Showing posts with label Universe. Show all posts
Showing posts with label Universe. Show all posts
Thursday, April 11
Dark Energy Used to Map Universe
With 5,000 tiny robots in a mountaintop telescope, researchers can look 11 billion years into the past. The light from far-flung objects in space is just now reaching the Dark Energy Spectroscopic Instrument (DESI), enabling us to map our cosmos as it was in its youth and trace its growth to what we see today.
Understanding how our universe has evolved is tied to how it ends, and to one of the biggest mysteries in physics: dark energy, the unknown ingredient causing our universe to expand faster and faster.
To study dark energy's effects over the past 11 billion years, DESI has created the largest 3D map of our cosmos ever constructed, with the most precise measurements to date. This is the first time scientists have measured the expansion history of the young universe with a precision better than 1%, giving us our best view yet of how the universe evolved. READ MORE...
Friday, March 22
Deciphering the Dark
Dark energy’s role in propelling the universe’s accelerated expansion presents a pivotal challenge in astrophysics, driving ongoing research and space missions dedicated to uncovering the nature of this mysterious force.
Some 13.8 billion years ago, the universe began with a rapid expansion we call the Big Bang. After this initial expansion, which lasted a fraction of a second, gravity started to slow the universe down. But the cosmos wouldn’t stay this way. Nine billion years after the universe began, its expansion started to speed up, driven by an unknown force that scientists have named dark energy.
But what exactly is dark energy? The short answer is: We don’t know. But we do know that it exists, it’s making the universe expand at an accelerating rate, and approximately 68.3 to 70% of the universe is dark energy. READ MORE...
Wednesday, March 13
Alone in the Universe
Are we alone in the universe?
It's a question that's been posed again and again. Carl Sagan posed it in the 1970s as a NASA mission scientist as the agency prepared to send its twin Viking landers to Mars.
And nearly 50 years after the first of two landers touched down on Mars, we're no closer to an answer as to whether there's life — out there.
Scientists haven't stopped looking. In fact, they've expanded their gaze to places like Saturn's largest moon, Titan and Jupiter's moon Europa.
The search for life beyond planet earth continues to captivate. And NASA has upcoming missions to both moons. Could we be closer to answering that question Carl Sagan asked some 50 years ago? READ MORE...
And nearly 50 years after the first of two landers touched down on Mars, we're no closer to an answer as to whether there's life — out there.
Scientists haven't stopped looking. In fact, they've expanded their gaze to places like Saturn's largest moon, Titan and Jupiter's moon Europa.
The search for life beyond planet earth continues to captivate. And NASA has upcoming missions to both moons. Could we be closer to answering that question Carl Sagan asked some 50 years ago? READ MORE...
Sunday, March 10
The Dawn of Time
We finally know what brought light to the dark and formless void of the early Universe.
According to data from the Hubble and James Webb Space Telescopes, the origins of the free-flying photons in the early cosmic dawn were small dwarf galaxies that flared to life, clearing the fog of murky hydrogen that filled intergalactic space.
"This discovery unveils the crucial role played by ultra-faint galaxies in the early Universe's evolution," says astrophysicist Iryna Chemerynska of the Institut d'Astrophysique de Paris.
"They produce ionizing photons that transform neutral hydrogen into ionized plasma during cosmic reionization. It highlights the importance of understanding low-mass galaxies in shaping the Universe's history." READ MORE...
Tuesday, February 27
Materialism Matters
A short disclaimer before we read further: I’m a materialist. Materialism is a branch of philosophy to which the sciences, particularly the physical and life sciences, owe a lot. Materialism posits that the material world — matter — exists, and everything in the Universe, including consciousness, is made from or is a product of matter. An objective reality exists and we can understand it. Without materialism, physics, chemistry, and biology as we know it wouldn’t exist.
Another branch of philosophy, idealism, is in direct contradiction to materialism. Idealism states that, instead of matter, the mind and consciousness are fundamental to reality; that they are immaterial and therefore independent of the material world.
A lot of scientists and researchers don’t necessarily have a conscious philosophy, or else don’t consider philosophy to be particularly relevant to their day-to-day work. But by not having a conscious philosophy, scientists – like anyone else – can unconsciously pick up other philosophies and outlooks in the society around them. READ MORE...
Saturday, January 20
Searching for the Universe's Missing Pieces
Scientists at the Large Hadron Collider are probing new particles beyond the Standard Model of Particle Physics, aiming to unravel its limitations and foster advancements in technology.
It seemed like the Standard Model of Particle Physics was complete with the discovery of the Higgs boson particle in 2012. The Standard Model is physicists’ current best explanation of the major building blocks of the universe and three out of four of the major forces.
But there are still a number of mysteries that the Standard Model simply can’t explain. These include dark matter and dark energy. Physicists supported by the Department of Energy (DOE) are trying to figure out if there are particles and forces beyond those in the Standard Model, and if so, what they are. READ MORE...
Tuesday, January 16
A Cosmological Mystery
Astronomers have discovered a cosmic "ring" that's so enormous, it defies explanation with our best theories of the universe.
Named the Big Ring, the gigantic spiral of galaxies and galaxy clusters is 1.3 billion light-years wide and has a circumference of 4 billion light-years, making it one of the largest objects ever seen.
Because the Big Ring is so far from Earth — 9 billion light-years away — its light is too dim to be viewed with the naked eye. But if it were brighter, it would appear 15 times the size of the full moon in the night sky. READ MORE...
Tuesday, January 9
Cosmological Distance Measurements
Measurements of the distance to extragalactic sources allow us to infer the major energy constituents of our Universe.
Two decades ago such measurements revealed that most of the energy in the Universe is in `dark energy’ — a discovery that has had immense implications for fundamental physics.
Currently there is a 10% discrepancy in cosmic distances inferred with the two most accepted techniques, despite 1-2% errors claimed on both methods, with the model that is most successful at reconciling this discrepancy being an earlier era where something like dark energy was again important.
Interpreting mild tensions can be challenging and ideally a much more precise measurement would be performed. Such a measurement could also lead to entirely new discoveries. READ MORE...
Friday, December 1
Observing Something Rare
Astronomers have observed a rare instance of a solar system inside the Milky Way whose planets orbit in sync around their host star, according to a study published yesterday. Researchers believe the motion of the planets has remained virtually unchanged since the system's formation roughly 4 billion years ago.
The four closest planets display what is known as 3:2 resonance—for every three orbits a planet makes around the host star, the next farthest planet completes two orbits. The next two planets display a similar 4:3 resonance. Typically, newborn systems are knocked out of balance by some disruptive event (for example, collisions with asteroids). Because the planets in question have maintained their original orbits, their study is expected to shed light on the early stages of star system formation.
The host star is also the brightest discovered to date to have more than four planets orbiting around it. Visualize the motion of the six planets here.
Tuesday, September 19
Blobs of Dark Matter
Dark matter fluctuations in the lens system MG J0414+0534. The whitish blue color represents the gravitationally lensed images observed by ALMA. The calculated distribution of dark matter is shown in orange; brighter regions indicate higher concentrations of dark matter and dark orange regions indicate lower concentrations. Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue et al.
Astronomers Observe Blobs of Dark Matter Down to a Scale of 30,000 Light-Years Across
Dark matter remains mysterious and… well… dark. While we don’t yet have a definite idea of what this cosmic “stuff” is made of, astronomers are learning more about its distribution throughout the Universe.
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Since we can’t see it directly, observers need to use indirect methods to detect it. One way is through gravitational lensing. Another is by looking for emissions from hydrogen gas associated with small-scale dark matter structures in the Universe.
A group of astronomers led by Kaiki Taro Inoue of Kindai University in Japan used the Atacama Large Millimeter Array in Chile to study a distant gravitational lens system called MG J0414+534. A massive foreground galaxy is bending and distorting the light from a distant quasar that lies some 11 billion light-years away.
A group of astronomers led by Kaiki Taro Inoue of Kindai University in Japan used the Atacama Large Millimeter Array in Chile to study a distant gravitational lens system called MG J0414+534. A massive foreground galaxy is bending and distorting the light from a distant quasar that lies some 11 billion light-years away.
The result is four images of the quasar. When they looked at the data, the team found some strange anomalies in the images. They are actually variations in the distribution of dark matter along the line of sight between us and the quasar.
The gravitational lens magnified the fluctuations and analysis of the data allowed them to map the fluctuations down to a scale of 30,000 light-years.
What The Blobs of Dark Matter Mean
Throughout the universe, dark matter is associated with massive galaxies and galaxy clusters. However, small-scale clumps and distributions aren’t as well understood. So, astronomers want to find ways to map the smaller concentrations of it. Gravitational lensing provides one way to do that.
What The Blobs of Dark Matter Mean
Throughout the universe, dark matter is associated with massive galaxies and galaxy clusters. However, small-scale clumps and distributions aren’t as well understood. So, astronomers want to find ways to map the smaller concentrations of it. Gravitational lensing provides one way to do that.
In the case of MG J0414+0534, the positions and shapes of the lensed quasar images look a little strange. They don’t fit the model of gravitational lensing predicted when you plug in the numbers for the galaxy and its associated dark matter component. READ MORE...
Tuesday, August 29
FIFTH Fundamental Force of Nature
Quarks and antiquarks, which interact with the strong nuclear force, have color charges that correspond to red, green, and blue (for the quarks) and cyan, magenta, and yellow (for the antiquarks). Any colorless combination, of either red + green + blue, cyan + yellow + magenta, or the appropriate color/anticolor combination, is permitted under the rules of the strong force. If new phenomena appear in these well-studied systems, they could be indicative of a new fundamental force beyond the known four.
Back in the late 1800s, only two forces, electromagnetism and gravity, were thought to describe all of the interactions that occurred in the Universe.
Over the 20th century, new phenomena resulted in the discovery of two more fundamental forces: the strong and weak nuclear forces, revealed by precise high-energy experiments.
Now, in the 21st century, more precise experiments than ever before are occurring, and each anomaly holds the tantalizing possibility of revealing a new fundamental force. Will we ever find a 5th?
Despite all we’ve learned about the nature of the Universe — from a fundamental, elementary level to the largest cosmic scales fathomable — we’re absolutely certain that there are still many great discoveries yet to be made.
Our current best theories are spectacular: quantum field theories that describe the electromagnetic interaction as well as the strong and weak nuclear forces on one hand, and General Relativity describing the effects of gravity on the other hand.
Wherever they’ve been challenged, from subatomic up to cosmic scales, they’ve always emerged victorious. And yet, they simply cannot represent all that there is.
There are many puzzles that hint at this. We cannot explain why there’s more matter than antimatter in the Universe with current physics.
There are many puzzles that hint at this. We cannot explain why there’s more matter than antimatter in the Universe with current physics.
Nor do we understand what dark matter’s nature is, whether dark energy is anything other than a cosmological constant, or precisely how cosmic inflation occurred to set up the conditions for the hot Big Bang.
And, at a fundamental level, we do not know whether all of the known forces unify under some overarching umbrella in some way.
We have clues that there’s more to the Universe than what we presently know, but is a new fundamental force among them? Believe it or not, we have two completely different approaches to try and uncover the answer to that. READ MORE...
We have clues that there’s more to the Universe than what we presently know, but is a new fundamental force among them? Believe it or not, we have two completely different approaches to try and uncover the answer to that. READ MORE...
De all we’ve learned about the nature of the Universe — from a fundamental, elementary level to the largest cosmic scales fathomable — we’re absolutely certain that there are still many great discoveries yet to be made. Our current best theories are spectacular: quantum field theories that describe the electromagnetic interaction as well as the strong and weak nuclear forces on one hand, and General Relativity describing the effects of gravity on the other hand. Wherever they’ve been challenged, from subatomic up to cosmic scales, they’ve always emerged victorious. And yet, they simply cannot represent all that there is.
TOP STORIES
Top Stories00:0501:00Recognize the “performance paradox” and break freefrom stagnation at work
There are many puzzles that hint at this. We cannot explain why there’s more matter than antimatter in the Universe with current physics. Nor do we understand what dark matter’s nature is, whether dark energy is anything other than a cosmological constant, or precisely how cosmic inflation occurred to set up the conditions for the hot Big Bang. And, at a fundamental level, we do not know whether all of the known forces unify under some overarching umbrella in some way.
We have clues that there’s more to the Universe than what we presently know, but is a new fundamental force among them? Believe it or not, we have two completely different approaches to try and uncover the answer to that.
TOP STORIES
Top Stories00:0501:00Recognize the “performance paradox” and break freefrom stagnation at work
There are many puzzles that hint at this. We cannot explain why there’s more matter than antimatter in the Universe with current physics. Nor do we understand what dark matter’s nature is, whether dark energy is anything other than a cosmological constant, or precisely how cosmic inflation occurred to set up the conditions for the hot Big Bang. And, at a fundamental level, we do not know whether all of the known forces unify under some overarching umbrella in some way.
We have clues that there’s more to the Universe than what we presently know, but is a new fundamental force among them? Believe it or not, we have two completely different approaches to try and uncover the answer to that.
Thursday, August 17
Evidence that Gravity is Breaking Down the Universe
A scientist claims to have discovered a “gravitational anomaly” that calls into question our fundamental understanding of the universe.
Astronomer Kyu-Hyun Chae from the university of Sejong University in South Korea made the discovery while studying binary star systems, which refer to two stars that orbit each other.
His observations appear to go against the standard gravitational models established by Isaac Newton and Albert Einstein, and instead offer evidence that an alternative theory first proposed in the 1980s may explain the anomaly.
Analysis of data collected by the European Space Agency’s Gaia space telescope revealed accelerations of stars in binaries that did not fit the standard gravitational models.
At accelerations of lower than 0.1 nanometres per second squared, the orbit of the two stars deviated from Newton’s universal law of gravitation and Einstein’s general relativity.
Instead, Professor Chae theorised that a model known as Modified Newtonian Dynamics (MOND) could explain why these previous theoretical frameworks were unable to explain the stars’ movements.
“The deviation represents a direct evidence for the breakdown of standard gravity at weak acceleration,” Professor Chae wrote in a paper, titled ‘Breakdown of the Newton-Einstein standard gravity at low acceleration in internal dynamics of wide binary stars’, that was published in The Astrophysics Journal. READ MORE...
Friday, August 11
Star Older Then Universe
The star HD 140283 has been called the "Methuselah star" for its extreme age. At an estimated over 14 billion years old, it’s the oldest star we know, at least within our galaxy. A star that old is certainly interesting, particularly when it is so close to us it can be seen with binoculars, however, that appears to put it older than the universe. How that can be? A closer examination reveals the star is special, but not that special.
The standard estimate of the time since the Big Bang is 13.79 billion years. The figure is derived from the rate of expansion of the universe using Einstein's relativity but has been validated through a variety of methods. However, that number is now facing at least three distinct challenges. As evidence, proponents point to the existence of stars estimated to be either older than 13.8 billion years, or so close to that age that there shouldn’t have been time for them to form.
Not surprisingly HD 140283 gets prime billing (helped by its catchy nickname derived from a Biblical ancestor of Noah said to have lived to 969) due to a 2013 study using Hubble data that estimated it is 14.46 billion years old, plus or minus 800 million years. That would make it potentially older than the universe.
The biggest claim regarding HD 140283 is that it disproves the Big Bang. After all, if there is even one star 14.5 billion years old then the explosion that started the universe couldn’t have happened less than 14 billion years ago. The Big Bang is now so central to our cosmology that were it to be disproved it would create a scientific revolution the like of which we have not seen for a long time.
A smaller, but still dramatic, change would be required to adapt to the recent claim that the Big Bang happened, but almost twice as long ago as most estimates put it, at 26.7 billion years ago.
Neither of these views has much support among astrophysicists, but some do suspect we’ve got our estimates of the timing of the Big Bang more modestly wrong, and the universe is really around 15 billion years old. Although such an estimate would raise a few questions about why our estimates for the universe’s expansion rate are out, if proven, accompanying changes to our thinking would be evolutionary not revolutionary.
In that context, it’s worth asking: if the universe was 26 billion years old, wouldn’t we expect to find 20 billion-year-old stars? It’s true we’ve only really looked across a small portion of the galaxy, but if the universe is that old, Methuselah looks suspiciously young. Then take that question a step further and ask what we might expect to see if the universe had no beginning and has always been here. READ MORE...
Tuesday, June 27
Sunday, June 25
Universe Expansion Could be a Mirage
Astronomers use the light from distant stars, such as the Helix Nebula seen here, to measure the apparent expansion of the universe. New resaerch suggests there may be more to the pictue that we're not seeing. (Image credit: NASA/JPL-Caltech/SSC)
The expansion of the universe could be a mirage, a potentially controversial new study suggests. This rethinking of the cosmos also suggests solutions for the puzzles of dark energy and dark matter, which scientists believe account for around 95% of the universe's total energy and matter but remain shrouded in mystery.
The novel new approach is detailed in a paper published June 2 in the journal Classical and Quantum Gravity, by University of Geneva professor of theoretical physics Lucas Lombriser.
Scientists know the universe is expanding because of redshift, the stretching of light's wavelength towards the redder end of the spectrum as the object emitting it moves away from us.
The expansion of the universe could be a mirage, a potentially controversial new study suggests. This rethinking of the cosmos also suggests solutions for the puzzles of dark energy and dark matter, which scientists believe account for around 95% of the universe's total energy and matter but remain shrouded in mystery.
The novel new approach is detailed in a paper published June 2 in the journal Classical and Quantum Gravity, by University of Geneva professor of theoretical physics Lucas Lombriser.
Scientists know the universe is expanding because of redshift, the stretching of light's wavelength towards the redder end of the spectrum as the object emitting it moves away from us.
Distant galaxies have a higher redshift than those nearer to us, suggesting those galaxies are moving ever further from Earth.
More recently, scientists have found evidence that the universe's expansion isn't fixed, but is actually accelerating faster and faster. This accelerating expansion is captured by a term known as the cosmological constant, or lambda.
The cosmological constant has been a headache for cosmologists because predictions of its value made by particle physics differ from actual observations by 120 orders of magnitude. The cosmological constant has therefore been described as "the worst prediction in the history of physics."
Cosmologists often try to resolve the discrepancy between the different values of lambda by proposing new particles or physical forces but Lombriser tackles it by reconceptualizing what's already there. READ MORE...
More recently, scientists have found evidence that the universe's expansion isn't fixed, but is actually accelerating faster and faster. This accelerating expansion is captured by a term known as the cosmological constant, or lambda.
The cosmological constant has been a headache for cosmologists because predictions of its value made by particle physics differ from actual observations by 120 orders of magnitude. The cosmological constant has therefore been described as "the worst prediction in the history of physics."
Cosmologists often try to resolve the discrepancy between the different values of lambda by proposing new particles or physical forces but Lombriser tackles it by reconceptualizing what's already there. READ MORE...
Saturday, May 6
Spacetime - Is It Real?
An illustration of heavily curved spacetime, outside the event horizon of a black hole. As you get closer and closer to the mass’s location, space becomes more severely curved, eventually leading to a location from within which even light cannot escape: the event horizon. At large distances, the spatial curvature is indistinguishable for equal mass black holes, neutron stars, white dwarfs, or any other comparably massed object. Credit: JohnsonMartin/Pixabay
When most of us think about the Universe, we think about the material objects that are out there across the great cosmic distances. Matter collapses under its own gravity to form cosmic structures like galaxies, while gas clouds contract to form stars and planets. Stars then emit light by burning their fuel through nuclear fusion, and then that light travels throughout the Universe, illuminating anything it comes into contact with.
But there’s more to the Universe than the objects within it. There’s also the fabric of spacetime, which has its own set of rules that it plays by: General Relativity. The fabric of spacetime is curved by the presence of matter and energy, and curved spacetime itself tells matter and energy how to move through it.
But what, exactly, is the physical nature of spacetime? Is it a real, physical thing, like atoms are, or is it merely a calculational tool that we use to give the right answers for the motion and behavior of the matter within the Universe?
It’s an excellent question and a tough one to wrap your head around. Moreover, before Einstein came along, our conception of the Universe was very different from the one we have today. Let’s go way back to the Universe before we even had the concept of spacetime, and then come forward to where we are today.
But what, exactly, is the physical nature of spacetime? Is it a real, physical thing, like atoms are, or is it merely a calculational tool that we use to give the right answers for the motion and behavior of the matter within the Universe?
It’s an excellent question and a tough one to wrap your head around. Moreover, before Einstein came along, our conception of the Universe was very different from the one we have today. Let’s go way back to the Universe before we even had the concept of spacetime, and then come forward to where we are today.
The journey from macroscopic scales down to subatomic ones spans many orders of magnitude, but going down in small steps can make each new one more accessible from the previous one. Humans are made of organs, cells, organelles, molecules, atoms, then electrons and nuclei, then protons and neutrons, and then quarks and gluons inside of them. This is the limit to how far we’ve ever probed nature.Credit: Magdalena Kowalska/CERN/ISOLDE team
At a fundamental level, we had long supposed that if you took everything that was in the Universe and cut it up into smaller and smaller constituents, you’d eventually reach something that was indivisible. Quite literally, that’s what the word “atom” means: from the Greek ἄτομος: not able to be cut.
The first record we have of this idea goes back some 2400 years to Democritus of Abdera, but it’s plausible that it may go back even farther. These “uncuttable” entities do exist; each one is known as a quantum particle. Despite the fact that we took the name “atom” for the elements of the periodic table, it’s actually subatomic particles like quarks, gluons, and electrons (as well as particles that aren’t found in atoms at all) that are truly indivisible. READ MORE...
Thursday, April 20
Rewriting Laws of the Universe
When we look out at the night sky across vast, cosmic distances using our most sensitive and advanced telescopes, we look back in time. Einstein taught us that light has a finite speed; therefore, it takes light longer to travel to us the further one looks.
Thanks to this, cosmologists have been able to see light dating back to about 14 billion years ago. This light reveals something spectacular and mysterious – the Universe is filled with a sea of energy, waves of tangled electrons and photons in the form of a hot fluid, known as a plasma. We call this plasma the Cosmic Microwave Background (CMB).
We cosmologists have precise theoretical and observational evidence that this plasma underwent gravitational collapse with the aid of an invisible form of matter, called dark matter, forming the first stars and eventually forming the organised superstructure that inhabits the current Universe.
However, a mystery still lurked: the properties of this sea of energy seem to originate from what Einstein called “spooky action-at-a-distance” - objects communicating with each other at instantaneous speeds across ridiculously large distances. This is known as the horizon problem.
In 1981, my colleague, Alan Guth of MIT, proposed an elegant solution to this problem. The idea was to introduce a new player called the inflation field that filled the Universe, and whose energy caused space to expand extremely rapidly. The repulsion that arises due to gravitational effects caused by inflation neatly solves the horizon problem – it makes those regions that we thought to be spookily interacting subject to the weird, but well-confirmed, laws of quantum physics.
The theory of cosmic inflation also provided us with a physical mechanism that answers a question that had long troubled cosmologists: how did the seeds of structure originate in a seemingly featureless primordial Universe over 14 billion years ago? READ MORE...
Sunday, April 16
Is There Really a Multiverse?
The notion of parallel universes leapt out of the pages of fiction into scientific journals in the 1990s. Many scientists claim that mega-millions of other universes, each with its own laws of physics, lie out there, beyond our visual horizon. They are collectively known as the multiverse.- The trouble is that no possible astronomical observations can ever see those other universes. The arguments are indirect at best. And even if the multiverse exists, it leaves the deep mysteries of nature unexplained.
In the past decade an extraordinary claim has captivated cosmologists: that the expanding universe we see around us is not the only one; that billions of other universes are out there, too. There is not one universe—there is a multiverse.
In Scientific American articles and books such as Brian Greene’s latest, The Hidden Reality, leading scientists have spoken of a super-Copernican revolution. In this view, not only is our planet one among many, but even our entire universe is insignificant on the cosmic scale of things. It is just one of countless universes, each doing its own thing.
The word “multiverse” has different meanings. Astronomers are able to see out to a distance of about 42 billion light-years, our cosmic visual horizon. We have no reason to suspect the universe stops there. Beyond it could be many—even infinitely many—domains much like the one we see.
The word “multiverse” has different meanings. Astronomers are able to see out to a distance of about 42 billion light-years, our cosmic visual horizon. We have no reason to suspect the universe stops there. Beyond it could be many—even infinitely many—domains much like the one we see.
Each has a different initial distribution of matter, but the same laws of physics operate in all. Nearly all cosmologists today (including me) accept this type of multiverse, which Max Tegmark calls “level 1.” Yet some go further. They suggest completely different kinds of universes, with different physics, different histories, maybe different numbers of spatial dimensions.
Most will be sterile, although some will be teeming with life. A chief proponent of this “level 2” multiverse is Alexander Vilenkin, who paints a dramatic picture of an infinite set of universes with an infinite number of galaxies, an infinite number of planets and an infinite number of people with your name who are reading this article.
Similar claims have been made since antiquity by many cultures. What is new is the assertion that the multiverse is a scientific theory, with all that implies about being mathematically rigorous and experimentally testable. I am skeptical about this claim.
Similar claims have been made since antiquity by many cultures. What is new is the assertion that the multiverse is a scientific theory, with all that implies about being mathematically rigorous and experimentally testable. I am skeptical about this claim.
I do not believe the existence of those other universes has been proved—or ever could be. Proponents of the multiverse, as well as greatly enlarging our conception of physical reality, are implicitly redefining what is meant by “science.” READ MORE...
Wednesday, April 12
Our Universe - Gravity Creates Light
A star is being consumed by a distant supermassive black hole. Astronomers call this a tidal disruption event (TDE). As the black hole rips apart the star, two jets of material moving with almost the speed of light are launched in opposite directions. One of the jets was aimed directly at Earth. Image credit: Carl Knox (OzGrav, ARC Centre of Excellence for Gravitational Wave Discovery, Swinburne University of Technology)
Physicists Discover that Gravity Can Create Light
Researchers have discovered that in the exotic conditions of the early universe, waves of gravity may have shaken space-time so hard that they spontaneously created radiation.
The physical concept of resonance surrounds us in everyday life. When you’re sitting on a swing and want to go higher, you naturally start pumping your legs back and forth. You very quickly find the exact right rhythm to make the swing go higher. If you go off rhythm then the swing stops going higher. This particular kind of phenomenon is known in physics as a parametric resonance.
Your legs act as an external pumping mechanism. When they match the resonant frequency of the system, in this case your body sitting on a swing, they are able to transfer energy to the system making the swing go higher.
These kinds of resonances happen all over the place, and a team of researchers have discovered that an exotic form of parametric resonance may have even occurred in the extremely early universe.
Perhaps the most dramatic event to occur in the entire history of the universe was inflation. This is a hypothetical event that took place when our universe was less than a second old. During inflation our cosmos swelled to dramatic proportions, becoming many orders of magnitude larger than it was before. The end of inflation was a very messy business, as gravitational waves sloshed back and forth throughout the cosmos. READ MORE...
Monday, April 10
Understanding our Universe
A new study amplifies the Hubble tension, a discrepancy in cosmic expansion rate measurements, by providing the most accurate calibration of Cepheid stars for distance measurements. This discrepancy calls into question fundamental concepts in physics and has implications for understanding dark energy, the time-space continuum, and gravity.
When it comes to measuring how fast the Universe is expanding, the result depends on which side of the Universe you start from. An EPFL study has calibrated the best cosmic yardsticks to unprecedented accuracy, shedding new light on the Hubble tension.
The Hubble tension, a discrepancy in the cosmic expansion rate (H0) between early Universe and late Universe measurement methods, has puzzled astrophysicists and cosmologists.
The Hubble tension, a discrepancy in the cosmic expansion rate (H0) between early Universe and late Universe measurement methods, has puzzled astrophysicists and cosmologists.
A study by the Stellar Standard Candles and Distances research group at EPFL’s Institute of Physics has achieved the most accurate calibration of Cepheid stars for distance measurements, amplifying the Hubble tension. The discrepancy calls into question the basic concepts of physics and has implications for the nature of dark energy, the time-space continuum, and gravity.
The Universe is expanding – but how fast exactly? The answer appears to depend on whether you estimate the cosmic expansion rate – referred to as the Hubble’s constant, or H0 – based on the echo of the Big Bang (the cosmic microwave background, or CMB) or you measure H0 directly based on today’s stars and galaxies. This problem, known as the Hubble tension, has puzzled astrophysicists and cosmologists around the world.
A study carried out by the Stellar Standard Candles and Distances research group, lead by Richard Anderson at EPFL’s Institute of Physics, adds a new piece to the puzzle.
The Universe is expanding – but how fast exactly? The answer appears to depend on whether you estimate the cosmic expansion rate – referred to as the Hubble’s constant, or H0 – based on the echo of the Big Bang (the cosmic microwave background, or CMB) or you measure H0 directly based on today’s stars and galaxies. This problem, known as the Hubble tension, has puzzled astrophysicists and cosmologists around the world.
A study carried out by the Stellar Standard Candles and Distances research group, lead by Richard Anderson at EPFL’s Institute of Physics, adds a new piece to the puzzle.
Their research, published today (April 4) in the journal Astronomy & Astrophysics, achieved the most accurate calibration of Cepheid stars – a type of variable star whose luminosity fluctuates over a defined period – for distance measurements to date based on data collected by the European Space Agency’s (ESA’s) Gaia mission. This new calibration further amplifies the Hubble tension. READ MORE...
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