Posted on July 9, By Scott Youngren Despite the scientific and philosophical arguments for the existence of God presented on this website and elsewhere, some readers may still be haunted by a persistent question:
Values not in the table can be calculated by using linear interpolation. Slum is stellar luminosity, it is the Lum column on the table. BC is bolometric correction, it is the Bolo. Steff is effective temperature, it is the Teeff column on the table. These will be used in the equations below. In Dole's Habitable Planets for Manhe estimates that an average planet requires about 3.
This is important, since generally the only way a planet has oxygen in its atmosphere is by the action of native plant life. This means that the primary star needs a lifetime longer than 3.
This disqualifies stars with a spectral class of higher than F2. But keep in mind that Dole's 3 billion year figure is more of an educated guess than it is ironclad scientific fact. Obviously even though K0 stars has a lifespan of 1.
It is of type F7, which means it is hotter and whiter than Sol. Its mass is 1: The diameter is little greater, but spots, prominences, corona, and output of charged particles solar wind are fewer. It is a younger star than ours, though by less than a billion years.
Either because of this, or because of variations in galactic distribution, the proportion of heavy elements in it and its planets is somewhat more than for the Solar System.
In earlier days, science fiction customarily put planets around the familiar ones like Sirius, Vega, Antares, or Mira. It was then legitimate enough, if a trifle repetitious.
|Colony Sites - Atomic Rockets||I want to start with some apologies. For the record, here and upfront, I apologise for having spent several years ripping up GM crops.|
|Planet of weeds | Harper's Magazine||The incredible scale of this loss has led to significant changes throughout many parts of the world, and in recent years these changes have been accelerating.|
|By John Mauldin||I read this article in English class because I have taken a keen interest in the articles which are submitted to Harpers. I find they are fairly unbiased and they come from a wide spectrum of people around the world who have familliarized themselves with the topic they have wrote about.|
But today we know, or believe we know, that few of the naked-eye stars will serve. Mostly they are giants, visible to us only because they are so brilliant that we can pick them out across immense gulfs of space.
Sol would no longer be discernible without instruments at a distance of about 55 light-years. Now the red giants like Antares, the variables like Mira, are dying stars, well on their way to the dim, ultra-dense white-dwarf condition.
If ever they had planets—their mass makes that unlikely, as we will see in a minute—the inner attendants have been seared or even consumed, as these suns expanded. Probably the majority of stars in the universe are still enjoying health.
Their temperatures and luminosities vary enormously. The most important reason for this is the difference in their masses. The more massive a sun is, the more intensely compressed it becomes at its core, and thus the more fierce and rapid are the thermonuclear reactions which cause it to shine.
This dependence of output on mass is a highly sensitive one, so that the latter covers a much smaller range than the former. These stars form a well-defined series, from the largest and brightest to the smallest and dimmest, which is called the main sequence.
That last, G0, was formerly the classification of our own sun; but more recent information has gotten Sol to be labeled G2. Figure 1 shows a large part of the main sequence. It omits the extremes, because they really are too extreme to diagram very well.
That is, the main sequence runs from the hottest Type O blue giants, some as much as a million times the strength of Sol, on through the yellowish F and G stars, to the red dwarfs of Class M, the dimmest of which may be less than a thousandth as intense as our daystar.This website is a culmination of articles and user comments that discuss evidence of God based on Science, Philosophy, and Experience.
Feb 24, · An apparent slowing in the rise of global temperatures at the beginning of the twenty-first century, which is not explained by climate models, was referred to as a “hiatus” or a “pause” when first observed several years ago.
COMMUNIQUE #3 Haymarket Issue "I NEED ONLY MENTION in passing that there is a curious reappearance of the Catfish tradition in the popular Godzilla cycle of films which arose after the nuclear chaos unleashed upon Japan.
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news · resources · e-sermons · snuff it · family album music · video · catalog · faq · press · links · contact: PLANET OF WEEDS Tallying the losses of Earth's animals and plants by David Quammen.
Hope is a duty from which paleontologists are exempt. news · resources · e-sermons · snuff it · family album music · video · catalog · faq · press · links · contact: PLANET OF WEEDS Tallying the losses of Earth's animals and plants by David Quammen.
Hope is a duty from which paleontologists are exempt.