Credit: What The Physics?!
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Category: physics
Our ultimate user’s guide to fundamental physics – all on one spectacular poster for you to download for free.
Download the poster as a PDF file.
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The grand theory of almost everything actually represents a collection of several mathematical models that proved to be timeless interpretations of the laws of physics.
Here is a brief tour of the topics covered in this gargantuan equation.
This version of the Standard Model is written in the Lagrangian form. The Lagrangian is a fancy way of writing an equation to determine the state of a changing system and explain the maximum possible energy the system can maintain.
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Deep learning has transformed the field of artificial intelligence, but the limitations of conventional computer hardware are already hindering progress. Researchers at MIT think their new “nanophotonic” processor could be the answer by carrying out deep learning at the speed of light.
In the 1980s, scientists and engineers hailed optical computing as the next great revolution in information technology, but it turned out that bulky components like fiber optic cables and lenses didn’t make for particularly robust or compact computers.
In particular, they found it extremely challenging to make scalable optical logic gates, and therefore impractical to make general optical computers, according to MIT physics post-doc Yichen Shen. One thing light is good at, though, is multiplying matrices—arrays of numbers arranged in columns and rows. You can actually mathematically explain the way a lens acts on a beam of light in terms of matrix multiplications.
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The term “moonshot” is sometimes invoked to denote a project so outrageously ambitious that it can only be described by comparing it to the Apollo 11 mission to land the first human on the Moon. The Breakthrough Starshot Initiative transcends the moonshot descriptor because its purpose goes far beyond the Moon. The aptly-named project seeks to travel to the nearest stars.
The brainchild of Russian-born tech entrepreneur billionaire Yuri Milner, Breakthrough Starshot was announced in April 2016 at a press conference joined by renowned physicists including Stephen Hawking and Freeman Dyson. While still early, the current vision is that thousands of wafer-sized chips attached to large, silver lightsails will be placed into Earth orbit and accelerated by the pressure of an intense Earth-based laser hitting the lightsail.
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Nuclear fusion is the process that powers the sun, but closer to home scientists are trying to develop fusion reactors that could provide immense amounts of energy. These reactors are big and (currently) inefficient, but a NASA-funded startup called Princeton Satellite Systems is working on a small-scale fusion reactor that could power advanced fusion rockets. Suddenly, other planets and even other star systems could be in reach.
All the forms of rocket propulsion we currently have involve accelerating propellant out of a nozzle. Then, physics takes over and the vessel moves in the opposite direction. Most spacecraft use chemical propulsion, which provides a large amount of thrust over a relatively short period of time. Some missions have been equipped with ion drives, which use electrical currents to accelerate propellant. These engines are very efficient, but they have low thrust and require a lot of power. A fusion rocket might offer the best mix of capabilities.
Current nuclear reactors use fission to generate energy; large atomic nuclei are broken apart and some of that mass is transformed into energy. Fusion is the opposite. Small atomic nuclei are fused together, causing some mass to be converted into energy. This is what powers stars, but we’ve had trouble producing the necessary temperatures and pressure on Earth to get net positive energy generation.
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What’s wrong with this illustration of the planets in our solar system? »
For one thing, it suggests that the planets line up for photos on the same solar ray, just like baby ducks in a row. That’s a pretty rare occurrence—perhaps once in several billion years. In fact, Pluto doesn’t even orbit on the same plane as the planets. Its orbit is tilted 17 degrees. 
So, forget it lining up with anything, except on rare occasions, when it crosses the equatorial plane. On that day, you might get it to line up with one or two planets.
But what about scale? Space is so vast. Perhaps our solar system looks like this ↓
No such luck! Stars and planets do not fill a significant volume of the void. They are lonely specs in the great enveloping cosmic dark.* 
Space is mostly filled with—well—space! Lots and lots of it. In fact, if Pluto and our own moon were represented by just a single pixel on your computer screen, you wouldn’t see anything around it. Even if you daisy chain a few hundred computer screens, you will not discern the outer planets. They are just too far away.
Josh Worth has created an interactive map of our solar system. For convenience, it also assumes that planets are lined up like ducks. But the relative sizes and distance between planets are accurate. Prepare to change your view of the cosmos…
Just swipe your finger from the right edge of the screen to move away from the sun. Despite a fascinating experience (and many cute, provocative Easter eggs hidden between the planets), few readers swipe all the way out to Pluto and the author credits. On my high-resolution monitor, it requires more than a thousand swipes. Imagine if the Moon had been more than 1 pixel…It would take a long, long time! I would rather go out to dinner and a movie. But I urge you to travel at least to Jupiter. At 1/7 of the trip to Pluto, it should take less than 5 minutes.
On this scale, you won’t see the 1½ or 2 million asteroids between Mars and Jupiter. They aren’t large enough to merit a pixel. As Josh states, “Most space charts leave out the most significant part – all the space.” (an Easter egg at 1.12 billion km on the map).
* I borrowed this phrase from my former Cornell professor, Carl Sagan. He uses it in Pale Blue Dot [timestamp 2:14.]. This video tribute became a touchstone in my life; even more than having Sagan as a professor and mentor.
If you view it, be sure to also view Consider Again, Sagan’s follow-up in the video below. It is a thought-provoking observation of human-chauvinism throughout history—even among ancient Greeks. Carl isn’t the first atheist, of course. But he is eloquent in describing mankind’s ego trip: The delusion of a privileged place in the universe, or the religious depiction of God and his relationship with our species.
https://www.youtube.com/watch?v=XUxZwEYeuXE
Related:
- Carl Sagan Pale Blue Dot, a most impactful short video
- Consider Again the Pale Blue Dot, the arrogance of man throughout history
- Scale of the Universe: Powers of 10 (Charles & Ray Eames)
- Learn more about Charles and Ray Eames at Snore & Guzzle
- Our Universe is Finely Tuned for Life—Why?
Credit: ▪ Josh Worth and Sachin Gadhave who offers an illustrative answer at Quora.com
Philip Raymond co-chairs Crypsa & Bitcoin Event, columnist & board member at Lifeboat, editor
at WildDuck and will deliver the keynote address at Digital Currency Summit in Johannesburg.
Several firms are working on training environments like Star Trek’s Holodeck, but for machines.
When future robots enter the world, they won’t have a learning curve.
Artificial intelligence researchers are creating tools to help teach the robots that will assemble our gadgets in factories, or do chores around our home, before they ever step (or roll) into the real world. These simulators, most recently announced by Nvidia as a project called Isaac’s Lab but also pioneered by Alphabet’s DeepMind and Elon Musk’s OpenAI, are 3D spaces that have physics just like reality, with virtual objects that act the same way as their physical counterparts.
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N” Scientists have for a third time detected ripples in space from black holes that crashed together billions of light years from Earth, a discovery that confirms a new technique for observing cataclysmic events in the universe, research published on Thursday shows.
Such vibrations, known as gravitational waves, were predicted by Albert Einstein more than 100 years ago and were detected for the first time in September 2015. They are triggered by massive celestial objects that crash and merge, setting off ripples through space and across time.
The latest detection occurred on Jan. 4, 2017. Twin lasers in Louisiana and Washington picked up the faint vibrations of two black holes that were 20 and 30 times more massive than the sun, respectively, before they spiraled toward each other and merged into a larger black hole.
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