Comments by Oystein Elgaroy

Comment #273995 by Oystein Elgaroy on October 29, 2008 at 1:20 pm

Comment #273864 by Vaal

Great post!

Comment #273905 by Oystein Elgaroy on October 29, 2008 at 11:54 am

I can only speak for myself, but if it had not been for the efforts of the "New Atheists" (what a horrible term), I would probably not have ended up as an atheist. Their books and this site (which I visited frequently before deconverting and coming out) forced me to think about why I held the beliefs that I held. Before that I had basically operated with double standards, requiring evidence and reason in my scientific work but believing in miracles based on unsubstantiated claims outside of work.

I am sure that ad campaigns on buses and slogans on t-shirts will just seem annoying or even childish to many, but if my experience is anything to go by they will also have a positive effect on some people.

203. Premier debates with Dawkins

Comment #272965 by Oystein Elgaroy on October 28, 2008 at 12:02 am

What I have never heard a theist explain is how an incorporeal being (if such a concept even makes sense) can be the physical cause of anything.

Regarding the fine tuning business, the argument from the alleged fine tuning could be killed at the outset by noting the simple fact that the probability of fine tuning given naturalism is not equal to the probability of naturalism given fine tuning. They are related, but not equal. Two relate the two you have to know the intrinsic probability of naturalism given everything else we know about the universe. If you want to argue for the existence of a personal, incorporeal being you then have to estimate the same probabilities given this hypothesis. How on Earth can you do that in any meaningful way?

The multiverse may indeed turn out to be the explanation of the apparent fine-tuning of some of the parameters of our universe, but I don't think it is necessary to invoke it to refute the argument for a Fine Tuner.

204. Children need to be sprinkled with fairy dust

Comment #272185 by Oystein Elgaroy on October 27, 2008 at 4:59 am

If you pray for 100 things, and one of them happens, then clearly the prayer has worked.

And in the other 99 cases it was on hindsight best that you didn't get what you prayed for. God works in mysterious ways.

205. The soul? It may all be in your mind

Comment #267843 by Oystein Elgaroy on October 21, 2008 at 6:38 am

Comment #267841 by qomak

To shoot religion in the heart we simply need to attack the soul

I don't think it is that simple. Dualism is not required by, for example, the New Testament where resurrection seems to be physical, not just spiritual.

206. Free to Think for Themselves

Comment #267158 by Oystein Elgaroy on October 20, 2008 at 9:47 am

Comment #267152 by decius

My hope is that the frontiers of cosmology will get out of my way to avoid the second-hand smoke.

207. Free to Think for Themselves

Comment #267149 by Oystein Elgaroy on October 20, 2008 at 9:37 am

Comment #267146 by decius

Oystein must be an idiot, because he smokes!

Correction: I am an idiot, but not ONLY because I smoke. I find new reasons to question my intelligence every day.

208. From Science Fiction to Science Fact

Comment #266170 by Oystein Elgaroy on October 18, 2008 at 7:10 am

Of Kaku's books I've only read "Parallel Worlds". That book, at least, is in my mind a clear example of science porn. It is okay to write about the speculative topics in modern physics and cosmology as long as it is made clear that this could turn out to be fantasy and not fact. I don't think Kaku even tries to do that. The best popular book on cosmology ever written is, in my view, Steven Weinberg's "The first three minutes". No time travel, multiverses or extra dimensions, but plenty of wonderful science explained by a top-rate physicist.

209. Math Skills Suffer in U.S., Study Finds

Comment #263868 by Oystein Elgaroy on October 13, 2008 at 7:06 am

Comment #263861 by decius

find it absurd that there is no Nobel prize for maths, while there is one for astrology economics.
Just been awarded, btw.

The fact that there is no Nobel prize for mathematics is sometimes ascribed to the strained relation between Alfred Nobel and the Swedish mathematician Gosta Mittag-Leffler. The closest thing to a Nobel prize for maths is possibly the Abel prize which is handed out in Norway annualy.

http://en.wikipedia.org/wiki/Abel_Prize

210. Religion vs science: can the divide between God and rationality be reconciled?

Comment #263615 by Oystein Elgaroy on October 12, 2008 at 2:31 am

Though the reality of quarks has been convincingly established, nobody has ever seen one in isolation in the laboratory. Their very nature prevents this, just as the nature of God makes Him invisible.

So the argument would be

1) Individual quarks are invisible, but are known to exist.
2) God is invisible, and is in this respect just like a quark.
3) Hence, God exists.

211. Palin: average isn't good enough

Comment #263465 by Oystein Elgaroy on October 11, 2008 at 8:37 am

Comment #263463 by decius

Keep your spirits up, I'll bring you Oystein to Oxford in just a few days.

Not the kind of redistribution that will increase support for socialism.

212. Broken symmetry: Answering the solace of quantum

Comment #263282 by Oystein Elgaroy on October 10, 2008 at 1:21 pm

The article almost gives the impression that the work of Kobayashi and Maskawa solved the puzzle of the matter-antimatter asymmetry. They provided a vital ingredient, CP violation, but the detailed mechanism that gave rise to the sligh excess of baryons over antibaryons (about one billion plus one baryons per billion antibaryons) is still unknown.

213. Big Bang or Big Bounce?: New Theory on the Universe's Birth

Comment #261802 by Oystein Elgaroy on October 7, 2008 at 12:02 pm

Comment #261791 by Steve Zara

One of the dangers of Science Porn is that it makes subjects like cosmology look more like guesswork and speculation than science. For people who are not specialists bouncing universes, inflation and dark matter all seem like equally crazy ideas, and unless one explains clearly what the empirical basis for these ideas is (respecitvely none, some, and quite a lot in these three cases), the impression they are left with is that cosmology is pure speculation, and that "goddidit" is as valid a theory as any other.

214. Big Bang or Big Bounce?: New Theory on the Universe's Birth

Comment #261763 by Oystein Elgaroy on October 7, 2008 at 10:34 am

This is interesting, but I think it is worth to bear in mind that this is just one possible scenario within a framework for quantum gravity which is every bit as lacking in empirical evidence as string theory. Any theory of quantum gravity would have to get rid of the singularities in classical general relativity to be counted as successful.

215. Do We Live in a Giant Cosmic Bubble?

Comment #258161 by Oystein Elgaroy on October 1, 2008 at 1:40 pm

Comment #258150 by aprocess

It may account for the missing Dark Matter as well as the faster outer Galaxies, because it influences the matter from our Big Bang through gravitation only.

I doubt if it could account for the dark matter in the observable universe, since we haven't seen this blue shifted region yet. There is evidence for dark matter on the scales of galaxies, clusters of galaxies etc.

You would also need a funny matter distribution in order to make the collapsing region cause galaxies at the boundary of the observable universe to accelerate. For a spherical distribution of matter, if you consider a test particle at distance R from the center only matter inside rR.

216. Do We Live in a Giant Cosmic Bubble?

Comment #258132 by Oystein Elgaroy on October 1, 2008 at 12:54 pm

A model of the universe where we live in an expanding region surrounded by a collapsing one could possibly be constructed. It would be fun, but I can't see what it would help us to explain.

217. Do We Live in a Giant Cosmic Bubble?

Comment #258061 by Oystein Elgaroy on October 1, 2008 at 11:54 am

Comment #258058 by prettygoodformonkeys

Are we talking 6,000 light years close? Because I know of some folks who would LOVE that!

More like 6 billion. I am afraid that science lets those folks down once again. But they don't care anyway.

218. Do We Live in a Giant Cosmic Bubble?

Comment #258047 by Oystein Elgaroy on October 1, 2008 at 11:36 am

Comment #258030 by amalthea

As I understood the whole concept of inflation, post-Big Bang, the spread of matter would be random, not even (it's not like it was engineered to impress, like, say a firework) and so I would naturally expect some random patches of concentration and, conversely, of void. I wouldn't really see ourselves as special by being in a 'void'. We just happen to be where we are.

Looking at what we can in the near universe, there seems to be a definite lack of uniformity, so it also seems reasonable to expect clumps and big gaps, or voids.

It is true that the universe had small inhomogeneities after inflation, and that these have grown to the large-scale structures we see in the universe today. But in most models for inflation you would not expect to produce underdense bubbles of the size we are talking about here, of the order of a billion light years.

219. Do We Live in a Giant Cosmic Bubble?

Comment #258012 by Oystein Elgaroy on October 1, 2008 at 10:44 am

Comment #257967 by Ultraviolet G

Question: if the age of the universe is approx. 13.7 billion years: and the observable universe is approx 90 billion lightyears across, how much if any of the universe is outside of our observable part? beyond *that*, do we get nothing? or do we get other bubbles with possibly different physical laws?

First of all, the kind of bubble they talk about in the article has a radius of a few billion light years, so it is smaller than the observable universe. Then you have the kind of bubbles you get in inflationary scenarios. The exact size of these bubbles depends on the details of the inflation model, but they are typically much larger than the observable universe. What the conditions are like outside the observable universe is again hard to tell. There might be different "physical laws", at least for those laws where the details were determined by events taking place after inflation. And outside our bubble, the laws may be very different.

220. Do We Live in a Giant Cosmic Bubble?

Comment #257754 by Oystein Elgaroy on October 1, 2008 at 4:28 am

These "bubble" models are different from the standard Big Bang-models, so the concepts of "open" and "closed" geometries don't apply straighforwardly. As far as I know, it has not been shown how to combine a "Hubble bubble" with inflation. But what has been shown is that we have to live very close to the center of a bubble, otherwise the cosmic microwave background would look very different from what it does. To my mind, at least, dark energy seems like a simpler explanation of the observations.

221. Mysterious New 'Dark Flow' Discovered in Space

Comment #255807 by Oystein Elgaroy on September 28, 2008 at 9:22 am

Comment #255786 by NewEnglandBob

But would that be observable for us? Just as a ruler will change length due to velocity that we can not detect locally (special relativity), would it be possible that time 'stretching' would have a similar effect? (Ow, my head is hurting thinking about this!)

This particular effect is observable for us as the cosmic redshift of spectral lines from distant galaxies.

222. Why There Almost Certainly Is a God, By Keith Ward

Comment #255798 by Oystein Elgaroy on September 28, 2008 at 8:35 am

Comment #255794 by decius

Hilarious!

223. Why There Almost Certainly Is a God, By Keith Ward

Comment #255796 by Oystein Elgaroy on September 28, 2008 at 8:33 am

Comment #255793 by Swordmaiden

Of course any one with an ounce of reason discounts the God=Big Bang thing, but the fact that our minds are truly open to any evidence which may, in the future, present itself is what sets us apart from the close minded people of faith.

My mind is possibly very closed, but I can't see how any empirical evidence can point in the direction of the supernatural. At least I would like to see a consistent model for how a disembodied spirit can interact with matter first.

224. Why There Almost Certainly Is a God, By Keith Ward

Comment #255788 by Oystein Elgaroy on September 28, 2008 at 8:16 am

Comment #255783 by Steve Zara

There really is quantum mystery, I believe.

Unfortunately, "mystery" is often misinterpreted as meaning "room for a spiritual dimension" or something equally silly.

225. Mysterious New 'Dark Flow' Discovered in Space

Comment #255779 by Oystein Elgaroy on September 28, 2008 at 7:48 am

Comment #255774 by decius

So, in an expanding universe with redshifted distant objects, why don't we observe a 'timeshift' (bleurgh), too, if space and time are part of the same continuum?

If you consider light pulses emitted at a constant time interval dt by a distant object following the expansion of space, then those pulses are observed by us to be separated by a longer time interval dt'. The increase is equal to the amount space has stretched while the light has been on its way to us. You can actually look at this has the reason for the cosmic redshift.

226. Mysterious New 'Dark Flow' Discovered in Space

Comment #255759 by Oystein Elgaroy on September 28, 2008 at 6:28 am

Comment #255748 by decius

I find it all very confusing. If expansion is empirically measured, how can it be a 'misleading notion'.

What we measure is that distant galaxies have redshifted spectra. If the universe is homogeneous and described by general relativity, this can be interpreted as a result of physical distances between objects increasing with time, or expanding space if you will.

But some people, like John Peacock, think that this notion is misleading in some respects. The classic rubber sheet analogy can perhaps make his point clear.
If you imagine expanding space as a rubber sheet being stretched in all directions, you would expect that if you put a coin on the sheet it would be dragged along with the fabric. What Peacock shows is that this is not what happens if you add a test particle with zero intial velocity with respect to us into expanding space. It will actually start moving towards us!

As far as "expanding time" is concerned, I am not sure if I can make sense of that notion. In one sence, of course, time is always stretching since there is an arrow of time. But now you are making my head spin. I will have another pot of coffee and see if that clears my thoughts.

227. Mysterious New 'Dark Flow' Discovered in Space

Comment #255744 by Oystein Elgaroy on September 28, 2008 at 5:16 am

Comment #255700 by Steve Zara

Whether the term "expanding space" should be used at all is still debated from time to time. Some think it is a misleading notion, see for example John Peacock's web page at
http://www.roe.ac.uk/~jap/book/additions.html

Others, including Lineveawer and Davis, have defended the concept. The technical paper behind the SciAm article can be found at

http://arxiv.org/abs/astro-ph/0104349

Øyvind Grøn and I also wrote an article dealing directly with the issue raised by Peacock:

http://arxiv.org/abs/astro-ph/0603162

228. Why There Almost Certainly Is a God, By Keith Ward

Comment #255593 by Oystein Elgaroy on September 28, 2008 at 1:04 am

To paraphrase, what is the point of being a theist when we are not exactly sure what god is? Whatever matter is, we can be pretty sure that it exists. The same cannot be said for supernatural entities.

229. Mathematics and faith explain altruism

Comment #255344 by Oystein Elgaroy on September 27, 2008 at 10:49 am

Comment #255328 by decius

Why doesn't this idiot apply his math to virgin's birth, miraculous healing, ghostly apparitions, stigmata and resurrections and test how much logical sense they make.

Looks like it has already been done: see

http://home.mindspring.com/~hdf1/id1.html

Scroll down to the bottom of the page.

230. Mysterious New 'Dark Flow' Discovered in Space

Comment #255233 by Oystein Elgaroy on September 27, 2008 at 5:21 am

Comment #255232 by PERSON

So why can't the sheet stretch up as well as down? Would the effect not be inverted? Why does GR not allow this? Is it due to Occam's razor, or something more intrinsic to the theory?

I suppose you refer to the picture where a massive objects makes a dent in a rubber sheet. If that is the case, then yes, the sheet can be stretched up as well. That would correspond to a repulsive gravitational force. Dark energy is an example of this.

231. Mysterious New 'Dark Flow' Discovered in Space

Comment #255228 by Oystein Elgaroy on September 27, 2008 at 4:56 am

Regarding expanding space, it is useful to bear a couple of things in mind:

1) It is an approximation which is valid on large scales, of the order of a few hundred million light years, where the matter distribution can be considered homogeneous.

2) Within the Big Bang model there is no explanation of why the universe is expanding. It is simply an empirical fact that the universe is expanding now. Matter slows the expansion down, dark energy speeds it up. Speculative models like eternal inflation may explain how the universe started to expand.

Expanding space is a confusing concept. A few years ago Charles Lineweaver and Tamara Davis had an article in Scientific American about this topic which I find helpful:

http://www.sciam.com/article.cfm?id=misconceptions-about-the-2005-03

232. Mysterious New 'Dark Flow' Discovered in Space

Comment #253344 by Oystein Elgaroy on September 24, 2008 at 10:24 am

Comment #253323 by Steve Zara

It doesn't seem that convincing, as one of the main points about inflation is that it largely wipes out any existing features leaving behind a pretty featureless and flat spacetime.

I agree with that. I haven't seen any alternative explanations yet. Wish I had the time to look into this, but I have to prepare lectures now.

233. Mysterious New 'Dark Flow' Discovered in Space

Comment #253321 by Oystein Elgaroy on September 24, 2008 at 9:45 am

I think the idea is that the flow was induced by structures present before inflation, and that the exponential expansion afterwards blasted these structures outside of the bubble that became our observable universe.

234. Jewish 'ultras' defend morals with menace

Comment #251967 by Oystein Elgaroy on September 22, 2008 at 11:49 am

Why does it never strike these weirdos as a bit odd that God after starting the Big Bang, fine-tuning all the constants of nature and intelligently designing life on Earth should realize that what REALLY matters is that women dress modestly and that we all stay away from pork.

235. Robert Winston criticises dangerous 'science delusion'

Comment #247431 by Oystein Elgaroy on September 14, 2008 at 12:15 pm

"Far too many scientists including my good friend Richard Dawkins present science as the truth and present it as factually correct. And actually of course that clearly isn't true."

This statement really made my jaw drop. How can you "engage in dialogue" with someone who makes such statements? Why would you want to?

236. The Origins of the Universe: A Crash Course

Comment #246568 by Oystein Elgaroy on September 12, 2008 at 1:47 pm

It is definitely not intuitive that a scalar can be instantiated as a particle. However, the intuitive requirement for particle physics went away about a hundred years ago.

The Higgs particles are the quantum mechanical ripples of the Higgs field. You take a classical scalar field, quantize it, and you get scalar particles. Electrons are actually much harder to grasp since they are quanta of a field with no classical limit.

237. The Origins of the Universe: A Crash Course

Comment #246543 by Oystein Elgaroy on September 12, 2008 at 1:13 pm

Comment #246533 by Quine

Øystein, how do theorists reconcile the Higgs field with the absence of a preferred inertial frame?

The Higgs field does not violate special relativity in any way. Technically it transforms as a scalar when you transform between different inertial frames.

238. The Origins of the Universe: A Crash Course

Comment #246538 by Oystein Elgaroy on September 12, 2008 at 1:02 pm

So....just how much would a proton weigh when traveling at 99% etc ?

At the speed quoted the energy of a proton is approximately 7000 times its rest mass energy. There is a nice article on the art of accelerating protons at
http://askanexpert.web.cern.ch/AskAnExpert/en/Accelerators/Howaccel-en.html#7

239. The Origins of the Universe: A Crash Course

Comment #246528 by Oystein Elgaroy on September 12, 2008 at 12:42 pm

Comment #246488 by zeroangel

I have to say, despite really having solid knowledge about these things; I feel uncomfortable with the whole "Higgs field" thing. It seems too much like the old "aether theories."

Surely there are physicists that feel this way as well? Or, am I just way off base?

The Higgs field does sound a bit like the aether. Not all physicists like it. But there is one crucial difference: the old aether could not be detected in any way. It was just there to provide electromagnetic waves with a medium to travel through. If the Higgs field exists, the Higgs boson will be found at the LHC. If they fail to find it, the Higgs field has to go.

Comment #246508 by Friend Giskard

If sparticles are a candidate for dark matter, they must be long lived. I wonder if these sparticles can also combine to form satoms, smolecules, splanets, sstars, and even sbiology?

Only the lightest of the hypothetical sparticles is stable, so there is very little hope of having schemistry or sbiology.

240. The Origins of the Universe: A Crash Course

Comment #246481 by Oystein Elgaroy on September 12, 2008 at 11:06 am

Comment #246479 by APPlet

This confused me. What is the "something"? It is a "something" that has no mass only a resistance to the Higgs field?

The "something" is any elementary particle. Mass is related to inertia, and inertia is resistance to changes in the state of motion. Greene says that it is a particle's interaction with the Higgs field that is responsible for its inertia, and hence its mass.

241. 'Big Bang' experiment starts well

Comment #245641 by Oystein Elgaroy on September 11, 2008 at 8:29 am

The LHC was renamed "The Doomsday Machine" on the front page of one of the Norwegian tabloids. Sigh...

OT: The Kavli prizes in astrophysics, neuroscience and nanoscience were handed out in Oslo for the first time this week. Lectures by the laureates will soon be available at www.kavliprize.no

242. 'Climate crisis' needs brain gain

Comment #244234 by Oystein Elgaroy on September 8, 2008 at 1:16 pm

Mark, thanks for those words.

bsolutely, I agree entirely (apart from [and although I know you didn't mean it in at all this way] the possibility that your comment could be misconstrued by those of a sufficiently mendacious mind to imply that cosmology isn't useful).

It depends on what you mean by useful. I think contributing to our knowledge of the universe is useful. I know a lot of people who don't. A prominent Norwegian politician once said that he could not understand why we should fund particle physics in Norway. According to his view, we should leave this field to the US and just read books if we wanted to learn about the microcosmos.

243. 'Climate crisis' needs brain gain

Comment #244200 by Oystein Elgaroy on September 8, 2008 at 12:38 pm

Am I going to tell students to stop doing cosmology and switch to something useful instead? Sorry, I think not. I am sick and tired of politicians and religious nutheads telling scientists what to do and not to do.

244. Large Hadron Collider readies for world's biggest experiment

Comment #243916 by Oystein Elgaroy on September 7, 2008 at 10:32 pm

It is claimed that only one gluon is massless and the other seven gluons are massive. Out of eight gluons, six are colored and two are neutral. Among neutral gluons, one is massless and other one is massive. The massive neutral gluon is heavier than the colored gluons.

Where did you read this? When I was young I was taught that all gluons are massless and coloured.

245. Large Hadron Collider readies for world's biggest experiment

Comment #243385 by Oystein Elgaroy on September 5, 2008 at 2:53 pm

decius -

a Google search on the combination graviton and god came up with this beauty:
http://www.web-books.com/GoodPost/Articles/Gravitation.htm

246. Large Hadron Collider readies for world's biggest experiment

Comment #243366 by Oystein Elgaroy on September 5, 2008 at 2:16 pm

Comment #243363 by decius

My money is on the graviton. They have one divine property, though: they have never been observed.

247. Large Hadron Collider readies for world's biggest experiment

Comment #243357 by Oystein Elgaroy on September 5, 2008 at 2:00 pm

Comment #243342 by zeroangel

What else is there in the Helium atom? That is, I get that is has 2 protons, 2 neutrons, and 2 electrons. The Neutrons and Protons being made up of quarks. But then, there are also W, Z bosons, photons, and presumably Higgs Bosons flying around "inside" the Helium atom constantly exchanging forces, correct?

Yes, but these are virtual particles in this context, not part of the stable makeup of the helium atom.

Then, the graviton is a theoretical particle that carries gravity?

Yes.

I guess I am confused because I was thinking that since gravity is a consequence of mass, isn't the Higgs Boson the thing that mediates gravity?

For technical reasons the particle that mediates gravity has to have zero mass and two units of spin. The Higgs boson is massive and has no spin.

248. Large Hadron Collider readies for world's biggest experiment

Comment #243340 by Oystein Elgaroy on September 5, 2008 at 1:20 pm

Comment #243336 by bugaboo

Although ive ended up confused(again)since they say that the Higgs particle has different spin from a graviton. But I read at wiki that Higgs is scalar and has no spin!

The two statements are consistent. The Higgs particle has zero spin, the graviton (if it exists) has spin equal to two.

249. Large Hadron Collider readies for world's biggest experiment

Comment #243334 by Oystein Elgaroy on September 5, 2008 at 1:08 pm

zeroangel -

A stable, normal, helium atom is made up 2 protons, 2 neutrons, and 2 electrons.

Correct. The neutron is made of one u quark and two d quarks, the proton consists of two u quarks and one d quark.

Electrons are leptons with a negative charge

Correct.

Neutrons are a proton and an electron fused(?) and beta decay is when a neutron gives off an electron

Not quite. For the structure of the neutron, see above. Beta decay of a neutron occurs when one of its d quarks decays to a u quark, emitting an electron and an antineutrino in the prosess.

Photons are massless wave/particles tht carry electromagnetic radiation such as visible light.

Correct.

Gluons are W and Z bosons carry the Strong and weak forces (respectively) are they also massless? Do they behave in a similar fashion as photons?

Gluons are massless. They carry no electromagnetic charge, and only take part in strong interactions. In contrast to photons, gluons can interact with each other.

W and Z bosons are massive particles. This is part of the explanation for why the weak force is so much weaker than the electromagnetic force in the unified electroweak theory.

Where does the Higgs Boson come in?

The mathematical formulation of the standard model requires certain symmetries to make sense. This symmetry implies that all the particle masses should vanish. The Higgs boson is a way of getting masses in the through the back door. You can add the Higgs field to the standard model in such a way that the symmetry is preserved while the particles get their masses by interacting with the Higgs field.

http://particleadventure.org/

is a good place to start if you want to learn more about the Standard Model.

250. Large Hadron Collider readies for world's biggest experiment

Comment #243316 by Oystein Elgaroy on September 5, 2008 at 12:20 pm

The Higgs boson, like the photon and (possibly) neutrinos, is its own antiparticle.