the way it hunted has been a subject of debate for decades.

In a new paper, published today in Nature, a group of paleontologists have taken a different approach to decipher the lifestyle of long-extinct creatures: examining the density of their bones.

By analyzing the density of Spinosaurid bones and comparing them to other animals like penguins, hippos, and alligators, the team found that Spinosaurus and its close relative Baryonyx from the Cretaceous of the UK both had dense bones that would have allowed them to submerge themselves underwater to hunt.

Scientists already knew that Spinosaurids had certain affinities with water – their elongate jaws and cone-shaped teeth are similar to those of fish-eating predators, and the ribcage of Baryonyx, from Surrey, even contained half-digested fish scales.

Undersea sediment reveals clues about seismic activity

The Chikyu is capable of drilling deeper below the seafloor than any other science drilling vessel to date.
Credit: Sean Toczko (JAMSTEC staff scientist) ECORD/IODP/JAMSTEC.

Earthquakes are famously impossible to predict, and have been the cause of some of the most devastating events in human history. But could we learn more about these natural disasters by tracking them backwards through time?

One research mission, dubbed Expedition 386, wants to use sediment records in the Pacific Ocean off the coast of Japan to track and record thousands of years of past seismic activity.

Although the offshore portion of the expedition ended last summer, the scientific portion of the mission, a month-long investigation into the recovered samples, recently ended on March 15.

Roughly 30 international scientists are involved with the project, including Derek Sawyer, an associate professor of earth sciences at The Ohio State University.

A Laser-Powered Upgrade to Cancer Treatment

Kei Nakamura, Antoine Snijders and Lieselotte Obst-Huebl (from left) at the BELLA laser facility aligning cartridges containing human cells in the proton beam path. This setup enabled measurements of the biological effects of laser-driven protons.
Credit: Lawrence Berkeley National Laboratory

Biologists and physicists at Lawrence Berkeley National Laboratory (Berkeley Lab) have teamed up to create new opportunities for cancer treatment using laser-generated proton beams.

The ongoing project seeks to adapt the nascent technology of laser-driven ion accelerators – which are as cool as they sound – to make a more effective type of radiation therapy more readily available to patients.

“Proton therapy centers are large, expensive facilities, so they are limited around the world,” said co-lead author Antoine Snijders, a cancer researcher and senior scientist in the Biological Sciences and Engineering (BSE) Division. “There is currently limited geographic distribution and access to proton therapy worldwide.  The way to get broader access, and potentially lower costs, is to reduce the cost and footprint of these types of facilities. And that means we need more compact sources of ions for proton accelerators.”

Scientists are also investigating the potential benefit of using these accelerators to deliver proton beam radiation therapy at ultrahigh doses within extremely short exposure times – a technology called FLASH radiotherapy. Though the approach remains experimental for now, FLASH radiotherapy could change the landscape of radiation oncology. “If our work could also bring FLASH radiotherapy to patients, it could be the best of both worlds,” Snijders added.

Artificial Intelligence Tool May Help Predict Heart Attacks

Damini Dey, PhD

Investigators from Cedars-Sinai have created an artificial intelligence-enabled tool that may make it easier to predict if a person will have a heart attack.

The tool described in The Lancet Digital Health accurately predicted which patients would experience a heart attack in five years based on the amount and composition of plaque in arteries that supply blood to the heart.

Plaque buildup can cause arteries to narrow, which makes it difficult for blood to get to the heart, increasing the likelihood of a heart attack. A medical test called a coronary computed tomography angiography (CTA) takes 3D images of the heart and arteries and can give doctors an estimate of how much a patient’s arteries have narrowed. Until now, however, there has not been a simple, automated and rapid way to measure the plaque visible in the CTA images.

“Coronary plaque is often not measured because there is not a fully automated way to do it,” said Damini Dey, PhD, director of the quantitative image analysis lab in the Biomedical Imaging Research Institute at Cedars-Sinai and senior author of the study. “When it is measured, it takes an expert at least 25 to 30 minutes, but now we can use this program to quantify plaque from CTA images in five to six seconds.”

Dey and colleagues analyzed CTA images from 1,196 people who underwent a coronary CTA at 11 sites in Australia, Germany, Japan, Scotland and the United States. The investigators trained the AI algorithm to measure plaque by having it learn from coronary CTA images, from 921 people, that already had been analyzed by trained doctors.

Preserving the past

Christina Chavez is Sandia National Laboratories’ first full-time archaeologist. She established the Labs’ cultural resources program within the Environment, Safety and Health group.
Photo by Bret Latter

When archaeologist Christina Chavez surveys Sandia National Laboratories land and finds rusted tobacco tins, ceramic fragments, glass shards or rocks resting in deliberate formations, she documents and determines who at the Labs needs to know.

“Archaeological resources are all around us, and even if most people don’t see them, there’s still a potential that they’re there,” Chavez said.

Chavez, the Labs’ first full-time archaeologist, works with teams throughout Sandia to ensure the U.S. Department of Energy remains in compliance with Section 106 of the National Historic Preservation Act. Established in 1966, the act requires federal agencies to consider the effects on historic properties when carrying out or funding projects. For Sandia, projects can mean anything from construction to an experiment or explosion taking place in remote areas.

Scientists discover when beetles became prolific

 Credit: Vladimka production

Researchers at the University of Bristol have found that beetles first roamed the world in the Carboniferous and later diversified alongside the earliest dinosaurs during the Triassic and Jurassic.

Using a previously published and carefully curated 68-gene dataset, the scientists ran a battery of mathematical models to reconstruct the evolution of protein sequences - the results of which have been published today in Royal Society Open Science.

After a year and a half of running on a supercomputer at the University of Bristol’s Advanced Computing Research Centre, the scientists were able to build a robust evolutionary tree of beetles which also included data on 57 beetle fossils to contain the timescale of beetle evolution. Their findings provide one of the most comprehensive evolutionary trees of beetles.

Different beetle clades diversified independently, as various new ecological opportunities opened up. “There was not a single epoch of beetle radiation, their secret seems to lie in their remarkable flexibility,” explained author Professor Chenyang Cai of Bristol’s School of Earth Sciences. “The refined timescale of beetle evolution will be an invaluable tool for investigating the evolutionary basis of the beetle’s success story.”

Nearby star could help explain why our sun didn’t have sunspots for 70 years

This image depicts a typical 11-year cycle on the sun, with the fewest sunspots appearing at its minimum (top left and top right) and the most appearing at its maximum (center).
Credit: NASA

The number of sunspots on our sun typically ebbs and flows in a predictable 11-year cycle, but one unusual 70-year period when sunspots were incredibly rare has mystified scientists for 300 years. Now a nearby sun-like star seems to have paused its own cycles and entered a similar period of rare starspots, according to a team of researchers at Penn State. Continuing to observe this star could help explain what happened to our own sun during this “Maunder Minimum” as well as lend insight into the sun's stellar magnetic activity, which can interfere with satellites and global communications and possibly even affect climate on Earth.

  The star — and a catalog of 5 decades of starspot activity of 58 other sun-like stars — is described in a new paper that appears online in the Astronomical Journal.

  Starspots appear as a dark spot on a star’s surface due to temporary lower temperatures in the area resulting from the star’s dynamo — the process that creates its magnetic field. Astronomers have been documenting changes in starspot frequency on our sun since they were first observed by Galileo and other astronomers in the 1600s, so there is a good record of its 11-year cycle. The exception is the Maunder Minimum, which lasted from the mid-1600s to early 1700s and has perplexed astronomers ever since.