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Einstein, Symmetry and the Future of Physics

Insights of Albert Einstein

Many insights of Albert Einstein are now part of popular imagination: black holes, time warps, and wormholes show up in movies and books.

Less famous, but probably the most revolutionary part of Einstein's phenomena, is a simple idea that shows how pieces fit together and illuminate the road ahead.

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Insights of Albert Einstein

Many insights of Albert Einstein are now part of popular imagination: black holes, time warps, and wormholes show up in movies and books.

Less famous, but probably the most revolutionary part of Einstein's phenomena, is a simple idea that shows how pieces fit together and illuminate the road ahead.

Some changes don't change anything

The most fundamental aspects of nature stay the same.

*For example, Einstein's papers on relativity show that the relationship between energy and mass is invariant, even though energy and mass can take on many different forms.*

Even though matter produces energy, the energy-matter content of the universe never changes. **Matter and energy are less fundamental than the underlying relationship between them.**

Relationships over things

We often think of things as the heart of reality. But most often the relationship is more important, not the stuff.

We may think "stuff" like space and time are unchangeable aspects of nature. In reality, the relationship between space and time stays the same.

Symmetry

The relationship that mattered most to Einstein's ideas was symmetry. **Scientists describe symmetry as changes that don't really change anything**. More complicated symmetries have led to the discoveries from neutrinos to quarks.

**Symmetry is at the root of our description of nature.** But symmetry has not been able to explain why gravity is so weak or vacuum energy is so small. The idea of symmetry may be very powerful, but we may have to give up on these principles that have worked so well.

Einstein and Light

Albert Einstein did not think about symmetry when he wrote his first relativity papers in 1905. He was considering several seemingly unrelated puzzles and connecting the dots.

- Einstein realized that the speed of light - a speed that stayed constant - was a measurable manifestation of the symmetrical relationship between electric and magnetic fields.
- Light didn’t need anything to travel through because it was itself electromagnetic fields in motion.
- There was no universal here and now.
- It took some years for Einstein to acknowledge that space and time are interwoven and impossible to disentangle.

Unified space-time

Unified space-time starts to make sense if we think that the speed of light is a relationship between the distance traveled over time.

Because the speed of light can't change, your laser beam won't go any faster. The measurement of distance and time must be changed instead, depending on the state of motion. This leads to effects known as "space contraction" and "time dilation."

*As you work at your desk, you move through time, but not through space. A cosmic ray moves over vast distances at nearly the speed of light but takes little time.*

Gravity

Einstein's special theory of relativity applies only to steady, unchanging motion through space-time, not accelerating motion like an object falling toward Earth.

- It troubled Einstein that his theory didn't include gravity, and his battle to incorporate it made symmetry central to his thinking.
- Einstein later understood that gravity is the curvature of space-time itself. Falling objects follow the space-time path carved out for them.
- After general relativity was published, it appeared that energy might not be conserved in strongly curved space-time. But mathematician Emmy Noether proved that the amount of energy (including mass), the amount of electric charge, the amount of momentum, are all associated with a particular symmetry, a change that doesn't change anything.
- Noether showed that the symmetries of general relativity ensure that energy is always conserved.

Matter

After Einstein, the pull of symmetry became more powerful.

- Paul Dirac, trying to make quantum mechanics compatible with the symmetry requirements of special relativity, found a minus sign in an equation, suggesting the existence of "antimatter."
- Wolfgang Pauli, trying to account for the energy that seemed to go missing during the disintegration of radioactive particles, discovered that the missing energy was carried away by a particle, known now as the neutrino.

Gauge symmetry

*From the 1950s, invariances took on a life of their own. New symmetries, known as "gauge" invariances, became productive by requiring the existence of everything from W and Z bosons to gluons.*

Gauge symmetry dictates what other ingredients you have to introduce. Gauge symmetries describe the internal structure of the system of particles in our world. Physicists can move, rotate and distort their equations without changing anything important. The result is a look at the hidden structures that supports the basic ingredients of nature.

Broken Symmetries

Symmetry, as it is understood, seems not to answer the biggest questions in physics. In some cases, symmetries show the underlying laws of nature that do not show up in reality.

*For example, when energy congeals into matter (E = mc2), the result is an equal amount of matter and antimatter - a symmetry. Yet if the energy of the Big Bang created both matter and antimatter equally, they should have destroyed each other, leaving nothing behind.*

Dualities

*Duality is a closely related idea to symmetry*. Wave-particle duality has been around since the beginning of quantum mechanics. But newfound dualities have shown interesting relationships. *For example, a three-dimensional world without gravity can be mathematically equivalent to a four-dimensional world with gravity.*

Certain dualities suggest that space-time emerges from something more basic, what Einstein called the "spooky" connection between entangled quantum particles.

Not giving up on symmetry

The idea of symmetry proved very powerful. Giving it up would mean giving up on naturalness - the idea that the universe has to be exactly the way it is for a reason.

*But inside black holes, the speed of light (which grounded Einstein's work) will not play a vital role in the future. "The speed of light can't remain constant if space-time is crumbling," says physicist Stephon Alexander.*

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Time Travel

The Science Fiction’s holy grail, Time Travel has been a popular topic in various books, movies and TV series for decades.

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Understanding Time

According to physicist Albert Einstein, time is not a constant phenomenon as it appears, but is an illusion, and can vary from different vantage points.

Space is three-dimensional, and Time, according to the famous physicist, is the fourth dimension. It also speeds up or slows down, so is actually subjective, as stated in his Theory Of Special Relativity.

Space-Time

Einstein's theory of general relativity says that Time can be bent, stretched and squeezed, and the four-dimensional fabric with a huge mass creates a dimple, or bending of Space-Time, causing gravity.

This effect of time dilation is proven using GPS satellite technology in space, making astronauts not only travel space but in a slightly different time than the earthlings.

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Star Trek has a lot to answer for. Not content to tease us with unreasonable expectations of phasers and warp drive, it also thrust into the popular imagination the idea of teleportation, in which we step into a giant scanner of some sort and instantaneously find ourselves somewhere else, mind, body and soul intact (and hopefully, unlike Jeff Goldblum, untainted).

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Teleportation

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Teleportation is possible in principle

Recently, scientists were able to "teleport" photons to a satellite 300 miles away, using "quantum entanglement." This is where a pair of photons are able to simultaneously share the same state, even when separated by distance. Change the state of one particle, and the other changes too.

Teleportation can have big implications for a new “quantum internet.” It will be faster, more powerful, unhackable.

Teleporting humans

Scientists are still working out how to teleport photons. Assuming they figure out how to teleport atoms, then molecules, the amount of bits to record and transmit, is unthinkable.

A person is made of an estimated 32 trillion cells. They would require a huge bandwidth and roughly 10th gigawatt-hours of power. Teleporting one person would require using the entire UK power supply for more than a million years and take 4.8 million million years to transfer - that is if you survive the transfer. It would be quicker to walk.

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How do geniuses come up with ideas? What is common to the thinking style that produced "Mona Lisa," as well as the one that spawned the theory of relativity? What characterizes the thinking strategies of the Einsteins, Edisons, daVincis, Darwins, Picassos, Michelangelos, Galileos, Freuds, and Mozarts of history?

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Key Ideas

Intelligence is not genius

Genius is not about having an extraordinarily high IQ, or even about being smart. It is not about finishing Mensa exercises in record time or mastering fourteen languages at the age of seven.

Geniuses and problem solving

*Leonardo da Vinci believed you begin by learning how to restructure the problem by looking at it from many different angles.*

In order to creatively solve a problem, the thinker should not use the usual approach that is based on past experience. **Geniuses use several different perspectives to solve an existing problem and thereby also identify new ones.**

Making your thoughts visible

*Galileo revolutionized science by making his idea visible with diagrams, maps, and drawings. **Einstein believed that words and numbers as they are spoken did not play a significant role in his thinking process.*

**Geniuses seem to develop a skill to display information in visual and spatial forms, rather than only mathematical or verbal lines.**

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