All this and stamp collecting?paraphrase Lord Kelvin.
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Correction to what I say at 14:22 — The KATRIN experiment does not look for neutrinoless double beta decay, it’s trying to measure the absolute neutrino masses. There are several other experiments looking for neutrinoless double beta decay. Sorry about that mixup!
Some physicists are claiming that there is something “wrong” with our understanding of the universe. Oftentimes, it’s just to justify asking for funding for new experiments, a better detector, a new telescope, a bigger collider, but what if there’s something more than that? Do we have evidence of new physics? Or not? In this video, we will look at dark matter and dark energy, quantum gravity, the mass of the Higgs-boson, neutrino masses, and the matter-antimatter asymmetry.
There is increasing talk of quantum computers and how they will allow us to solve problems that traditional computers cannot solve. It’s important to note that quantum computers will not replace traditional computers: they are only intended to solve problems other than those that can be solved with classical mainframe computers and supercomputers. And any problem that is impossible to solve with classical computers will also be impossible with quantum computers. And traditional computers will always be more adept than quantum computers at memory-intensive tasks such as sending and receiving e-mail messages, managing documents and spreadsheets, desktop publishing, and so on.
There is nothing “magic” about quantum computers. Still, the mathematics and physics that govern their operation are more complex and reside in quantum physics.
The idea of quantum physics is still surrounded by an aura of great intellectual distance from the vast majority of us. It is a subject associated with the great minds of the 20th century such as Karl Heisenberg, Niels Bohr, Max Planck, Wolfgang Pauli, and Erwin Schrodinger, whose famous hypothetical cat experiment was popularized in an episode of the hit TV show ‘The Big Bang Theory’. As for Schrodinger, his observations of the uncertainty principle, serve as a reminder of the enigmatic nature of quantum mechanics. The uncertainty principle holds that the observer determines the characteristics of an examined particle (charge, spin, position) only at the moment of detection. Schrödinger explained this using the theoretical experiment, known as the paradox of Schrödinger’s cat. The experiment’s worth mentioning, as it describes one of the most important aspects of quantum computing.
Detecting extremely distant stars, or those closest in time to the big bang, can provide insights into the first few chapters of the history of our universe. In 2022, the Hubble Space Telescope broke its own record, and spotted the most distant star yet. This star, nicknamed Earendel, emitted its light within the universe’s first billion years.
Spotting, and confirming, the distance of the star is just the beginning, though. That’s where NASA’s James Webb Space Telescope comes in. Webb’s initial observations of Earendel have revealed insights into the star’s type, and even the galaxy surrounding the star. Future analysis of Webb spectroscopic observations of Earendel and its host galaxy, the Sunrise Arc, could also reveal information about brightness, temperature, and composition.
NASA’s James Webb Space Telescope has followed up on observations by the Hubble Space Telescope of the farthest star ever detected in the very distant universe, within the first billion years after the big bang. Webb’s NIRCam (Near-Infrared Camera) instrument reveals the star to be a massive B-type star more than twice as hot as our sun, and about a million times more luminous.
When Albert Einstein famously said “God does not play dice with the universe” he wasn’t objecting to the idea that randomness exists in our everyday lives.
What he didn’t like was the idea that randomness is so essential to the laws of physics, that even with the most precise measurements and carefully controlled experiments there would always be some level at which the outcome is effectively an educated guess. He believed there was another option.
This video discusses how probability is determined in quantum mechanics. Let’s play some dice with the universe and talk about it.
Join Katie Mack, Perimeter Institute’s Hawking Chair in Cosmology and Science Communication, over 10 short forays into the weird, wonderful world of quantum science. Episodes are published weekly, subscribe to our channel so you don’t miss an update.
A group of international researchers led by the Center for Astrophysics | Harvard and Smithsonian (CfA) achieved the once-unimaginable four years ago: using a groundbreaking telescope to capture an image of a black hole.
Last month some of those researchers, engineers, and physicists convened at Harvard to consider and begin drawing up plans for the next step: a closer study of the photon rings that encircle black holes in glowing orange. The mission has been dubbed the Event Horizon Explorer (EHE), and the group hopes it will offer additional insight into black holes, which sit at the center of galaxies.
The $300 million project examining the nature of space and time builds on the success of the Event Horizon Telescope (EHT) project of 2019, when researchers took the first-ever picture of a black hole, a focal point so tiny “the biggest ones on the sky are only about the same size as an atom held at arm’s length,” said Michael Johnson, an astrophysicist at the CfA.
Astronomers using the James Webb Space Telescope have discovered a feeding supermassive black hole from when the universe was less than 600 million years old.
We have no idea what dark matter is, other than it’s some source of gravity that is completely invisible but exerts way more pull that all of the regular matter. More than all of the stars, all of the gas, all of the black holes…unless dark matter is black holes, then black holes are most of everything. Dark matter constitutes 80% or so of the mass in the universe, which means even our Milky Way galaxy is mostly a vast ball of dark matter that happens to have attracted a relative sprinkling of baryons—atoms in the form of gas, which lit up as starry glitter spinning in the middle of this invisible gravitational well.
“I view string theory as the most promising way to quantize matter and gravity in a unified way. We need both quantum gravity and we need unification and a quantization of gravity. One of the reasons why string theory is promising is that there are no singularities associated with those singularities are the same type that they offer point particles.” — Robert Brandenberger.
In this thought-provoking conversation, my grad school mentor, Robert Brandenberger shares his unique perspective on various cosmological concepts. He challenges the notion of the fundamental nature of the Planck length, questioning its significance and delving into intriguing debates surrounding its importance in our understanding of the universe. He also addresses some eyebrow-raising claims made by Elon Musk about the limitations imposed by the Planck scale on the number of digits of pi.
Moving on to the topic of inflation and its potential detectability, Robert sheds light on the elusive B mode fluctuations and the role they play in understanding the flaws of general relativity. He explains why detecting these perturbations at the required scale may be beyond our current technological capabilities. The discussion further explores the motivations behind the search for cosmic strings in the microwave sky and the implications they hold for particle physics models beyond the standard model.
With his expertise in gravity and the quantization of mass, Robert Brandenberger emphasizes the need for a quantum mechanical approach to gravity. He discusses the emergence of time, space, and a metric from matrix models, offering new insights into the foundations of our understanding of the universe. The speaker’s work challenges conventional notions of inflation and proposes alternative models, such as string gas cosmology, as potential solutions.
Beyond the scientific aspects, Robert Brandenberger reflects on his role as a scientist and educator. He expresses his gratitude to a mentor and shares advice he received about navigating the academic world. Additionally, he discusses the evolution of being a professor over the past three decades and shares his thoughts on the profession as a whole.
This episode leaves us with many questions, tantalizing possibilities, and a deeper appreciation for the mysteries of the cosmos. We invite you to join us in this cosmic journey as we explore the frontiers of theoretical cosmology.
There is a lot of speculation about the end of the universe. Humans love a good ending after all. We know that the universe started with the Big Bang and it has been going for almost 14 billion years. But how the curtain call of the cosmos occurs is not certain yet. There are, of course, hypothetical scenarios: the universe might continue to expand and cool down until it reaches absolute zero, or it might collapse back onto itself in the so-called Big Crunch. Among the alternatives to these two leading theories is “vacuum decay”, and it is spectacular – in an end-of-everything kind of way.
While the heat death hypothesis has the end slowly coming and the Big Crunch sees a reversal of the universe’s expansion at some point in the future, the vacuum decay requires that one spot of the universe suddenly transforms into something else. And that would be very bad news.
There is a field that spreads across the universe called the Higgs field. Interaction between this field and particles is what gives the particles mass. A quantum field is said to be in its vacuum state if it can’t lose any energy but we do not know if that’s true for the Higgs field, so it’s possible that the field is in a false vacuum at some point in the future. Picture the energy like a mountain. The lowest possible energy is a valley but as the field rolled down the slopes it might have encountered a small valley on the side of that mountain and got stuck there.
