Category: 7. Science

(Web Desk) – Scientists have discovered that the shark’s tooth-like skin scales house guanine platelets and melanin vesicles that work together to produce a vivid blue hue.

What’s more, these nanostructures may actually shift depending on environmental conditions like water pressure, potentially allowing sharks to subtly change color as they move through the ocean.

A new study on the blue shark (Prionace glauca) has uncovered an intricate nanostructure within its skin that not only creates the shark’s signature blue hue but may also allow for subtle shifts in color.

“Blue is one of the rarest colors in the animal kingdom, and animals have developed a variety of unique strategies through evolution to produce it, making these processes especially fascinating,” says Dr. Viktoriia Kamska, a post-doctoral researcher in the lab of Professor Mason Dean at City University of Hong Kong.

Researchers found that the vivid blue appearance comes from structures located inside the pulp cavities of dermal denticles—tiny, tooth-like scales that form a protective layer over the shark’s skin. These cavities contain guanine crystals, which reflect blue light, and melanin-filled vesicles called melanosomes, which absorb other wavelengths.

The discovery also reveals that the shark’s trademark color is potentially mutable through tiny changes in the relative distances between layers of guanine crystals within the denticle pulp cavities. Whereas narrower spaces between layers create the iconic blues, increasing this space shifts the color into greens and golds.

 

Gravitational waves—ripples in space-time caused by violent cosmic events—travel at the speed of light in every direction, eventually fading out like ripples in water. But some events are so destructive and extreme that they create disturbances in spacetime more like powerful waves than small ripples, with enough energy to reach our own detectors here on Earth. 

Today, the LIGO Collaboration announced the detection of the most colossal black hole merger known to date, the final product of which appears to be a gigantic black hole more than 225 times the mass of the Sun. Much about this signal, designated GW231123, contradicts known models for stellar evolution, sending physicists scrambling to apprehend how such a merger was even possible.

LIGO, or the Laser Interferometer Gravitational-wave Observatory, made physics history in 2015 by detecting gravitational waves for the first time, capturing the cosmological echo of two colliding black holes. Since its Nobel-winning discovery, the LIGO Collaboration, an international partnership between LIGO and Virgo and KAGRA in Italy and Japan, respectively, has continued its meticulous surveillance of the galaxy. The collaboration has detected numerous signals from neutron stars, supernovas, and some 300 black hole mergers.

But GW231123, first observed on November 23, 2023, seems to be an unprecedented beast of a black hole merger. Two enormous black holes—137 and 103 times the mass of the Sun—managed to keep it together despite their immense combined mass, spinning at 400,000 times the speed of Earth’s rotation to form an ever bigger black hole. To put its size into perspective, the previous record holder for such a merger, GW190521, is roughly 140 times the mass of the Sun.

Considering the gravitationally chaotic nature of black hole environments, with their pushes and pulls, it’s remarkable that this merger was stable enough for the resulting gravitational waves to reach LIGO, which detected the signals for a duration of 0.1 seconds. Such episodes should be “forbidden” according to standard evolution models, said Mark Hannam, LIGO member and physicist at Cardiff University, in a statement. 

“One possibility is that the two black holes in this binary formed through earlier mergers of smaller black holes,” he surmised. “This is the most massive black hole binary we’ve observed through gravitational waves, and it presents a real challenge to our understanding of black hole formation.”

“The black holes appear to be spinning very rapidly—near the limit allowed by Einstein’s theory of general relativity,” explained Charlie Hoy, LIGO member and physicist at the University of Portsmouth in England, in the same release. “That makes the signal difficult to model and interpret. It’s an excellent case study for pushing forward the development of our theoretical tools.”

Scientists will present their findings about GW231123 next week at the 24th International Conference on General Relativity and Gravitation (GR24) and the 16th Edoardo Amaldi Conference on Gravitational Waves, held jointly as the GR-Amaldi meeting in Glasgow, U.K. Following that, the data will be out for public scrutiny, kicking off the race to unravel GW231123’s mystery—though it’s unlikely we’ll have a clear answer any time soon.

“It will take years for the community to fully unravel this intricate signal pattern and all its implications,” added Gregorio Carullo, also a LIGO member and physicist at the University of Birmingham, England. “Despite the most likely explanation remaining a black hole merger, more complex scenarios could be the key to deciphering its unexpected features. Exciting times ahead!”

Physicists first conceived of gravitational waves as early as the late 19th century, but the idea gained popular momentum thanks to Albert Einstein. As one of the few observational methods that doesn’t need light to “see” cosmic phenomena, gravitational waves are unmatched in their potential for helping humanity uncover the many mysteries of black holes, ancient stars, and even dark matter. So, indeed—exciting times ahead!

Scientists have detected ripples in space-time from the violent collision of two massive black holes that spiralled into one another far beyond the distant edge of the Milky Way.

The black holes, each more than 100 times the mass of the sun, began circling each other long ago and finally slammed together to form an even more massive black hole about 10bn light years from Earth.

The event is the most massive black hole merger ever recorded by gravitational wave detectors and has forced physicists to rethink their models of how the enormous objects form. The signal was recorded when it hit detectors on Earth sensitive enough to detect shudders in space-time thousands of times smaller than the width of a proton.

“These are the most violent events we can observe in the universe, but when the signals reach Earth, they are the weakest phenomena we can measure,” said Prof Mark Hannam, the head of the Gravity Exploration Institute at Cardiff University. “By the time these ripples wash up on Earth they are tiny.”

Evidence for the black hole collision arrived just before 2pm UK time on 23 November 2023 when two US-based detectors in Washington and Louisiana, operated by the Laser Interferometer Gravitational-wave Observatory (Ligo), twitched at the same time.

The sudden spasm in space-time caused the detectors to stretch and squeeze for one tenth of a second, a fleeting moment that captured the so-called ringdown phase as the merged black holes formed a new one that “rang” before settling down.

Analysis of the signal revealed that the colliding black holes were 103 and 137 times the mass of the sun and spinning about 400,000 times faster than Earth, close to the theoretical limit for the objects.

“These are the highest masses of black holes we’ve confidently measured with gravitational waves,” said Hannam, a member of the Ligo scientific collaboration. “And they’re strange, because they are slap bang in the range of masses where, because of all kinds of weird things that happen, we don’t expect black holes to form.”

Most black holes form when massive stars run out of nuclear fuel and collapse at the end of their life cycle. The incredibly dense objects warp space-time so much that they create an event horizon, a boundary within which even light cannot escape.

Physicists at Ligo suspect the black holes that merged were themselves products of earlier mergers. That would explain how they came to be so massive and why they were spinning so fast, as merging black holes tend to impart spin on the object they create. “We’ve seen hints of this before, but this is the most extreme example where that’s probably what’s happening,” Hannam said.

Scientists have detected about 300 black hole mergers from the gravitational waves they generate. Until now, the most massive merger known produced a black hole about 140 times the mass of the sun. The latest merger produced a black hole up to 265 times more massive than the sun. Details are to be presented on Monday at the GR-Amaldi meeting in Glasgow.

Before the first gravitational wave detectors were built in the 1990s, scientists could observe the universe only through electromagnetic radiation such as visible light, infrared and radio waves. Gravitational wave observatories provide a new view of the cosmos, allowing researchers to see events that were otherwise hidden from them.

“Usually what happens in science is, when you look at the universe in a different way, you discover things you didn’t expect and your whole picture is transformed,” said Hannam. “The detectors we have planned for the next 10 to 15 years will be able to see all the black hole mergers in the universe, and maybe some surprises we didn’t expect.”

1 of 3 | A SpaceX Falcon 9 rocket launches the “Commercial GTO-1” payload at 1:04 AM from Launch Complex 40 at the Cape Canaveral Space Force Station, Florida, on Sunday. The payload contained the Israel Aerospace Industries’ “Dror-1” communications satellite. Photo by Joe Marino/UPI | License Photo

July 13 (UPI) — SpaceX launched a Falcon 9 rocket from Cape Canaveral Space Force Station early Sunday carrying an Israel Aerospace Industries communications satellite, a payload that had been kept largely secret until liftoff.

“We at IAI are extremely proud of the development and successful launch into space of the State of Israel’s ‘Dror 1’ national communications satellite, Boaz Levy, CEO and President of IAI said in a statement. “Dror 1 is the most advanced communications satellite ever built in Israel, designed to preserve this national strategic capability in the country while providing Israel with essential satellite communications capabilities for years to come.”

The satellite, which weighs 4.5 tons and spans nearly 60 feet in diameter when its solar panels are fully deployed, is scheduled to reach its fixed point destination over Earth in about two weeks.

SpaceX has only been involved in a handful of such secret missions.

This was the 13th mission for the stage one 9 booster rocket that sent the Falcon 9 into low-Earth orbit. About 8.5 minutes after liftoff, the rocket landed on the droneship “Just Read the Instructions,” which was stationed in the Atlantic Ocean.

It was the 128th time the droneship has been used to retrieve a returning craft, and was the 474th SpaceX booster rocket landing overall.

NASA’s Parker Solar Probe made history with the closest-ever approach to the sun last December, and we’re finally getting a look at some of the images it captured. The space agency released a timelapse of observations made using Parker’s Wide-Field Imager for Solar Probe (WISPR) while it passed through the sun’s corona on December 25, 2024, revealing up close how solar wind acts soon after it’s released. The probe captured these images at just 3.8 million miles from the solar surface. To put that into perspective, a NASA video explains, “If Earth and the sun were one foot apart, Parker Solar Probe was about half an inch from the sun.”

The probe got an unprecedented view of solar wind and coronal mass ejections (CMEs) during the approach, which could be invaluable for our understanding of space weather. “We are witnessing where space weather threats to Earth begin, with our eyes, not just with models,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters. After completing its December flyby, the Parker Solar Probe matched its record distance from the surface in subsequent approaches in March and June. It’ll make its next pass on September 15.

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On Dec. 24, 2024, NASA’s Parker Solar Probe traveled closer to the Sun than any spacecraft had before. During this close approach, or perihelion, the spacecraft’s four instruments observed the Sun’s atmosphere from inside. This week, NASA released images collected by the spacecraft’s Wide-Field Imager for Solar Probe (WISPR) instrument.

Since the close approach in late 2024, Parker Solar Probe has performed two more perihelia passes at the same distance on March 22 and June 19, the latter marking the 24th and final perihelion of the spacecraft’s primary mission. Throughout its nearly seven-year mission, the probe has helped scientists better understand the Sun and its solar wind. The latest images add to a wealth of information about our star.

“Parker Solar Probe has once again transported us into the dynamic atmosphere of our closest star,” said Nicky Fox, associate administrator for NASA’s Science Mission Directorate. “We are witnessing where space weather threats to Earth begin, with our eyes, not just with models. This new data will help us vastly improve our space weather predictions to ensure the safety of our astronauts and the protection of our technology here on Earth and throughout the solar system.”

The images show bursts of plasma release from the Sun in so-called coronal mass ejections (CME) at the start of their journey through space. When these streams of charged particles reach Earth they drive space weather, which can potentially damage satellites, harm astronauts, or interrupt communications systems. Additionally, the particles are responsible for the auroras when they interact with the upper atmosphere after being trapped in Earth’s magnetic field.

(Video: CMEs observed by Parker Solar Probe’s WISPR instrument during perihelion 22 in December 2024. Credit: NASA/Johns Hopkins APL/Naval Research Lab)

“In these images, we’re seeing the CMEs basically piling up on top of one another,” said WISPR instrument scientist Angelos Vourlidas of the Johns Hopkins Applied Physics Laboratory, which designed, built, and operates the spacecraft. “We’re using this to figure out how the CMEs merge together, which can be important for space weather.”

Additionally, the images show the heliospheric current sheet, which forms the boundary where the Sun’s magnetic field changes direction. As this boundary interacts with the solar wind, it changes the intensity of space weather near Earth.

As it took these images during its 22nd perihelion, Parker Solar Probe broke its own record for closest approach to the Sun, at 6.2 million km from the Solar surface, taking the spacecraft through the Sun’s atmosphere, known as the corona. At the same time, it travelled faster than any other human-made object, at 687,000 km/h. The subsequent 23rd and 24th perihelia repeated this close approach at the same distance and velocity.

The spacecraft was launched atop a Delta IV Heavy from Cape Canaveral on Aug. 12, 2018. In 2021, Parker Solar Probe became the first spacecraft to “touch” the Sun by flying through its atmosphere. Throughout its mission, the spacecraft has flown by Venus seven times, performing gravity assist maneuvers to lower its perihelion, culminating in its current orbit after a flyby in early November 2024.

While breaking its own distance records, Parker Solar Probe studied the solar corona with its four instruments: the aforementioned WISPR instrument as well as the Fields Experiment (FIELDS), the Integrated Science Investigation of the Sun (IS☉IS), and the Solar Wind Electrons Alphas and Protons (SWEAP) instruments. The data collected by these instruments helped scientists study different varieties of solar wind up close.

In a study published in 2024, Parker Solar Probe teamed up with the European Space Agency’s (ESA) Solar Orbiter. The two spacecraft lined up to reveal that the fast class of solar wind is in part powered by so-called switchbacks, where the Sun’s magnetic field zigzags. Earlier, Parker Solar Probe discovered that these switchbacks are more common than previously thought.

Meanwhile, the spacecraft confirmed that the slow variety of solar wind exists in two kinds of its own. One type, called Alfvénic, features small-scale switchbacks, while the non-Alfvénic type lacks this quality. Moreover, the probe pinpointed the origin of Alfvénic solar wind to the cool coronal holes, while the non-Alfvénic variety comes from the large loops connecting active regions.

“The big unknown has been: how is the solar wind generated, and how does it manage to escape the Sun’s immense gravitational pull?” said project scientist for Parker Solar Probe Nour Rawafi of the Johns Hopkins Applied Physics Laboratory. “Understanding this continuous flow of particles, particularly the slow solar wind, is a major challenge, especially given the diversity in the properties of these streams — but with Parker Solar Probe, we’re closer than ever to uncovering their origins and how they evolve.”

Although the probe has now completed the 24th and final perihelion of its primary mission, it will continue studying the Sun from its current orbit. It will perform its next perihelion on Sept. 15. Its fate will be decided next year, when NASA plans to formally review the mission’s next steps.

While the agency’s science budget is in turmoil, Parker Solar Probe’s future seems safe for now, as the budget requested by the current administration funds the mission with $15 million USD per year through 2030. While this is substantially lower than the amount requested for the spacecraft’s extended mission in previous years, it means that Parker Solar Probe will likely continue delivering science for the foreseeable future.

“Parker Solar Probe remains in excellent health, with both the spacecraft and its instruments ready to continue their groundbreaking mission,” said NASA Parker Solar Probe program scientist Arik Posner after the 24th perihelion in June. “The spacecraft will keep exploring the solar atmosphere as the Sun enters the declining phase of its 11-year cycle, providing a unique opportunity to study how solar activity evolves and shapes the heliosphere during this pivotal period.”

(Lead image: Illustration showing Parker Solar Probe in front of the Sun. Credit: NASA/Johns Hopkins APL/Steve Gribben)

(Web Desk) – Scientists have warned that this summer could include some of the shortest days of your entire life.

On July 22 and August 5, experts predict the day will be 1.38 and 1.51 milliseconds shorter than average, respectively.

This is because the planet’s rotation has entered an unexpected period of acceleration, shaving a millisecond or so off the length of a solar day.

But what would happen if the world just kept getting faster?

Given that a blink takes 100 milliseconds, you are unlikely to notice any big changes for a long time.

However, scientists say that unchecked acceleration would eventually lead to disastrous consequences.

If Earth were spinning just 100 miles per hour faster than it does now, the world would be hit by stronger hurricanes, catastrophic flooding, and the collapse of satellite networks.

And, if the world were to double its speed, it would likely be the end of life as we know it.

On average, it takes the planet 24 hours, or 86,400 seconds, to complete one full rotation, which is called a solar day.

Small fluctuations like the location of the moon or volcanic eruptions can shift this around a millisecond in either direction, but the rotation is generally fairly stable.

Because the Earth is a sphere, its circumference is smaller near the poles than at the equator, so the planet’s surface moves faster the further you get from the poles.

Someone standing at the equator is rotating in space at around 1,037 mph (1,668 kmph) while somebody in London is only moving at about 646 mph (1,041 kmph).

Compared to these speeds, an increase of just one mile per hour might not seem like a big difference.

The days would be about a minute and a half shorter overall, which our body clocks probably wouldn’t notice right away.

Witold Fraczek, an analyst at ESRI, a mapping software firm, told Popular Science: ‘It might take a few years to notice it.’

However, an unexpected effect is that satellites in orbit would soon be knocked out of sync.

Some satellites are ‘geosynchronous’, meaning they move at the same speed as Earth’s rotation to stay over the same location.

If the Earth speeds up, those satellites will lose their position and navigation, communication, and weather monitoring services would start to fail.

However, some satellites carry fuel to adjust their orbit, and others could be replaced, so the results should not be disastrous.

Mr Fraczek says: ‘These could disturb the life and comfort of some people, but should not be catastrophic to anybody.

The bigger impact is that water would start to move from the poles to the equator due to the increased centrifugal forces.

Even at just one mile per hour, this would cause sea levels to rise by a few inches around the equator.

For cities already at or very near sea level, this could lead to devastating flooding. 

Planting trees is a simple idea, yet the details – from which species are used to how they’re arranged within a forest – shape the climate benefits we reap.

Advanced computer models make it possible for scientists to peer inside virtual forests. They can test every possible arrangement before a single sapling goes into the ground.

A new study used those models to show that layout matters almost as much as species choice. The research was led by Rémy Beugnon at the German Centre for Integrative Biodiversity Research (iDiv).

Mixing trees boosts growth

Researchers call the fine‑grained mix of species in a stand spatial heterogeneity. When that mix is high, neighboring trees draw different nutrients, share light, and leave a patchwork of leaf litter that fuels underground life.

Beugnon’s team modeled eight subtropical species in thousands of simulated plots and compared designs ranging from single‑species blocks to fully shuffled grids.

The models predicted that random layouts move nutrients faster through the system, lifting both growth and recycling.

“The models show that random planting designs increased tree biomass by 11 percent compared to clustered layouts,” said Rémy Beugnon, first author of the study.

Random forest designs pay off

Across the forest simulations, shuffling species raised aboveground biomass by 11 percent over block plantings, even though every plot carried the same number of stems.

The extra wood comes from chance neighbors; tall shade‑tolerant trunks share space with shorter sun‑lovers, wasting less light and soil.

A 2023 global analysis of more than 10,000 plots found a similar pattern, reporting that each additional tree species added roughly one‑third of a ton of extra wood per acre by boosting canopy complexity.

For managers locked into mechanical harvesting, random layouts can be intimidating. Yet the payoff shows why many reforestation guides now favor flexible rows or small patches over the classic monoculture block.

Mixed trees enrich soil

Dead leaves are not waste; they drive litter decomposition that returns nitrogen and carbon to roots. In the models, mixed canopies dropped litter more evenly across the forest floor, smoothing out nutrient hot and cold spots.

Carbon loss from litter after nine months climbed from 36.5 percent in block plantings to 47.1 percent in random mixes, a jump big enough to shift the soil’s entire carbon budget.

Field experiments in subtropical China showed that doubling tree species richness sped up decomposition by up to 25 percent through thicker, more varied leaf fall.

Faster turnover does not mean carbon is lost. Instead, it channels organic matter into microbial pathways that lock it deeper in the soil profile.

A tidy path to forest diversity

The Leipzig group tested a middle ground called “line planting,” alternating single or double rows of different species. Lines keep machinery lanes clear while still mixing neighbors along their edges.

Their simulations showed that line layouts decomposed 40.4 percent of litter carbon in nine months -halfway between blocks and fully random, yet easy to mark out with a tape measure.

“We can leverage biodiversity in forests if we arrange it in the right way,” said Nico Eisenhauer, professor at Leipzig University and iDiv group leader.

For many operational foresters, that design tweak may be the cheapest route to healthier soils – without rewriting the entire planting manual.

Planting diversity fuels forest gains

Layout is only half of the equation; adding species amplifies its effect. In mixed stands, each extra species multiplied the layout benefit, but in block designs the diversity effect nearly vanished.

When eight species were scattered randomly, decomposition leapt by more than ten percentage points compared with similar blocks. In contrast, two‑species plots barely budged.

A pan‑American census reported that forests holding a wider spread of life‑history strategies stored more carbon over time, even after accounting for climate. Thus, thinking in two dimensions – what trees and where – can stretch every acre planted toward national carbon targets.

Climate goals need forest designs

Beugnon and colleagues plan long‑term field tests to see how windthrow, pests, and thinning interact with mixed layouts over decades.

Policymakers drafting reforestation incentives could build spatial criteria into grant rules, rewarding forest designs that mix species at the row scale rather than the stand scale.

With roughly 470 million acres already pledged for restoration worldwide, even a 10 percent biomass lift adds up. That increase translates into gigatons of extra carbon locked away.

Choosing the right forest design from the start costs nothing yet pays dividends for centuries, making it one of the simplest levers in the climate toolkit.

The study is published in the journal Nature Communications.

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When you hear the term ‘space laser,’ your mind likely leaps to weapons technology. Indeed, lasers can be used as lasers, and a giant laser gun in space would be a huge threat. Fortunately, China’s new space laser isn’t made to attack, but rather to locate other satellites and prove out the possibility of using lasers for communication during the day.

The researchers set out to find the Tiandu-1 satellite, which was about 130,000 kilometers (81,000 miles) away from Earth, orbiting the moon. To do this, they sent a laser from their Earth station, bounced it off a retroreflector device that was placed on the Tiandu-1 satellite, and had it return to Earth, all in less than a second. The returning laser was seen by a 1.2-meter telescope located at the Chinese Academy of Sciences Yunnan Observatories.

This is a pretty remarkable achievement given the distances and the fact that it happened during a time when the objects were exposed to the sun’s light. Lasers are great for many things, but can be disrupted by the bright sun.

Lasers are often used in space for things like measuring distance, communicating, determining location, and more. NASA, for example, has used lasers to locate two separate craft on the moon’s surface. The laser was shot by the Lunar Reconnaissance Orbiter (LRO) and detected both India’s Vikram lander and the Smart Lander for Investigating Moon (SLIM) from Japan.

What makes this particularly remarkable is that the LRO wasn’t designed for this type of use. Xiaoli Sun led the team that built the SLIM’s retroreflector at NASA’s Goddard Space Flight Center. He put out a statement, saying:

“LRO’s altimeter wasn’t built for this type of application, so the chances of pinpointing a tiny retroreflector on the Moon’s surface are already low.”

This type of test shows that lasers can indeed be used even in the bright sun. This may be important if bases are ever set up on Mars, where it takes around 8 minutes for light to travel between there and Earth.

Using lasers for communication would be much more efficient than radio waves, since it would be possible to encode much greater amounts of data.

If you thought that was interesting, you might like to read about a quantum computer simulation that has “reversed time” and physics may never be the same.