Scientists have recreated the first matter that appeared after the Big Bang in the Large Hadron Collider.
Category: cosmology – Page 288
Gravitational Waves Will Soon Lift Veil On Black Holes, Says Portuguese Astrophysicist
Of the cosmos’ four fundamental forces, gravity is the one that grasps us even before we exit the womb. From our first few minutes of life until we lose the fight to lift our heads from death’s pillow, this weakest of nature’s fundamental forces continues to elude researchers.
In the last few years, however, gravitational wave astronomy has made great strides in detecting gravitational radiation rippling through spacetime at the speed of light.
Einstein first predicted that any accelerating mass should emit gravitational radiation in the form of waves. Gravitational waves were first indirectly detected almost 20 years ago. But it was only recently, in 2,015 that the ground-based LIGO (Laser Interferometer Gravitational-wave Observatory) detected waves from two merging stellar mass black holes over a billion light years distant in the general direction of the Southern Hemisphere’s Magellanic Clouds.
Look: Largest-ever catalog of gravitational-wave events
In 2,015 researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) captured the first direct evidence of gravitational waves, more than a century after the phenomenon was first proposed.
Gravitational-wave events have only been detectable for a few years, and a new study shows the remarkable diversity of waves caused by black hole mergers.
SEVEN CONVERGING TECHNOLOGICAL FUNCTIONS WILL PERMANENTLY CHANGE CITIZEN ASTRONOMY
By Jeremy Batterson 11-09-2021
The equivalent of cheap 100-inch binoculars will soon be possible. This memo is a quick update on seven rapidly converging technologies that augur well for astronomy enthusiasts of the near future. All these technologies already exist in either fully developed or nascent form, and all are being rapidly improved due to the gigantic global cell phone market and the retinal projection market that will soon replace it. Listed here are the multiple technologies, after which they are brought together into a single system.
1) Tracking.
2) Single-photon image sensing.
3) Large effective exit pupils via large sensors.
4) Long exposure non-photographic function.
5) Flat optics (metamaterials)
6) Off-axis function of flat optics.
7) Retinal projection.
1) TRACKING: this is already being widely used in so-called “go-to” telescopes, where the instrument will find any object and track it, so Earth’s rotation does not take the object viewed out of the field of vision. The viewer doesn’t have to find the object and doesn’t have to set up the clock drive to track it. Tracking is also partly used in image stabilization software for cameras and smart phones, to prevent motion blurring of images.
2) SINGLE-PHOTON IMAGE SENSORS, whether of the single-photon avalanching diode type, or the type developed by Dr. Fossum, will allow passive imaging in nearly totally dark environments, without the use of IR or other illumination. This new type of image sensor will replace the monochromatic analogue “night-vision” devices, allowing color imaging at higher resolution than they can produce. Unlike these current devices, such sensors will not be destroyed by being exposed to normal or high lighting. Effectively, these sensors increase the effective light-gathering power of a telescope by at least an order of magnitude, allowing small telescopes to see what observatory telescopes see now.
3) EXIT PUPIL: The pupil of the dark-adapted human eye is around 7mm, which means light exiting a telescope must not have a wider-cross axis than this, or a percent of the light captured by the objective lens or mirror will be lost. If the magnification of a system is lowered, to give brighter images, this is limited by this roadblock. This is a well-known problem for visual astronomers. Astro-photographers get around this by two tricks. The first is to use a photographic sensor wider than 7mm, allowing a larger exit pupil and thus brighter images. A 1-inch sensor or photographic plate, for example, already allows an image thirteen times brighter than what a 7mm human pupil can see.
4) LONG EXPOSURE: The other trick astro-photographers use is to keep the shutter of their cameras open for longer periods, thus capturing more light, and allowing a bright image of a faint object to build up over time. As a telescope tracks the stars–so that they appear motionless in the telescopic view–this can be done for hours. The Hubble Space Telescope took a 100 hour long-exposure photograph leading to the famous “deep field” of ultra-faint distant galaxies. An example of a visual use of the same principle is the Sionyx Pro camera, which keeps the shutter open for a fraction of a second. If the exposures are short enough, a video can be produced which appears brighter than what the unaided eye sees. Sionyx adds to this with its black-silicon sensors, which are better at retaining all light that hits them. For astronomy, where stellar objects do not move and do not cause blurring if they are tracked, longer exposures can be created, with the image rapidly brightening as the viewer watches. Unistellar’s eVscope and Vaonis’s Stellina telescope, already use this function, but without an eyepiece. Instead, their images are projected onto people’s cell phones or other viewing devices. However, most astronomers want to be able to see something directly with their eyes, which is a limiting point on such types of telescopes.
Scientists detect a ‘tsunami’ of gravitational waves
A team of international scientists, including researchers from The Australian National University (ANU), have unveiled the largest number of gravitational waves ever detected.
The discoveries will help solve some of the most complex mysteries of the Universe, including the building blocks of matter and the workings of space and time.
The global team’s study, published on ArXiv, made 35 new detections of gravitational waves caused by pairs of black holes merging or neutron stars and black holes smashing together, using the LIGO and Virgo observatories between November 2019 and March 2020.
Loop Quantum Cosmology Theory: Cosmic Tango Between the Very Small and the Very Large
Theory of loop quantum cosmology describes how tiny primordial features account for anomalies at the largest scales of the universe.
While Einstein’s theory of general relativity can explain a large array of fascinating astrophysical and cosmological phenomena, some aspects of the properties of the universe at the largest-scales remain a mystery. A new study using loop quantum cosmology—a theory that uses quantum mechanics to extend gravitational physics beyond Einstein’s theory of general relativity—accounts for two major mysteries. While the differences in the theories occur at the tiniest of scales—much smaller than even a proton—they have consequences at the largest of accessible scales in the universe. The study, which was published online on July 29 2020, in the journal Physical Review Letters, also provides new predictions about the universe that future satellite missions could test.
While a zoomed-out picture of the universe looks fairly uniform, it does have a large-scale structure, for example because galaxies and dark matter are not uniformly distributed throughout the universe. The origin of this structure has been traced back to the tiny inhomogeneities observed in the Cosmic Microwave Background (CMB)—radiation that was emitted when the universe was 380 thousand years young that we can still see today. But the CMB itself has three puzzling features that are considered anomalies because they are difficult to explain using known physics.
We now know the big bang theory is (probably) not how the universe began
The Big Bang still happened a very long time ago, but it wasn’t the beginning we once supposed it to be.
Where did all this come from? In every direction we care to observe, we find stars, galaxies, clouds of gas and dust, tenuous plasmas, and radiation spanning the gamut of wavelengths: from radio to infrared to visible light to gamma rays. No matter where or how we look at the universe, it’s full of matter and energy absolutely everywhere and at all times. And yet, it’s only natural to assume that it all came from somewhere. If you want to know the answer to the biggest question of all — the question of our cosmic origins — you have to pose the question to the universe itself, and listen to what it tells you.
Today, the universe as we see it is expanding, rarifying (getting less dense), and cooling. Although it’s tempting to simply extrapolate forward in time, when things will be even larger, less dense, and cooler, the laws of physics allow us to extrapolate backward just as easily. Long ago, the universe was smaller, denser, and hotter. How far back can we take this extrapolation? Mathematically, it’s tempting to go as far as possible: all the way back to infinitesimal sizes and infinite densities and temperatures, or what we know as a singularity. This idea, of a singular beginning to space, time, and the universe, was long known as the Big Bang.
Did Time Start at the Big Bang?
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Our universe started with the big bang. But only for the right definition of “our universe”. And of “started” for that matter. In fact, probably the Big Bang is nothing like what you were taught.
A hundred years ago we discovered the beginning of the universe. Observations of the retreating galaxies by Edwin Hubble and Vesto Slipher, combined with Einstein’s then-brand-new general theory of relativity, revealed that our universe is expanding. And if we reverse that expansion far enough – mathematically, purely according to Einstein’s equations, it seems inevitable that all space and mass and energy should once have been compacted into an infinitesimally small point – a singularity. It’s often said that the universe started with this singularity, and the Big Bang is thought of as the explosive expansion that followed. And before the Big Bang singularity? Well, they say there was no “before”, because time and space simply didn’t exist. If you think you’ve managed to get your head around that bizarre notion then I have bad news. That picture is wrong. At least, according to pretty much every serious physicist who studies the subject. The good news is that the truth is way cooler, at least as far as we understand it.
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The Simulation Hypothesis | Is Anything ‘Real’
Have you ever seen the popular movie called The Matrix? In it, the main character Neo realizes that he and everyone else he had ever known had been living in a computer-simulated reality. But even after taking the red pill and waking up from his virtual world, how can he be so sure that this new reality is the real one? Could it be that this new reality of his is also a simulation? In fact, how can anyone tell the difference between simulated reality and a non-simulated one? The short answer is, we cannot. Today we are looking at the simulation hypothesis which suggests that we all might be living in a simulation designed by an advanced civilization with computing power far superior to ours.
The simulation hypothesis was popularized by Nick Bostrum, a philosopher at the University of Oxford, in 2003. He proposed that members of an advanced civilization with enormous computing power may run simulations of their ancestors. Perhaps to learn about their culture and history. If this is the case he reasoned, then they may have run many simulations making a vast majority of minds simulated rather than original. So, there is a high chance that you and everyone you know might be just a simulation. Do not buy it? There is more!
According to Elon Musk, if we look at games just a few decades ago like Pong, it consisted of only two rectangles and a dot. But today, games have become very realistic with 3D modeling and are only improving further. So, with virtual reality and other advancements, it seems likely that we will be able to simulate every detail of our minds and bodies very accurately in a few thousand years if we don’t go extinct by then. So games will become indistinguishable from reality with an enormous number of these games. And if this is the case he argues, “then the odds that we are in base reality are 1 in billions”.
There are other reasons to think we might be in a simulation. For example, the more we learn about the universe, the more it appears to be based on mathematical laws. Max Tegmark, a cosmologist at MIT argues that our universe is exactly like a computer game which is defined by mathematical laws. So for him, we may be just characters in a computer game discovering the rules of our own universe.
With our current understanding of the universe, it seems impossible to simulate the entire universe given a potentially infinite number of things within it. But would we even need to? All we need to simulate is the actual minds that are occupying the simulated reality and their immediate surroundings. For example, when playing a game, new environments render as the player approaches them. There is no need for those environments to exist prior to the character approaching them since this can save a lot of computing power. This can be especially true of simulations that are as big as our universe. So, it could be argued that distant galaxies, atoms, and anything that we are actively not observing simply does not exist. These things render into existence once someone starts to observe them.
On his podcast StarTalk, astrophysicist Neil deGrasse Tyson and comedian Chuck Nice discussed the simulation hypothesis. Nice suggested that maybe there is a finite limit to the speed of light because if there wasn’t, we would be able to reach other galaxies very quickly. Tyson was surprised by this statement and further added that the programmer put in this limit to make sure we cannot get too far away places before the programmer has the time to program them.