Tag Archives: Research

News

How tidal effects improve the habitability of a planet

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Circumstellar Habitable Zone
Circumstellar Habitable Zone

Science Daily reports on a new factor that affects planetary habitability: tides. Specifically, tides can affect the surface temperature of a planet, which has to be within a certain range in order to support liquid water – a requirement for life of any conceivable kind.

Excerpt:

Tides can render the so-called “habitable zone” around low-mass stars uninhabitable. This is the main result of a recently published study by a team of astronomers led by René Heller of the Astrophysical Institute Potsdam.

[…]Until now, the two main drivers thought to determine a planet’s temperature were the distance to the central star and the composition of the planet’s atmosphere. By studying the tides caused by low-mass stars on their potential earth-like companions, Heller and his colleagues have concluded that tidal effects modify the traditional concept of the habitable zone.

Heller deduced this from three different effects. Firstly, tides can cause the axis of a planet`s rotation to become perpendicular to its orbit in just a few million years. In comparison, Earth’s axis of rotation is inclined by 23.5 degrees — an effect which causes our seasons. Owing to this effect, there would be no seasonal variation on such Earth-like planets in the habitable zone of low-mass stars. These planets would have huge temperature differences between their poles, which would be in perpetual deep freeze, and their hot equators which in the long run would evaporate any atmosphere. This temperature difference would cause extreme winds and storms.

The second effect of these tides would be to heat up the exoplanet, similar to the tidal heating of Io, a moon of Jupiter that shows global vulcanism.

Finally, tides can cause the rotational period of the planet (the planet’s “day”) to synchronize with the orbital period (the planet’s “year”). This situation is identical to the Earth-moon setup: the moon only shows Earth one face, the other side being known as “the dark side of the moon.” As a result one half of the exoplanet receives extreme radiation from the star while the other half freezes in eternal darkness.

The habitable zone around low-mass stars is therefore not very comfortable — it may even be uninhabitable.

Here is my previous post on the factors needed for a habitable planet. Now we just have one more. I actually find this article sort of odd, because my understanding of stars was that only high-mass stars could support life at all. This is because if the mass of the planet was too low, the habitable zone wouldbe very close to the star. Being too close to the star causes tidal locking, which means that the planet doesn’t spin on its axis at all, and the same side faces the star. This is a life killer.

This astrophysicist who teaches at the University of Wisconsin explains it better than me.

Excerpt:

Higher-mass stars tend to be larger and luminous than their lower-mass counterparts. Therefore, their habitable zones are situated further out. In addition, however, their HZs are much broader. As an illustration,

  • a 0.2 solar-mass star’s HZ extends from 0.1 to 0.2 AU
  • a 1.0 solar-mass star’s HZ extends from 1 to 2 AU
  • a 40 solar-mass star’s HZ extends from 350 to 600 AU

On these grounds, it would seem that high-mass starts are the best candidates for finding planets within a habitable zone. However, these stars emit most of their radiation in the far ultraviolet (FUV), which can be highly damaging to life, and also contributes to photodissociation and the loss of water. Furthermore, the lifetimes of these stars is so short (around 10 million years) that there is not enough time for life to begin.

Very low mass stars have the longest lifetimes of all, but their HZs are very close in and very narrow. Therefore, the chances of a planet being formed within the HZ are small. Additionally, even if a planet did form within the HZ, it would become tidally locked, so that the same hemisphere always faced the star. Even though liquid water might exist on such a planet, the climactic conditions would probably be too severe to permit life.

In between the high- and low-mass stars lie those like our own Sun, which make up about 15% percent of the stars in the galaxy. These have reasonably-broad HZs, do not suffer from FUV irradiation, and have lifetimes of the order of 10 billion years. Therefore, they are the best candidates for harbouring planets where life might be able to begin.

This guy is just someone I found through a web search. He has a support-the-unions-sticker on his web page, so he’s a liberal crackpot. But he makes my point, anyway, so that’s good enough for me.

Maybe the new discovery is talking about this now, but I already knew about the tides and habitability, because I watched The Privileged Planet DVD. Actually that whole video is online, and the clip that talks about the habitable zone and water is linked in this blog post I wrote before.

News

Are gay relationships more stable than straight ones?

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Sherlock Holmes and John Watson are going to take a look at the data
Sherlock Holmes and John Watson are going to take a look at the data

Let’s look at this post from The Public Discourse and see if gay relationships are as stable, or even more stable, than straight ones.

Excerpt:

The [NFSS] study found that the children who were raised by a gay or lesbian parent as little as 15 years ago were usually conceived within a heterosexual marriage, which then underwent divorce or separation, leaving the child with a single parent. That parent then had at least one same-sex romantic relationship, sometimes outside of the child’s home, sometimes within it. To be more specific, among the respondents who said their mother had a same-sex romantic relationship, a minority, 23%, said they had spent at least three years living in the same household with both their mother and her romantic partner. Only 2 out of the 15,000 screened spent a span of 18 years with the same two mothers. Among those who said their father had had a same-sex relationship, 1.1% of children reported spending at least three years together with both men.

This strongly suggests that the parents’ same-sex relationships were often short-lived, a finding consistent with the broader research on elevated levels of instability among same-sex romantic partners. For example, a recent 2012 study of same-sex couples in Great Britain finds that gay and lesbian cohabiting couples are more likely to separate than heterosexual couples.[3] A 2006 study of same sex marriages in Norway and Sweden found that “divorce risk levels are considerably higher in same-sex marriages”[4] such that Swedish lesbian couples are more than three times as likely to divorce as heterosexual couples, and Swedish gay couples are 1.35 times more likely to divorce (net of controls). Timothy Biblarz and Judith Stacey, two of the most outspoken advocates for same-sex marriage in the U.S. academy, acknowledge that there is more instability among lesbian parents.[5]

This paper from the Family Research Council makes the same point:

The 2003-2004 Gay/Lesbian Consumer Online Census surveyed the lifestyles of 7,862 homosexuals. Of those involved in a “current relationship,” only 15 percent describe their current relationship as having lasted twelve years or longer, with five percent lasting more than twenty years.[4] While this “snapshot in time” is not an absolute predictor of the length of homosexual relationships, it does indicate that few homosexual relationships achieve the longevity common in marriages.

In The Sexual Organization of the City, University of Chicago sociologist Edward Laumann argues that “typical gay city inhabitants spend most of their adult lives in ‘transactional’ relationships, or short-term commitments of less than six months.”[5]

A study of homosexual men in the Netherlands published in the journal AIDS found that the “duration of steady partnerships” was 1.5 years.[6]

In his study of male homosexuality in Western Sexuality: Practice and Precept in Past and Present Times, Pollak found that “few homosexual relationships last longer than two years, with many men reporting hundreds of lifetime partners.”[7]

In Male and Female Homosexuality, Saghir and Robins found that the average male homosexual live-in relationship lasts between two and three years.[8]

It’s a Grindr lifestyle. And it’s not a good environment for meeting the needs of children. (Example)

There is one study (Rosenfeld, 2014) that tries to argue against the conclusion of all these other studies, and the problems with it are discussed in this post.

The right way to think about gay marriage is to think about it as an extension of no-fault divorce. The same feminists and leftists who pushed for the legalization of no-fault divorce told us back then that the children would be fine, that children are resilient. No-fault divorce was a change in the definition of marriage. The leftists said that divorce would never become widespread, and that it would not harm children in any way. It was all a pack of lies. If the practices of the gay lifestyle become conflated with marriage, then marriage will come to denote relationships engaged in for “love” not children, such that unchastity, infidelity, increased domestic violence and frequent break-ups are incorporated back into the definition of marriage. Marriage is about permanence, exclusivity and building an environment that can welcome children and supply for their needs. It’s not about government giving people respect for their romantic feelings. Those are volatile. What government ought to be rewarding is lifelong commitment.

Polemics

New software calculates the probability of generating functional proteins by chance

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Apologetics and the progress of science
Apologetics and the progress of science

Here’s an article sent to me by JoeCoder about a new computer program written by Kirk Durston.

About Kirk:

Kirk Durston is a scientist, a philosopher, and a clergyman with a Ph.D. in Biophysics, an M.A. in Philosophy, a B.Sc. in Mechanical Engineering, and a B.Sc. in Physics. His work involves a significant amount of time thinking, writing and speaking about the interaction of science, theology and philosophy within the context of authentic Christianity. He has been married for 34 years to Patti and they have six children and three grandchildren. He enjoys landscape photography, antiques of various types, wilderness canoeing and camping, fly fishing, amateur astronomy, reading, music, playing the saxophone (alto), and enjoying family and friends.

Kirk grew up on a cattle and grain farm in central Manitoba, Canada, where he spent countless hours wandering around on his own in the forest as a young boy, fascinated with the plants and animals that are native to that region of the province. Throughout his teen years he spent six days a week in the summer working as a farm hand with cattle and grain. He left his father’s farm at the age of 19 to go to university.

Canada? Can anything good come out of Canada? Oh well, at least he’s not from Scotland. Anyway, on to the research, that’s what we care about. Code!

Summary of the article:

  • Biological life requires proteins
  • Proteins are sequences of amino acids, chained together
  • the order of amino acids determines whether the sequence has biological function
  • sequences that have biological function are rare, compared to the total number of possible sequences
  • Durston wrote a program to calculate the number of the probability of getting a functional sequence by random chance
  • The probability for getting a functional protein by chance is incredibly low

With that said, we can understand what he wrote:

This program can compute an upper limit for the probability of obtaining a protein family from a wealth of actual data contained in the Pfam database. The first step computes the lower limit for the functional complexity or functional information required to code for a particular protein family, using a method published by Durston et al. This value for I(Ex) can then be plugged into an equation published by Hazen et al. in order to solve the probability M(Ex)/N of ‘finding’ a functional sequence in a single trial.

I downloaded 3,751 aligned sequences for the Ribosomal S7 domain, part of a universal protein essential for all life. When the data was run through the program, it revealed that the lower limit for the amount of functional information required to code for this domain is 332 Fits (Functional Bits). The extreme upper limit for the number of sequences that might be functional for this domain is around 10^92. In a single trial, the probability of obtaining a sequence that would be functional for the Ribosomal S7 domain is 1 chance in 10^100 … and this is only for a 148 amino acid structural domain, much smaller than an average protein.

For another example, I downloaded 4,986 aligned sequences for the ABC-3 family of proteins and ran it through the program. The results indicate that the probability of obtaining, in a single trial, a functional ABC-3 sequence is around 1 chance in 10^128. This method ignores pairwise and higher order relationships within the sequence that would vastly limit the number of functional sequences by many orders of magnitude, reducing the probability even further by many orders of magnitude – so this gives us a best-case estimate.

There are only about 10^80 particles in the entire physical universe – 10^85 at the most. These are long odds. But maybe if we expand the probabilistic resources by buying more slot machines, and we pull the slot machine lever at much faster rate… can we win the jackpot then?

Nope:

What are the implications of these results, obtained from actual data, for the fundamental prediction of neo-Darwinian theory mentioned above? If we assume 10^30 life forms with a fast replication rate of 30 minutes and a huge genome with a very high mutation rate over a period of 10 billion years, an extreme upper limit for the total number of mutations for all of life’s history would be around 10^43. Unfortunately, a protein domain such as Ribosomal S7 would require a minimum average of 10^100 trials, about 10^57 trials more than the entire theoretical history of life could provide – and this is only for one domain. Forget about ‘finding’ an average sized protein, not to mention thousands.

So even if you have lots of probabilistic resources, and lots of time, you’re still not going to get your protein.

Compare these numbers with the 1 in 10^77 number that I posted about yesterday from Doug Axe. There is just no way to account for proteins if there is no intelligent agent to place the amino acids in sequence. When it comes to writing code, writing blog posts, writing music, or placing Scrabble letters, you need an intelligence. Sequencing amino acids into proteins? You need an intelligence.