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| Low gravity life | |
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| Topic Started: May 30 2009, 01:05 PM (3,818 Views) | |
| lamna | May 30 2009, 01:05 PM Post #1 |
 
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I have long wondered what would happen to earth life if it had to live in very low gravity. Suppose for some reason humans create ecosystems with very low gravity. Perhaps on Deimos. And that this habitat is maintained for millions of years. What would develop? |
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Living Fossils Fósseis Vibos: Reserva Natural 34 MYH, 4 tonne dinosaur. [flash=500,450] Video Magic! [/flash] | |
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| T.Neo | Sep 1 2010, 03:27 PM Post #31 |
Translunar injection: TLI
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I've heard figures of 0.2 Earth masses to hold onto an atmosphere, and 0.3 Earth masses to continue being tectonically active. |
| A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork. | |
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| shomas | Sep 1 2010, 09:32 PM Post #32 |
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Zygote
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Before there were plants our atmosphere didn't have oxygen, plants terraformed the atmosphere to what we have today. At 1 G of acceleration 9.8m/s^2, 1 mole or 22.4l of: diatomic oxygen at standard temperature and pressure weighs 32 grams. carbon-dioxide at standard temperature and pressure weighs 48 grams. Under the theory that earth expanded in both size and mass, a younger earth can still keep its early atmosphere because its atmosphere had more mass with the addition of carbon bonded to diatomic oxygen. It was theorized by some scientist that the Carboniferous period had higher oxygen levels then today so that they could explain dinosaurs size and their hearts (3 chamber) inefficient ability to pump newly oxygenated blood to such massive creatures, but does not explain their height. Under an expanding earth theory, a peek concentration of oxygen in the Carboniferous period is not needed, only that plants continue to convert carbon-dioxide to oxygen until we have the concentrations we have today. I never said or suggested that expanding earth lead directly to the immediate appearance of the largest pterosaurs, but if it helps I'll attempt to clarify what I was trying to say. Pterosaurs went through a rapid period of evolution evidenced by the lack of fossil records of missing links between them and earlier species. Original estimates had the largest at 15m but last i read estimates were downsized to 10-12 meters. It would be interesting to note if the estimates were downsized based on assumed air density, oxygen concentration and gravity, and that they be able to still fly. maybe some one will be interested in clarifying why the estimates were downsized. Just as land animals sizes have upper limits based many things, among which very importantly their heart's ability to pump blood, so do different classes of plants have limits on their size based on their evolved structures. Similar plants with same structures have shrunk over time. which can be easily explained under an expanding earth theory. What was the biggest land animal that ever lived I am not interested in aquatic animals because are not subjected to the same evolutionary pressures land animals are. Debate is welcome but, one does not need to use insults to advance his position. Also never forget that the whole of science is built on theories that are dependent on other theories that sometimes seem stable and sound but in reality shifts like sand when new evidence contradicts the foundations on which a theory is built. In asserting that I was inclined to believe in an expanding earth, I was saying that of the material I have researched they make some pretty compelling cases. I will also admit it lacks a good or complete explanation of where the mass came from, and which may or may not be resolved, yet need not be immediately resolved as other merits or deficits are debated. If it turns out that an expanding earth is not a model to understand what happed in the past, it still served a purpose in that it drove us to better explain that which we have observed. |
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| colddigger | Sep 1 2010, 11:02 PM Post #33 |
Joke's over! Love, Parasky
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You've angered me. Actually you've amused me. Our high levels of oxygen did not come from plants but rather from cyanobacteria long before plants existed, plants themselves use oxygen and couldn't possibly evolve or exist before there was any in the atmosphere. |
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Oh Fine. Oh hi you! Why don't you go check out the finery that is SGP?? v Don't click v Spoiler: click to toggle | |
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| Toad of Spades | Sep 1 2010, 11:15 PM Post #34 |
Clorothod
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............dinosaurs had four-chambered hearts and didn't live in the Carboniferous............ -_- Edited by Toad of Spades, Sep 1 2010, 11:26 PM.
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Sorry Link, I don't give credit. Come back when you're a little...MMMMMM...Richer. Bread is an animal and humans are %90 aluminum. | |
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| Forbiddenparadise64 | Sep 2 2010, 02:50 AM Post #35 |
Adult
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LOL. Do some people neverlearn? Plants breath oxygen just like animals. What does he think that plants respirate with without photosynthesis? Oxygen. Tests on rocks have proven that oxygen levels were up to 35% in the Carboniferous and nearly as high in the Cretaceous when the largest pterosaurs. Oxygen atoms are actually more massive than carbon atoms if you look at the periodic table. The rapidness of pterosaur evolution is exagerated by a poor fossil record as it happened no quicker than the evolution of bats or birds. It can easily be explained as diversification of niches after the Permian extinction, where oxygen levels dropped from 25% to just 15% according to the fossil record, and shouldn't the synapsids that rules before the dinosaurs have been bigger as they lived earleir with supposedly lower gravity and denser atmosphere. If Earth lost even 20-30% of it's current mass, the atmosphere would deteriate away, unless it had a different composition suddenly. As said before, the earth CANNOT and WILL NOT EVER gain mass from nowhere, it doesn't happen any where else in the universe (as the basic laws of nuclear energy tell it is impossible) so how could it happen on Earth? I'm sure they'll believe in that wacko process mentioned earlier, but scientists are already disproving it with mantle and core simulations, as well as the fact subduction would destroy the old crust. Supercontinents like Pangea gave existed before and will probably exist again. So expanded Earth theory is debunked by basic laws of physics, biology, chemistry and geology. The theory cannot and will not ever be accepted as mainstream science, mostly due to the fact coastlines have changed greatly in the past and other theories easily fill in the gaps of expanding Earth which is very outdated as scientists havendispriven it hundreds if times. |
Prepare for the Future Walking with the future: Allozoic (pts 4-6)http://s1.zetaboards.com/Conceptual_Evolution/topic/3252142/14/#new 
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| Wibnice | Sep 2 2010, 05:33 AM Post #36 |
Newborn
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By the way, I think we haven't define "very low gravity" yet. Does it mean having a surface gravity of less than 0.1 g? Less than 0.5 g? |
| My project: Life on Sri. | |
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| shomas | Sep 2 2010, 07:27 AM Post #37 |
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Zygote
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Potential places for low gravity living are asteroids that could supply raw materials. Many are already spinning in part due to uneven heating of irregular surface from the sun. Living inside rotating asteroid sets up artificial gravity making getting around a little easer for people. Yes there will be muscular atrophy but animals still need muscles to get around. Life finds a way, and over time I expect natural selection with dramatically different levels of gravity will comparatively rapidly alter both plants and animals. |
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| Holben | Sep 2 2010, 09:42 AM Post #38 |
Rumbo a la Victoria
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Temprature, axial tilt, rotation speed and eccentricities make asteroids not pleasant places to set up camp. |
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Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea. "It is the old wound my king. It has never healed." | |
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| Sliver Slave | Sep 2 2010, 09:45 AM Post #39 |
I'm going back to basics.
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If you're one of those wimpy multicellular animals, yeah.
Edited by Sliver Slave, Sep 2 2010, 09:47 AM.
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Something is upsetting the ostriches. Spoiler: click to toggle | |
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| Holben | Sep 2 2010, 09:46 AM Post #40 |
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Rumbo a la Victoria
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Oh no, not them.  Although stromatolite-like chemosynthesisers might just cope- stretching it, tardigrade analogues. |
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Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea. "It is the old wound my king. It has never healed." | |
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| T.Neo | Sep 2 2010, 10:30 AM Post #41 |
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Translunar injection: TLI
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Some people refuse to listen...after I've explained away Expanding Earth theory, we're still going on about plants "terraforming the atmosphere" and dinosaurs living in the Carboniferous (they lived in the Mesozoic) being limited by their primitive circulatory systems- while dinosaurs had quite advanced circulatory systems complete with 4 chambered hearts! Their circulatory systems were much like mammals, and incidentally, biologically they were very different from modern reptiles. I've explained that: (A): Infalling space material will fry planetary surfaces making the uninhabitable to life, and would not provide a similar pattern to what Expanding Earth proponents describe. (B): The Earth could not have gained mass from nowhere. This could not happen, without inventing new science. And scientific theory is not "I had an idea", it is essentially the currently accepted truth, that is backed up by enough evidence. This is not the case with the "Expanding Earth" theory. And asteroids are far too small to have acceptable gravity- their spin would only produce pitiful artificial gravity. Natural selection doesn't work if your first generation cannot reproduce... But asteroids have plenty raw materials that could be used to construct proper spinning habitats... Edited by T.Neo, Sep 2 2010, 12:05 PM.
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| A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork. | |
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| lamna | Sep 3 2010, 01:39 AM Post #42 |
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Pfft, you're all being silly. The earth is hollow, stars are just city lights on the other side of the world. And is their any reason to believe that animals would not be able to live in minimal gravity for generations? |
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Living Fossils Fósseis Vibos: Reserva Natural 34 MYH, 4 tonne dinosaur. [flash=500,450] Video Magic! [/flash] | |
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| Pando | Sep 3 2010, 01:50 AM Post #43 |
Obey or I'll send you to the moon
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I know that they would, as long as it isn't too low. Although mammals giving birth might be a problem, eggs might have problems too, and if the gravity is too low birds can't eat. Adjusting to higher gravity though would be impossible without GM. |
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| Holben | Sep 3 2010, 03:17 AM Post #44 |
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Rumbo a la Victoria
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Not impossible, perhaps, in cnidarians. But still difficult. |
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Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea. "It is the old wound my king. It has never healed." | |
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| lamna | Sep 3 2010, 05:52 AM Post #45 |
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Reptiles would probably have trouble, given that they need an air bubble to remain at the top of the egg. I don't see how mammals giving birth would cause a problem. |
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Living Fossils Fósseis Vibos: Reserva Natural 34 MYH, 4 tonne dinosaur. [flash=500,450] Video Magic! [/flash] | |
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