Find Out About the Future of Science

Science magazine writer Charles Seife has written a new book, Alpha and Omega: The Search for the Beginning and End of the Universe. According to Publishers Weekly, Charles claims, "Scientists...now know how the universe will end and are on the brink of understanding its beginning. Their findings will be among the greatest triumphs of science, even towering above the deciphering of the human genome." A brave statement! Charles is happy to answer your questions about ongoing research that is busily revealing the basic nature of life, the universe, and everything in a serious (as opposed to humorous) sense, so ask away. One question per post, please. We'll post the answers as soon as we get them beck.

Comments

Publishing hype

[BobTheLawyer]

do you get embarassed by publishing hype such as "Scientists...now know how the universe will end"?

Well obviously

[Timesprout]

the Universe will end with a cliff hanger to set things up for Universe II

Question:

[cybercuzco]

Since we now know how the universe will end, would it be possible to set up some sort of restaurant there?

Re:Errr..

[gantrep]

Thank you for that pointless comment. You have taken usefull energy and turned it into a slashdot comment, thereby bringing the universe closer to heat death.

Why does the rate of expansion change?

[Anonymous Coward]

Can we explain the expansion of the universe and why the rate is changing? Can we claim to know how the universe will end if we can't answer that?

Universe's container

[bios10h]

It's a question I've had for a long time and I sometimes think about it and it freaks me out :) no really. Ok, we "know" (until someone else proves it's wrong) how the universe is going to end. We are about to "know" how it really started. Great! However, when we are talking about the universe... we are assuming that it is infinite. I just have a hard time with this Infinite Universe concept... the universe NEEDS to be contained within something... however, even if we discover the container... it will end up being a part of our definition of universe and then we'll need to search for the container's container. Anyway, any thoughts on that?

Re:Universe's container

[MegaFur]

Brace yourself. Infinity within a container coming right up... drum roll please...

(0,1)

ta da! In case you can't read the notation, that's all the real numbers between 0 and 1 but excluding 0 and 1 themselves. There are infinitely many of them, but they are bounded by 0 and 1 (a container). Also note: although 0 and 1 were used in the definition of this interval, they are not actually a part of it.

Perhaps the real problem is that infinity is a hard concept. I don't think we humans can ever truly understand it. But we can still throw it around in math and physics problems and come up with interesting results.

Re:I've been doing some thinking about this lately

[aug24]

Intelligent Design

Oh god (irony), not this crap again.

Haven't you got anything better to do that to keep 'refining' Creationism whenever in response to Evolution showing it to be unnecessary.

There is NO NEED for intelligent design. It's only purpose is to allow you justify your belief in God. I don't care if it's the Bombadier Beetle, the jinking Moth, whatever, it's just as sensible to think of a way it could've evolved than to allege that there is a God. And a God is a damn big hypothesis that only serves to abstract out the thing you can't explain.

Justin.
Bored of bloody desperate religionists arguing over who's got the best imaginary friend.

Dark Matter

[notcreative]

I remember from college courses that the composition of dark matter is one of the most important issues in cosmology today. One example of this importance is that there are some estimates that 90% of the mass of galaxies is not visible. There was some work that was presented to the public a while ago from WMAP at NASA. I read that it had implications for the sources of dark matter, but I don't understand what they are.

Since it is something of an open issue, what is the current understanding of the nature of dark matter in our universe? What kinds of questions are still being investigated? What kinds of hypotheses do we have now, and what do they imply?

Which end do we know will happen now?

[Christopher Thomas]

So, which end are we certain will happen now - or rather, which end is the author hyping, since most scientists would still be reluctant to call this an open and shut case?

Possible scenarios include:

• The Big Crunch
  
  This fell out of favour a while back, when the need for a flat universe became apparent. In this scenario, the universe's espansion halts and it re-collapses. Once it was thought that this would involve time running backwards/entropy reversal during the crunch phase, but it was later shown that scenarios with increasing entropy also existed. There was much speculation about whether the universe would "bounce" after it crunched, forming a new expanding universe.
• The Whimper, Version 1
  
  This scenario was popular when we'd made a detailed enough survey to know that that amount of bright matter in the universe was far too low to counteract the expansion. It fell out of favour when our estimates of the amount of dark matter got better.
  
  In this scenario, the universe keeps expanding quickly, and all matter that isn't gravitationally bound into clusters is separated by vast empty regions of space. As the universe's expansion represents the expansion of space itself, sufficiently large gravitationally bound clusters might still be disrupted, due to distances changing internally. Galaxies burn out as stars exhaust their fuel, stellar corpses eventually merge with each other and with the central black hole, which finally decays after a mind-bogglingly huge length of time.
• The Flat Whimper (Version 2)
  
  This scenario assumes that the amount of matter - light and dark - is perfectly balanced with the expansion of the universe. There was strong circumstantial evidence for a scenario like this, due to the fact that deviations from flatness amplify over time and that our universe was still _roughly_ flat - but the linchpin was a variety of models for the early universe - and the big bang - that required the universe to be flat. More detailed measurements of the amount of dark matter in the universe seemed to be consistent with this model.
  
  In this scenario, the rate of expansion slows, approaching zero as time goes to infinity. Distance still goes to infinity as time goes to infinity, but not as rapidly. From a local point of view this looks a lot like Whimper Version 1.
• Whimper Version 3 - We're Expanding Again
  
  This model arose when evidence for dark energy was discovered by observations of distant parts of the universe. In this model, the universe started out as flat, but a weak repulsive effect comes into play that causes expansion to accelerate. The effect is small enough that we haven't diverged that greatly from flatness yet, but in the end, it'll be Whimper Version 1 all over again. This is one of the two currently plausible scenarios.
• The Never-Ending Fractal Universe (Steady-State Reborn)
  
  This model was the result of closer examination of the scalar field models used to drive inflation in the early universe. In the inflationary model - which itself was proposed to solve the problem of the universe's matter distribution being so smooth - a "scalar field" existed in the early universe that permeated space and caused vast amounts of new space to be created. In the original version of the inflationary model, this scalar field's effects died out shortly after the big bang. A later model, however, proposed that the field was not cancelled everywhere - in some regions of the universe, constructive interference would cause it to be strong enough for inflation to continue.
  
  Thus, we have a model where the universe looks mostly like our own, except for regions where it "buds" to form new universes. This process continues forever. This is the second scenario currently considered plausible (with the scalar field taking on the role of "dark energy").
• Colliding Membranes
  
  This is the model proposed by

variable constants

[Cally]

As a layperson with an interest in cosmology and physics, I seem to hear about an increasing number of hacks to the Standard Model. By hacks I mean things like dark energy, whose value apparently fluctuates over (cosmological) timescales; there's another idea that the speed of light(I think?) ha varied over time, and that this is the only way to explain the cepheid data (supernovae of known brightness) as we get to see supernovae from further and further away (which occured further and further back in time of course.)

Isn't the use of ugly hacks to prop up an established theory in the face of contradictory observations an indicator of a theory which needs to be chucked out en masse and reformulated in the light of a more fundamental description of physics?

Physics and Consciousness

[Remus Shepherd]

There have been some recent experiments, mostly spearheaded by Roger Nelson of the Princeton Global Consciousness Project, that show a correlation between human consciousness and quantum events. Some have speculated that consciousness may lay outside of what we know about physics.

Do you think there will be any fruitful (i.e., predictive) experimentation in this matter? Could we someday develop a theory that will unite physics and consciousness?