answersLogoWhite

0

« Putting the Heat in the Hot Big BangThe Atom Smashers on PBS Nov. 25 »

What if Time Really Exists?The Foundational Questions Institute is sponsoring an essay competition on "The Nature of Time." Needless to say, I'm in. It's as if they said: "Here, you keep talking about this stuff you are always talking about anyway, except that we will hold out the possibility of substantial cash prizes for doing so." Hard to resist.

The deadline for submitting an entry is December 1, so there's still plenty of time (if you will), for anyone out there who is interested and looking for something to do over Thanksgiving. They are asking for essays under 5000 words, on any of various aspects of the nature of time, pitched "between the level of Scientific American and a review article in Science or Nature." That last part turns out to be the difficult one - you're allowed to invoke some technical concepts, and in fact the essay might seem a little thin if you kept it strictly popular, but hopefully it should be accessible to a large range of non-experts. Most entries seem to include a few judicious equations while doing their best to tell a story in words.

All of the entries are put online here, and each comes with its own discussion forum where readers can leave comments. A departure from the usual protocols of scientific communication, but that's a good thing. (Inevitably there is a great deal of chaff along with the wheat among the submitted essays, but that's the price you pay.) What is more, in addition to a judging by a jury of experts, there is also a community vote, which comes with its own prizes. So feel free to drop by and vote for mine if you like - or vote for someone else's if you think it's better. There's some good stuff there.

My essay is called "What if Time Really Exists?" A lot of people who think about time tend to emerge from their contemplations and declare that time is just an illusion, or (in modern guise) some sort of semi-classical approximation. And that might very well be true. But it also might not be true; from our experiences with duality in string theory, we have explicit examples of models of quantum gravity which are equivalent to conventional quantum-mechanical systems obeying the time-dependent Schrödinger equation with the time parameter right there where Schrödinger put it.

And from that humble beginning - maybe ordinary quantum mechanics is right, and there exists a formulation of the theory of everything that takes the form of a time-independent Hamiltonian acting on a time-dependent quantum state defined in some Hilbert space - you can actually reach some sweeping conclusions. The fulcrum, of course, is the observed arrow of time in our local universe. When thinking about the low-entropy conditions near the Big Bang, we tend to get caught up in the fact that the Bang is a singularity, forming a boundary to spacetime in classical general relativity. But classical general relativity is not right, and it's perfectly plausible (although far from inevitable) that there was something before the Bang. If the universe really did come into existence out of nothing 14 billion years ago, we can at least imagine that there was something special about that event, and there is some deep reason for the entropy to have been so low. But if the ordinary rules of quantum mechanics are obeyed, there is no such thing as the "beginning of time"; the Big Bang would just be a transitional stage, for which our current theories don't provide an adequate spacetime interpretation. In that case, the observed arrow of time in our local universe has to arise dynamically according to the laws of physics governing the evolution of a wave function for all eternity.

Interestingly, that has important implications. If the quantum state evolves in a finite-dimensional Hilbert space, it evolves ergodically through a torus of phases, and will exhibit all of the usual problems of Boltzmann brains and the like (as Dyson, Kleban, and Susskind have emphasized). So, at the very least, the Hilbert space (under these assumptions) must be infinite-dimensional. In fact you can go a bit farther than that, and argue that the spectrum of energy eigenvalues must be arbitrarily closely spaced - there must be at least one accumulation point.

Sexy, I know. The remarkable thing is that you can say anything at all about the Hilbert space of the universe just by making a few simple assumptions and observing that eggs always turn into omelets, never the other way around.

http://blogs.discovermagazine.com/cosmicvariance/2008/11/24/what-if-time-really-exists/

User Avatar

Wiki User

15y ago

What else can I help you with?

Continue Learning about Astronomy

Is the goldilocks planet in a solar system?

The "Goldilocks planet" refers to a planet that is situated at just the right distance from its star to potentially support liquid water on its surface, which is a key factor for life as we know it. While there are candidates that fit this description in various solar systems, Earth is currently the only confirmed Goldilocks planet in our own solar system.


How does the Goldilocks zone help scientist narrow down the search for life on other planets?

The 'Goldilocks Zone,' or habitable zone, is the range of distance with the right temperatures for water to remain liquid. Discoveries in the Goldilocks Zone, like Earth-size planet Kepler-186f, are what scientists hope will lead us to water––and one day life.


Is Venus located in the Goldilocks zone?

Ah, that's a good question, friend! Venus is a bit too close to the sun to be considered part of the Goldilocks zone, where temperatures are just right for liquid water to exist. But every planet is unique and special, just like your painting — you create the perfect conditions for beauty to thrive, no matter where you are.


Is Mars located in the Goldilocks zone?

Mars is not located in the Goldilocks zone, which is the region around a star where conditions are just right for liquid water to exist on a planet's surface. Mars is too far from the sun to be in the Goldilocks zone, so its surface is too cold for liquid water to exist.


What are the three goldilocks conditions that earth has that life as you know it needs to exist?

A Breathable Atmosphere, temperature rate, breathable atmosphere, and liquid water. it has nothing to do with Justin bieber and how sexy he is. he has nothing to do with the Goldilocks condition's

Related Questions

What is the nickname of Gliese 581 g?

Goldilocks Zone or Goldilocks Planet.


When did they find the new planet Goldilocks?

The Goldilocks planet, which refers to a habitable exoplanet with conditions suitable for life, has not been discovered as of now. Scientists are continuously searching for potentially habitable planets outside our solar system, but the discovery of a true "Goldilocks" planet has yet to be confirmed.


Is there a planet called Goldilocks?

No, there is no planet called Goldilocks. The term "Goldilocks planet" refers to a planet that is neither too hot nor too cold to support liquid water on its surface, making it potentially habitable for life.


Is there a planet called the goldilocks?

no, goldilocks is a zone around a star where a planet with appropriate atmospheric pressure can maintain the liquid water on its surface


How did the Goldilocks planet get its name?

The Goldilocks planet got its name from the children's story "Goldilocks and the Three Bears." The term is used to describe planets that are neither too hot nor too cold to support liquid water, making them potentially habitable for life.


Does Goldilocks planet exist?

yes ,Goldilocks is a planet but so far no life exists just a big dense ball


Does goldilocks planet have a moon?

While the term "Goldilocks planet" is used to describe a planet that is in the habitable zone of its star, the presence of a moon does not impact whether a planet falls into this category. The habitability of a planet is mainly determined by its distance from its star and other factors such as atmosphere and surface conditions.


Why is the sun called the goldilocks planet?

The sun is not called the Goldilocks planet. The term "Goldilocks planet" refers to a planet that is neither too hot nor too cold, and is capable of supporting liquid water on its surface, like Earth. The sun is actually a star, not a planet, and it is too hot to support life on its own.


Is the goldilocks planet in a solar system?

The "Goldilocks planet" refers to a planet that is situated at just the right distance from its star to potentially support liquid water on its surface, which is a key factor for life as we know it. While there are candidates that fit this description in various solar systems, Earth is currently the only confirmed Goldilocks planet in our own solar system.


Are golden evil aliens real?

yes.... in goldilocks planet


What does a goldilocks planet look like?

Finding Earth-sized Goldilocks planets is a key part of NASA's Kepler mission, which uses an orbital deep-space telescope launched on March 7, 2009.The mission will survey and compile the characteristics of habitable-zone planets to find those that might provide Earth-like atmospheres and climates.


How did they now Goldilocks is a planet?

A "Goldilocks planet" is ANY planet that orbits its star at a distance from that star where the heat from the star means that any water present on the planet is in liquid form. This can be determined by measuring the stars temperature (its size and colour) and observing the planets orbital distance.