Tag Archives: Cause

News

Did the universe have a beginning or has it always existed?

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Here’s a short article from the Massachusetts Institute of Technology’s Physics arXiv blog. (H/T Wes)

Excerpt:

The Big Bang has become part of popular culture since the phrase was coined by the maverick physicist Fred Hoyle in the 1940s. That’s hardly surprising for an event that represents the ultimate birth of everything.

However, Hoyle much preferred a different model of the cosmos: a steady state universe with no beginning or end, that stretches infinitely into the past and the future. That idea never really took off.

In recent years, however, cosmologists have begun to study a number of new ideas that have similar properties. Curiously, these ideas are not necessarily at odds with the notion of a Big Bang.

For instance, one idea is that the universe is cyclical with big bangs followed by big crunches followed by big bangs in an infinite cycle.

Another is the notion of eternal inflation in which different parts of the universe expand and contract at different rates. These regions can be thought of as different universes in a giant multiverse.

So although we seem to live in an inflating cosmos,  other universes may be very different. And while our universe may look as if it has a beginning, the multiverse need not have a beginning.

Then there is the idea of an emergent universe which exists as a kind of seed for eternity and then suddenly expands.

So these modern cosmologies suggest that the observational evidence of an expanding universe is consistent with a cosmos with no beginning or end. That may be set to change.

Today, Audrey Mithani and Alexander Vilenkin at Tufts University in Massachusetts say that these models are mathematically incompatible with an eternal past. Indeed, their analysis suggests that these three models of the universe must have had a beginning too.

Their argument focuses on the mathematical properties of eternity–a universe with no beginning and no end. Such a universe must contain trajectories that stretch infinitely into the past.

However, Mithani and Vilenkin point to a proof dating from 2003 that these kind of past trajectories cannot be infinite if they are part of a universe that expands in a specific way.

They go on to show that cyclical universes and universes of eternal inflation both expand in this way. So they cannot be eternal in the past and must therefore have had a beginning. “Although inflation may be eternal in the future, it cannot be extended indefinitely to the past,” they say.

They treat the emergent model of the universe differently, showing that although it may seem stable from a classical point of view, it is unstable from a quantum mechanical point of view. “A simple emergent universe model…cannot escape quantum collapse,” they say.

The conclusion is inescapable. “None of these scenarios can actually be past-eternal,” say Mithani and Vilenkin.

Since the observational evidence is that our universe is expanding, then it must also have been born in the past. A profound conclusion (albeit the same one that lead to the idea of the big bang in the first place).

They link to this peer-reviewed paper featuring Alexander Vilenkin at the end of the article, which was published in the Proceedings of the 10th Incternational Conference on Gravitation, Astrophysics and Cosmology, Quy-Nhon, Vietnam, December 2011.

The paper concludes:

Did the universe have a beginning?

At this point, it seems that the answer to this question is probably yes. Here we have addressed three scenarios which seemed to offer a way to avoid a beginning, and have found that none of them can actually be eternal in the past. Both eternal inflation and cyclic universe scenarios have Hav > 0, which means that they must be past-geodesically incomplete. We have also examined a simple emergent universe model, and concluded that it cannot escape quantum collapse. Even considering more general emergent universe models, there do not seem to be any matter sources that admit solutions that are immune to collapse.

So where do we stand? There is no eternal universe. There was a beginning to space and time. The entire physical universe came into being out of nothing at some point in the past.

Here’s my previous post on the BVG theorem that explains a bit more about how this data applies to the question of God’s existence.

Commentary

Is there a gay gene? Are gay people born that way?

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Stanton L. Jones writes about what the research shows in First Things.

Excerpt:

Frank Bruni, in his essay “Genetic or Not, Gay Will Not Go Away“(New York Times, January 28, 2012), makes a broad point regarding which I am in complete agreement: Our societal, legal, and cultural debates will not be solved by science. But when you do cite the science, you ought to get it right.

[…]In support of the argument that at least sometimes sexual orientation is a condition of birth, Bruni describes how “One landmark study looked at gay men’s brothers and found that 52% of identical twin brothers were also gay.” This brief explanation both fails as a description of that 20+ year old study and fails to reflect the better research published since.

Bruni gets the number right; the 1990 landmark study by Bailey and Pillard reported a 52% “probandwise concordance” for homosexual orientation among genetically identical sibling groups, but this does not mean what Bruni says it means. A proband wise concordance is a technical calculation, one that in this case results from the following actual results: There were 41 genetically identical sibling groups (40 identical twin pairs and one triplet trio) and of these 41 groups, only in 14 of the groups did the genetically identical brothers match for sexual orientation; in the remaining 27 sets the identical twin brothers did not match.

But this 1990 study was actually based on a sample that was apparently distorted by volunteer bias and hence not representative of homosexual persons in general. Bailey’s own study of a decade later, and the recently published “gold standard” study by Långström et. al. of the Swedish Twin Registry, both found even lower matching among identical twins with much larger and more representative samples. Both studies reported about 10% matching (for Långström, 7 identical twin pairs matched with both identical brothers gay out of 71 total pairs of male identical twin pairs).

So in plain English, the best contemporary scientific findings are that when one identical twin brother is gay, the probabilities of the second twin being gay are approximately 10%. This suggests that the contribution of genetics to the determination of homosexual orientation is modest at best.

When forming your views on any controversial issue, it’s important to get your facts straight.

My previous post discusses what the peer-reviewed research shows about homosexuality.

News

16 scientists explain why global warming is not a threat

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From the Wall Street Journal. (H/T Levin)

Excerpt:

Perhaps the most inconvenient fact is the lack of global warming for well over 10 years now. This is known to the warming establishment, as one can see from the 2009 “Climategate” email of climate scientist Kevin Trenberth: “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t.” But the warming is only missing if one believes computer models where so-called feedbacks involving water vapor and clouds greatly amplify the small effect of CO2.

The lack of warming for more than a decade—indeed, the smaller-than-predicted warming over the 22 years since the U.N.’s Intergovernmental Panel on Climate Change (IPCC) began issuing projections—suggests that computer models have greatly exaggerated how much warming additional CO2 can cause. Faced with this embarrassment, those promoting alarm have shifted their drumbeat from warming to weather extremes, to enable anything unusual that happens in our chaotic climate to be ascribed to CO2.

And:

Although the number of publicly dissenting scientists is growing, many young scientists furtively say that while they also have serious doubts about the global-warming message, they are afraid to speak up for fear of not being promoted—or worse. They have good reason to worry. In 2003, Dr. Chris de Freitas, the editor of the journal Climate Research, dared to publish a peer-reviewed article with the politically incorrect (but factually correct) conclusion that the recent warming is not unusual in the context of climate changes over the past thousand years. The international warming establishment quickly mounted a determined campaign to have Dr. de Freitas removed from his editorial job and fired from his university position. Fortunately, Dr. de Freitas was able to keep his university job.

This is not the way science is supposed to work, but we have seen it before—for example, in the frightening period when Trofim Lysenko hijacked biology in the Soviet Union. Soviet biologists who revealed that they believed in genes, which Lysenko maintained were a bourgeois fiction, were fired from their jobs. Many were sent to the gulag and some were condemned to death.

Why is there so much passion about global warming, and why has the issue become so vexing that the American Physical Society, from which Dr. Giaever resigned a few months ago, refused the seemingly reasonable request by many of its members to remove the word “incontrovertible” from its description of a scientific issue? There are several reasons, but a good place to start is the old question “cui bono?” Or the modern update, “Follow the money.”

Alarmism over climate is of great benefit to many, providing government funding for academic research and a reason for government bureaucracies to grow. Alarmism also offers an excuse for governments to raise taxes, taxpayer-funded subsidies for businesses that understand how to work the political system, and a lure for big donations to charitable foundations promising to save the planet. Lysenko and his team lived very well, and they fiercely defended their dogma and the privileges it brought them.

Read the whole thing! This is a must-read.

UPDATE: My friend Neil Simpson has found another recent study showing that there has been no significant global warming for 15 years – and the numbers come from the British Met Office, and the University of East Anglia (home of Climategate).

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