#spacetime curvature

[fashionfotorecccluse]

Curved spacetime

#art #artist #artists on tumblr #conceptual #conceptual art #concept #concept art #conceptual photography #conceptual art photography #curve #curvature #spacetime #curved spacetime

[scarletcomet]

the idea of spacetime confuses me so much

#im sorry mr. einstein plz help #curvature of spacetime?!? #learning about black holes in astrophysics without knowing anything about relativity is kinda rough #i want to learn about relativity tho!! #not me kinda wishing i was a physics major #:(

[mysticstronomy]

WHAT IS THE SPACE - TIME CONTINUUM??

Blog#364

Saturday, January 6th, 2024.

Welcome back,

The space-time continuum is a concept in physics that refers to the idea that space and time are two aspects of a single entity, called spacetime. In other words, instead of thinking of space and time as separate entities, the theory of relativity suggests that they are intimately connected and should be considered together as a four-dimensional fabric that makes up the universe.

The concept of the space-time continuum arises from Albert Einstein’s theory of relativity. According to Einstein, the passage of time and the curvature of space are affected by the presence of mass and energy. Massive objects like planets and stars can warp the fabric of space and time, causing other objects to move along curved paths.

The theory of relativity also predicts that time passes differently for observers in different states of motion. Specifically, time dilation occurs when an object is moving at high speeds, causing time to appear to pass more slowly for the moving object relative to a stationary observer. This effect has been observed in experiments and is an important factor in the operation of devices like GPS satellites.

The concept of the space-time continuum has important implications for our understanding of the nature of the universe, including the behavior of particles traveling at high speeds, the structure of black holes, and the origin and evolution of the universe as a whole. It also provides a framework for understanding the fundamental laws of physics and the behavior of matter and energy in the universe.

Originally published https://medium.com

COMING UP!!

(Wednesday, January 10th, 2024)

"IS TIME INFINITE IN BLACK HOLES??"

#astronomy #outer space #alternate universe #astrophysics #universe #spacecraft #white universe #space #parallel universe #astrophotography

[spaceadvances]

Gravitational lensing occurs when a massive celestial body — such as a galaxy cluster — causes a sufficient curvature of spacetime for the path of light around it to be visibly bent, as if by a lens. The body causing the light to curve is accordingly called a gravitational lens.

#nasa #astrophotography #astronomy #solar system #astrophysics #hubble #nebula #physics #james webb space technology #james webb images

[mindblowingscience]

New theoretical research by Michael Wondrak, Walter van Suijlekom and Heino Falcke of Radboud University has shown that Stephen Hawking was right about black holes, although not completely. Due to Hawking radiation, black holes will eventually evaporate, but the event horizon is not as crucial as had been believed. Gravity and the curvature of spacetime cause this radiation too. This means that all large objects in the universe, like the remnants of stars, will eventually evaporate.

Using a clever combination of quantum physics and Einstein's theory of gravity, Stephen Hawking argued that the spontaneous creation and annihilation of pairs of particles must occur near the event horizon (the point beyond which there is no escape from the gravitational force of a black hole).

A particle and its anti-particle are created very briefly from the quantum field, after which they immediately annihilate. But sometimes a particle falls into the black hole, and then the other particle can escape: Hawking radiation. According to Hawking, this would eventually result in the evaporation of black holes.

In this new study the researchers at Radboud University revisited this process and investigated whether or not the presence of an event horizon is indeed crucial.

Continue Reading

#science #stem #astronomy #astrophysics #stephen hawking #hawking radiation #black holes

[factsandstuffbyd]

Unveiling the Mysteries of Black Holes

Black holes, enigmatic cosmic phenomena predicted by Einstein's theory of general relativity, have captivated scientists and the public alike for decades. These mysterious entities, formed from the remnants of massive stars, possess gravity so strong that even light cannot escape their grasp. Exploring black holes has reshaped our understanding of space, time, and the fundamental laws of physics.

Birth of a Black Hole: Stellar Collapse Black holes originate from the explosive aftermath of massive star deaths. When a star exhausts its nuclear fuel, gravity overpowers the outward pressure, causing the star's core to collapse. If the core's mass exceeds a critical threshold, known as the Chandrasekhar limit, it collapses into a singularity, an infinitely dense point, surrounded by an event horizon – the boundary beyond which nothing can escape.

The Gravity Abyss: Warping Space and Time Einstein's theory of general relativity describes gravity as the curvature of spacetime caused by massive objects. Black holes embody this concept to the extreme, warping space and time so severely that they create a gravity well from which nothing, not even light, can emerge. This phenomenon challenges our classical understanding of gravity and beckons us to explore its most extreme consequences.

Revealing the Unseen: Detecting Black Holes Detecting black holes poses a unique challenge due to their invisible nature. Scientists rely on indirect methods. X-ray emissions from matter spiraling into black holes can betray their presence, as can gravitational effects on nearby stars. The LIGO and Virgo observatories have pioneered gravitational wave detection, allowing us to sense the ripples in spacetime generated by black hole mergers.

Size Matters: Stellar and Supermassive Black Holes Black holes vary in size. Stellar-mass black holes, formed from individual star collapses, typically range from a few to several tens of solar masses. In contrast, supermassive black holes inhabit galactic centers and can weigh millions or even billions of times our sun's mass. The processes behind these size differences remain active areas of research.

Dance of Destruction: Black Hole Accretion Disks As black holes pull surrounding matter into their grasp, they create accretion disks – swirling discs of gas and dust. Friction and heat generated within these disks cause them to emit powerful X-rays and other forms of radiation. Studying these emissions provides insights into black hole properties and behavior.

Event Horizon Telescope: Peering into the Abyss In April 2019, the Event Horizon Telescope made history by capturing the first-ever image of the event horizon of a supermassive black hole at the center of galaxy M87. This feat involved coordinating multiple radio telescopes globally, simulating a telescope the size of Earth. The image not only confirmed the existence of black holes but also provided visual evidence of their mind-bending nature.

Hawking Radiation: Black Holes Aren't So Black Black holes aren't completely dark. According to physicist Stephen Hawking, black holes can emit radiation due to quantum effects near the event horizon. This phenomenon, known as Hawking radiation, challenges our perception of black holes as purely consuming entities. It implies that they can slowly lose mass and evaporate over time.

Black Hole Information Paradox: Cosmic Conundrum The nature of information within black holes is a conundrum known as the "black hole information paradox." According to quantum mechanics, information cannot be destroyed, yet black holes seem to violate this principle by absorbing everything that falls within their grasp. Resolving this paradox is a frontier in theoretical physics.

Black Holes and the Cosmos: Galactic Evolution and Beyond Black holes play an integral role in galactic evolution. Supermassive black holes influence their host galaxies through processes like quasars, which emit immense energy. Black hole interactions and mergers also contribute to the universe's dynamism. Understanding these roles enhances our grasp of cosmic evolution.

Beyond the Horizon: Ongoing Exploration The exploration of black holes is an ongoing endeavor, intertwining multiple disciplines, from astrophysics to quantum mechanics. As technology advances, we inch closer to unlocking the secrets of these cosmic enigmas. With initiatives like the upcoming LISA mission to detect gravitational waves from space, our understanding of black holes is poised to expand further, offering glimpses into the deepest corners of the cosmos.

In conclusion, black holes stand as some of the most enigmatic and awe-inspiring entities in the universe. Their influence stretches across space and time, defying our conventional understanding of reality. From their mysterious birth to the intricate dance of matter around them, black holes continue to challenge our intellect and inspire us to unravel the mysteries that lie within their gravitational grasp.

#astrophysics #astronomy #cosmology #space #physics #black holes #blackholes

[yamameta-inc]

it’s so fun how hwbm declares that gravity is agency. because gravity is what happens between things that have mass ie take up space in the universe. you have agency because you take up space, and so you have a weight, and the universe can feel your weight, and other things—people—can feel your weight even if it’s very light. and gravity is attraction between things—and people—and your agency lies in that attraction. even though agency can be pictured as breaking free from the gravity of the things around you, even though the children of space talk of how impossibly heavy earth’s gravity would be for them, they also need a certain level of pressure to live.

and then because gravity is the curvature of spacetime, you can see leftover gravity in some places, the remnants—proof?—of past agency. the ruins of the school where they were trained, the lab, the eye. something like a ghost of the past lingers there, almost tangibly, because spacetime in a story is the narrative. and so the characters can break the fourth wall, and gravity is their agency within the narrative

[thickness-protection-program]

how does the density of black holes make time slow down? (is that real or just a myth?)

No it's very real. Gravity is the curvature of spacetime so the bigger the gravity is the deeper the curve and the slower time moves relative to you, since time is experienced differently for everyone. Imagine traveling in a straight line from point A to point B and let's say it takes maybe 5 minutes. Now imagine going straight from point A to B again but this time you have to go down a deep valley (gravity). Yes you made it but it took you maybe 20 minutes, your time has slowed. Now same scenario but this time the valley is imperceptibly deep, to the point where it might as well be a bottomless pit (a black hole). Time for you has essentially stopped by this point (at least that's what we on the outside would perceive) bc you are no longer moving through spacetime but down (for lack of a better term bc down is also a relative term). Nothing can escape the suckingham of gravity not even time itself

#did this answer your question

[z-and-the-space-child]

my head is all currently midnight burger podcast so here's everything i like about this wonderful piece of media:

it's pretty fun and very funny!! i smile like an idiot on public transport and on my way to class at least once a day listening to this.

the characters are so. idk how to describe them but theyre so full of life and you can tell that they are loved greatly by the creator(s)

the WRITING. i could seriously pluck a quote from damn near every episode to carry me through the day. i don't need affirmations i need gloria to talk me through my problems.

i was doing a lil analysis of the themes in this show and i came up with "the best thing you can ever do is the best thing you can do right now" and it is FUEL, babey.

The el triste monologue. also just gloria being a POC and being proud of herself and her culture. there's a lot of cultural mish-mash in podcasts, so this is very refreshing.

It's very, very sweet and heartfelt. kind of like wolf 359 if they communicated more instead of dodging their issues until they came to a peak (love them for it.)

the PHYSICS of it all. i'm a physics/astrophysics major because i think space and looking at the stars is my lifeblood so i won't shut up about it. i don't want ava and leif (certainly ava) to shut up about it ever. HOW much reasearch did they have to do to get this kinda grasp on it. im in awe, i'm LEARNING actual things from them. i could go on. the gravity waves, the stellar nuclear fusion, the time dilation of it all. and all without using over-flowery language!!! i can actually follow a good chunk of the time. are we sure ava didn't take one of those science communication seminars. maybe 5 phds does it. when she and leif talk i vibrate like an electron in a lazer. wonderful.

star sequencing??? stellar nucleosequencing??? right up my alley. thats my kinda stuff. the romanticization of space, i've seen. the romanticization of physics, however, is not something i haven't seen in such a beautiful modern fashion. (Ie, not oppenheimer or even richard feyman)

and it's not too science-y to the point that they think they can't have fun. yes they discuss the implications of gravity waves and wax poetic about space and pulsars. (it beats for you, berts) but they have FUN! they meet their parents because they can. they get a plant drunk. there's an atmosphere(?????) around the diner that allows them to fly around and mind-numbing speeds and look at the curvature of spacetime and also sit on the roof. (I imagine the entire place is the temperature of a summer night.) they have a whole wild west planet. leif builds things inexplicably. how? where does he get the materials??? shhhhh don't question it just let him have the gravity wave detector. nobody actually knows what engineers do, not even engineers. let him be. also time crystals??????

ALSO ava being a woman in stem and being so blunt yet covert about it. she's been dealing with it for so long. why are all (recognized) physicists a)white b) men c) both. it's such a sucky thing to work into because of the outward appearance. ava is a proud mad scientist which i aspire to so much. i am keeping her in my little arsenal of people to think about when i don't want to study. (picture the do it for her meme but it's pics of ava) I don't think i aptly put how much i love her. i'm not all the way finished yet but i've heard she was forced to marry someone? i think it would be a thing for sure if she cheated on him. so many physicists cheated on their spouses (wives ): ) and i think ava should also do it. as a treat. if that's what she'd like.

when people have done bad, bad things but show/are capable of redemption upon reflecting on their past/current shortcomings is just something that gets me so much directly in the heart. the hiddenness of people. the tragedy. we contain MULTITUDES and this show demonstrates that so well. how they support each other! they are everchanging and that's good for them. Leif the engineer the ex criminal the diner cook.

leif exploding a man in cold blood. if i could draw i'd draw that. maybe i will anyways.

food as a form of affection/way to bond. grief. doing your best. making amends. using the time you have. death is inevitable but that's okay.

And if time and tide roil you too harshly, or diurnal courses leave you with no safe havens, just remember we’re out there, somewhere, lookin’ for ya’

they open at six

#midnight burger #fiction podcasts #my rambles #hopefully this will get it out of my brain #i believe in womens (ava and gloria) rights and also their wrongs #we open at six

[oliviabutsmart]

Physics Friday #6: WTF is Dark Energy/Dark Matter? (Part 3)

Preamble

Education level: High School (Y9/10)

Topic: Cosmology (Astronomy)

This is the last part of the Dark Energy vs. Dark Matter post. In this part, I'm going to cover the possible ideas behind what dark energy is. And more importantly, what exactly it does.

From the last two parts, what you need to know is that:

The "cosmological constant" was created by Einstein in order keep general relativity in a flat universe. He later thought of this as a really bad mistake

We later found out that we do need this constant, so that we can explain the accelerating expansion of the universe

In the Friedmann equations, the cosmological constant appears as a sort-of 'negative' energy density

Introduction: So what does this whole "Dark Energy" thing mean?

The Equation with a bunch of Ω

Dark energy is great and all, but what does this substance really do? What actually happens because of an accelerating universe?

Well, let's take a look at the Freidman equations again, however this time, I'm going to rephrase it into something else:

Image source: Wikipedia

Now what do all these terms mean?

The H's are the Hubble constant (H0) and the Hubble parameter (H), are just expressions of how quickly the universe is expanding. The larger the value H the larger the expansion.

The a variable is the scale factor. It basically says how big the universe is at a particular point in time. To make things easy, we always set a = 1 at our present time. And at the big bang, a = 0 (the universe has no size).

These omegas are the interesting parts. They represent the density of particular substances in the universe. The omega term with the R in it, is the density of radiation (like light). The omega term with the M in it is the matter density. Lastly, the Λ term is the dark energy density.

The omega with the k in it is a sort of 'fake density' - it actually refers to the innate curvature of spacetime, however we can conveniently express it as a sort of 'density' of space itself.

Each of these omega terms are actually unitless. As they are the ratio between the actual density and the so-called 'critical density' - the density at which we achieve a flat spacetime.

How we get Expansion

So notice, how, the matter and radiation terms shrink very quickly with increasing scale factor? While because of E = mc^2 we know that these two are equivalent, radiation shrinks faster because it undergoes redshift whereas matter just becomes less dense.

Unlike this, dark energy always remains constant. This means that dark matter will always try to expand the universe at an accelerating rate, as if it's there, and it's constant, it will always be there.

Now there are multiple ways we can play around with end-of the universe scenarios, but we'll leave that for later.

A "big crunch" scenario occurs when there is no dark energy at all to counteract the pull of gravity. All of the universe's stuff starts falling into itself suddenly.

If the dark energy density is large enough, but the curvature of the universe is large enough to counteract this, we get a "big bounce" where the universe will start shrinking and then suddenly jump up into an expanding universe.

The "big chill", is simply where we have just the perfect mixture of everything that the universe continues to expand together.

But what if dark matter was not constant? What if more continued to get added, more and more?

What we'd get is the "big rip" where the density of dark matter overcomes the strongest of gravitational interactions.

Image source: my lecture notes

So What is it? What is it made of?

Just like dark matter, we need to find a source. Unlike dark matter, we're less concerned with what it's made of because we already kinda know what it does and how it behaves, and we know it's likely it's own thing.

But let's assess the properties of dark energy:

It is everywhere

It is of constant density; expansion and curvature does not affect the amount of it

It either is intrinsically tied to space itself or more of it keeps getting created as space expands

It behaves as a negative energy density, pushing space apart instead of pulling it together

Quintessence and Quantum Mechanics

So what this dark energy could be is some sort of quantum field, as fields permeate the entire universe, and aren't affected suddenly by a change in spacetime. In fact, they are special because they are locally invariant under changes in things like the speed of an observer.

Perhaps the vacuum itself has a constant negative energy density? You may object to that because it violates the conservation of energy. But conservation doesn't mean it all sums up to zero, it just means it sums up to the same number.

Under the quintessence model, there exists a new field, which has a non-zero potential energy. But unlike this "vacuum energy field", this new field, can change it's strength and can interact with gravity easier.

This changing strength is where we get models like the big rip. It can even explain the cosmological crisis, which is another future post for sure.

Related to Dark Matter?

As the title says, maybe dark energy and dark matter are very similar? Current theories of this form state that dark matter actually decays into dark energy.

And additionally, the DE/DM relation is related to by the mass-energy equivalence E = mc^2.

This type of dark energy would interact with itself via the method of dark matter.

Black Holes! Probably ...

When we do calculations in the universe we usually do them in isolation.

When we formulated the physics of black holes, we formulated them in isolation, and assumed that normal newton's laws just applied far away from the event horizon.

But what if we instead assumed that far out the space would follow the Friedmann solutions?

What we get is that black holes should gain mass as the universe expands. In fact they expand in such a way that the black hole energy density remains constant.

Perhaps this imitation of the effects of dark energy is the real dark energy.

Maybe we're just Wrong?

Perhaps the universe is not as homogenous as we think, and that the density of what we see changes as we look out into the universe. Maybe this explains the affects of redshift and distance models, and because of this, we see that the universe is expanding, when it's actually just a visual illusion caused by matter distributions.

There are many alternative solutions that try to explain away dark energy by simply showing that one of the other assumptions we make when doing cosmological calculations are wrong.

The problem with this is that it creates more questions than answers. Why would the universe not be homogenous? Why should our view of the universe suddenly change?

Conclusion

Well, it's clear that dark energy still remains pretty elusive. That we don't really know what it is. But I'd certainly say that the idea of it being a quantum field or effect of general relativity may be the right direction. The problem, of course, is that we might require a theory of quantum gravity to answer this sort of stuff.

These posts were a doozy, covering the discovery of, and the search for dark energy and dark matter. The topics obviously go much much much deeper, however I certainly hope I got into the weeds enough.

Both mysteries are really important to our modern-day understanding of cosmology and physics. They offer new ideas to fields, particles, or phenomena that might affect our perceptions of gravity itself.

Clearly gravity is part of the problem here, because both of these theories are related to gravity in some way, one on the local scale, and one on the global scale.

As always follow if you would like to see more of these posts! And please, feedback is very welcome.

Next week I was considering talking about thermodynamics, but I might want to do one on E = mc^2. I might actually want to poll this one. I know not a lot of people will vote on it but if I were to do anything else I would just flip a coin.

Edit: the poll is on this post

#physics friday #stemblr #astrophysics #physics #astronomy #academics #stem #science #dark energy

[vital-deloin]

As long as the known laws of physics remain true, these methods might be the closest way to achieving immortality that any creature within this Universe can experience: 1) by moving as quickly as possible through the fabric of spacetime, leveraging the effects of special relativity and relativistic time dilation, or 2) by getting as close as possible to the event horizon of a black hole, leveraging the effects of spacetime curvature and gravitational time dilation. ↓

[investmentassistant]

Einsteinian harmony of the universe: unraveling the mysteries of relativity

In the realm of physics, few concepts have captured the imagination and reshaped our understanding of the cosmos as profoundly as Albert Einstein's Theory of Relativity. Born out of Einstein's insatiable curiosity and quest for a deeper understanding of the universe, the theory has become a cornerstone of modern physics, fundamentally altering the way we perceive space, time, and gravity.

Einstein's leap of insight

At the dawn of the 20th century, Einstein set out to reconcile the principles of classical mechanics with the behavior of light. This intellectual journey culminated in the formulation of the Theory of Relativity, a revolutionary framework that encompasses both Special and General Relativity.

Special relativity: a cosmic twist on time and space

Special Relativity, the first component of Einstein's theory, introduces us to a cosmic dance where time and space are intertwined. As objects accelerate and approach the speed of light, time dilates, and lengths contract. Concepts like simultaneity and the absolute nature of time give way to a more flexible and dynamic understanding.

General relativity: gravity as the curvature of spacetime

General Relativity extends the theory to include the effects of gravity. Instead of perceiving gravity as a force between masses, Einstein proposed that massive objects, like planets and stars, curve the fabric of spacetime around them. This curvature dictates the motion of objects, giving rise to the familiar force of gravity that we experience.

Everyday impacts: from black holes to GPS

While the concepts might sound esoteric, the Theory of Relativity has practical implications. Black holes, once considered speculative, find their basis in General Relativity. Even the Global Positioning System (GPS) relies on corrections from Special Relativity to provide accurate location data due to the relativistic effects of satellites in motion.

The unfinished symphony: toward a unified theory

Despite its profound success, the Theory of Relativity is not the final chapter in our quest to understand the universe fully. The search for a unified theory, one that seamlessly combines the principles of General Relativity with those of quantum mechanics, remains a frontier of scientific exploration.

Conclusion

Albert Einstein's Theory of Relativity stands as a testament to the power of human intellect and curiosity. It has transformed our cosmic perspective, offering a framework to comprehend the vastness of the universe and the intricacies of its fabric. As we continue to peer into the mysteries of space and time, the Theory of Relativity remains a guiding light, illuminating the wondrous and ever-expanding cosmos that surrounds us.

[mysticstronomy]

HOW DO WE KNOW THE UNIVERSE IS INFINITE??

Blog#332

Saturday, September 16th, 2023

Welcome back,

The simplest cosmology that fits the large-scale characteristics of the universe is the so-called Friedmann—Lemaître—Robertson—Walker cosmology describing a spacetime that is homogeneous (same everywhere) and isotropic (has no preferred direction).

This simple cosmology is characterized, among other things, by a variable that represents spatial curvature. It can be positive, negative, or zero.

Our best observations to date strongly suggest that the universe has no spatial curvature. It may be expanding in time, but the geometry of space, at any given time, is Euclidean.

The simplest topology that corresponds to Euclidean geometry is that of flat, infinite space. So by Occam’s razor, i.e., the parsimony of assumptions, we can conclude that in the absence of evidence to the contrary, the universe appears infinite.

That does not mean that we know this for sure. In fact, there really is no way of knowing. What is beyond the limits of the observable universe is, well, not observable, not even in principle. So for all we know, just outside the observable universe there is a big bad wall.

Or a brane-type singularity. Or fire-breathing pink unicorns preventing us from going any further. Nature is under no obligation, after all, to behave in a manner that we humans call reasonable.

But in our experience, Nature by and large does behave reasonably, and we might expect it to continue behaving reasonably even beyond the boundaries of the observable universe. That expectation, combined with the observation that the universe appears to lack spatial curvature, leads to the concept of a spatially infinite universe.

Originally published on www-forbes-com

COMING UP!!

(Wednesday, September 20th, 2023)

"CAN HUMANS REALLY LIVE ON THE RED PLANET??"

#astronomy #outer space #alternate universe #astrophysics #universe #spacecraft #white universe #space #parallel universe #astrophotography #infinite #how will the universe end #cosmology #cosmos

[spacetimewithstuartgary]

Eventually everything will evaporate, not only black holes New theoretical research by Michael Wondrak, Walter van Suijlekom and Heino Falcke of Radboud University has shown that Stephen Hawking was right about black holes, although not completely. Due to Hawking radiation, black holes will eventually evaporate, but the event horizon is not as crucial as had been believed. Gravity and the curvature of spacetime cause this radiation too. This means that all large objects in the universe, like the remnants of stars, will eventually evaporate. Using a clever combination of quantum physics and Einstein’s theory of gravity, Stephen Hawking argued that the spontaneous creation and annihilation of pairs of particles must occur near the event horizon (the point beyond which there is no escape from the gravitational force of a black hole). A particle and its anti-particle are created very briefly from the quantum field, after which they immediately annihilate. But sometimes a particle falls into the black hole, and then the other particle can escape: Hawking radiation. According to Hawking, this would eventually result in the evaporation of black holes. Spiral In this new study the researchers at Radboud University revisited this process and investigated whether or not the presence of an event horizon is indeed crucial. They combined techniques from physics, astronomy and mathematics to examine what happens if such pairs of particles are created in the surroundings of black holes. The study showed that new particles can also be created far beyond this horizon. Michael Wondrak: ‘We demonstrate that, in addition to the well-known Hawking radiation, there is also a new form of radiation.’ Everything evaporates Van Suijlekom: ‘We show that far beyond a black hole the curvature of spacetime plays a big role in creating radiation. The particles are already separated there by the tidal forces of the gravitational field.’ Whereas it was previously thought that no radiation was possible without the event horizon, this study shows that this horizon is not necessary. Falcke: ‘That means that objects without an event horizon, such as the remnants of dead stars and other large objects in the universe, also have this sort of radiation. And, after a very long period, that would lead to everything in the universe eventually evaporating, just like black holes. This changes not only our understanding of Hawking radiation but also our view of the universe and its future.’ The study was published on 2 June in the leading journal “Physical Review Letters” of the American Physical Society (APS). Michael Wondrak is excellence fellow at Radboud University and an expert in quantum field theory. Walter van Suijlekom is a Professor of Mathematics at Radboud University and works on the mathematical formulation of physics problems. Heino Falcke is an award-winning Professor of Radio Astronomy and Astroparticle Physics at Radboud University and known for his work on predicting and making the first picture of a black hole.

#space #science #Astronomy #physics #news #cosmology #black holes

[poweredbystarlight]

Gravity is mutual attraction between all things with mass and energy

Determines the motion of planets, stars, galaxies, light

Gives weight to physical objects

Moon's gravity responsible for sub-lunar tides in oceans

Guides the growth of plants through gravitropism

Influences circulation of fluid in multicellular organisms

May play a role in immune system function and cell differentiation

Curvature of spacetime caused by uneven distribution of mass, causing uneven masses to move along geodesic lines (general theory of relativity)- most extreme example is a black hole

Has infinite range, but effects are are weaker as objects grow further

[factsandstuffbyd]

Time dilation is a fascinating and counterintuitive phenomenon predicted by Albert Einstein's theory of special relativity. It reveals that time is not absolute but is relative to the motion of an observer. When objects move at significant fractions of the speed of light or experience strong gravitational fields, time appears to pass differently for them compared to observers in a different frame of reference. This means that time "dilates" or stretches out, causing different rates of time passage for different observers. To understand how time dilation works in space, we must delve into the core principles of special relativity and explore its implications for our understanding of the universe.

In the early 20th century, Einstein revolutionized physics with his theory of special relativity, which introduced the concept of the speed of light being constant in all inertial reference frames. According to this theory, the laws of physics are the same for all non-accelerating observers, regardless of their relative motion. One of the profound consequences of this theory is the time dilation effect.

Time dilation occurs when objects travel at relativistic speeds, i.e., speeds approaching the speed of light (approximately 299,792,458 meters per second in a vacuum). The theory posits that the faster an object moves, the more time appears to slow down for it compared to a stationary observer. To the moving object, time seems to pass at a normal pace, but to an observer at rest, the moving object's time appears to pass more slowly. This relative difference in the passage of time is known as time dilation.

The formula that describes time dilation is derived from the Lorentz transformation, and it states that the time experienced by the moving object (Δt) is equal to the time experienced by the stationary observer (Δt_0) divided by the Lorentz factor (γ), which is dependent on the object's velocity (v) relative to the speed of light (c):

Δt = Δt_0 / γ

where γ = 1 / √(1 - (v^2 / c^2))

As an object's velocity approaches the speed of light (v → c), the Lorentz factor approaches infinity, causing time dilation to become increasingly significant. This effect has been confirmed through various experiments, such as the observation of cosmic ray particles that constantly bombard the Earth. These particles, which are moving at relativistic speeds, have a longer lifetime than predicted by their half-life when at rest, providing empirical evidence of time dilation.

Apart from relative motion, time dilation also occurs in the presence of strong gravitational fields. According to Einstein's general theory of relativity, gravity is not just a force but a curvature of spacetime caused by massive objects. In regions with intense gravity, such as around massive stars or black holes, spacetime is curved, and clocks closer to the gravitational source experience time at a slower rate than clocks further away. This phenomenon, known as gravitational time dilation, has been verified through precise experiments and measurements.

In summary, time dilation is a remarkable consequence of Einstein's theory of special relativity and general relativity. It reveals that time is not an absolute quantity but is affected by an object's motion or the presence of strong gravitational fields. As objects approach the speed of light or encounter intense gravity, time appears to slow down relative to observers in different reference frames. Time dilation has profound implications for our understanding of the universe, impacting everything from satellite navigation systems to the behavior of massive celestial bodies. Its exploration continues to shape our understanding of the fabric of spacetime and the fundamental nature of reality.

#space #astrophysics #astronomy #science #physics #time dilation #outer space