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Thursday, April 08, 2010

The origin and destiny of our earth and sun (part two)

In part one of this series, we watched a National Geographic documentary about the death of the sun. In part two, we consider the same subject from the point of view of Carl Sagan (1934-1996) who co-wrote and presented the TV series Cosmos: A Personal Voyage (viewed by more than 500 million people worldwide). Carl Sagan wrote a companion book titled Cosmos in which he talks about the death of our sun:

"Billions of years from now, there will be a last perfect day on Earth. Thereafter the Sun will slowly become red and distended, presiding over an Earth sweltering even at the poles. The Arctic and Antarctic icecaps will melt, flooding the coasts of the world. The high oceanic temperatures will release more water vapor into the air, increasing cloudiness, shielding the Earth from sunlight and delaying the end a little. But solar evolution is inexorable. Eventually the oceans will boil, the atmosphere will evaporate away to space and a catastrophe of the most immense proportions imaginable will overtake our planet. In the meantime, human beings will almost certainly have evolved into something quite different. Perhaps our descendants will be able to control or moderate stellar evolution. Or perhaps they will merely pick up and leave for Mars or Europa or Titan or, at last, as Robert Goddard envisioned, seek out an uninhabited planet in some young and promising planetary system.

"The Sun's stellar ash can be reused for fuel only up to a point. Eventually the time will come when the solar interior is all carbon and oxygen, when at the prevailing temperatures and pressures no further nuclear reactions can occur. After the central helium is almost all used up, the interior of the Sun will continue its postponed collapse, the temperatures will rise again, triggering a last round of nuclear reactions and expanding the solar atmosphere a little. In its death throes, the Sun will slowly pulsate, expanding and contracting once every few millennia, eventually spewing its atmosphere into space in one or more concentric shells of gas. The hot exposed solar interior will flood the shell with ultraviolet light, inducing a lovely red and blue fluorescence extending beyond the orbit of Pluto. Perhaps half the mass of the Sun will be lost in this way. The solar system will then be filled with an eerie radiance, the ghost of the Sun, outward bound.

"When we look around us in our little corner of the Milky Way, we see many stars surrounded by spherical shells of glowing gas, the planetary nebulae. (They have nothing to do with planets, but some of them seemed reminiscent in inferior telescopes of the blue-green discs of Uranus and Neptune.) They appear as rings, but only because, as with soap bubbles, we see more of them at the periphery than at the center. Every planetary nebula is atoken of a star in extremis. Near the central star there may be a retinue of dead worlds, the remnants of planets once full of life and now airless and ocean-free, bathed in a wraithlike luminance. The remains of the Sun, the exposed solar core at first enveloped in its planetary nebula, will be a small hot star, cooling to space, collapsed to a density unheard of on Earth, more than a ton per teaspoonful. Billions of years hence, the Sun will become a degenerate white dwarf, cooling like all those points of light we see at the centers of planetary nebulae from high surface temperatures to its ultimate state, a dark and dead black dwarf." (Carl Sagan, Cosmos, 1980, Ballentine paperback edition, pp.188-189.)

2 Comments:

Anonymous Dave C. said...

Wow. Sagan had a way with words. It sure is a good thing that the earth will become celestialized and whisked back to the presence of God before this great destruction takes place. I think that our sun will eventually go through the events as Sagan described them, but this earth will not be third rock from the sun when it happens.
Funny thing is that Sagan was right about those living on the earth when our sun expires. He said that they might have interstellar travel capabilities. According to Brigham Young, celestial beings can travel throughout the universe, like when angels visit our world from other celestialized planets. I dare say that the earth will be celestialized and full of interstellar travelling beings when our sun goes through its last stages of existence.

4/15/2010 10:08:00 PM  
Anonymous kh said...

I have found this quote. Apostle Melvin J. Ballard said,“When a child at school I learned that if an icycle a mile square were dropped into the sun it would melt in an instant, and when I learned how intense the heat of that orb and that our sun is a Celestial world, I did not know whether I wanted to live in a Celestial world or not if it was that hot. But when I come to understand, if I have a body suitable to dwell in eternal burnings then I think I would like it. If I should come forth and find myself in the Telestial world, or in the Terrestrial world, and look up to this earth, when it shall attain its place as a Celestial orb, shining like a sun, when this earth will no longer need the sun to shine upon it by day nor the moon by night, when it shall become the sun of a reflector of light, when it shall become the sun of another group of planets, similar to our solar system, if I should be so unfortunate as to lose my chance of obtaining an inheritance in that place, and be compelled to dwell upon a Telestial orb, I surely will feel the full force of the poet's statement, "Of all the sad words of tongue and pen, the saddest of them all, it might have been."
Sagan and his kind are "ever learning and never coming to the knowledge of the truth." Truly the false philosophies of men are foolishness unto God.

6/10/2010 05:32:00 PM  

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