Science Funda, Bandra to Virar (2026)

12/07/2021

Why planting tons of trees isn’t enough to solve climate change

Massive projects need much more planning and follow-through to succeed – and other tree protections need to happen too
By Carolyn Gramling

JULY 9, 2021 AT 6:00 AM

Trees are symbols of hope, life and transformation. They’re also increasingly touted as a straightforward, relatively inexpensive, ready-for-prime-time solution to climate change.

When it comes to removing human-caused emissions of the greenhouse gas carbon dioxide from Earth’s atmosphere, trees are a big help. Through photosynthesis, trees pull the gas out of the air to help grow their leaves, branches and roots. Forest soils can also sequester vast reservoirs of carbon.

Earth holds, by one estimate, as many as 3 trillion trees. Enthusiasm is growing among governments, businesses and individuals for ambitious projects to plant billions, even a trillion more. Such massive tree-planting projects, advocates say, could do two important things: help offset current emissions and also draw out CO2 emissions that have lingered in the atmosphere for decades or longer.

Even in the politically divided United States, large-scale tree-planting projects have broad bipartisan support, according to a spring 2020 poll by the Pew Research Center. And over the last decade, a diverse garden of tree-centric proposals — from planting new seedlings to promoting natural regrowth of degraded forests to blending trees with crops and pasturelands — has sprouted across the international political landscape.
Trees “are having a bit of a moment right now,” says Joe Fargione, an ecologist with The Nature Conservancy who is based in Minneapolis. It helps that everybody likes trees. “There’s no anti-tree lobby. [Trees] have lots of benefits for people. Not only do they store carbon, they help provide clean air, prevent soil erosion, shade and shelter homes to reduce energy costs and give people a sense of well-being.”

Conservationists are understandably eager to harness this enthusiasm to combat climate change. “We’re tapping into the zeitgeist,” says Justin Adams, executive director of the Tropical Forest Alliance at the World Economic Forum, an international nongovernmental organization based in Geneva. In January 2020, the World Economic Forum launched the One Trillion Trees Initiative, a global movement to grow, restore and conserve trees around the planet. One trillion is also the target for other organizations that coordinate global forestation projects, such as Plant-for-the-Planet’s Trillion Tree Campaign and Trillion Trees, a partnership of the World Wildlife Fund, the Wildlife Conservation Society and other conservation groups.

The root of the problem
The pace of climate change is accelerating into the realm of emergency, scientists say. Over the last 200 years, human-caused emissions of greenhouse gases, including CO2 and methane, have raised the average temperature of the planet by about 1 degree Celsius (SN: 12/22/18 & 1/5/19, p. 18).

The litany of impacts of this heating is familiar by now. Earth’s poles are rapidly shedding ice, which raises sea levels; the oceans are heating up, threatening fish and food security. Tropical storms are becoming rainier and lingering longer, and out of control wildfires are blazing from the Arctic to Australia (SN: 12/19/20 & 1/2/21, p. 32).

The world’s oceans and land-based ecosystems, such as forests, absorb about half of the carbon emissions from fossil fuel burning and other industrial activities. The rest goes into the atmosphere. So “the majority of the solution to climate change will need to come from reducing our emissions,” Fargione says. To meet climate targets set by the 2015 Paris Agreement, much deeper and more painful cuts in emissions than nations have pledged so far will be needed in the next 10 years.

19/06/2021

Scientists have found the origins of a mysterious, deadly flood in India
On February 7, a massive flood rushed through a valley in India’s Himalayan Uttarakhand state, washing out two hydroelectric power plants and leaving at least 200 people dead or missing. What triggered the deadly flood has been a mystery — but after amassing evidence from satellite images, seismic records and eyewitness accounts, a team of over 50 scientists now say they have solved the case.

The ultimate culprit was a massive avalanche of rock and glacier ice that tumbled 1,800 meters down a steep slope of Ronti Peak, setting off a cascade of events that led to the disaster, the researchers report online June 10 in Science.

This was no ordinary landslide, says Daniel Shugar, a geomorphologist at the University of Calgary in Canada. “This was a multi-hazard scenario where it was much more fluid and mobile than a landslide would be expected to be. It was a worst-case scenario of rock and ice and [the] height of the fall.”Initially, the culprit was suspected to be a well-known high mountain hazard called a glacial lake outburst flood, in which dammed-up water suddenly spills over its bounds and rushes down the mountainside (SN: 2/9/21). But what little data were available in the immediate aftermath pointed to a possible landslide instead, Shugar says.

In the months that followed, he and his colleagues used numerous sources of data as well as computer simulations to painstakingly reconstruct what happened that day.

Here’s what the data show:

Starting around 10:21 a.m. local time on February 7, about 27 million cubic meters of rock and ice fell from the steep north face of Ronti Peak, which stands 6,063 meters above sea level. The landslide, consisting of about 80 percent rock and 20 percent ice, originated at a height of about 5,500 meters and tumbled downslope about 1,800 meters, traveling at a speed of up to 60 meters per second.
Digital elevation models now reveal a rock scar on the slope that wasn’t there previously. Earlier images of the site suggest that a very long and wide fracture in the overhanging glacier had opened up by 2018.

As the landslide then rushed down the Ronti Gad stream valley, wet material splashed up the valley’s sides, depositing sediment and large boulders on the valley walls. Satellite images also captured thick blankets of airborne dust — the first indicators that a landslide might be the culprit.

As the landslide continued downhill, the ice began to melt due to the friction, helping to speed it along. Then, the landslide encountered a sharp bend in the valley, and much of the solid material dropped out, shifting it from a thick, viscous flow to a faster-moving, more fluid flow. These rushing waters were now on their way to the two hydroelectric power plants in their path downstream. Eyewitness accounts saw only this part of the flood.

https://twitter.com/WaterSHEDLab/status/1358442899713662977?s=19

18/06/2021

Physicists used LIGO’s mirrors to approach a quantum limit

Quantum mechanics usually applies to very small objects: atoms, electrons and the like. But physicists have now brought the equivalent of a 10-kilogram object to the edge of the quantum realm.

Scientists with the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, reduced vibrations in a combination of the facility’s mirrors to nearly the lowest level allowed by quantum mechanics, they report in the June 18 Science.

The researchers quelled differences between the jiggling of LIGO’s four 40-kilogram mirrors, putting them in near-perfect sync. When the mirrors are combined in this way, they behave effectively like a single, 10-kilogram object.

LIGO is designed to measure gravitational waves, using laser light that bounces between sets of mirrors in the detector’s two long arms (SN: 2/11/16). But physicist Vivishek Sudhir of MIT and colleagues instead used the laser light to monitor the mirrors’ movements to extreme precision and apply electric fields to resist the motion. “It’s almost like a noise-canceling headphone,” says Sudhir. But instead of measuring nearby sounds and canceling out that noise, the technique cancels out motion.

The researchers reduced the mirrors’ relative motions to about 10.8 phonons, or quantum units of vibration, close to the zero-phonon quantum limit.

The study’s purpose is not to better understand gravitational waves, but to get closer to revealing secrets of quantum mechanics. Scientists are still trying to understand why large objects don’t typically follow the laws of quantum mechanics. Such objects lose their quantum properties, or decohere. Studying quantum states of more massive objects could help scientists pin down how decoherence happens.

Previous studies have observed much smaller objects in quantum states. In 2020, physicist Markus Aspelmeyer of the University of Vienna and colleagues brought vibrations of a nanoparticle to the quantum limit (SN: 1/30/20). LIGO’s mirrors are “a fantastic system to study decoherence effects on super-massive objects in the quantum regime,” says Aspelmeyer.

18/06/2021

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06/06/2021

NASA will be heading back to Venus for the first time in decades

By Lisa Grossman

JUNE 2, 2021 AT 5:23 PM

UPDATED JUNE 3, 2021 AT 9:15 AM

Earth’s evil twin, here we come. NASA’s next two missions, named DAVINCI+ and VERITAS, are heading to Venus, administrator Bill Nelson announced at a news conference June 2.

“These two sister missions both aim to understand how Venus became an inferno-like world capable of melting lead at the surface,” Nelson said. “We hope these missions will further our understanding of how Earth evolved and why it’s currently habitable, when others in our solar system are not.”

The missions were selected from four finalists, two headed to Venus, one to Jupiter’s volcanic moon Io, and one to Neptune’s largest moon Triton. The two Venus missions had applied and been rejected in earlier spacecraft selection rounds.

Venus is almost the same size as Earth, but it seems to have had a different history. Although there’s evidence that it was once covered in oceans and could have been habitable, today it’s a scorched hellscape with clouds of sulfuric acid. No spacecraft has lasted more than two hours on its surface (SN: 2/13/18). And no NASA mission has visited in more than 30 years.
One of the newly selected missions, DAVINCI+, will be the first in decades to send a probe into the planet’s thick, hot atmosphere. The spacecraft will be a ball about a meter in diameter that will sink through Venus’ atmosphere over the course of about an hour, taking measurements of how the content of the planet’s atmosphere changes from top to bottom. The probe will also take some of the highest-resolution photos of the Venusian surface yet on its way down.

Those observations will help scientists figure out how Venus’ water has changed over time, its volcanic activity now and in the past, and the planet’s past potential for habitability (SN: 8/26/16).

“DAVINCI+ is going to give us measurements of the atmosphere that we absolutely, critically need, simply to put some basic bounds on one of the two scenarios for Venus: That it was always the way it is today, or that it was habitable and got ruined,” says planetary scientist Paul Byrne of North Carolina State University in Raleigh. Byrne is not involved in either mission but is on NASA’s Venus exploration committee. The data will also help scientists interpret observations of Earth-sized exoplanets with atmospheres that could be taken with the upcoming James Webb Space Telescope, giving researchers a way to tell exo-Earths from exo-Venuses (SN: 10/4/19).

The other mission, VERITAS, will orbit Venus and study the planet’s surface to figure out its history and why it’s so different from Earth. The orbiter will map the surface with radar, chart elevations to make 3-D maps and look for plate tectonics and volcanism still ongoing on Venus. These observations could provide data for a future mission to land on Venus (SN: 12/23/20).

“We will become acquainted with a brand new Venus with VERITAS,” Byrne says.

The missions are expected to launch sometime between 2028 and 2030, NASA said in a statement.

The European Space Agency is considering another Venus orbiter called EnVision that would provide complementary data to VERITAS and DAVINCI+, if it’s selected. That decision could come as early as next week, Byrne says.

“Having those three missions at Venus would be astonishing,” Byrne says. “It would mean we were finally taking it as seriously as we should have all along.”

31/05/2021

Laser experiments suggest helium rain falls on Jupiter

Sprinkles of helium rain may fall on Jupiter.

At pressures and temperatures present within the gas giant, the hydrogen and helium that make up the bulk of its atmosphere don’t mix, according to laboratory experiments reported in the May 27 Nature. That suggests that deep within Jupiter’s atmosphere, hydrogen and helium separate, with the helium forming droplets that are denser than the hydrogen, causing them to rain down (SN: 4/19/21).

Jupiter’s marbled exterior is pretty familiar territory, but it’s still not clear what happens far below the cloud tops. So researchers designed an experiment to compress hydrogen and helium, reaching pressures nearly 2 million times Earth’s atmospheric pressure and temperatures of thousands of degrees Celsius, akin to inner layers of gas giants.

“We are reproducing the conditions inside the planets,” says physicist Marius Millot of Lawrence Livermore National Laboratory in California.

Millot and colleagues squeezed a mixture of hydrogen and helium between two diamonds and hit the concoction with a powerful laser to compress it even further. As the pressure and temperature increased, the researchers saw an abrupt increase in how reflective the material was. That suggests that helium was separating from the hydrogen, which becomes a liquid metal under these conditions (SN: 8/10/16). At even higher pressures and temperatures, the reflectivity decreased, suggesting that hydrogen and helium began mixing again.

The researchers calculated that hydrogen and helium would separate about 11,000 kilometers below the cloud tops of Jupiter, down to a depth of about 22,000 kilometers.

The results could help scientists explain observations made by spacecraft Galileo (SN: 2/18/02) and Juno (SN: 3/7/18), such as the fact that Jupiter’s outer layers of atmosphere have less helium than expected

30/05/2021

🪐💥🪐

24/05/2021

⚡Record-breaking light has more than a quadrillion electron volts of energy⚡
By Emily Conover

MAY 21, 2021 AT 6:00 AM

The cosmos keeps outdoing itself.

Extremely energetic light from space is an unexplained wonder of astrophysics, and now scientists have spotted this light, called gamma rays, at higher energies than ever before.

The Large High Altitude Air Shower Observatory, LHAASO, spotted more than 530 gamma rays with energies above 0.1 quadrillion electron volts, researchers report online May 17 in Nature. The highest-energy gamma ray detected was about 1.4 quadrillion electron volts. For comparison, protons in the largest accelerator on Earth, the Large Hadron Collider, reach mere trillions of electron volts. Previously, the most energetic gamma ray known had just under a quadrillion electron volts (SN: 2/2/21).

In all, the scientists spotted 12 gamma ray hot spots, hinting that the Milky Way harbors powerful cosmic particle accelerators. In order for gamma rays to reach such energies, electromagnetic fields must first rev up charged particles, namely protons or electrons, to immense speeds. Those particles can then produce energetic gamma rays, for example, when protons interact with other matter in space.

Scientists aren’t yet sure what environments are powerful enough to produce light with energies reaching more than a quadrillion electron volts. But the new observations point to two possibilities. One hot spot was associated with the Crab Nebula, the turbulent remains of an exploded star (SN: 6/24/19). Another potential source was the Cygnus Cocoon, a region where massive stars are forming, blasting out intense winds in the process.

LHAASO, located on Haizi Mountain in China’s Sichuan province, is not yet fully operational. When it is completed later this year, it is expected to find even more energetic gamma rays.

21/05/2021

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20/05/2021

Watch this beautiful, high-resolution simulation of how stars are born

https://youtu.be/M0Rj3hkkPf0

The most realistic computer simulation of star formation yet offers stunning views of what the inside of a stellar nursery might look like.

In the Star Formation in Gaseous Environments simulation, or STARFORGE, a giant virtual cloud of gas collapses into a nest of new stars. Unlike other simulations, which could render only a small clump of gas within a larger cloud, STARFORGE simulates an entire star-forming cloud. It’s also the first simulation to account for the whole medley of physical phenomena thought to influence star formation, researchers report online May 17 in Monthly Notices of the Royal Astronomical Society.

“We sort of know the basic story of star formation … but the devil is in the details,” says Mike Grudić, a theoretical astrophysicist at Northwestern University in Evanston, Ill. (SN: 4/21/20). Astronomers still don’t fully understand, for instance, why stars have different masses. “If you really want to get the full picture, then you really have to just simulate the whole thing.”
STARFORGE starts with a blob of gas that can be tens to hundreds of light-years across and up to millions of times the mass of the sun. Turbulence inside the cloud creates dense pockets that collapse to forge new stars. Those stars then launch powerful jets, give off radiation, shed stellar winds and explode in supernovas. Eventually, these phenomena blow the last vestiges of the cloud away and leave behind a hive of young stars. The whole process takes millions of years — or months of computing time, even running on supercomputers.

Using STARFORGE, Grudić and colleagues have confirmed that jets launched by new stars help regulate how much material a star amasses. In simulations without jets, typical stars were about 10 times the mass of the sun — way bigger than the actual average star. “As soon as you add this jet feedback to your simulation,” Grudić says, “stellar masses start coming out more or less right on the dot for what they’re observed to be.”

18/05/2021

🪐Saturn has a fuzzy core, spread over more than half the planet’s diameter🪐
One of Saturn’s rings has revealed properties of its core, hidden deep beneath the planet’s golden atmosphere.

That core isn’t the lump of rock and ice that many scientists had envisioned, the new study finds. Instead, the core is diffuse, pervaded by huge amounts of hydrogen and helium and so spread out that it spans 70,000 kilometers, or about 60 percent of the planet’s diameter, researchers report April 28 at arXiv.org.

The new intel should help planetary scientists better understand not only how giant planets formed in our solar system but also the nature of such worlds orbiting other stars.

To ascertain the structure of Saturn’s core, astronomer Christopher Mankovich and astrophysicist Jim Fuller, both at Caltech, examined the giant planet’s rings. Just as earthquakes help seismologists probe Earth’s interior, oscillations inside Saturn can reveal its internal composition. These oscillations alter Saturn’s gravitational forces, inducing waves in the rings —especially the C ring, which is the nearest of the three main rings to the planet (SN: 1/22/19).
By analyzing a wave in that ring, along with data on Saturn’s gravity field from the now-defunct Cassini spacecraft (SN: 9/15/17), Mankovich and Fuller found that the core has about 17 Earth masses of rock and ice. But there’s so much hydrogen and helium mixed in, the core encompasses 55 Earth masses altogether — more than half of Saturn’s total, which is equivalent to the mass of 95 Earths. This “ring seismology” work will appear in a future Nature Astronomy.

“It’s a new way to look at gas giant planets in the solar system,” says Ravit Helled, a planetary scientist at the University of Zurich who was not involved with the work. “This knowledge is important because it reflects on our understanding of giant exoplanets,” and indicates that giant planets in other solar systems probably have more complex structures than many researchers had thought.

The discovery also illuminates how Saturn formed, says Nadine Nettelmann, a planetary scientist at the German Aerospace Center in Berlin.

Older theories posited that a gas giant such as Saturn arises when rock and ice orbiting the sun start to conglomerate. Tenuous gaseous envelopes let additional solid materials sink to the center, forming a compact core. Only later, according to this theory, does the core attract lots of hydrogen and helium — the ingredients that make up most of the planet. Although these elements are gases on Earth, Saturn’s great gravity squeezes most of them into a fluid.

But newer theories say instead that plenty of gas got incorporated into the core of rock and ice when it was taking shape 4.6 billion years ago. As the planet accreted additional mass, the proportion of gas rose. The structure Mankovich and Fuller deduce for Saturn’s core preserves this formation history, Nettelmann says, because the planet’s very center, representing the oldest part of Saturn, has the greatest proportion of rock and ice. The fraction of rock and ice decreases gradually rather than abruptly from the core’s center to its edge, reflecting the core’s development over time.

“I find the conclusions very important and very exciting and the line of reasoning very convincing,” Nettelmann says. Still, she cautions that additional waves in the rings should be analyzed for confirmation.

The type of oscillation that Mankovich and Fuller detect inside Saturn also implies that the core is stable rather than bubbling like a pot of water on a hot stove, which is one way a planet can carry heat from its hot interior outward. The core’s stability may help explain a long-standing puzzle: why Saturn emits more energy than it gets from the sun.

After the planet formed, it was warm with the heat of its birth, but then it cooled off. The core’s stability could have put a lid on some of this cooling, however, which helped the planet retain heat that it still radiates to this day. In contrast, if the core had instead transported heat via the upwelling and downwelling of material, the planet would have cooled off faster and no longer give off so much heat.

17/05/2021

🧠🗣️Brain implants turn imagined handwriting into text on a screen🧠🗣️

Electrodes in a paralyzed man’s brain turned his imagined handwriting into words typed on a screen. The translation from brain to text may ultimately point to ways to help people with disabilities like paralysis communicate using just their thoughts.

A 65-year-old man had two grids of tiny electrodes implanted on the surface of his brain. The electrodes read electrical activity in the part of the brain that controls hand and finger movements. Although the man was paralyzed from the neck down, he imagined writing letters softly with his hand. With an algorithm, researchers then figured out the neural patterns that went with each imagined letter and transformed those patterns into text on a screen.

From his brain activity alone, the participant produced 90 characters, or 15 words, per minute, Krishna Shenoy, a Howard Hughes Medical Institute investigator at Stanford University, and colleagues report May 12 in Nature. That’s about as fast as the average typing rate of people around the participant’s age on smartphones.

The thought-to-text system worked even long after the injury. “The big surprise is that even years and years after spinal cord injury, where you haven’t been able to use your hands or fingers, we can still listen in on that electrical activity. It’s still very active,” Shenoy says.

Thought-powered communication is still in its early stages (SN: 4/24/19). Research with more volunteers is needed, but “there’s little doubt that this will work again in other people,” says Shenoy. The researchers plan to test the system with a person who has lost both the ability to move and speak.

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