SciBlogs

Posts Tagged universe

Mindboggling Ken Perrott Feb 27

1 Comment

Click image for larger version

Douglas Adams says in The Hitch-hikers Guide to the Galaxy:

“Space is big. Really big. You just won’t believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.”

The immensity of the galaxy almost seems beyond human comprehension. But this image does start to bring it home to me. It shows the extent of penetration of human radio signals into our galaxy since we have had radio. It’s that small blue dot, 200 light years in diameter, you can see in the enlarged section.

And our galaxy is only an extremely small and irrelevant part of the universe.

Finding out about the astronomers who found the universe Ken Perrott Nov 29

No Comments

Book review: The Day We Found the Universe by Marcia Bartusiak

Price: US$11.53; NZ$20.82

Hardcover: 368 page
Publisher: Pantheon (April 7, 2009)
Language: English
ISBN-10: 0375424296
ASIN: B005IUVQGY

This is a great book – just the sort of history of science I enjoy. One that smashes a few illusions, introduces new personalities, describes the significant research and debates of the time. And also describes the key scientists in a human way, with all their foibles, prejudices and illusions as well as their scientific contributions.

The title is apt. The book describes the work and people which produced our modern day understanding of the universe. Less than a century ago we used to think that our galaxy, the milky way, comprised the whole universe. And that it was static.  Now we see it a infinitely bigger, with billions of galaxies similar to ours. We also understand that it is expanding and that we can trace this expansion back almost 14 billion years to the “big bang.”

The big illusion the book shatters is the received story of how this happened through the work of Edwin Hubble. Of course he played a key role – but we normally never hear the background stories, the other personalities involved or details of the disputes and resolutions. It’s normally all about Edwin Hubble.

Island universes

Marcia Bartusiak reveals that concepts of a larger universe go back a long way. In fact many had a concept of a “multiverse” containing large numbers of “island universes” like our own – the milky way galaxy.

As far back as the first century B.C., the Roman poet and philosopher Lucretius argued against a finite universe. These arguments were revived in the sixteenth century by Thomas Digges in England and the Italian Giordano Bruno (one of his many heresies for which he was burned at the stake by the inquisition in 1600). In the Eighteenth Century Thomas Wright speculated on:

” whether certain cloudy spots, then being observed in the heavens in greater numbers, might be additional creations, bordering upon us but ’too remote for even our telescopes to reach,’ countless spheres with many ’Divine Centres.’ He seemed to be echoing the Swedish philosopher Emanuel Swedenborg, who in 1734 also wondered if ’there may be innumerable other spheres, and innumerable other heavens similar to those we behold, so many, indeed, and so mighty, that our own may be respectively only a point.”

In 1755 Kant described nebular patches in the nighttime sky as:

’just universes and, so to speak, Milky Ways… These higher universes are not without relation to one another, and by this mutual relationship they constitute again a still more immense system.’

The German scientist Alexander von Humboldt later dubbed them Kant’s ’island universes’ – and the description stuck. Astronomers passionately debated the ’mystery of the nebulae’ for almost two centuries until  Edwin Hubble announced, on January 1, 1925, his findings that ultimately established that our universe was a thousand trillion times larger than previously believed, filled with myriad galaxies like our own.

This, of course, radically reshaped how humans understood their place in the cosmos. Einstein abandoned his immobile cosmic model, finally accepting the concept of an expanding universe resulting from Hubble’s findings.

Bartusiak’s book provides an intricate history of the discoveries behind this work. With battles of will, clever insights, and wrong turns made by the early investigators in this great twentieth-century pursuit. While describing the contribution of the better known scientists like Einstein, Hubble and Harlow Shapley) she also describes the work of those we usually never hear of.

People like Henrietta Leavitt, who discovered the means to measure the vast dimensions of the cosmos. Her story illustrates the secondary role allowed for women in astronomy as “computers’, who did the repetitive calculations and recording from plates and were not allowed to observe. Leavitt, who overcame problems of health and deafness to produce such vital astronomical methods was even considered for a Nobel prize nomination – until the nominators realised she had died two years previously.

The biographies and contributions of many others are recorded in the book. Vesto Slipher, the first and unheralded discoverer of the universe’s expansion; Georges Lemaître, the Jesuit priest who correctly interpreted Einstein’s theories in relation to the universe; Milton Humason, who, with only an eighth-grade education, became a world-renowned expert on galaxy motions… and others.

“An odd bird”

These comments by the author about Edwin Hubble illustrate how she has presented the scientists in all their complexity  – warts and all:

“He was an odd bird, but certainly a handsome one. Friends called him an Adonis. I think he resembles the British actor Jeremy Irons. Raised in Missouri, in a solid middle-class household, Hubble somewhere along the line yearned to be singular and distinct. Once he graduated from the University of Chicago, he went to Oxford University as a Rhodes scholar, where he completely reinvented himself; he adopted a British accent that he maintained for the rest of his life, dressed like a dandy, and began to add dubious credentials to his resume, like saying he once practiced law, which he never did. He married into a rich Los Angeles family, and throughout his life seemed intent on erasing his Midwestern roots. His wife never met Hubble’s mother or siblings. Hubble was not chums with his astronomy colleagues but preferred to socialize with the actors and writers in nearby Hollywood. One astronomer called Hubble, often arrogant and standoffish, a ’stuffed shirt.’

Yet, while Hubble fibbed to his friends about his background, he was meticulously careful about his science. In fact, when he obtained the first evidence in early 1924 that the Andromeda nebula was truly a distant galaxy, he held off an official report for almost a year. He first wanted to counter every possible argument against his find. Being caught in a scientific error was Hubble’s greatest nightmare. And when he did finally release the data at that astronomy meeting on New Year’s Day in 1925, after a lot of arm-twisting from his colleagues, he wasn’t even there. He had someone else relay the findings.”

Bartusiak certainly has the ability to describe her characters well – and colourfully. But this ability also extends to her description of their work and discoveries.

I found the book a real pleasure to read – as well as being informative.

Similar articles

Fine-tuning fallacies Ken Perrott Nov 10

No Comments

In Fiddling with ’fine-tuning’ I discussed the way theologians and philosophers of religion have used claims of fine-tuning of the cosmological constant erroneously. That they have taken the fact that the value of the measured cosmological constant is 120 orders of magnitude different to the value of vacuum energy used to explain it. This has been described as the “worst calculation in physics history.” But never mind, these apologists have just utilised the huge mistake to claim that the cosmological constant is fine-tuned to 1 part in 10120! So there god must be responsible.

This is what happens when you use scientific knowledge opportunistically. Like a drunk uses a lamppost – more for support than illumination. Because the problem with the theological approach is that there is no interest in understanding the world around us – just in using science to support any argument they can drag up to “prove” the existence of their particular god.

Mind you, some non-theists also find the fine tuning concept beguiling. And they can also uncritically accept some of the fine-tuning claims that circulate. The idea that many of the physical and cosmological constants in our universe are extremely delicately balanced to values necessary for life to exist. The so-called anthropic principle.

So, Victor Stenger’s new book The Fallacy of Fine-Tuning: Why the Universe Is Not Designed for Us will be very useful for anyone attempting to check out these arguments by actually considering the science. He describes the physical and cosmological background to the constants, or parameters as he prefers to call them, usually used in fine-tuning arguments. And then he considers, one by one, just how valid – or invalid – the fine-tuning arguments are.

Here I will just deal with two “fine-tuned” constants – the “Hoyle resonance” for carbon nuclei and the “nuclear efficiency.” I think they illustrate two common mistakes made in estimating the degree of fine-tuning.

Hoyle resonance

This refers to the 1953 prediction of astronomer Fred Hoyle that the reactions necessary for the nucleosynthesis of carbon in stars would “not occur with sufficient probability unless that probability was boosted by the presence of an excited nuclear state of C12 at a very specific energy. Hoyle proposed that this previously unknown state must exist at about 7.7 MeV. The existence of such a state was quickly confirmed experimentally.”

Although Hoyle did not connect this resonance with the existence of life (and therefore an example of the anthropic principle) it has often been quoted by theists as a miraculous example of fine-tuning. And they like to quote Hoyle himself:

“A commonsense interpretation of the facts suggests that a superintellect has monkeyed with physics, as well as with chemistry and biology, and that there are no blind forces worth speaking about in nature. The numbers one calculates from the facts seem to me so overwhelming as to put this conclusion almost beyond question.”

But Stenger points out that many physicists question how fine-tuned this excited resonance state of carbon really is. He demonstrates this in the following figure from his book.

Here (a) shows two energy levels: (1) the amount by which the total rest energy of Be8 + He4 exceeds that of the C12 nucleus, which is 7.3367 MeV; (2) the excited state of C12 predicted by Hoyle and observed at 7.656 MeV. On this scale, the ground state of C12 is zero.

And (b) shows the range of values this excited state could assume and still produce that same amount of carbon in the universe. That is 7.596 – 7.716 Mev. So this excited state is not as fine-tuned as often claimed. The “miracle” is disappearing.

But the fine-tuning really evaporates when we acknowledge that while the existence of life like ours requires the presence of carbon, it does not necessarily require the exact amount of carbon that exists in our universe.  As (c) shows, an excited state anywhere from 7.933 Mev down to near the minimum energy would produce adequate carbon!

In this case the fine-tuning argument has been fallacious because recent work of the required values has been ignored. And it has been unnecessarily assumed that life requires exactly the same amount of carbon as present in the current universe.

Nuclear efficiency

Martin Rees describes “nuclear efficiency” in his book Just Six Numbers: The Deep Forces That Shape The Universe. It refers to the fact that in the synthesis of helium from protons and neutron in stars the mass of the original particles and final nuclear differs – 0.007 of the mass is converted into energy. He defines this as the “nuclear efficiency,” Є, and the value of this depends on the forces holding nuclei together determines how long stars can exist. Rees concludes that “any universe with complex chemistry requires Є to be in
the range 0.006-0.008.”

“If the nuclear ‘glue’ were weaker, so that Є were 0.006 rather than 0.007, a proton could not be bonded to a neutron and deuterium would not be stable. Then the path to helium formation would be closed off. We would have a simple universe composed of hydrogen, whose atom consists of one
proton orbited by a single electron, and no  chemistry. Stars could still form in such a universe (if everything else were kept unchanged) but they would have no nuclear fuel. They would deflate and cool, ending up as dead remnants. There would be no explosions to spray the debris back into space so
that new stars could form from it, and no elements would exist that could ever form rocky planets.”

“But we couldn’t have existed if Є had been more than 0.008, because no hydrogen would have survived from the Big Bang. In our actual universe, two protons repel each other so strongly that the nuclear ‘strong interaction’ force can’t bind them together without the aid of one or two neutrons (which add to the nuclear ‘glue’, but, being uncharged, exert no extra electrical repulsion). If Є were to have been 0.008, then two protons would have been able to bind directly together. This would
have happened readily in the early universe, so that no hydrogen would remain to provide the fuel in ordinary stars, and water could never have existed.”

But these estimates assume that other physical constant remain constant. Stenger argues that this is unrealistic because if the value of one parameter could be randomly selected during formation of a universe, so could the values of others.

In particular he considers the effect of just varying one other constant – the electromagnetic strength α. The figure below demonstrates the situation.

If α remains fixed at its current value of 1/137 then Ð„ must take a value between 0.006 and 0.008. Higher and all hydrogen would be converted to helium. Lower and no nuclei would form. But as shown in the figure - if  α varies between 1/191 and 1/107 then Ð„ can vary between 0.004 and >0.01.

So, in this case the fine-tuning fallacy has relied on the unwarranted assumption that the value of only one parameter is varied at a time in the calculations,. In reality this is unlikely.

This particular fallacy will be common to most of the physical and cosmological constants that are usually quoted as examples of fine-tuning by religious apologists.

Similar articles

Answer simple question — win an iPad Ken Perrott Nov 06

No Comments

The catch – you are limited to 140 characters on Twitter.

Oh, yes, also the entry must “explain the origins of the Universe.”

Credit: Wikipedia

Simple – should be plenty of entries for that!

I guess the trick is in the syntax, as well as the science.

Have a look at Otago University‘s Centre for Science Communication Twitter Competition for the details.

Deadline is Tuesday 15 November. You will have a chance to vote on your favourite entry from Wednesday 16 November until noon Saturday 19 November.

And, Professor Lawrence Krauss, author of the forthcoming book A Universe from Nothing: Why There Is Something Rather than Nothing, will then select the winning tweet from the five tweets receiving the highest number of votes.

I still have a week or so to solve that problem and send my entry.

Thanks to: Best Science Tweet Competition.

An unnecessary being? Ken Perrott Sep 11

No Comments

Have a look at this brief interview of Leonard Mlodinow – the co-author with Stephen Hawking of the just published book The Grand Design

The extreme media reaction to this book was based on the simple sentence:  ’It is not necessary to invoke God to light the blue touch paper and set the universe going.’ Apparently some theologians were so bent out of shape by the “audacity” of the claim they just had to attack a number of straw men, and assist the book up the best seller list in the process*. You would think they would be used to this by now. As far back as 1878 George Romanes, a biologist and lapsed catholic, wrote  “There can no longer be any doubt that the existence of God is wholly unnecessary to explain any of the phenomena of the universe.”

In this interview Mlodinow expands a little on the extract and helps bring some sense into the discussion.

YouTube – Leonard Mlodinow: God Is Unnecessary.

* One of the worst comments I read was by Mike Bara (see Hawking’s Latest Absurdity Spells the Death Knell for Scientific Materialism). He called Hawking ’arrogant and ignorant’, a ’self-appointed academic elite’, ’deluded’, ’a broken, ill and crippled man’, ’narcissist’ and a victim of ’the Darwinian delusion’. He added, for good measure, that ’science is an empty path bereft of meaning’ and ’the scientific materialists day is over, and Hawking, their champion, deserves not our wrath, but our pity.’

Move over Dawkins – we have another demon to stick pins in.

Enhanced by Zemanta

We don’t know! Ken Perrott May 14

No Comments
Isaac Asimov

Isaac Asimov via last.fm

I like the quote from Isaac Asimov which goes something like:

“The most exhilarating statement in science is not ‘Eureka!’ but ‘Hmm, that’s funny’!”

Every researcher knows the feeling. When our experiments or observations produce the result we didn’t expect. That conflicts with our hypothesis – or even better conflicts with current theory.

Because we know this means progress. We have found something we can’t explain and that gives us a chance to discover something new.

Good scientists are not afraid to say “I don’t know!” Ignorance is nothing to be ashamed of. However, we should not be satisfied with it. So scientists usually add “Let’s find out!”

That’s why it is galling to hear opponents of science claim that we are an arrogant lot. That we claim to know everything. Or that we claim we can, eventually, know everything.

I confronted these sort of arguments recently in a discussion with some religious apologists (see Science and Religion: Theism and Explanatory Idleness). They were criticising scientific arrogance. Claiming that many scientists had a “science of the gaps” approach – assuming everything could eventually be explained by science alone.  I challenged the claim – asking for evidence of any scientist advancing the argument. And was told to google Dawkins!

Ah, the Dawkins who doesn’t exist but has been invented as an apologist voodoo doll (see The Dawkins Delusions).

Mysteries of the universe

Anyway – this brings me to an excellent series of podcasts that are worth subscribing to – Astronomy Cast. In these astronomer Dr Pamela Gray discusses a different topic each week with Fraser Cain. Its always interesting and informative.

Their “mission statement” is usually to tell the listener what we know about astronomy and how we know it. But recently they devoted  six podcasts to things we can’t explain. Things we can’t explain yet, or may never be able to explain. Questions for which our answer is, unashamedly, “we don’t know!” Even - “we may never know!”

I especially liked  Ep. 178: Mysteries of the Universe, Part 1 and recommend it to readers. It really discredits the charges of scientific arrogance and “science of the gaps”.

See also:

Ep. 174: Mysteries of the Solar System, Part 1
Ep. 175: Mysteries of the Solar System, Part 2
Ep. 176: Mysteries of the Milky Way, Part 1
Ep. 177: Mysteries of the Milky Way, Part 2
Ep. 178: Mysteries of the Universe, Part 1
Ep. 179: Mysteries of the Universe, Part 2

Permalink

Similar articles

Reblog this post [with Zemanta]

Share

A Universe From Nothing Ken Perrott Oct 29

No Comments

The origin of the universe is one of the biggest questions there is. Some people resort to easy answers — which don’t answer anything. But its good to know that others do take the question seriously and actively research it.

Here is a great lecture from Lawrence Krauss — ’A Universe from Nothing’.

He is always an informative and entertaining lecturer. He injects quite a bit of humour into this talk he gave at the Athiest Alliance International Convention held in California earlier this month.

‘A Universe From Nothing’ by Lawrence Krauss, AAI 2009.

YouTube Preview Image

Permalink

Similar articles

Share

Reblog this post [with Zemanta]

Humanity’s most important image Ken Perrott Sep 30

No Comments

This is a lovely video. Brings home just how big our universe is. And that’s without consider possible other parts of an even larger universe.

Really gets you thinking.

YouTube Preview Image

Reblog this post [with Zemanta]


Network-wide options by YD - Freelance Wordpress Developer