Physics

don’t look back, you’re not going that way


No One Can Explain Why Planes Stay In The Air

On a strictly mathematical level, engineers know how to design planes that will stay aloft. But equations don’t explain why aerodynamic lift occurs.

There are two competing theories that illuminate the forces and factors of lift. Both are incomplete explanations.

{ Scientific American | Continue reading }

my wife said I never listen to her, or something like that

[W]hile time moves forward in our universe, it may run backwards in another, mirror universe that was created on the “other side” of the Big Bang.

{ PBS (2014) | Continue reading }

how many oysters does it take to get horny

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Make a sound in the east, then strike in the west

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Physicists have long struggled with a perplexing conundrum: How do we reconcile what we see in the quantum world with what we don’t in the classical world? In a phenomenon called quantum superposition, particles have been shown to shift between particle-like and wave-like states, meaning they’re in two places at once.

But this phenomenon hasn’t been observed with more massive objects—it’s only been seen in the smallest particles, such as atoms, photons, and electrons. That’s beginning to change. […]

Physicist Markus Arndt of the University of Vienna and an international team of researchers have demonstrated quantum superposition in molecules, the largest particles ever tested.

{ Popular Mechanics | Continue reading }

photo { Andy Warhol: Elvis Paintings, Ferus Gallery, Los Angeles, 1963 }

‘We are all deep in a hell each moment of which is a miracle.’ –Cioran

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Beer bottles are often used in physical disputes. If the bottles break, they may give rise to sharp trauma. However, if the bottles remain intact, they may cause blunt injuries. […]

We tested the fracture properties of beer bottles in a drop-tower. Full bottles broke at 30 J impact energy, empty bottles at 40 J. These breaking energies surpass the minimum fracture-threshold of the human neurocranium. […]

The phenomenon of empty beer bottles breaking at higher energies than full ones is explainable by two factors. Firstly, beer is an almost incompressible fluid. Even a slight deformation of the bottle due to the impact of the steel ball leads to an increase of the pressure within the bottle and its destruction. Another possibly major additional factor may be that beer is carbonated.

{ Journal of Forensic and Legal Medicine | Continue reading }

photo { Stephen Shore, Miami, Oklahoma, July 1972 }

No sunshine, no moonlight, no stardust, no sign of romance

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We suggest that advanced civilizations could cloak their presence, or deliberately broadcast it, through controlled laser emission.

Such emission could distort the apparent shape of their transit light curves with relatively little energy, due to the collimated beam and relatively infrequent nature of transits.

We estimate that humanity could cloak the Earth from Kepler-like broad-band surveys using an optical monochromatic laser array emitting a peak power of ∼30 MW for ∼10 hours per year.

{ Monthly Notices of the Royal Astronomical Society | Continue reading }

Don’t fall into the trap of thinking because a line of attack didn’t work at first that it isn’t effective. Repetition is key.

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Have you heard the one about the biologist, the physicist, and the mathematician? They’re all sitting in a cafe watching people come and go from a house across the street. Two people enter, and then some time later, three emerge. The physicist says, “The measurement wasn’t accurate.” The biologist says, “They have reproduced.” The mathematician says, “If now exactly one person enters the house then it will be empty again.”

{ Nautilus | Continue reading }

‘Everybody is raving about the Trump Home Mattress.’ —@realDonaldTrump

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Excitement is in the air at the Large Hadron Collider (LHC), the powerful accelerator at CERN (the European Laboratory for Particle Physics) near Geneva. Last year, researchers there recorded faint but extremely promising signs of what could be a new particle that does not fit within the current theoretical model. The LHC is now about to resume operation after being shut down since December for annual maintenance. If its next run confirms the existence of the new particle, that could open the long-sought passage to ‘the new physics’ – and, hopefully, answer some big, longstanding questions.

Experimental physicists and theorists have always worked together trying to understand nature’s underlying laws. Out of this collaboration emerged the ‘Standard Model’, which describes the fundamental particles and the ways that they interact to form all matter we see around us. At some times, experimental discoveries prompted fresh insights or confirmed what theorists already suspected. At others, theoretical predictions sent the experimentalists on a specific search. This was the case back in 1964 when physicists Robert Brout, François Englert and Peter Higgs predicted the existence of the Higgs boson, the particle that was discovered in 2012.

The Higgs boson filled in the last missing piece of the Standard Model, but this model is itself clearly incomplete. None of its particles has the properties of dark matter, a mysterious entity that is five times as prevalent as all the ordinary matter (everything made of atoms, which in turn are built from quarks and electrons) visible in the stars and galaxies. The Standard Model also does not explain the wide range of masses of the fundamental particles, nor why antimatter seems to have nearly completely disappeared, leaving the Universe filled almost exclusively with matter.

That is why, after spending nearly 60 years building the Standard Model, particle physicists are now terribly excited at the prospect of finally breaking it. The flaws of the model were well known, but no one knows what the right model might be. Theorists have been stuck for decades, exploring a vast array of ideas but lacking the data to tell them if they were on the right path. Only an experimental breakthrough can help them move forward, and the LHC might have already made it.

{ Aeon | Continue reading }

‘Being is the absence that appearances conceal.’ –Georges Bataille

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The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein’s theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.

The widely accepted age of the universe, as estimated by general relativity, is 13.8 billion years. In the beginning, everything in existence is thought to have occupied a single infinitely dense point, or singularity. Only after this point began to expand in a “Big Bang” did the universe officially begin.

Although the Big Bang singularity arises directly and unavoidably from the mathematics of general relativity, some scientists see it as problematic because the math can explain only what happened immediately after—not at or before—the singularity.

{ Phys.org | Continue reading }

The night that hides things from us

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Penrose and many others argue from practical considerations, Godel’s theorem, and on philosophical grounds, that consciousness or awareness is non-algorithmic and so cannot be generated by a system that can be described by classical physics, such as a conventional computer, but could perhaps be generated by a system requiring a quantum (Hilbert space) description. Penrose suspects that aspects of quantum physics not yet understood might be needed to explain consciousness. In this paper we shall see that only known quantum physics is needed to explain perception.

{ James A. Donald | Continue reading }

photo { Martin Parr }

When most I wink, then do my eyes best see

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Einstein wondered what would happen if the Sun were to suddenly explode. Since the Sun is so far away that it takes light eight minutes to travel to Earth, we wouldn’t know about the explosion straight away. For eight glorious minutes we’d be completely oblivious to the terrible thing that was about to happen.

But what about gravity? The Earth moves in an ellipse around the Sun, due to the Sun’s gravity. If the Sun wasn’t there, it would move off in a straight line. Einstein’s puzzle was when that would happen: straight away, or after eight minutes? According to Newton’s theory, the Earth should know immediately that the Sun had disappeared. But Einstein said that couldn’t be right. Because, according to him, nothing can travel faster than the speed of light — not even the effects of gravity. […]

Before Einstein people thought of space as stage on which the laws of physics play out. We could throw in some stars or some planets and they would move around on this stage.

Einstein realised that space isn’t as passive as that. It is dynamic and it responds to what’s happening within it. If you put something heavy in space — let’s say a planet like Earth — then space around it gives a little. The presence of the planet causes a small dent in space (and in fact, in time as well). When something else moves close to the planet — say the Moon — it feels this dent in space and rolls around the planet like a marble rolling in a bowl. This is what we call gravity. […] Stars and planets move, causing space to bend in their wake, causing other stars and planets to move, causing space to bend in their wake. And so on. This is Einstein’s great insight. Gravity is the manifestation of the curvature of space and time.

{ Plus Magazine | Part One | Part Two }

‘The road up and the road down is one and the same.’ –Heraclitus

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Our best theories of physics imply we shouldn’t be here. The Big Bang ought to have produced equal amounts of matter and antimatter particles, which would almost immediately annihilate each other, leaving nothing but light.

So the reality that we are here – and there seems to be very little antimatter around – is one of the biggest unsolved mysteries in physics.

In 2001, Tanmay Vachaspati from Arizona State University offered a purely theoretical solution. Even if matter and antimatter were created in equal amounts, he suggested that as they annihilated each other, they would have briefly created monopoles and antimonopoles – hypothetical particles with just one magnetic pole, north or south.

As the monopoles and antimonopoles in turn annihilated each other, they would produce matter and antimatter. But because of a quirk in nature called CP violation, that process would be biased towards matter, leaving the matter-filled world we see today.

If that happened, Vachaspati showed that there should be a sign of it today: twisted magnetic fields permeating the universe. […] So Vachaspati and his colleagues went looking for them in data from NASA’s Fermi Gamma ray Space Telescope.

{ New Scientist | Continue reading }

related { Rogue antimatter found in thunderclouds }