Perspectives New science of years.6 So this answer to the young implausible that our sun could undergo sun issue applies atmospheric science. this magnitude of mass loss and settle on the young Sagan’s original idea is not likely down to the present sun we benefit because ammonia is very susceptible from. sun, and Earth to destruction by ultraviolet radiation. migration Methane, in addition to being subject to A new solution from planetary ultraviolet, also tends to form organic science hazes that reduce the light levels. In Wayne Spencer the greenhouse effect, if a substance Minton has recently proposed a like methane is of higher concentration, new answer to the young sun paradox, or many years planetary scientists this makes the greenhouse heating suggesting that Earth was once Fand Earth scientists have debated greater, but if the concentration is approximately 6–7% closer to the what is called the ‘faint young sun too great, the hazes start cooling the sun than today and migrated outward paradox’. Creationists have also earth because of the lower light levels. to its current orbit. Planet migration addressed the issue, as it demonstrates Concentrations of carbon dioxide much is now a well-accepted theory in a problem with evolutionary origin of greater than today’s have also been planetary science and has been applied 1-3 life scenarios on Earth. The sun’s considered.2 An important difficulty to explain the origin and history of luminosity increases gradually with with carbon dioxide and the young many extrasolar planetary systems. time and projecting this back more sun is that it tends to cause more cloud There are three types of mechanisms than about 2 Ga implies Earth would cover, which cools Earth.7 Scientists for planet migration that have been receive much less energy from the who have worked on the problem proposed. First is essentially that the sun. The lower luminosity of the sun have generally concluded that carbon protoplanetary dust disk causes the could possibly freeze Earth’s entire dioxide, methane, and ammonia in planet to migrate. Scientists believe surface. One recent source looking Earth’s early atmosphere are not both inward and outward migration is at variations in solar luminosity has likely to be adequate explanations of possible, depending on the scenario. it about 15% less at 2 Ga before the young sun paradox. Creationist The second mechanism more recently present (BP), about 20% at 3 Ga BP, Michael Oard also recently addressed proposed is that a massive disk of and reaching a minimum of 26% less some of these aspects of the problem.2 planetesimals could make a planet than today’s luminosity at around 4.2 migrate. The third says that another 4 planet (or possibly another star in some Ga BP. In 1972 Carl Sagan estimated Difficulties with planetary systems) could make a planet migrate. the luminosity to be roughly 40% less motion solutions than today at about 4.5 Ga BP.5 Thus It is the third of these possibilities the questions come up, ‘How could life There are other proposed ex- that Minton is suggesting for causing evolve?’ and ‘How did life survive?’. planations of the young sun issue Earth’s orbit to change. The idea has from planetary science. One is that not been fully developed in detail Difficulties with atmospheric our sun was approximately 7% more yet and apparently Minton has not 8 solutions massive in the past. When it was yet published a paper on it, as of this more massive, its radiation to Earth writing. But Minton did a presentation In 1972, Carl Sagan addressed the would have been greater by a few at the Space Telescope Science Institute issue of the young sun by suggesting percent, enough to provide for the in April 2012, the video of which is that ammonia in the atmosphere of origin of life. Noted Purdue University available on the internet.9 Some non- the early Earth would have enhanced planetary astronomer Dr David Minton technical articles have picked this the greenhouse effect and kept Earth has recently addressed some of the up and have been published on the warm, similar to the way Venus’s thick difficulties with this scenario.7 The internet.10,11 atmosphere is kept hot. Scientists have main objection to it may be that young Minton seems rather tentative explored a number of variations on stars similar to our sun are not observed about this proposal, judging from Sagan’s idea, such as the atmosphere to be losing mass at the high rates that his presentation. The most likely having higher concentrations of this model would require. Our sun scenario for Earth migration would be methane and carbon dioxide. The usual would have to lose mass at a high rate something like the following: Mercury, accepted answer today in the scientific for a very long time of over 2 Ga. It Venus, and Earth form near where they community to the young sun paradox is true that some stars are observed to are now but a fourth unnamed rocky is still that Earth’s atmosphere was apparently go through stages where planet forms somewhere near Earth once more dense than today and had they lose mass at a greater rate, such or Venus. This fourth rocky planet an enhanced greenhouse effect that as from an enhanced solar wind or collides with Venus. Venus is disrupted kept it hot for possibly tens of millions coronal mass ejections. But it seems to some degree by the collision and JOURNAL OF CREATION 26(3) 2012 5 Perspectives reforms from the debris; it is also subsequently resurfaced by volcanism. Presumably Earth’s orbit would be caused to migrate outward because of the fourth planet passing near Earth before it strikes Venus. Another possibility is that the fourth planet was in an elliptical orbit that crossed both Venus’s and Earth’s orbits. Planets in relatively close proximity like this could also affect each other by orbit resonances. So a number of scenarios along these lines are conceivable. Minton calculates that if Earth were only about 6‒7% nearer the sun in its semi-major axis, this would increase the radiation on the earth, with the sun as it is today, so as to allow for liquid Photo: ©iStockphoto.com/adventtr water on Earth. Figure 1. Earth orbiting the sun. New theories on the young sun point to the stability of the earth and sun as a designed system. New solution: science fact or science fiction? very dramatic. It may even be possible would also be long after the origin of In his presentation Minton for the moon to collide with the earth life on Earth. Apparently in Minton’s acknowledges that this idea may as a result of this kind of event. The approach, Earth would be presumably be closer to science fiction than to moon’s orbit could also undergo warm enough for liquid water to exist real science. But, a modification of various oscillations that could last to on the surface from 3 Ga to 1 Ga ago or Earth’s orbit of a few percent does not the present. Scientists have indeed until Earth’s orbit settled to its present seem too implausible from a celestial debated why the moon has the unique configuration. What about the increase mechanics standpoint, when you orbit it does around the earth. This in the sun’s luminosity before the Venus believe in an old solar system and allow aspect of the earth migration idea has impact event? Before Earth migrated it only natural processes in explaining apparently not been seriously studied may have had to endure significant origins. Purposeful design of the solar yet by Minton. The effect of Earth temperature changes from the sun’s system to be a safe abode for life is migration on the moon could have luminosity over approximately 2.5 Ga. not usually considered in planetary major consequences for life on Earth. The migration of Earth’s orbit science. Considering the great variety Another important question about from the gravitational influence of of extrasolar planetary solar systems Minton’s scenario is about the timing a lost planet may seem like science that has been discovered today, this and relationship with Earth’s early fiction. Yet planetary origins models approach might seem, to some, to be a history. Scientists generally believe today explore such ideas seriously.12 logical application of today’s ideas to Earth formed over 4.5 Ga ago and In planetary systems outside Earth, our own planet. But what are some of that life evolved possibly over 3 Ga the planets can be less stable in some the potential difficulties with the earth’s ago. Minton seems to put the Venus way than in our solar system.13,14 orbit migrating? collision and Earth-scattering event Thus planetary scientists accept the First, what would happen to the at around 1 Ga ago at the latest. This possibility that in the multi-billion- moon? When a planet has a moon like puts it long after the solar nebula has year processes of the formation of a Earth, anything causing Earth’s orbit dissipated and the heavy cratering solar system, some planets could form to change would also significantly event has happened in the early solar that get destroyed or thrown out of the affect the motion of the moon. The system, by evolutionary models. It also system. There is now some possible moon could possibly be thrown out of puts the event long after the alleged observational evidence for a few rogue its orbit, especially if the fourth planet impact of a Mars-sized object with exoplanets drifting in space, not tied came near it.