Emily Fuhrman for Quanta Magazine, with text by Natalie Wolchover and art direction by Olena Shmahalo.

“Ever since the dawn of civilization,” Stephen Hawking wrote in his international bestseller A Brief History of Time, “people have not been content to see events as unconnected and inexplicable. They have craved an understanding of the underlying order in the world.”

In the quest for a unified, coherent description of all of nature — a “theory of everything” — physicists have unearthed the taproots linking ever more disparate phenomena. With the law of universal gravitation, Isaac Newton wedded the fall of an apple to the orbits of the planets. Albert Einstein, in his theory of relativity, wove space and time into a single fabric, and showed how apples and planets fall along the fabric’s curves. And today, all known elementary particles plug neatly into a mathematical structure called the Standard Model. But our physical theories remain riddled with disunions, holes and inconsistencies. These are the deep questions that must be answered in pursuit of the theory of everything.

Our map of the frontier of fundamental physics, built by the interactive developer Emily Fuhrman, weights questions roughly according to their importance in advancing the field. It seemed natural to give greatest weight to the quest for a theory of quantum gravity, which would encompass general relativity and quantum mechanics in a single framework. In their day-to-day work, though, many physicists focus more on rooting out dark matter, solving the Standard Model’s hierarchy problem, and pondering the goings-on in black holes, those mysterious swallowers of space and time. For each question, the map presents several proposed solutions. Relationships between these proposals form a network of ideas.

The map provides concise descriptions of highly complex theories; learn more by exploring the links to dozens of articles and videos, and vote for the ideas you find most elegant or promising. Finally, the map is extensive, but hardly exhaustive; proposed additions are welcome below.

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  • As I understand it now. The most elusive particle ever searched for was the Higgs-Boson. I just learned of the Little Higgs. Am I to understand now that the most difficult to find particle that completes the Standard Model, was the big one?

  • Beautifully done.
    Silly question. When particles pop into and out of existence do they also impart a gravitational effect on the universe?

  • Thank you very much for this. This is a marvelous way to show how the theoretical physics at the frontier are tied together.

  • Phil Morey
    They pop out in pairs and their net effect is zero.
    Also their size and liftime is very very very small.

  • The idea of the map is nice, but so far it is mostly a map of ideas promoted in the US. When US was the center of science, 20-30 years ago, a US-centric map would have been a good approximation. But now, after the failure of the SSC and of string theory, this is no longer the case.

  • we have only been studying quantam mechanics for about 100 years and have only been sending probes into space for 70, its like we are studying 1 or 2 pixels in a 10000 inch hd television and hoping to get the big picture…. we still have a long way to go

  • Where is this map? I only have the picture on my Facebook page. That is about one inch by two inches in size. Well I guess a larger phone might help.

  • It's exciting to me that the explanatory power of the causal diamond work using entropy as a proxy for observers seems to line up with Jeremy England's line of investigation into the origins of life based on dissipation of energy. If England's work proves similarly powerful, it will provide a solid rationale for the use of entropy as a gauge for the the likelihood of sentient observers within a diamond.

    If the causal diamond approach continues to provide verifiable predictions these will undoubtedly serve to convince some former multiverse skeptics. Even without the calculations, multiverse naysayers ought to be convinced of its existence by Whitehead's reasoning about what he called the continuum. First, the continuum is extensive because non-existence is non-existence; it's incapable of producing a boundary or limit on existence. Second, the continuum is divisible. In fact, Whitehead argued that that is the fundamental property of the continuum: its divisibility. The first axiom is pure logic; the second is self-evident.

    As I've said to friends in the past: the rumor that runs through Nature is that — somewhere in the continuum — every conceivable form of existence is actualized. And the conceivable is not limited to what humans can conceptualize. I think it was the evolutionary biologist J.B.S. Haldane who originated the thought that "the Universe is not only queerer than we suppose, but queerer than we can suppose."

  • @kp (reply to Phil)

    I am not convinced by this reply: for the gravitational effect of a pair to cancel out the two particles would have to feature opposite masses and one of them should therefore exert anti-gravity. Is this what happens? I used to believe that gravitation was always attractive actually.

  • @Carl: The map is best viewed on a desktop computer. Unfortunately it is not compatible with all mobile devices (and the text would be too small to read on a phone).

  • This map is fantastic! I'd love to see it expanded upon though, as most of the topics I would like to know more about. Perhaps if it was open to editing like wiki??

  • "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement" – Lord Kelvin

  • Ah what we have discovered as we explore the miraculous bosons as they interact with fermions. Miracles of science have made our lives easier and cured many of our ailments, but we are infants in understanding still.
    How many times have I read that we still can't explain common phenomena? Is there an extraordinary dimension of existence coexisting alongside us but not yet uncovered? We mimic the expressions of the world creatures, yet can barely communicate except for a few "sit, beg, fetch, and roll over" commands. I worry that fallen angels mislead us and that our better angels we ignore. God we are not, but we humans have come a long way!

  • Is there any version of this that could be used as a screen saver?
    It would be nice to have this on my desktop so I could study it at my leisure.

  • @Christophe
    My thoughts too. Never heard of antigravity. Although it could be dark energy? . Assuming gravity transmits at light speed then I'm being attracted to particles that ceased to exist long ago?

  • @Christophe
    There are particles that travel backwards in time .
    Then there is negative mass.
    I am no authority on this subject, but this are facts.
    Bizarre it may sounds, but scientists have also proposed (which is verified or not ?)anti-gravity.

  • Awesome! If you're interested in more about holography, I highly recommend David Bohm's Wholeness and the Implicate Order. He elucidates what I think is one of the most fascinating and unifying theories about what the fundamental ground of the universe could be said to be. Now, how can I make this interactive map my background on my desktop? Please please please!

  • @kp

    Those are not facts – the tachyon is a hypothetical particle for which no evidence has been found and negative mass is a hypothetical concept.

  • Beautifully done. Excellent work. It's kind of a guide to people like me who wonder about the universe and understand the great work being done by many beautiful minds.

  • Does somebody know about books, articles or similar that explain this concepts in a technical way although for the non specialist? Thanks.
    And congratulations for the great work, Quanta Magazine!

  • This is wonderful work; I managed to view it on my BBQ10 but the screen is too small,so I've just done a tour on my laptop:quite mesmerising and my favourite is the mysterious amplituhedron.
    I don't understand it properly but I find it quite fascinating;so much so that I've got an amplituhedron fridge magnet.
    Interractive displays are such a good way to educate non-physicists like me,who are intrigued by current theories.
    Thank you Quanta.

  • This map needs to be sent to high school and college physics teachers and professors, it would be so helpful to the students.

  • This is a GREAT start! We needed a place where we could 'see' these elusive theories in one place, along with the brief explanation of them (as shown in the interactive). As an amateur science guy, I would've put the Dark Matter & Dark Energy closer together since they have similar properties. Again, great job!

  • Wonderful job! Now its more easy to visualize and understand the relations between different theories and their parameters.
    Thanks Quanta.

  • I've often wondered if gravity even really exists. What if the Universe is simply pushing? Energy from expansion would make powerful waves. Perhaps we have been held in space all along by the results of such energy. What if dark matter works a bit like water when a person jumps into a pool – dispersing weight, slowing and sort of wrapping around the body? The energy waves and pressure that hit the Earth and the waves that bounce back into space after hitting the Earth (or any other planetary items) would react like the water in the pool. So, we'd get a steady flow of waves coming in and going out that could possibly caress all space material into a practical suspension. How would these unsolved mysteries play out if gravity was a push and dark matter was like water?

  • Phil M's question amounts to the Cosmological Constant Problem, among the deepest outstanding questions in fundamental physics.

  • Is there any translation of this map planned?
    I'm sure, different language versions would be in demand.

  • Is there a Zoom in & out? This is a lovely format, but it's too small. (and forget that 'fullscreen' nonsense, my monitor is Landscape.)
    After "ctrl +" & "ctrl -", it re-sizes itself back to difficult.

  • Wonderful article and great graphics. Can you please insure this remains available until the end of time or three years, whichever comes first. Thanks for an intriguing article.
    /s/ John

  • Kudos to everyone in Quanta Magazine for developing this visually-pleasing, yet very informative succinct overview of the quandaries in theoretical physics!

    Having this written this, I propose two things: a) Despite that I know English, other language speakers might fell left out; I suggest translating this first in Spanish, German, Portuguese and in a Slavic lingo, such as Russian, e.g.7/ b) I recommend updating the section of the black hole information paradox with the Stephen Hawking's newly proposed 'solution' to it (i.e.: information actually escapes the black hole by hitching a ride on the photons making up his eponymous Radiation).

    Thank you so much for contributing to our growing knowledge!

  • Lovely work, but is funny to have us amateurs vote on the theories as though we had a clue. Only downside was that I often couldn't see the ends of arcs when zoomed in on an interactive domain. Maybe there's a minimum pixel size so arc targets can be seen? (I'm using a smallish desktop display.)

    Many kudos to the design team.

  • Very nice indeed. I probably shouldn't but oh well. I for one do not agree with Einstein and the connection between space and time I know I know its accepted and proven by experiment but I see a misinterpretation of data. Why? well since we measure time in accordance to reactionary dynamic forces whether it is a ticking of a clock or the vibration of an atom all are measurements of change(discrepancies) at a fixed or predictable rate. What is actually taking place is a change in rate of reactions due to outside forces acting upon that which we use to obtain a measurement of a reaction, reactions such as these are not time itself only these reactions in time. It is not time that is changing it is the forces in time, time itself is so infinitesimally fast that even the speed of light does not come close to the theoretical shortest measurement a planck's length, so why is it logical to surmise it it time slowing down it's not only forces at work. Yes C is a constant for anything traveling through the vacuum of space but not as fast as time itself but since light itself can be slowed and such phenomena as time dilation is not time changing only the forces at work on given object traveling at a velocity, if time did change than therefore no dilation would occur(we would not be able to measure it) why since a stationary observer can view the object accelerating away(of course if below C otherwise object would theoretically appear stationary). The fact the observation can be made consequently negates that time has changed only the forces at work on object accelerating away from observer.

  • Fantastic idea and fantastic execution. I think this is a really important collection of knowledge to help the younger generation of physicists understand what we don't yet understand.

    My Topic Suggestions

    1) What is time and will the fundamental physical theory ("theory of everything") posses the unitarity of QM? .

    2) Relating to the black hole paradox: which of the fundamental principles of relativity and quantum physics should be abandoned and which should be preserved to resolve the paradox?

    3) Why are there three generations of particles in the standard model and why is our world on Earth made of only three of these particles? Are there more generations?

    4) What are the geometry and topology of the Universe?

    5) What is the nature of space-time? Does the strong equivalence property hold? Is quantum gravity "background independent"?

    and the big request….
    6) A section on the quantum measurement problem and related topics such as multiple universes, decoherence and objective wavefunction collapse. How does macroscopic reality emerge from quantum mechanics? Is quantum mechanics truly a fundamental theory? Does wavefunction collapse occur? Is there unknown physics operating at mesoscopic mass scales, serving as a transition between quantum and classical mechanics?

    Great work!

  • @Phil Morey:

    "Silly question. When particles pop into and out of existence do they also impart a gravitational effect on the universe?"

    This is not a silly question! Virtual particles do indeed contribute to gravity, namely to something called the 'cosmological constant' , that specifies the gravitational effect of the vacuum. Unfortunately, the resulting physics is famous for being the most spectacularly wrong prediction of all time. What this means is that we do not yet understand the connection between the quantum vacuum ("popping particles") and gravity. Hopefully we'll get there some day.

  • the most exciting thing about this map is that it shows how much we DON'T understand. Therefor, vast and incredible discoveries await! As well as technological application of those discoveries. I wish i could live another few centuries, just to witness it!

  • @Phil Morey:

    "Silly question. When particles pop into and out of existence do they also impart a gravitational effect on the universe?"

    This is not a silly question! Virtual particles do indeed contribute to gravity, namely to something called the 'cosmological constant' , that specifies the gravitational effect of the vacuum. Unfortunately, the resulting physics is famous for being the most spectacularly wrong prediction of all time. What this means is that we do not yet understand the connection between the quantum vacuum ("popping particles") and gravity. Hopefully we'll get there some day.

    Sooner than you think, read up on Don Hotson's theory at http://www.infinite-energy.com/iemagazine/issue86/hotson.html
    Be sure to check out his previous submissions.

  • Wonderful model!
    Can you add the Coney Island Green Theory (CIG Theory) to the model? It is documented in the book "I Have Become Space"

    Thank you
    douglas w lipp

  • Hey you need to put some equations on that map. Think it like this, you're leaving a clear path for young physicists!

  • number theory and physics will converge

    number systems are based on human perception of quantity

    they formalise natural, pre-existing quantitative relationships into symbolic language

    they do not constitute quantitative relationships

    quantitative relationships are natural laws

    that's why maths is so unreasonably useful to physics

    they both develop from the same first principles

  • Well done !! ……….. Amazing & appreciate it !!
    The idea of the map is fantastic .
    Is it possible to elaborate this mapped with a specific equation??

  • In keeping with the real time collaboration of widely separated mathematicians, wouldn't it be possible to set up a daily window of time (eg, 2 hours before noon GMT to 2hours after noon GMT) and line of communication (eg, HD videoconferencing network connecting leading math centres worldwide) to stimulate more face-to-face contacts and, hopefully, cross-pollenation of ideas?

  • Pretty cool site! Although I did find it annoying/unnecessary that it enforces fullscreen mode. Even if I exit fullscreen it goes back to the start page. For a site like this, I don't see a reason why fullscreen would be a requirement.

  • You should make this map an open source project. I would love to contribute additions to the midtier and backend!

  • I would love it, when this map is available as document in *.html or in *.pdf format to read this offline, for to explore it better because there are still some words like loanwords to me (here is struggling sometimes as German with English vocabulary). Thank you.

  • This is simply AMAZING. Should be given to kids in schools and learnt as science homework – I would have been so grateful for something like this when I was at school!

  • Carl Vickers, go to quanta magazine.com. larger map should be there, front page.

    Randy, I think the quantum computer will help speed up your, pixel number search 🙂

    If no answers in say another decade, then perhaps most scientists and physicists have been looking at things more wrongfully than they cared to think of or admit.
    For instance, black holes exist ? How do they Function, in an electric universe ?
    Dark Matter exists ? if filling in space making universe expand; then why is the energy density of the universe low ? I like the triangle search, see where it leads 🙂 but our computers who we so highly admire, are nothing compared to the new ones of, 2030
    Again, a quantum computer will do far more to accelerate the, present understanding.

  • I have a real problem with any attempt to explain the universe that starts out saying on the one hand: 'all known elementary particles plug neatly into a mathematical structure called the Standard Model' and then, merely a paragraph later notes that: 'many physicists focus more on . . . solving the Standard Model’s hierarchy problem.' This same author goes on, in a related article, to note that physicists 'have spent decades devising clever ways to fit the Standard Model into a larger, natural pattern.'

    Yes, I believe that the understanding of the universe is an incredible and beautiful story to tell, but don't make it seem simpler than it really is. I try and teach this stuff, the basic stuff at that, to high school students and know first hand how hard it is for them to comprehend it all.

    The deeper we go, the more complex it becomes.

  • The solution for a unified, coherent description of all of nature is much more simple than thought! =

  • Thank you so much for this map! Loving the spatial relationship concepts and scaling up or down feature that enables you to organically explore the connections between theories. This is so immersive and mesmerizing. It is exactly the perfect presentation for these ideas. The ease and fluidity that the viewer experiences interacting here does not convey the complex thought that went into designing it. Many thanks.

  • I on behalf of my experience I would like to tell you that the "Theory of everything" would combine all the scientific theory (physical,natural and cognitive science).So why the people working as string theorists,loop quantum gravitist or metaphysician blaming each of their theories are the powerful to unblock the secrets of reality.So please stop doing that and let us unite to reach the ultimate.

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