12 posts tagged with spacetime.
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Greg Egan's Orthogonal Trilogy is perhaps the ultimate in hard sci-fi world building: starting by simply "changing a minus sign to a plus sign in a simple equation that governs the geometry of space-time", Mr Egan then derived, from first principles, how light, matter, energy, motion, gravity and time would work in this alternate universe. The result is 80,000 words on his web site describing the physics and cosmology of the universe (minor spoilers) and three novels: The Clockwork Rocket (extract), The Eternal Flame (extract) and The Arrows of Time (extract) [more inside]
posted by memebake on Jan 13, 2015 - 53 comments

A Universe In Which Time Has No Beginning

"Maybe the Big Bang never happened because the universe never began because it has always existed." Scientific American magazine revisits the decade-old idea that we live in a "Rainbow" universe (where different wavelengths of light experience spacetime differently and where the big bang may never have happened) following the publication of new physics research on the subject.
posted by rcraniac on Dec 10, 2013 - 83 comments

Gravity Visualized

Dan Burns explains his space-time warping demo at a PTSOS workshop at Los Gatos High School, on March 10, 2012. [more inside]
posted by Blasdelb on Dec 3, 2013 - 27 comments

My God, it's full of... everything

Revelations in the field of quantum physics have resulted in the discovery of the Amplituhedron, a jewel-like higher dimensional object whose volume elegantly predicts fundamental physical processes that took the brilliant Dr. Richard Feynman hundreds of pages of abstruse mathematics to describe. The theoretical manifold not only enables simple pen-and-paper calculation of physics that would normally require supercomputers to work out, but also challenges basic assumptions about the nature of reality -- forgoing the core concepts of locality and unitarity and suggesting that space and time are merely emergent properties of a timeless, infinitely-sided "master amplituhedron," whose geometry represents the sum total of all physical interactions. More: The 152-page source paper on arXiv [PDF] - Lead author Nima Arkani-Hamed's hour-long lecture at SUSY 2013 - Scans of Arkani-Hamed's handwritten lecture notes - A far more detailed lecture series "Scattering Without Space Time": one, two, three - Arkani-Hamed previously on MeFi - A hot-off-the-presses Wikipedia page (watch this space)
posted by Rhaomi on Sep 18, 2013 - 128 comments

conservation of information

A Black Hole Mystery Wrapped in a Firewall Paradox - "A paradox around matter leaking from black holes puts into question various scientific axioms: Either information can be lost; Einstein's principle of equivalence is wrong; or quantum field theory needs fixing." [more inside]
posted by kliuless on Aug 18, 2013 - 36 comments

First Toy Multiverse Created in a Laboratory, Say Physicists

foundational notions of classic science fiction seem to be moving closer to reality there's way more here than I am capable of comprehending, but anything that talks about Minkowski spacetime has my attention.
posted by TMezz on Feb 5, 2013 - 40 comments

This view of time does not look encouraging for time travelers

The concept of time as a way to measure the duration of events is not only deeply intuitive, it also plays an important role in our mathematical descriptions of physical systems. For instance, we define an object’s speed as its displacement per a given time. But some researchers theorize that this Newtonian idea of time as an absolute quantity that flows on its own, along with the idea that time is the fourth dimension of spacetime, are incorrect. They propose to replace these concepts of time with a view that corresponds more accurately to the physical world: time as a measure of the numerical order of change.
posted by finite on Apr 25, 2011 - 127 comments

riverrun, past Eve and Adam's, from swerve of shore to bend of bay, brings us by a commodius vicus of recirculation back to Howth Castle and Environs.

to talk about the concept of "time" before the big bang; the Cyclic Universe Theory proposes an alternative to the predominant Inflation Theory that led to this intuition. Now Gurzadyan and Penrose have observed low-variance rings in the CMB, supporting the notion that it makes sense
posted by jjray on Nov 27, 2010 - 41 comments

The Future of Fundamental Physics

Renowned theoretical physicist Nima Arkani-Hamed gave a series of five Messenger lectures on "The Future of Fundamental Physics" at Cornell University two weeks ago. 1 3 4 5 [more inside]
posted by bread-eater on Oct 20, 2010 - 15 comments

Does the Past Still Exist?

Is our present defined by decisions we make in the future? And maybe we don't know who killed JFK because the universe hasn't decided yet. A Huffington Post science blogger discusses the nature of history from a quantum perspective. To quote Stephen Hawking, "The histories of the universe depend on what is being measured, contrary to the usual idea that the universe has an objective observer-independent history." [more inside]
posted by GnomeChompsky on Aug 20, 2010 - 95 comments

Dude, I knew it!

Maybe the entire universe as we know it really is just sitting inside a black hole of another, bigger universe.
posted by molecicco on Jul 29, 2010 - 104 comments

Holy Purple Potion Scientist Man!

Flash Friday Saturday Fun: Paradox Embrace is a platform puzzler similar to the Shift trilogy (2 & 3) but in COLOR! You shift between three space-times to negotiate the levels collecting keys and such. In game tutorial makes learning the game pretty quick. Deceptively simple at first but gets quite difficult.
posted by schyler523 on Jan 9, 2010 - 6 comments

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