Newswise — One of the annoying side effects of being absorbed in a gripping novel is that the cup of tea on the table becomes cold! Unfortunately, the tea would not heat itself by absorbing the heat around it, just as pieces of a broken egg would not put themselves together or milk mixed in coffee would not separate by itself. Such things are irreversible, and define a fixed direction of time—that from the past towards the future. This apparent progression of time is called the ‘arrow of time’.
In a recent study, Prof Mahendra Verma of the Indian Institute of Technology Kanpur, suggests a way, different from any previous ones, to determine the direction in which time is progressing. He uses the concept of energy cascade to define the arrow of time.
One would think that the ‘arrow of time’ is well captured in the laws of physics—those related to the fundamental forces of gravity, electromagnetism and the strong nuclear forces. However, the mathematical equations of these laws stay perfectly valid when we substitute t with -t, that is, reverse the time. So, using these laws, we cannot explain the world around us, so full of irreversible things and so clearly asymmetric in time. Then how could we capture this asymmetry of time?
“The arrow of time is an important question from the perspectives of biology, consciousness, and cosmology,” says Prof Verma. The concept is of interest to biologists in their study of evolution and ageing, to cosmologists in understanding how the Universe began and is evolving, to philosophers in answering questions such as ‘is time real?’.
Scientists believe that the second law of thermodynamics defines the arrow of time. They describe an entity called entropy, which is a measure of the amount of disorder in a system and can be expressed mathematically. The second law of thermodynamics states that the entropy of an isolated system can never decrease; it can either stay the same or increase. Thus the direction of increasing entropy is the forward direction of time, and the direction of decreasing entropy is the reverse direction of time.
Prof Verma offers an alternative definition of forward-moving time in this work published in the journal European Physical Journal B. He notes that in dissipative systems, energy always flows from large scale or bigger chunks to small scales or smaller chunks, and this defines the arrow of time.
When we pour milk in a cup of coffee and stir it, we see a large blob of milk swirl and then turn into vortices, smaller and smaller in size. The white blobs gradually turn to brown and finally mix completely with the coffee. The energy that we supply by stirring is transferred to the large blob of milk, which breaks into smaller blobs. The energy then transfers to these smaller blobs, which break into even smaller blobs, and the ‘cascade of energy’ continues until the milk mixes completely with the coffee.
Dissipative systems are those in which energy is lost to heat, via friction in mechanical systems, via resistance in electrical systems, and via viscosity in fluids. Similar to how milk mixes in coffee, in a dissipative system, the energy supplied at large scales gets transferred successively to smaller scales (energy cascade) and is finally dissipated at the smallest scale.
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“When we break an egg using a spoon, note that the initial strike causes the egg to break and that the initial energy injection by the spoon cascades down the scale. This energy transfer is asymmetric in time; the energy cannot flow from small pieces of the egg to the spoon that broke it. This asymmetry explains why we cannot put a broken egg together,” argues Prof Verma. The energy cascade thus defines the arrow of time.
In the current study, Prof Verma discusses the specific case of time reversal for turbulent flows. If we write the equations of energy transfers in turbulent fluids for reversed time (substitute t with -t), we get equations that indicate a flow of energy from small scale to large scale. Such energy transfers are never observed in reality (in dissipative systems). Thus, the energy flow from large scales to small scales defines forward-moving time, whereas energy flow from small scale to large scale defines reverse time.
Prof Verma suggests that we can apply this very principle of energy transfers to several other physical systems such as earthquakes, thermal convection and magnetohydrodynamic turbulence. However, researchers will need to work out the details of the energy transfers for these systems. “We hope that this multiscale framework may be useful for resolving some of the longstanding issues on the arrow of time in physical and biological systems, as well as in cosmology,” he concludes.
About IIT Kanpur:
Indian Institute of Technology (IIT) Kanpur was established on 2nd November 1959 by an Act of Parliament. The institute has a sprawling campus spread over 1055 acres with large pool of academic and research resources spanning across 19 departments, 22 centres, and 3 Interdisciplinary programs in engineering, science, design, humanities, and management disciplines with 540 full-time faculty members and approximately 9000 students. In addition to formal undergraduate and postgraduate courses, the institute has been active in research and development in areas of value to both industry and government.
3 Unforgettable Mother’s Day Meals That Will Make Her Heart (and Taste Buds) Sing
Create an unforgettable Mother’s Day with a home-cooked meal featuring three easy yet impressive recipes: Lemon Ricotta Pancakes, Mediterranean Brunch Board, and Herb-Crusted Salmon, paired with wines to enhance flavors and create lasting memories.
A beautifully arranged table set with plates, silverware, and candles. Perfect for formal dining or special occasions.
Want to make this Mother’s Day extra special? Skip the crowded restaurants and show Mom your love through a home-cooked meal she’ll never forget. We’ve crafted three foolproof recipes that even kitchen novices can master – because nothing says “I love you” quite like a meal made from the heart.
🌟 1. Heavenly Lemon Ricotta Pancakes with Berry Compote
Picture golden, cloud-like pancakes that practically float off the plate, their edges delicately crispy while their centers remain pillowy-soft and tender. The rich, creamy ricotta creates pockets of moisture that melt in your mouth, while bright lemon zest cuts through with citrusy sparkle. The warm berry compote cascades over the stack, its jewel-toned fruits bursting with sweet-tart juice that mingles perfectly with pure maple syrup.
A feast for both eyes and palate, this stunning spread features eggs with golden yolks that ooze luxuriously when broken, their richness enhanced by aromatic dukkah’s nutty crunch. Creamy, house-made hummus swirled with extra virgin olive oil sits alongside prosciutto roses that fold like silk. Fresh figs, split to reveal their honey-sweet crimson centers, nestle against wedges of artisanal cheese that range from buttery-soft to crystalline-sharp. Every bite tells a story of Mediterranean sunshine.
👑 3. Herb-Crusted Salmon with Champagne Cream Sauce
A masterpiece of textures and flavors: the salmon’s herb crust offers a satisfying crackle before revealing the perfectly cooked, rose-pink flesh beneath that flakes at the mere touch of a fork. The champagne cream sauce, velvety and sophisticated, pools elegantly around the fish, its subtle bubbles lending an air of celebration. Bright green asparagus spears provide the perfect crisp-tender contrast, while the wild mushroom risotto, infused with earthy aromatics and finished with a generous shower of Parmesan, creates a bed of creamy comfort that ties the whole dish together.
Why These Recipes Work:
Each recipe can be partially prepped in advance
Ingredients are easily found in most supermarkets
They’re impressive without being overly complicated
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Perfect balance of flavors and textures
Suitable for various dietary preferences
Each bite is carefully crafted to create not just a meal, but a memorable experience that shows Mom just how special she is. The interplay of textures and flavors in each dish creates a symphony of tastes that will linger in her memory long after the last bite.
Here are some Wine Pairings to make these dishes perfect:
🌟 Lemon Ricotta Pancakes
Perfect Pairing: Prosecco or Moscato d’Asti
Why it works: The light bubbles and subtle sweetness complement the citrus notes while cutting through the richness of the ricotta.
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🍳 Mediterranean Brunch Board
Perfect Pairing: Rosé or Albariño
Why it works: A crisp, dry rosé enhances the salty prosciutto and creamy cheeses, while Albariño’s mineral notes complement the Mediterranean flavors.
👑 Herb-Crusted Salmon
Perfect Pairing: Chardonnay or Pinot Noir
Why it works: A lightly oaked Chardonnay matches the richness of the champagne sauce, while a light-bodied Pinot Noir works beautifully with the herb crust.
Plating Instructions:
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Lemon Ricotta Pancakes:
Stack 3-4 pancakes slightly off-center on a warm, white plate
Drizzle berry compote in an artistic swoosh from 2 o’clock to 7 o’clock
Garnish with fresh mint leaves and a light dusting of powdered sugar
Pro tip: Use a wide, flat plate to let the colors pop against the white background
Mediterranean Brunch Board:
Start with a large wooden board or slate platter
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Create height by placing small bowls of hummus and dips at different points
Arrange prosciutto roses in a cascading pattern
Group cheeses by type, creating a gradient from soft to hard
Fill negative space with fresh herbs and edible flowers
Pro tip: Use small olive wood bowls for dips to add rustic elegance
Herb-Crusted Salmon:
Place the risotto in a shallow bowl using a ring mold
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Position the salmon at a 45-degree angle, slightly overlapping the risotto
Arrange asparagus spears like a fan
Drizzle champagne sauce in an elegant circle around the plate
Garnish with micro herbs and edible flowers
Pro tip: Warm the plates before serving to keep everything at perfect temperature
Remember: The most important ingredient isn’t listed in any recipe – it’s the love and thought you put into making Mom’s day special. These meals aren’t just about the food; they’re about creating precious moments together.
Ready to make Mom’s day unforgettable? Save these recipes now and start planning your Mother’s Day menu. Trust us – seeing her face light up will be worth every minute in the kitchen.
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Here are some related links to further help you make Mother’s Day special:
At our core, we at STM Daily News, strive to keep you informed and inspired with the freshest content on all things food and beverage. From mouthwatering recipes to intriguing articles, we’re here to satisfy your appetite for culinary knowledge.
Visit our Food & Drink section to get the latest on Foodie News and recipes, offering a delightful blend of culinary inspiration and gastronomic trends to elevate your dining experience.
Black holes, like the one in this illustration, can spray powerful jets.
S. Dagnello (NRAO/AUI/NSF), CC BY-SADavid Garofalo, Kennesaw State University
One of the most powerful objects in the universe is a radio quasar – a spinning black hole spraying out highly energetic particles. Come too close to one, and you’d get sucked in by its gravitational pull, or burn up from the intense heat surrounding it. But ironically, studying black holes and their jets can give researchers insight into where potentially habitable worlds might be in the universe.
As an astrophysicist, I’ve spent two decades modeling how black holes spin, how that creates jets, and how they affect the environment of space around them.
What are black holes?
Black holes are massive, astrophysical objects that use gravity to pull surrounding objects into them. Active black holes have a pancake-shaped structure around them called an accretion disk, which contains hot, electrically charged gas.
The plasma that makes up the accretion disk comes from farther out in the galaxy. When two galaxies collide and merge, gas is funneled into the central region of that merger. Some of that gas ends up getting close to the newly merged black hole and forms the accretion disk.
There is one supermassive black holeat the heart of every massive galaxy.
Black holes and their disks can rotate, and when they do, they drag space and time with them – a concept that’s mind-boggling and very hard to grasp conceptually. But black holes are important to study because they produce enormous amounts of energy that can influence galaxies.
How energetic a black hole is depends on different factors, such as the mass of the black hole, whether it rotates rapidly, and whether lots of material falls onto it. Mergers fuel the most energetic black holes, but not all black holes are fed by gas from a merger. In spiral galaxies, for example, less gas tends to fall into the center, and the central black hole tends to have less energy.
One of the ways they generate energy is through what scientists call “jets” of highly energetic particles. A black hole can pull in magnetic fields and energetic particles surrounding it, and then as the black hole rotates, the magnetic fields twist into a jet that sprays out highly energetic particles.
Magnetic fields twist around the black hole as it rotates to store energy – kind of like when you pull and twist a rubber band. When you release the rubber band, it snaps forward. Similarly, the magnetic fields release their energy by producing these jets.
The accretion disk around a black hole can form a jet of hot, energetic particles surrounded by magnetic field lines.NASA, ESA, and A. Feild (STScI), CC BY
These jets can speed up or suppress the formation of stars in a galaxy, depending on how the energy is released into the black hole’s host galaxy.
Rotating black holes
Some black holes, however, rotate in a different direction than the accretion disk around them. This phenomenon is called counterrotation, and some studies my colleagues and I have conducted suggest that it’s a key feature governing the behavior of one of the most powerful kinds of objects in the universe: the radio quasar.
Radio quasars are the subclass of black holes that produce the most powerful energy and jets.
You can imagine the black hole as a rotating sphere, and the accretion disk as a disk with a hole in the center. The black hole sits in that center hole and rotates one way, while the accretion disk rotates the other way.
This counterrotation forces the black hole to spin down and eventually up again in the other direction, called corotation. Imagine a basketball that spins one way, but you keep tapping it to rotate in the other. The tapping will spin the basketball down. If you continue to tap in the opposite direction, it will eventually spin up and rotate in the other direction. The accretion disk does the same thing.
Since the jets tap into the black hole’s rotational energy, they are powerful only when the black hole is spinning rapidly. The change from counterrotation to corotation takes at least 100 million years. Many initially counterrotating black holes take billions of years to become rapidly spinning corotating black holes.
So, these black holes would produce powerful jets both early and later in their lifetimes, with an interlude in the middle where the jets are either weak or nonexistent.
When the black hole spins in counterrotation with respect to its accretion disk, that motion produces strong jets that push molecules in the surrounding gas close together, which leads to the formation of stars.
But later, in corotation, the jet tilts. This tilt makes it so that the jet impinges directly on the gas, heating it up and inhibiting star formation. In addition to that, the jet also sprays X-rays across the galaxy. Cosmic X-rays are bad for life because they can harm organic tissue.
For life to thrive, it most likely needs a planet with a habitable ecosystem, and clouds of hot gas saturated with X-rays don’t contain such planets. So, astronomers can instead look for galaxies without a tilted jet coming from its black hole. This idea is key to understanding where intelligence could potentially have emerged and matured in the universe.
Black holes as a guide
By early 2022, I had built a black hole model to use as a guide. It could point out environments with the right kind of black holes to produce the greatest number of planets without spraying them with X-rays. Life in such environments could emerge to its full potential.
Looking at black holes and their role in star formation could help scientists predict when and where life was most likely to form.
Where are such conditions present? The answer is low-density environments where galaxies had merged about 11 billion years ago.
These environments had black holes whose powerful jets enhanced the rate of star formation, but they never experienced a bout of tilted jets in corotation. In short, my model suggested that theoretically, the most advanced extraterrestrial civilization would have likely emerged on the cosmic scene far away and billions of years ago.
David Garofalo, Professor of Physics, Kennesaw State University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The Role of Bike Lanes in Shaping Modern Urban Development
Bike lanes in urban areas promote sustainability, improve mobility, boost economic growth, enhance public health, and increase property values, symbolizing a shift toward inclusive community-focused city planning.
Cycle path in the city park. Bicycle sign on the road.
As cities continue to grow and urban spaces evolve, the integration of bike lanes has emerged as a transformative element in urban development. Beyond just providing a space for cyclists, bike lanes symbolize a shift toward sustainable, inclusive, and community-focused city planning.
Sustainability and Environmental Benefits Bike lanes contribute to reducing carbon emissions by encouraging more people to opt for cycling over driving. This not only lowers air pollution but also supports greener urban environments.
Improved Urban Mobility Cities with well-designed bike lane networks experience enhanced traffic flow. By reducing congestion and offering safe zones for cyclists, bike lanes create a more balanced transportation ecosystem.
Economic Growth Bike-friendly cities often see increased local business activity. Cyclists are more likely to stop and shop at small businesses along their routes, boosting neighborhood economies.
Health and Community Well-being Encouraging cycling promotes physical activity, improving public health. Additionally, bike lanes foster a sense of community by creating shared, accessible spaces for all residents.
Urban Aesthetic and Property Value Bike lanes enhance the visual appeal of cities and often lead to increased property values in surrounding areas. They signal modern, forward-thinking development, attracting young professionals and families.
Bike lanes are more than just pavement—they are investments in a city’s future. By prioritizing sustainable transit, healthier lifestyles, and economic growth, urban planners can create cities that thrive for generations. To embrace the future of urban living, integrating bike lanes into development plans must remain a top priority.
Call to Action Join the movement for sustainable cities by supporting bike lane initiatives in your community. Together, we can build cities that benefit everyone.
Image Credit: Adobe Stock
Learn more about Bike Lanes…
Check out these sites related to biking and urban development:
CicLAvia: CicLAvia catalyzes vibrant public spaces, active transportation, and good health through car-free streets. https://www.ciclavia.org/
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