Does it happen?

[sriram]

Guys! One of my pals told me that when we go to space our height will be increased by about 2 inch!

 

Is is so? Is true, plz tell me the reason!

 

Thanks!

[[Tycho?]]

Uh, well, your height changes while on earth actually. While walking around your back gets compressed due to gravity. If you get up in the morning, measure your height, and then measure it again after being on your feet the whole day you will be shorter.

 

With no gravity to compress you, you will just "stretch out" in space, and compress back down after you stood in gravity.

[Sisyphus]

I'd think that as a child, when you're already growing, you would grow a lot taller (and weaker) in a weightless environment because you're not fighting gravity, but I'm not sure how much or if that's even actually true. I don't think merely being weightless would cause you to grow if you weren't already, except what Tycho said.

[Cap'n Refsmmat]

According to a book I have from an ex-Space Shuttle astronaut, people do "grow" in space a significant amount, and get very nasty backaches as a result. Spacesuits and such have to be made 2 or so inches bigger to fit the astronauts in space.

[mooeypoo]

I wonder how they first found out about this 2 inch difference. I can see the situation:

 

Huston: "Okay, You should not prepare for the first walk in space, let's make sure we beat Aleksei Leonov, shall we?"

Astronaut: "Acknowledge, huston, I am preparing the space suit now..."

[sTATIC]

Astronaut: "Ahhh.. huston.. we have a problem.. The suit is 2 inches too small."

Huston: "Someone get the tailor! Make sure he converted inches to centimeters right!!"

 

...

 

 

~moo

[Cap'n Refsmmat]

In the first space missions, astronauts wore their spacesuits from launch to landing. In Gemini, for example, when the first spacewalk (and all subsequent ones) were carried out, they just let all the air out and opened a hatch. Both people in the capsule, including the non-spacewalker, had to have spacesuits on to survive, and there wasn't enough space to squirm into one during the mission.

[mooeypoo]

Ah.

 

So that would've made a horrible realization mid-mission to find out your suit is really pressuring your body, I would imagine.

 

~moo

[Rocket Man]

im not sure about two inches, but two centimetres is common between morning and evening under 1g. the vertebrae compress a little during the day.

 

5cm might be attanable if the curvature went out, as happened to an american astronaut a few months back, his return flight had to be specialised because his back couldnt handle gravity, it took a lot of physio to get him walking again.

[mooeypoo]

I was just kidding about the centimeter comparison, as a small joke reffering to NASA's recent mistake with the mars rover

 

Anyways, it could've been a funny caricature to its time, and quite a funny occasion.. but it was a joke eh

 

Interresting though.. I wonder what would happen if human beings start a colony in a lower-gravity place (you dont have to have it in space - Mars, for that matter, or even the moon, is enough). Will children born in space have severe back problems?

[Rocket Man]

you will only really devolp back problems related to the curvature if you dont have any load whatsoever.

children born on mars would grow a lot taller because height is regulated by load and stability. they would however collapse from a weak back under 1g

(they'd probably also die from circulation problems due to increased demand for blood pressure)

[mooeypoo]

Interresting concept for Sci-Fi writers...

 

That was completely off topic, and therefore I will drop this, but I had to thank you for explaining this, since (as the other post about artificial gravity in speculation forum) I am a sci-fi story/screenplays writer, and you just raised a GOOD point I should definately address in that story of mine.

 

So: Thanks

 

~moo

[CPL.Luke]

yeah arther C clark explored the idea in his book 3001, the main character lives in a "space tower", its a tower that extends all the way up into space. Now the character lived in the part of the tower that was 1/3rd g year round, and because of this he couldn't go back to the surface

[swansont]

I was just kidding about the centimeter comparison' date=' as a small joke reffering to NASA's recent mistake with the mars rover

 

[/quote']

 

 

Mars Polar Lander, not rover. The rovers have been quite successful.

 

Anyway, the difference between metric and English units is rocket science

[RichF]

I'd think that as a child, when you're already growing, you would grow a lot taller (and weaker) in a weightless environment because you're not fighting gravity, but I'm not sure how much or if that's even actually true. I don't think merely being weightless would cause you to grow if you weren't already, except what Tycho said.

 

 

A child may not grow at all; low gravity seems to cause a loss in bone density. According to NASA astronauts/cosmonauts on Mir lost 1-2% of their bone mass per month.

 

"The 1 to 2 percent per month loss is an estimate of bone loss -- an average value," Shapiro says. "Certain individuals on six month flights have lost as much as 20 percent of bone mass in their lower extremities, while a few have lost none during the same period in space."

 

Would a child be able to develop under such circumstances?

[JustStuit]

It might also be possible (pure speculation) that children are less affected because they are growing more new cells.

[Mokele]

A small correction: the vertebrae don't change in height at all (except during growth). What's changing is the thickness of the intervertebral disks between them.

 

Basically, structual biology is mostly about fibers. Fibers are great for having a little matter resist a lot of force, especially in tension, and so in a lot of situations in the body where compressive forces happen (not all situations, though), there are anatomical details that covert the forces to tension, allowing cheap, small collagen fibers to take the load.

 

Imagine you have two cylinders (vertebrae) on top of each other, flat ends meeting. Ordinarily, this would mean that something between the flat ends would be compressed. However, instead imagine that the edges of the cylinders are joined by a sheet of fibrous tissue, forming an enclosed cylindrical space between the two ends of the cylinders, and that this space is filled with an incompressible goop. Now, when you push down on the top cylinder, rather that smashing whatever's between the cylinders, you merely increase the pressure in the goop cavity, and that pressure change is resisted by tension in the wall of the goop cavity.

 

When you're in zero-g (or reduced gravity), there's nothing to generate pressure in the goop cavity, so it expands, making you taller.

 

Mokele

[[Tycho?]]

This seems like the sort of thing that experiments should/have been conducted on. Have mice get pregnant and give birth on the ISS or something, observe the results.

[Mokele]

It's unlikely that gravity plays a role in development. Most of development is governed by signal molecules moving within and between cells. Due to the tiny size of these molecules, the viscous forces of the fluid around them has much, much more influence on their motion than gravity.