Tag: physics

Elon Musk Says We’re Probably Characters In Some Advanced Civilization’s Video Game

I don’t want to freak you out here, but there’s a chance you’re not the only ‘you’ in existence.

I’m not talking about the possibility that you might actually have two different brains, which means it’s virtually impossible to tell which one is ‘you’.

I’m talking about the fact that there could well be countless parallel universes, and each one contains a slightly different version of you.

Within that parallel universe construct, our own reality might not be as ‘real’ as you think. Are some of the most massive objects in our Universe nothing but holograms?

Is our Universe itself a hologram? Is this whole thing one giant simulation and we’re just characters in the most advanced video game ever? I swear I’m not high.




Everything I just mentioned is part of actual thought experiments that have been devised and debated over by the world’s best thinkers for years now, because one way or another, we have to make sense of this very strange and incredibly unlikely reality we’ve found ourselves in.

At Recode’s annual Code Conference this week in California, billionaire tech genius Elon Musk was asked about the possibility of us humans being unwitting participants in a giant simulation built by some alien civilization that’s far more advanced than our own.

His argument is pretty simple, if we look at our own history of video games. Forty years ago, video games meant stuff like Pong and Space Invaders.

Now we have photorealistic, three-dimensional stuff that looks like this, and we could have millions, potentially even billions, of people all playing the same game online at the same time.

Sure, there’s a certain ‘uncanny valley‘ quality to our video game counterparts right now, but think of what things are going to look like in another 40, or even 20 years’ time, with virtual and augmented reality already trying to inch its way into our living rooms.

Musk explains:

“If you assume any rate of improvement at all, then the games will become indistinguishable from reality, even if that rate of advancement drops by a thousand from what it is now. Then you just say, okay, let’s imagine it’s 10,000 years in the future, which is nothing on the evolutionary scale.

So given that we’re clearly on a trajectory to have games that are indistinguishable from reality, and those games could be played on any set-top box or on a PC or whatever, and there would probably be billions of such computers or set-top boxes, it would seem to follow that the odds that we’re in base reality is one in billions.”

It might not be the most comforting thing in the world to think about – our reality isn’t at all what we think it is – but Musk says all of this being one big video game is about the best option we could hope for, given the alternatives.

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What Came Before The Big Bang?

It is difficult enough to imagine a time, roughly 13.7 billion years ago, when the entire universe existed as a singularity.

According to the big bang theory, one of the main contenders vying to explain how the universe came to be, all the matter in the cosmos – all of space itself – existed in a form smaller than a subatomic particle.

Once you think about that, an even more difficult question arises: What existed just before the big bang occurred?

The question itself predates modern cosmology by at least 1,600 years. Fourth-century theologian St. Augustine wrestled with the nature of God before the creation of the universe.




His answer? Time was part of God’s creation, and there simply was no “before” that a deity could call home.

Armed with the best physics of the 20th century, Albert Einstein came to very similar conclusions with his theory of relativity.

Just consider the effect of mass on time. A planet’s hefty mass warps time — making time run a tiny bit slower for a human on Earth’s surface than a satellite in orbit.

The difference is too small to notice, but time even runs more slowly for someone standing next to a large boulder than it does for a person standing alone in a field.

The pre-big bang singularity possessed all the mass in the universe, effectively bringing time to a standstill.

Following this line of logic, the title of this article is fundamentally flawed.

According to Einstein’s theory of relativity, time only came into being as that primordial singularity expanded toward its current size and shape.

Case closed? Far from it. This is one cosmological quandary that won’t stay dead.

In the decades following Einstein’s death, the advent of quantum physics and a host of new theories resurrected questions about the pre-big bang universe. Keep reading to learn about some of them.

Here’s a thought: What if our universe is but the offspring of another, older universe? Some astrophysicists speculate that this story is written in the relic radiation left over from the big bang: the cosmic microwave background (CMB).

Astronomers first observed the CMB in 1965, and it quickly created problems for the big bang theory — problems that were subsequently addressed (for a while) in 1981 with the inflation theory.

This theory entails an extremely rapid expansion of the universe in the first few moments of its existence.

It also accounts for temperature and density fluctuations in the CMB, but dictates that those fluctuations should be uniform.

In chaotic inflation theory, this concept goes even deeper: an endless progression of inflationary bubbles, each becoming a universe, and each of these birthing even more inflationary bubbles in an immeasurable multiverse.

Other scientists place the formation of the singularity inside a cycle called the big bounce in which our expanding universe will eventually collapse back in on itself in an event called the big crunch.

A singularity once more, the universe will then expand in another big bang.

This process would be eternal and, as such, every big bang and big crunch the universe ever experiences would be nothing but a rebirth into another phase of existence.

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How Physics Can Help You Achieve The Perfect Egg Crack

cracked egg

What’s the best way to crack an egg?

Physicists explain that we’re predisposed to hit the egg against a hard surface where the egg is flattest, or, its center, where its oblong shape widens; that’s the point at which an egg is weakest.




The egg puts up more of a fight at its round, arched ends. This curvature creates an even distribution of pressure, which may explain why it’s all but impossible to crack an egg when it’s held lengthwise between your fingers.

To game this correctly, then, you should create an initial crack in the center of your egg that opens a cavity small enough to fit your thumb through.

egg

What comes next requires quick, careful precision: You expand this ripple ever so slightly with your hands so that the egg’s yolk tumbles out. Go too fast and the shell will collapse in your hands.

So, there you go. Now you’ve got some new vocabulary, borrowed from the wild world of fracture mechanics, to apply to a deceptively simple cooking act. If this registers as completely useless information, consider that egg-cracking is a difficult art to master for the less dexterous among us.

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The Physics Of Hitting A Baseball

Hitting the “sweet spot” is something that baseball players strive for. This is the location of the bat that is generally regarded as the best spot for hitting the ball.

It minimizes vibration of the bat and results in the maximum energy delivered to the ball, meaning it travels the farthest.

The “sweet spot” is a special point on the bat which minimizes stinging of the hands when the ball strikes there. Baseball players say that hitting the ball in this location “feels” the best, and results in the most solid hit.

If the baseball strikes outside of the sweet spot a painful stinging sensation is felt in the hands, due to bat vibration. In addition, this undesirable vibration reduces the energy that is delivered to the ball, so it doesn’t travel as far.




Here we are using physics to confirm what baseball players already know from experience.

It’s not easy to hit the sweet spot. For best results, contact with the ball must be made within 1/8″ of this special point. It is the main “good hit” criterion of players.

But it is one of the biggest challenges in Major League sports, where a round ball traveling at 90 mph has to hit a round bat swinging at 80 mph, at precisely this location.

The result is the ball flying off the bat at 110 mph, enough for a home run.

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Astrophysicists Spotted A ‘Galaxy Without Dark Matter’

An unusual galaxy far, far away is stumping astronomers not because of what’s there, but because of what’s missing.

About 65 million light-years away, the galaxy called NGC1052-DF2 is dim and diffuse, coming in at about one two-hundredths the mass of our Milky Way.

Normally, not all of a galaxy’s mass is visible. In addition to a mix of ordinary matter—like stars and planets and manatees—galaxies are expected to contain dark matter, an invisible substance that makes up most of the mass in the universe.

Although we can’t directly observe it, we know dark matter is there because we can see how its gravity affects ordinary matter.

Based on the ratio in other galaxies, an isolated galaxy like NGC1052-DF2 should have about a hundred times more dark matter than ordinary matter. But this one appears to have … almost none, scientists report today in Nature.




How did scientists figure that out?

Using a cluster of lenses called the Dragonfly Telephoto Array, a team led by Yale University’s Pieter van Dokkum took a really close look at NGC1052-DF2.

By tracking the motion of 10 embedded star clusters, the team could determine how much mass is tucked into the galaxy. And surprisingly, it’s about the same amount of mass they’d expect to see from the galaxy’s stars alone.

We really thought dark matter was not just an optional component of galaxies,” van Dokkum says, noting that the team has found several other similarly perplexing galaxies to scrutinize.

Why is this observation important?

One strange observation doesn’t necessarily break a theory. But finding a galaxy that’s more or less devoid of dark matter certainly suggests a few tantalizing things. First, it really challenges ideas about how galaxies form.

In modern galaxy formation theory, our understanding is that galaxies form in a dark matter halo,” says Stanford University’s Risa Wechsler.

There’s a pretty tight relationship between the amount of stars that formed and the dark matter there, at least when the galaxy formed.

In other words, no dark matter, no galaxy.

In theories proposing alternatives to dark matter, such as modifications to our understanding of gravity, whatever is mimicking the dark matter signature is not something that can be turned on or off—it should always be there.

So, van Dokkum says, “by not detecting the dark matter, we actually prove it’s real.”

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Astronomers Found Evidence For A ‘Dark’ Gravitational Force That Might Fix Einstein’s Most Famous Theory

Albert Einstein’s general theory of relativity predicts so much about the universe at large, including the existence of gravitational lenses or “Einstein rings.”

And yet his famous equations struggle to fully explain such objects.

While general relativity says a strong source of gravity — like the sun— will warp the fabric of space, bend light from a distant object, and magnify it to an observer, very big objects like galaxies and galaxy clusters make gravitational lenses that are theoretically too strong.




General relativity also can’t fully explain the spinning motions of galaxies and their stars.

That’s why most physicists think as much as 80% of the mass in the universe is dark matter: invisible mass that hangs out at the edges of galaxies.

Dark matter might be made of hard-to-detect particles, or perhaps an unfathomable number of tiny black holes. But we have yet to find smoking-gun evidence of either.

However, a contentious theory by Erik Verlinde at the University of Amsterdam suggests dark matter may not be matter at all.

What’s more, astronomers say his idea “is remarkable” in its ability to explain the behavior of more than 33,000 galaxies that they studied.

This does not mean we can completely exclude dark matter, because there are still many observations that Verlinde’s theory cannot yet explain,” study leader and physicist Margot Brouwer said in a YouTube video about the research.

However it is a very exciting and promising first step.”

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The Big Bang Wasn’t The Beginning, After All

A Universe that expands and cools today, like ours does, must have been hotter and denser in the past. Initially, the Big Bang was regarded as the singularity from which this ultimate, hot, dense state emerged. But we know better today.

The Universe began not with a whimper, but with a bang! At least, that’s what you’re commonly told: the Universe and everything in it came into existence at the moment of the Big Bang.

Space, time, and all the matter and energy within began from a singular point, and then expanded and cooled, giving rise over billions of years to the atoms, stars, galaxies, and clusters of galaxies spread out across the billions of light years that make up our observable Universe.

It’s a compelling, beautiful picture that explains so much of what we see, from the present large-scale structure of the Universe’s two trillion galaxies to the leftover glow of radiation permeating all of existence.

Unfortunately, it’s also wrong, and scientists have known this for almost 40 years.

The idea of the Big Bang first came about back in the 1920s and 1930s. When we looked out at distant galaxies, we discovered something peculiar: the farther away from us they were, the faster they appeared to be receding from us.




According to the predictions of Einstein’s General Relativity, a static Universe would be gravitationally unstable; everything needed to either be moving away from one another or collapsing towards one another if the fabric of space obeyed his laws.

The observation of this apparent recession taught us that the Universe was expanding today, and if things are getting farther apart as time goes on, it means they were closer together in the distant past.

An expanding Universe doesn’t just mean that things get farther apart as time goes on, it also means that the light existing in the Universe stretches in wavelength as we travel forward in time.

Since wavelength determines energy (shorter is more energetic), that means the Universe cools as we age, and hence things were hotter in the past.

It’s tempting, therefore, to keep extrapolating backwards in time, to when the Universe was even hotter, denser, and more compact.

First noted by Vesto Slipher, the more distant a galaxy is, on average, the faster it’s observed to recede away from us. For years, this defied explanation, until Hubble’s observations allowed us to put the pieces together: the Universe was expanding.

Theorists thinking about these problems started thinking of alternatives to a “singularity” to the Big Bang, and rather of what could recreate that hot, dense, expanding, cooling state while avoiding these problems.

The conclusion was inescapable: the hot Big Bang definitely happened, but doesn’t extend to go all the way back to an arbitrarily hot and dense state.

Instead, the very early Universe underwent a period of time where all of the energy that would go into the matter and radiation present today was instead bound up in the fabric of space itself.

That period, known as cosmic inflation, came to an end and gave rise to the hot Big Bang, but never created an arbitrarily hot, dense state, nor did it create a singularity.

What happened prior to inflation — or whether inflation was eternal to the past — is still an open question, but one thing is for certain: the Big Bang is not the beginning of the Universe!

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Professor Stephen Hawking, Renowned Scientist, Dies At 76

Renowned physicist Stephen Hawking has died at the age of 76.

Hawking, who was a professor at the University of Cambridge, made several discoveries in the field of physics, mathematics and cosmology that raised his profile internationally.

Cambridge University confirmed Hawking’s death.




His better-known works involve black holes and the theory of relativity. He also wrote a number of popular science books, including “A Brief History of Time.

Hawking suffered for most of his life from amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig’s disease. The condition causes nerve cells in the brain and spinal cord to degenerate.

ALS typically kills sufferers within the first few years, but Hawking survived the disease for decades. His early encounter with the disease during his younger years was depicted in the film “The Theory of Everything” in 2014.

In recent months, Hawking warned vocally about the dangers posed by artificial intelligence. Last year, he said A.I. could be the “worst event in the history of our civilization.”

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The Physics Behind Hitting A Home Run

On Monday night, some of Major League Baseball’s best sluggers will square off in the sport’s biggest annual display of brute strength: the home run derby.

Each batter has seven “outs” to hit as many balls as possible out of San Diego’s Petco Park.

To most fans, it’s just a fun spectacle. But to Alan Nathan, home-run hitting is a physics problem.

Given the distance between home plate and the outfield wall, what combination of ball speed, bat angle and external factors will send the ball out of the park?

By day, Nathan is a professor emeritus at the University of Illinois at Urbana-Champaign, working to elucidate the structure and interactions of subatomic particles.

But the rest of the time, he’s watching baseball with an eye for the underlying physics of the sport. He’s even written several peer-reviewed papers on the subject, which are all available on his website.

At the most basic level, he said, there are just two elements to a well-hit home run: exit speed and launch angle.

If you were a freshman physics student calculating the path of a projectile, these two numbers would be all you needed to know to predict how far the ball would travel.




According to ESPN’s hit tracker, the fastest-hit home run of the season so far was a solo shot slugged by the Angels’ Mike Trout in April.

That ball was traveling 120.5 mph when it left Trout’s bat. The optimum launch angle, Nathan said, is between 25 and 30 degrees. A ball hit at a lower angle will become a line drive or a grounder; a higher angle gives you a pop-up.

These factors can balance one another. A slower ball may make it out of the park if it’s hit at the right angle; a batter can make up for a bad trajectory by hitting the ball super fast.

But astute students of baseball science should take other factors into account.

Those first four all boil down to the same thing: air density. The less dense the air is, the less resistance the ball will encounter as it soars through the stadium.

The thin air at high elevations helps balls travel farther — that’s part of how Denver’s Coors Field, which sits at an MLB-high of 5,200 feet above sea level, got its reputation as a pitcher’s nightmare.

On the other hand, humidity in the stadium can help a home-run ball — if only ever so slightly — by making the air less dense.

Air temperature also plays a part, Nathan said. A 1995 study found that fly balls travel a few feet farther for every 10 degree increase in temperature.

The average fly ball distance in above-90-degree heat was 320 feet; on sub-50-degree days, that distance fell to 304 feet.

But the effect of air density pales in comparison to that of wind.

How far a ball flies also depends on the ball itself.

The stitches on a baseball help it travel farther by reducing drag, but only to a degree — high, loose seams, like those of the repeatedly reused baseballs of the “dead ball” era, will slow it down again.

Then there’s how you hit the ball. Side spin — which happens when the batter is out in front of the ball or just a little bit late — can cause a line drive to curve foul.

But a small amount of back spin gives the ball lift, allowing it to seemingly defy gravity for slightly longer than it otherwise would.

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Laws of Physics Say Quantum Cryptography Is Unhackable. It’s Not

In the never-ending arms race between secret-keepers and code-breakers, the laws of quantum mechanics seemed to have the potential to give secret-keepers the upper hand.

A technique called quantum cryptography can, in principle, allow you to encrypt a message in such a way that it would never be read by anyone whose eyes it isn’t for.

Enter cold, hard reality. In recent years, methods that were once thought to be fundamentally unbreakable have been shown to be anything but. Because of machine errors and other quirks, even quantum cryptography has its limits.

“If you build it correctly, no hacker can hack the system. The question is what it means to build it correctly,” said physicist Renato Renner from the Institute of Theoretical Physics in Zurich.

Regular, non-quantum encryption can work in a variety of ways but generally a message is scrambled and can only be unscrambled using a secret key.




The trick is to make sure that whomever you’re trying to hide your communication from doesn’t get their hands on your secret key.

Cracking the private key in a modern crypto system would generally require figuring out the factors of a number that is the product of two insanely huge prime numbers.

The numbers are chosen to be so large that, with the given processing power of computers, it would take longer than the lifetime of the universe for an algorithm to factor their product.

But such encryption techniques have their vulnerabilities. Certain products – called weak keys – happen to be easier to factor than others.

Also, Moore’s Law continually ups the processing power of our computers. Even more importantly, mathematicians are constantly developing new algorithms that allow for easier factorization.

Quantum cryptography avoids all these issues. Here, the key is encrypted into a series of photons that get passed between two parties trying to share secret information.

The Heisenberg Uncertainty Principle dictates that an adversary can’t look at these photons without changing or destroying them.

But in practice, quantum cryptography comes with its own load of weaknesses. It was recognized in 2010, for instance, that a hacker could blind a detector with a strong pulse, rendering it unable to see the secret-keeping photons.

 

Renner points to many other problems. Photons are often generated using a laser tuned to such a low intensity that it’s producing one single photon at a time.

There is a certain probability that the laser will make a photon encoded with your secret information and then a second photon with that same information.

In this case, all an enemy has to do is steal that second photon and they could gain access to your data while you’d be none the wiser.

Alternatively, noticing when a single photon has arrived can be tricky. Detectors might not register that a particle has hit them, making you think that your system has been hacked when it’s really quite secure.

Smart grids need to react to changes quickly lest some part of the system get damaged from electricity overflows.

But traditional cryptography usually requires time and processing power to encrypt and decrypt the large numbers used as keys.

The computers used in such cryptography could drive up the price of a smart grid. Quantum cryptography, on the other hand, simply requires pushing around some photons and the computations for decryption are much less complicated.

Hughes and his collaborators have worked with the University of Illinois Urbana-Champaign to show that quantum cryptography was two orders of magnitude faster than conventional techniques in encrypting smart grid information.

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