moon receding from earth receding from sun?

newtonian · Oct 4, 2004

The moon is receding at 4.5 cm per year (as of 1991) Nova Origins (the PBS miniseries) indicates that the moon was 200,000 miles closer when it was newborn. What about earth's orbit. Has it also been receding from the sun? Especially in view of the fact that the sun?s mass in decreasing. And how far will earth be from the sun 5 or 6 billion years from now?

mooware · Oct 4, 2004

"And how far will earth be from the sun 5 or 6 billion years from now" Probably won't matter much how far away, I think in about 5 billion years the sun will start to swell into a red giant, and likely humanity will not survive.

qzzq · Oct 4, 2004

The Sun's mass decreasing? Probably somewhat due to mass expulsions of matter in solar flares and such, but relative to its total mass, it doesn't amount to much. The Sun also feeds on comets that fall into it, so the weight loss may not be significant to Earth's orbit at all, or barely noticeable. And yes, in 5-6 billion years, or Sun will run out of fuel and start expanding, perhaps even eating Earth in the process. It will be hot around here no doubt. <div class="Discussion_UserSignature"> *** </div>

newtonian · Oct 8, 2004

crazyeddie- I agree with the flavor of your post, but not the detailed ingredients. Yes, solar gravitational bonds with the planets will weaken at red giant phase. However, this is not because of some instantaneous loss of mass of the sun - is it? The process of using up hydrogen fuel is part of an ongoing process. You all - can anyone post the math for the loss of mass of our sun in the last 4.5 billion years and then extend this to loss of gravitational bonds towards earth, and then extend this to actual earth orbital speed and position? BTW - I realize all of this is complicated by tidal interaction between earth and sun - comparable to the tidal interaction between earth and moon which is causing the moon's orbit to recede. Does tidal interaction likewise cause earth's orbit to recede from the sun. crazyeddie - BTW- I have doubts about the standard model of stellar evolution as applied to our sun, and the resulting position of earth during solar red giant phase- but that is discussed on another thread. In short, I believe internal solar mixing with a stirring time on the order (in powers of 10) of 10 billion years will greatly increase the decrease of the mass of our sun by the time of red giant phase - i.e. - our sun will burn a higher percentage of its hydrogen fuel than currently estimated by popular models- in my modeling.

newtonian · Oct 8, 2004

qzzq - Are you sure? I was under the understanding that solar accretion had stopped once the solar wind at star formation reached a certain speed or power? Of course, a comet with a high enough speed and mass could impact our sun - have astronomers observed this happenning? How fast would such a comet need to travel to overcome the solar wind? How far would such a comet penetrate the sun? I know this would depend on mass and speed and trajectory. What mass and speed, say of a sub-brown dwarf or even a massive asteroid, would be required to reach the core fuel area of our sun? I know some collisions would pass entirely through our sun.

newtonian · Oct 8, 2004

crazyeddie - Interesting suggestions. Perhaps good advice - I may get to that eventually. So far, I have preferred to remain completely independent of the system. This helps me think outside the box and come up with questions others ignore as well as avoid assumptions many base their models on. You can be sure I would get terrible grades as I would give what would be considered many wrong answers on tests - I would simply answer as accurately as possible. I made this decision long ago when I was marked wrong on a Regents question in High School when giving a correct answer which was different from the popular model taught at the time. I have simply refused to consider publishing any of my scientific reseach - rather like Newton did not publish his Biblical research. Almost completely independent - posting at SDC does involve some linking. Your suggestions are irrelevant, however, to the validity of my model. People with doctorates or letters publish all kinds of models with or without observational or reasonable basis. Do you have any objection to my model based on the sources you prefer?

newtonian · Oct 8, 2004

crazyeddie- I said accurate, not opinion. You ought to be more careful about jumping to conclusions. The answers have nothing to do with what pleases me- it is simply true vs. false. Except that I love truth so naturally the truth pleases me. I graduated in 1964 - you are not aware that much of what was taught as scientific truth back then has been shown to be at least questionable if not false? Now, your disrespectful attitude aside, I will let you see part of my model. And I will post the rest depending on your attitude. 1. The popular model assumes zero mixing of the solar core area with outer layers and therefore assumes a very low percentage of the solar hydrogen content will be available as fuel during the solar lifetime. 2. However, evidence of deep magnetic fields and field lines would cause mixing. Now, if you want to consider this line of reasoning logically, I will continue. Otherwise I will stop.

qzzq · Oct 8, 2004

I was under the understanding that solar accretion had stopped once the solar wind at star formation reached a certain speed or power? Of course, a comet with a high enough speed and mass could impact our sun - have astronomers observed this happenning? Yes, they have. SOHO has become a most effective comet finder. It has discovered 100's. These sunbound comets are called Kreutz sungrazers. You can see for yourself; Space.com hosts a pic and video of a comet-Sun encounter: http://www.space.com/scienceastronomy/solarsystem/soho_comet_011024.html How fast would such a comet need to travel to overcome the solar wind? The solar wind is not really much of a wind. Near Earth it's about six to ten particles per cm^3, and surely there will be a higher count the closer you get to the Sun, but to put that in perspective, Earth's atmosphere is about 2,5 10^19 particles per cm^3! Perhaps a solar flare, which is much denser and travels at three times the speed of the solar wind, could slow a comet down somewhat, but not much; the Sun's gravity is no match for the friction caused by a handfull of particles. I posted the Sun doesn't lose its mass, but it does; our Sun ejects one million tons of particles every second! You'd need an awful lot of Kreutz sungrazers to counter that! So I stand corrected. But one million tons still is peanuts compared to the Sun's total mass; 2 10^30 kg!! One billion kilograms per second over the lifetime of the Sun ( 5 billion years ) equals a total of ejected mass of ~1,6 10^26 kg!! Only just about 0,01 % of the solar mass, but still quite sizeable, about Neptune's mass. <div class="Discussion_UserSignature"> *** </div>

Saiph · Oct 8, 2004

crazyeddie: The gravitational reduction is due to mass loss. Not expansion. The size/density of the primary body has no effect on an objects orbit (assuming symettry). If all the mass is there, and earth doesn't move, it'll orbit the same. However the sun slowly looses mass via solar winds, flares, and just plain old fusion. The mass loss in the end stages of a stars life (due to winds etc) is considerable. Paul: I'm currently taking a stellar atmosphere's class. Actually, at this moment I am warily eying a take home test. The next section is about stellar evolution (what goes on inside) and hopefully I'll get some more info on this all for you. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Oct 8, 2004

qzzq - Thank you for the link. Now I also stand (actually sit) corrected! Now, am I at least correct in concluding the solar wind stops accretion during encounters with galactic gas and dust clouds in its travel? I don't mind being corrected - I actually welcome it. Now, from the figures you posted I would have to conclude the amount of solar hydrogen converted into Helium must be a very small percentage. Of course, I need to review the mass loss in Helium fusion from hydrogen - its hard to keep all those numbers in your head! Back to thread theme - it seems mass loss takes a back seat to tidal interactions - so that is one of my questions on this theme- how does tidal interaction effect the earth's orbit over 5 billion years - ballpark estimates welcome. Tangents welcome, btw. Btw - I'm offline for a bit.

qzzq · Oct 9, 2004

Now, from the figures you posted I would have to conclude the amount of solar hydrogen converted into Helium must be a very small percentage. Yes, again rather insignificant when compared to the total solar mass. You need four hydrogen atoms to fuse into one helium atom. The difference between the mass of four hydrogen atoms and one helium atom is about 0.7 %. This 0.7% 'weight loss' is converted into energy; Sunlight in this case ( E = Mc^2 ). The amount of mass converted into energy every second through fusion again seems staggering; about 4,5 billion kilograms!! But over the Sun's estimated total lifetime, 10 billion years, that still only amounts to 0.07 % in loss of mass. Add to that the amount lost through emissions like the solar wind and solar flares and it still isn't much, not enough to seriously alter Earth's orbit in any way. <div class="Discussion_UserSignature"> *** </div>

nexium · Oct 9, 2004

Thank you qzzq for giving numbers instead of generalitues. Is the solar flare about 20 particles per cubic centimeter at Earth distance? Is a CME = coronal mass ejection another name for a solar flare? It is generally thought, by main stream astronomers, that the solar wind is much more intense during the proto star phase = "at star formation" so the smallest particles typically miss the proto star due to this very strong solar wind. Accreation resumes (negligible scale) after a typical star reaches main sequence. The fastest and biggest incoming are typically not diverted by even the strongest possible solar wind. Neil

newtonian · Oct 9, 2004

qzzq - 10%? Even small solar mass loss should have an effect - has this effect on earth's orbit been able to be measured? Yes, solar radiation energy comes from that 0.7% mass loss from 4 hydrogens (via deuterium) to 2 Heliums. Solar main sequence stage, if your estimate is correct, involves mass loss of .07% over 10 billion years. Sounds like only 10% of solar hydrogen is fused- is that close? Meanwhile, I researched these estimates: Solar composition - 73% hydrogen; 25% helium. What was the composition at the beginning of main sequence? At the end of main sequence what composition would the standard model predict? Solar fusion uses up 4 million tons of matter per second. Solar wind ejects 1 million tons of electrons and protons [edit-correction: per second) into space. Is that correct: i.e. a 1:4 ratio in mass loss for solar wind compared with solar fusion? Other posters note that solar wind output has not and will not be constant. How variable is it? How does the mass of a low-mass brown dwarf compare with the mass loss of the sun in 10 billion years? See the Scientific American article on collisions outcomes, specifically brown dwarf + main sequence.

nexium · Oct 9, 2004

Hi Newtoniun: I'm also of the opinion that moderate to large amounts of fresh hydrogen will find it's way into the core over the next 6 billion years delaying the day the core runs out of hydrogen. I'm also of the opinion that no fissionable hydrogen will occur in less than one percent of the core volumn causing local collapse, which will shake things up allowing fresh hydrogen to penetrate deep into the core in adjecent areas, thus further delaying the red giant stage. Perhaps these local collapses are what causes variable stars. Please embllish, refute and/or comment. Neil

nexium · Oct 9, 2004

Hi Newtoniun: When you say brown dwarf, are you thinking almost main sequence, where fission was not sustained more than a billion years past proto star? If so, my guess is mass loss is a few tons per second rather than a few million tons per second. Alternately I have heard that low mass red dwarf stars frequently produce powerful CME = coronal mass ejection, but I have not heard a hypothesis as to why low mass main sequence stars should be violent. If they are less than 13.7 billion years old, they should have fussed less than 1% of their hydrogen. Perhaps local collapses occur in the thousand cubic mile cores as I suggested may be the cause of varriable stars. Neil

newtonian · Oct 9, 2004

nexium - Hi! Well, I am of the belief that "star differs from star in glory (1 Corinthians 15:41) in many, many ways - so there would be many varieties of brown dwarfs and red dwarfs, etc. I didn't have a specific variety in mind - I was wondering which variety at which speed and trajectory would most likely rejuvenate our sun [assuming future fine tuning] say some 5 billion years from now. I will respond to your model after I sleep on it and meditate about it. Meanwhile, here are a few facts about brown and red dwarfs: "Among stellar glow-worms, pride of place must go to the red dwarf RG 0050-2722 in Sculptor, with an absolute magnitude of 19. Some "brown dwarfs", such as the recently-discovered companion of Van Biesbroeck 8 (21 light years away) may be even feebler; their cores have never become hot enough for nuclear reactions to be triggered off." - "The World of Science," 1991, Vol.8, p. 24 The latter type of brown dwarf would therefore have a higher percentage of hydrogen, since no significant hydrogen fusion had yet occurred. Another point is that our sun is on the lower mass end of main sequence stars: "Those of less than 0.08 solar masses never reach this stage [main sequence] at all, but merely go on shrinking to become first brown and then black dwarfs."- Ibid., p. 29. Meanwhile, if I (and you) am (are) correct, then our sun will become a low-mass main sequence star. Concerning low-mass main sequence stars, still over 0.08 stellar masses, the same source notes: "at the other end of the scale the low mass stars, if they evolve to the main sequence at all, will outlive the sun many times over."- Ibid., p.31 So, I am not sure which would ultimately give our sun the longest lifespan: 1. Continued mixing to a point where it becomes a low mass main sequence star with a much longer life span 2. A brown dwarf collision-rejuvenation of our sun about 5 or 6 bi

nexium · Oct 9, 2004

Hi Newtonian; Some of your last post is main stream opinion. I can only guess on other parts. I suspect variations from star to star are frequent and predictions not worth much, because of unknown differences. Since qzzq said our Sun would loose a Neptune mass in the next 5 billion years, a Neptune mass impactor might move red giant stage from 5 billion to 10 billion years in the future, especially if it passed though the core and kept going, due to very high impact velosity. A class M impactor, or almost that big might scatter so much materal, that the impact would cause a net loss of hydrogen. The week of the impact would likely double the sun's average energy output, which could kill most everyone on Earth, even if the Sun was cooler for billions of years after the impact. Collisions are thought to be extremely rare even when galaxys collide. I think it is more correct to say our Sun is in the mid range of steller mass. Of the 50 closest stars I believe only Series has lots more mass than our Sun. Estimates run as high as 99% of the stars in our galaxtic group have less mass than our Sun. Compact stars may greatly out number main sequence stars and nearly all of these have (and had) more mass than our Sun. That is because O, B, A, and F stars typically fuse their hydrogen to helium much faster than stars with lower mass. In nearly all seanarios I think qzzq is correct: The Earth will be closer to the Sun than 120 million miles even a trillion years from now, and could be as close as 40 million miles inspite of loss of half the solar mass. Someone showed mathematically that the Earth moves a few cm closer to the Sun most years, but the change is still too small to measure. Unless mainstream science is wrong, the sun will provide little useful heat or light 25 billion years from now, and almost none by 50 billion years from now when it will be a cold white dwarf. Neil

newtonian · Oct 10, 2004

Nexium - Hi again. Yes our sun is different. Where did you get your figures? 99% of stars have less mass than our sun??? The article I will quote notes it is in the top 10%. Oh, were you including brown dwarfs? Yes, if they make up dark matter, there would be even more lower mass stars than greater mass stars- especially since higher mass stars would already have died- not literally, they still exist in another less massive form. For stars of similar surface temperatures to our sun, our sun is one of the lowest radius stars. Alpha Centauri is slightly larger. See the Hertzsprung-Russell diagram, albeit it is considering radius not mass. I'm gonna have to research this further! Edit: And I found this interesting article on how unique our sun is- note especially under the mass of our sun: "Most astronomy books say that our sun is an ordinary star, "a rather commonplace celestial object." But is the sun in every respect a "commonplace celestial object"? Guillermo Gonzalez, an astronomer at the University of Washington in Seattle, has suggested that our sun is exceptional. Should this affect the search for life on other planets? Gonzalez answers: "There are fewer stars suitable for intelligent life than people realise." He adds: "Unless astronomers narrow down their search to stars as exceptional as the Sun, they are wasting much of their time." What are some characteristics that make our sun suitable for nurturing life? As we examine these factors, we should keep in mind that many statements on the physics of the universe are theoretical in nature. Intriguing Characteristics · A single star: Astronomers estimate that 85 percent of the stars in the neighborhood of the sun are in groups of two or more stars that orbit one another. Such stars are bound together by gravitational forces. The sun, however, is a single star. "The case of the sun as a si

nexium · Oct 10, 2004

I rarely remember where I got bits of data. I suspect the 90% inferred by Gonzales is closer to reality than 99%. Apparently mainstream astronomers mean only main sequence stars when they use the term stars, unless they specified otherwise. So brown dwarfs and compact stars are excluded, perhaps even red giant stars. I did notice one site was giving the radius of stars, but I think they are calculated rather than measured: Our Sun may have a rather average radius compared to stars of similar brightness and color temperature. A small short fall of radius has little effect on intellegent life even if it is accompanied by a small short fall of mass. The Gonzolis hypothesis assumes that our Sun is unusual in many way = probably, but there is little compelling evidence. Gonzolis also hypothesises that intelegent life has the same enviromental needs as humans = possible but far from proven. 85%? others have suggested 50% and even lower percent of binary where the probability of planets is sharply reduced. A star of similar mass that does not come closer than two billion miles only slightly perturbs the inner planets which are most likely to have intelligent life. Few heavy elements in the star are unimportant, unless that means there are insufficient heavy elements to form Earth like planets/A likely corelation, but far from proven. I agree, very eliptic orbits are hostile to life even if favorable resonances exist with other stars in that solar system. Advanced life may however find ways to adapt to intermittant hostile conditions, especially if it has advanced technology. Neil

newtonian · Oct 10, 2004

Neil- Yes, intelligent life does not necessarily require an earth-like planet. Earth-like life does, some to more of an extent than others. The Bible speaks of a totally alien form of extraterrestrial life. These are energy based, not matter based. Spirit in the Bible is from the Hebrew ruahh and Greek pneuma which both mean invisible active force. I.e.: invisible energy. This type of life does not even require our universe to survive, let alone an earth-like planet! But we are way off thread theme- I would say we have reached escape velocity with this tangent! Getting more down to earth - us humans do require this type of star in this type of orbit in this type of solar system. And I suspect we may require adjustments in the distant future - what I am trying to determine in this thread is whether the future orbit is also fine tuned for human life. Mainstream popular models say no- but I doubt the popular model. Here is one verse which seems to be describing a distant future catastrophic change - I do not know if it is talking about the sun's red giant phase, or the upcoming merger with Andromeda, or the even more distant mergers near the Great Attractor, or even perhaps our universe expanding into another universe, or.... The prophecy is certainly interesting to me - I hope you also find it interesting: (Hebrews 1:10-12) . . .And: "You at [the] beginning, O Lord, laid the foundations of the earth itself, and the heavens are [the] works of your hands. 11 They themselves will perish, but you yourself are to remain continually; and just like an outer garment they will all grow old, 12 and you will wrap them up just as a cloak, as an outer garment; and they will be changed, but you are the same, and your years will never run out." The footnote on "perish" states: Literally, "will destroy themselves." Note, in narrowing the correct interpretation, that other verses

qzzq · Oct 10, 2004

But how? One of my myriads of questions. When the Sun starts to expand, move Earth away to a saver orbit. We may have to start moving it sooner than 5 or 7 or 10 billion years from now, when the Sun reaches red giant phase. In a billion years, the Sun will be a lot brighter, and radiate about 10% more energy. In 3 billion years, it will shine 30% brighter. It is highly unlikely we could survive even the 10% increase in energy. It would have serious repercussions for Earth's biosphere. Global warming like you've never seen before. Adapt or be destroyed. That's how evolution works. From SdC: <ul type="square">Recipe for Saving Earth: Move It Here's what you do: <li>Using humans or robotic spacecraft, attach retrorockets -- like those that maneuver spacecraft -- to the rock. Alter its course of so that it passes near Earth. The planet then steals some of the space rock's orbital energy and uses it to move into an orbit slightly farther from the Sun. (NASA employs a similar technique to propel spacecraft, sending them around a planet in order to boost them into new trajectories at higher speeds.) <li>Send the comet or asteroid back out around Jupiter and Saturn, where it will regain orbital energy by robbing it from the giant planets. (In effect, Earth is ultimately getting its orbital boost from Jupiter and Saturn.) Make the rock continue on a long, elliptical orbit that goes way the heck out there -- 325 times the distance from Earth to the Sun. <li>Bring the rock back around Earth every 6,000 years or so, and each time the planet will creep outward a few more miles. The goal: An ultimate retreat of several million miles (kilometers).</li></li></li></ul> Apparently we're already working on it. <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> *** </div>

qzzq · Oct 10, 2004

Hi nexium. You used to be CPoodle, right? ( please forgive me if I got that wrong ) Did someone eat your posts too? You posted: --Is a CME = coronal mass ejection another name for a solar flare? No, they are separate phenomena, I believe, but I'm not sure where they really differ. Perhaps it was event duration, or causality differences. A solar flare is basically a huge explosion on the Sun's surface, where the magnetic field between a Sunspot and its surroundings is neutral. A CME can last for hours, but I'm not sure what causes it. Perhaps size matters too. CME's are HUGE. <div class="Discussion_UserSignature"> *** </div>

CalliArcale · Oct 11, 2004

<blockquote>In reply to:<hr />I was under the understanding that solar accretion had stopped once the solar wind at star formation reached a certain speed or power? Of course, a comet with a high enough speed and mass could impact our sun - have astronomers observed this happenning? <hr /></blockquote> I'm not sure this has been answered yet, but the answer is YES, this has been observed happening. The comet's mass is negligible compared to the Sun's mass, but they can and do hit the Sun. How fast must they travel to overcome the solar wind? I don't know, but I would think that any comet (defined as an icy body with an eccentric orbit whose aphelion is out past Neptune) able to get near the Sun would have more than enough velocity to do it. The solar wind is fast, but also extremely thin. <blockquote>In reply to:<hr />How far would such a comet penetrate the sun? I know this would depend on mass and speed and trajectory. <hr /></blockquote> Heat is also a factor; the comet will be vaporized from the heat alone, which will make it less dense and probably less able to penetrate. I couldn't even begin to speculate on how far it would travel, however. <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

Saiph · Oct 11, 2004

Solar wind has very little effect on the cometary nucleus, as far as imparting an impulse (momentum) goes. It helps ablate the surface, and certainly carries away the vented dust and gas (due almost entirely to heating from sunlight). Basically, it can go as slow as you'd like as long as it's got a decent mass. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Saiph · Oct 12, 2004

Yep. Take a look at the equations here: F=GMm/R^2. Well, little m (planets mass) isn't really changing, and neither is G. The Radius is best thought of as a result of gravity, though as long as we consider it's initial position, that doesn't change either. The increased size of the star does nothing to the distance between the planet and the center of mass of the star (what R is). That leaves M, the mass of the star, is changing. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

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