Riku Sayuj's Reviews > The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality

The 4 Percent Universe by Richard Panek
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Aug 14, 2014

really liked it
bookshelves: science-gen, r-r-rs
Read from March 18 to 20, 2012

Now this is how an honest-to-goodness popular science book ought to be like. The book basically tracks the same story as A Universe from Nothing by Lawrence M. Krauss and even has Lawrence as a character every now and then. Because I was familiar with the story and its ending, this time around I could concentrate on the telling of the story more than the actual events themselves and I was struck by the high contrast of how Richard Panek handles the material and how Krauss had presented it in his book.

Krauss comes at it with a vehemence and a rejoicing attitude as if science has finally solved the big problems with the confirmation of the 'dunkel stuff' and from the extension of the flatness of the universe to how it was possible for it to have come from nothing. Throughout the book, the language is forceful and the story is convincing. The scientists know what they are doing and they are finally getting things right was the sonorous message. 'No doubts entertained' was Krauss's attitude and the percentages and the fractions were thrown at us as if there was no contention on those measurements whatsoever. I was convinced and I accepted them. After all, they were coming from a respected scientist who was part of these very breakthroughs. So with a few reservations about how Krauss had not really closed the door with the book, I had concluded my review.

The 4% Universe - 4% science... 96% stories.

Panek on the other hand has shown me the human version of what happened behind the scenes. Those astronomers and observers who found the standard candles and made the measurements, those theorists who made the elegant theories and the physicists who ran the accelerators in patient search of extreme particles, they were not really all that, exactly. They were mostly guessing and fumbling and playing scattergun. They had no idea whether Type Ia supernovae would really be standard candles, they had no clue why lambda should be non zero or for that matter, what dark matter or dark energy really is.

These uncertainties of the scientific procedure too should be captured when science is written or commented upon and Panek has done that in wonderful fashion. At times his obsession with detail and the pages and pages of detail about the letters exchanged and the worries of each group member of the High-z team and the SCP team does get tedious when the reader already knows the outcome of this famous spat and Panek doesn't quite manage to achieve the suspense that he tries so hard to build up. But what the detail does provide is an insight into the insecurities and the many mistakes of these Nobel laureates and exposes how almost everything they thought of the universe was wrong and that the Nobel they got was mostly for proving themselves and almost everyone else so completely wrong.

Let There Be Dark

That said, anyone who approaches the book to get answers to the big questions will quickly realize that the book is not about providing answers but about how circuitous the route to finding answers can be. The first half of the book details the work of astronomers discovering in steps, starting from Galileo, that there is more to the universe than what meets the eye. The astronomers progress to seeing the planets, the moon, then the stars and then even the galaxy and then, horror of horrors, other galaxies and clusters of galaxies. The theorists could not keep pace with the speed at which discovery was progressing, lockstep with technology and the theorists lagged far behind, still in the armchair with Newton and Einstein. Meanwhile, the astronomers were going ahead and finding out weirder and weirder things about the universe - they found that the Big Bang was real and had proof in the form of CMBR, they found that the universe is expanding, then that the expansion is accelerating. Then they found that the galaxies rotate too and that the rotation does not slow down towards the edges. The only way they could explain this was to posit a huge amount of 'dark matter' on the edges, stabilizing the rotation, only to be derided for reincarnating the discredited 'ether' of old days. But, evidence gathered and soon it was accepted. Weird thing, that. It was accepted purely because it solved problems, not because anyone could explain why it was there or what it was doing there, a trend that was soon going to dominate cosmology.

The next step was to come from the laggard theorists. Out of nowhere came the breakthrough idea of an 'Inflationary universe' - now this solved even more problems and also made acceptable a few arbitrary assumptions that the cosmologists had made about the universe such as homogeneity and isotropy. Who could resist that? It was soon standard truth. Now that universe was inflationary and the current state of the universe was satisfactorily explained, the question was how will it end, what is its future? The answer was to find out if the universe was 'flat'. The mathematics seemed to indicate that it indeed was. But for this, with the existing dark matter and matter put together, there still had to be much more energy (many orders of magnitude) than what the universe we can measure contains. Dark Energy was born, at least on paper. So there we have it, the universe we know, perhaps the universe we can ever know (baryonic matter) is just 4.56% (?) of the real thing.



They had to accept now that there might be less to the universe than what meets the eye. Of course, the theorists and the physicists are still devising new theories to explain away or to prove these unseen problems and millions are spent every month in remote corners with hopes of detecting these elusive stuff, the stuff of the universe.

The best response then, from scientists as well as from those of us trying to make sense of all this, should be humility and a willingness to entertain and rigorously examine the wildest ideas - they seem to have made a habit of coming true.
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03/23 marked as: read

Comments (showing 1-41 of 41) (41 new)

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message 1: by Clif (new)

Clif Hostetler It's all those strings from string theory. I'm talking about the dark stuff (dark matter and energy). Nobody else has come up with a better idea, so I'm sticking with it until proven wrong.

This isn't intended to be a serious comment, just a thought I had.


message 2: by Jim (new) - added it

Jim Awesome review, Riku. I have to go back and (re)read the one on A Universe from Nothing: Why There is Something Rather Than Nothing. Like you, I always have suspicion rising when anyone is absolutely certain of anything. Especially when they are certain about Everything.

When you figure out what Dark Energy is, send me a private message so I can be the first to know, okay?

We are still mulling the question of whether eukaryotes can evolve anywhere else in the universe:

http://www.goodreads.com/topic/show/8...

Now I have to think about the missing 96% - surely that must have a bearing on the answer!? :)


Riku Sayuj Jim wrote: "Awesome review, Riku. I have to go back and (re)read the one on A Universe from Nothing: Why There is Something Rather Than Nothing. Like you, I always have suspicion rising when an..."

Jim wrote: "Awesome review, Riku. I have to go back and (re)read the one on A Universe from Nothing: Why There is Something Rather Than Nothing. Like you, I always have suspicion rising when an..."

I have a few theories :)

Wish I could jump into that discussion too but I was not able to get a copy of the book being discussed.. but maybe I'll try my hand without reading?


Manny The only way they could explain this was to posit a huge amount of 'dark matter' on the edges, stabilizing the rotation

I thought it was more a roughly spherical 'dark matter halo' enclosing and permeating the galaxy. E.g. pictures on this page.


Riku Sayuj Manny wrote: "The only way they could explain this was to posit a huge amount of 'dark matter' on the edges, stabilizing the rotation

I thought it was more a roughly spherical 'dark matter halo' enclosing and p..."


dark matter is supposed to be highest at the edges of galaxies and from there on till the end of the galaxy 'halo'... so the suffusing part I am not that sure of... i have an image of a very small pearl in a shell


Manny When I look around, I see both pictures, so I am not sure. The Wikipedia article on Dark Matter says this about the Dark Matter density distribution:

Rotation curves of both low and high surface luminosity galaxies appear to suggest a universal density profile, which can be expressed as the sum of an exponential thin stellar disk, and a spherical dark matter halo with a flat core of radius r0 and density ρ0 = 4.5 × 10^−2(r0/kpc)^−2/3 M⊙pc^−3 (here, M⊙ denotes a solar mass, 2 × 1030 kg).

so permeating the galaxy and tailing off slowly.


Riku Sayuj Manny wrote: "When I look around, I see both pictures, so I am not sure. The Wikipedia article on Dark Matter says this about the Dark Matter density distribution:

Rotation curves of both low and high surface l..."


would the density be more at the center or at the edges?


message 8: by Manny (last edited Mar 21, 2012 01:43AM) (new) - rated it 3 stars

Manny The density would be higher at the center.

I've been thinking about this more over breakfast, and I believe I can say more clearly why I find the "pearl and shell" picture unconvincing. Most of the galaxy's mass is in the dark matter, and the visible part is basically just the icing on the cake. It feels wrong that the greater part of the galaxy would be spread out around the edges, rather than concentrated in the center; to start off with, the dark mass would be orbiting a comparatively empty core. That's maybe not quite impossible, since the center of mass would still be in the middle, but it seems very strange.


Riku Sayuj Manny wrote: "The density would be higher at the center.

I've been thinking about this more over breakfast, and I believe I can say more clearly why I find the "pearl and shell" picture unconvincing. Most of th..."


galaxies are imagined to behave like a drop of water that is rotated very fast... eventually assuming a disc shape... so it is not necessary for mass to be concentrated in the center. But, i do now feel that your picture is more convincing. however, considering that the halo is much bigger than the original galaxy, it is still possible that the bulk of dark matter still remains outside our visible galaxy, right?

One more thing, the nature of the interaction of dark matter with the two dominant forces, gravity and 'anti-gravity' is not known.. so any assumptions like this might well be off the mark anyway.


message 10: by Riku (new) - rated it 4 stars

Riku Sayuj i was just wondering about the implications to cosmology from the fact that we happen to inhabit the outer edges of our own galaxy


message 11: by Riku (new) - rated it 4 stars

Riku Sayuj Clif wrote: "It's all those strings from string theory. I'm talking about the dark stuff (dark matter and energy). Nobody else has come up with a better idea, so I'm sticking with it until proven wrong.

This ..."


ya, the supersymmetry aspect of string theory might explain dark matter and leads directly to the neutralinos.. so it is not such a wild guess really :) just out of fashion currently


Manny Riku wrote: "galaxies are imagined to behave like a drop of water that is rotated very fast... eventually assuming a disc shape... so it is not necessary for mass to be concentrated in the center. But, i do now feel that your picture is more convincing. however, considering that the halo is much bigger than the original galaxy, it is still possible that the bulk of dark matter still remains outside our visible galaxy, right?"

I think that's correct... the dark matter halo is so much bigger that most of it is outside the main visible area. Like, our own galaxy's halo apparently extends to cover a couple more small visible galaxies.

One more thing, the nature of the interaction of dark matter with the two dominant forces, gravity and 'anti-gravity' is not known.. so any assumptions like this might well be off the mark anyway.

Wait... the dark matter must interact more or less normally with gravity. That's how we know it's there, right? Less sure about interaction with 'anti-gravity'/dark energy...


message 13: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "Wait... the dark matter must interact more or less normally with gravity. That's how we know it's there, right? Less sure about interaction with 'anti-gravity'/dark energy... "

what if it doesn't.. it is also possible that there is far less dark matter than we think now and that they just interact very strongly with gravity?


message 14: by Manny (last edited Mar 21, 2012 03:06AM) (new) - rated it 3 stars

Manny what if it doesn't.. it is also possible that there is far less dark matter than we think now and that they just interact very strongly with gravity?

I am trying to think if that actually means something! If the only interaction is gravitational, is there a difference between a small amount interacting strongly and a larger amount interacting weakly? Is this idea discussed in the book?


message 15: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "what if it doesn't.. it is also possible that there is far less dark matter than we think now and that they just interact very strongly with gravity?

I am trying to think if that actually means so..."


No.. just a thought i had...


Manny I wish they would hurry up and figure out what dark matter actually is. All this speculation is making my head hurt :)


message 17: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "I wish they would hurry up and figure out what dark matter actually is. All this speculation is making my head hurt :)"

maybe the axions will ping us soon and we'll know a bit more about the universe... there would still be the dark energy though, can't imagine how anyone can test that unless by inference


Manny If I understood this right, the preliminary estimate for the mass of the Higgs particle was in a range which was compatible with the most popular supersymmetry theory. So the chances of finding a supersymmetric particle have gone up a bit again. Still not looking too great though.


message 19: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "If I understood this right, the preliminary estimate for the mass of the Higgs particle was in a range which was compatible with the most popular supersymmetry theory. So the chances of finding a s..."

the predictions for graviton too lends weight to that side of the theoretical battle..


Manny Is there a betting site that lets you put money on physics predictions? If not, there should be!


message 21: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "Is there a betting site that lets you put money on physics predictions? If not, there should be!"

lol. too many ponies to bet on


Manny Looking around, I find this intriguing proposal...


message 23: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "Looking around, I find this intriguing proposal..."

if it could solve killer peanut butter, it can solve anything. let's go for it!


message 24: by Paul (new)

Paul Bryant great review. "In the beginning it was weird. And weird was good."


message 25: by Riku (new) - rated it 4 stars

Riku Sayuj Paul wrote: "great review. "In the beginning it was weird. And weird was good.""

you might want to check out my blog post on this - I got a comment from Nicholas B. Suntzeff, one of the characters in the book! :) I was over the moon. He captured my whole review in a paragraph.


Manny Wow. Nice going, Riku!


message 27: by Clif (new)

Clif Hostetler Congratulations!
(... assuming he really is who he says he is ... I have no reason to doubt ... it's just that I would wonder if he replied to a review by me ... but it was a good review by you, so ... that is different.)


message 28: by Jim (new) - added it

Jim Congratulations, Riku!


message 29: by Riku (new) - rated it 4 stars

Riku Sayuj Clif wrote: "Congratulations!
(... assuming he really is who he says he is ... I have no reason to doubt ... it's just that I would wonder if he replied to a review by me ... but it was a good review by you, s..."


oh i did an ip check and everything... down to the university block (he he) it checks out :)


message 30: by Rozzer (new) - added it

Rozzer Now THAT's a REVIEW!!!


message 31: by Riku (new) - rated it 4 stars

Riku Sayuj Rozzer wrote: "Now THAT's a REVIEW!!!"

thanks rozz!


message 32: by Traveller (new) - added it

Traveller Nice! I haven't read the other book yet (still on the to-read shelf) but now I'm tempted to rather read this one first if i can find it soon enough. :)


message 33: by Riku (new) - rated it 4 stars

Riku Sayuj Traveller wrote: "Nice! I haven't read the other book yet (still on the to-read shelf) but now I'm tempted to rather read this one first if i can find it soon enough. :)"

I hope you find it it to your tastes... Thanks!


message 34: by Caroline (new) - added it

Caroline I got through Kraus but I can’t say I enjoyed it. This alternative, with more history of science and a soupcon of humility, sounds much more to my taste--thanks for the excellent review.


message 35: by Riku (new) - rated it 4 stars

Riku Sayuj Caroline wrote: "I got through Kraus but I can’t say I enjoyed it. This alternative, with more history of science and a soupcon of humility, sounds much more to my taste--thanks for the excellent review."

Thanks, Caroline. I hope you enjoy it!


message 36: by Lilo (new) - added it

Lilo That's my kind of book. I just doubt that my old, strained, stressed, and heavily used brain is still functional enough to comprehend the contents of this book.


Manny I liked this book, but I often found it difficult to remember who was who in the large cast of researchers hunting for evidence of dark energy. I think the author is more interested in science than people...


message 38: by Riku (new) - rated it 4 stars

Riku Sayuj Manny wrote: "I liked this book, but I often found it difficult to remember who was who in the large cast of researchers hunting for evidence of dark energy. I think the author is more interested in science than..."

As you tell in your review:

To summarize, then, a mixed bag. But despite the weaknesses, I give him a clear thumbs-up. He's got an incredible story to tell you about how science actually gets done.


message 39: by Riku (new) - rated it 4 stars

Riku Sayuj Lilo wrote: "That's my kind of book. I just doubt that my old, strained, stressed, and heavily used brain is still functional enough to comprehend the contents of this book."

Give it a go, Lilo. The universe is nothing to be scared of!


message 40: by Lilo (last edited Aug 15, 2014 08:18AM) (new) - added it

Lilo Riku wrote: "Lilo wrote: "That's my kind of book. I just doubt that my old, strained, stressed, and heavily used brain is still functional enough to comprehend the contents of this book."

Give it a go, Lilo. T..."


The universe is nothing to be afraid of, but my brain is. :-) I am afraid I'll find out how much my brain capacity has deteriorated since I was young. (I had wanted to study theoretical physics, but it never came to be. My father refused to pay for me going to university. University is free in Germany, but my upkeep would not have been.)


Zanna You make me pleased that I have a copy of this ready to read soon. I think you would like this: https://www.goodreads.com/book/show/2...


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