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'Mouse-Tronaughts' to Test Low-Gravity in Space
RandBlade writes "The Telegraph has an article about plans to launch mice into space with simulated low-gravity for five weeks, to test the effects of low-gravity on their bodies. This "will be the first time mammals of any kind have lived in partial gravity for an extended period." Hopes are that this will provide information useful for plans to launch men to Mars, which has one-third of the gravity of Earth."
I dont like the sound of that, They may be mice and all but dont they have a right to live also? Something could go wrong like!
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This "will be the first time mammals of any kind have lived in partial gravity for an extended period."
Skylab? Mir? The International Space Station? People coming back from hundred-day tours in space, their muscles weak from Low-G muscle atrophy, having to undergo extended rehabilitation and physical therapy to rebuild muscle mass after coming earthside?
Did I imagine all that?
I'm sure we'll have lots of posts about "animal cruelty". Is it better to test on mice or humans? Which life is worth more? Would it be fair to send humans to Mars and just watch their bodies essentially turn to jello from the lack of gravity? Those that spent time on the ISS are dealing with the consequences of little or no gravity for an extended period of time.
I'm not saying that it is necessarily "right" to test on animals, but from a scientific point of view, it will bring us much closer to knowing the effect of the conditions on Mars and will bring us closer to having manned missions and even maybe a space station there one day.
"Wisdom is not a product of schooling but of the life-long attempt to acquire it." -Albert Einstein
I was wondering if any Slashdotters new if the muscle and bone loss is only a problem if the astronaut returns to earth, or even if they stay in the low gravity environment.
(On a side note, make sure you check out the caption in the article.)
if anything, babies would be larger due to the ability to grow larger with fewer bad effects.
in that case, humans on the moon would be taller but weaker than earth humans and perhaps one day be diffrent enough that they would be considered a diffrent species.
I am the Alpha and the Omega-3
First, radiation is independant of low-g. Although they may of course occur together.
But have you thought about that bone "loss" (much more that the bones will grow less from the beginning) is maybe not even a problem under those conditions? That the human body simply adapts to the conditions of its environment? Bones we need on the earth would be overkill on the moon! Same is valid for muscles.
Unix makes easy tasks hard and hard tasks possible. Windows makes easy tasks easy and hard tasks $29.95.
>> If you have a calculator, determine the force from gravity applied to a human on earth. Then, calculate again from 1,000 km away. It's a small difference.
...
Sure! I'm Game!
Now, if a body of mass m is a distance r from the center of the earth, you know that the weight of the body is F given by the formula F=GmM/r^2 The gravitaional field strength is g = F/m = (GmM/r^2)/m = GM/r^2
(With me sofar?)
g=GM/r^2
= 6.7 * 10^-11 N m^2 kg^-2 * 6.0 * 10^24 kg/(6.4 * 10^6)^2
= 9.814 N kg^-1
Notice! We get a value which is gravity at earths surface...
Ok, so with the poster above... lets add on our 1,000 km
g=GM/r^2
= 6.7 * 10^-11 N m^2 kg^-2 * 6.0 * 10^24 kg/(6.401 * 10^6)^2
= 9.811 N kg^-1
Yes, we lost all of 0.001 N kg^-1... our poster above is right.
So, how can they make this worth while? Easy. Make them do a larger orbit, so that they are twice the distance r from the earth (notice above, you have to measure from the center of the earth...)
So, lets see how much N kg-1 our mice would have if they were twice as far out...
g=GM/r^2
= 6.7 * 10^-11 N m^2 kg^-2 * 6.0 * 10^24 kg/(12.8 * 10^6)^2
= 2.453 N kg^-1
Anyway, enough maths...
NeoThermic
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Bones we need on the earth would be overkill on the moon! Same is valid for muscles
That could well be true, however a lifetime of zero-g could mean you would never be able to leave space (so you'd have the same problem, in reverse).
As soon as you tried to land on a planetary body with noticeable gravity, your skeleton would probably be unable to support your own weight. Unless you also underwent significant weight loss - in which case you would find yourself abnormally frail, and could easily suffer a fatal bone fracture to something like your rib-cage or skull (weaker bones combined with lack of surrounding fat/muscle).
Nae bother
if anything, babies would be larger due to the ability to grow larger with fewer bad effects.
Thank you Doctor.
But seriously folks, we just don't know.
We do know that evolution makes a lot of assumptions about an organism's environment, and that gravity is one assumption that could be strongly relied on for the last three billion years, from the origin of life on earth until Laika's the dog's first orbit in 1957.
We also know that the genetic sequencer, as long as it is, is nowhere near long enough to provide an actual "blueprint" of the organism being built. The human genome is approximately 3.2 billion base pairs long, but the number of -- for example -- neurons in the human brain is perhaps 100 billion, making for the possibility of as many as 100 billion squared connections between neurons. There is simply not enough information in the genome to specify the type, position, or inter-connections of every neuron in the brain, much less every cell in the body.
How then, is a body built from the genetic code? The short is answer is that we don't (yet) fully know; the longer answer is that the genome does specify certain rules by which certain cells express certain parts of the genome, grow in certain directions, etc.
One typical strategy governing cell growth is a "tropism", growth toward or away from a particular environmental stimulus. Geotropism, growth toward the earth, is almost certainly mediated by gravity (as opposed to sensing the earth in some less obvious way).
It would be amazing if animal embryogenesis -- the growth of the baby organism -- did not involve geotropism to some degree. (We already know that the growth of plants and their seeds do rely on geotropism -- this is how roots grow down and stalks grow up). How geotropism is involved in animal embryogenesis, how and to what extent the developing embryo would be affected by reduced gravity -- all are unanswered questions.
A facile answer that lower gravity would means bigger babies with "fewer bad effects" isn't an answer at all; that is to say, the answer might even (though I doubt it) turn out to be right, but the answer is not reasoned.
Opinions on the Twiddler2 hand-held keyboard?
I'm not sure why that was modded up, as its genereally wrong.
To be more accurate, bone loss and muscular atrophy aren't problems in space, they're problems when you leave space. They don't degrade because you're in space, they degrade because you don't need them.
There's NO evidence that medically someone who lived in 1/3g and stayed there would have any more problems than here.
In zero G, sure some muscles will atrophy, the ones you don't need. Your skeleton weakens, because it doesn't NEED to be as strong.
Floating in the womb, surrounded by amniotic fluid considerably denser than water, is as close as most humans ever come to living in 0-g. I suspect that of all portions of the human life cycle, fetal development would be the least impacted by taking place in low gravity. (And pregnancy, and delivery, would probably be a lot less unpleasant for the mother, too.) OTOH, once the babies are born, we're going to have to figure out how to get them lots of exercise so their muscles and skeletons develop somewhere near normally. Adults can always spend more time in the gym to compensate; it's hard to persuade an infant to hit the bench. ;)
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.