The Naked Scientists

The Naked Scientists Forum

Author Topic: The effects of weightlessness in space ?  (Read 1952 times)

Offline DERYN

  • Jr. Member
  • **
  • Posts: 25
    • View Profile
The effects of weightlessness in space ?
« on: 22/12/2010 15:53:58 »
Hi everyone,  if a person was born into a weightless environment circling the earth, what differences would develop between them and us down here on the surface ? And, if we were to go into orbit around the earth as an adult, and remain there for the rest of your life, what effects on the body would you expect over time ?

Deryn


 

Offline CliffordK

  • Neilep Level Member
  • ******
  • Posts: 6321
  • Thanked: 3 times
  • Site Moderator
    • View Profile
The effects of weightlessness in space ?
« Reply #1 on: 22/12/2010 17:32:20 »
As adults, I believe the biggest problems are muscular weakness and osteoporosis.  Most astronauts have strict fitness routines to help prevent significant deterioration.  However, that is with the goal of returning to Earth or an environment with significant amounts of gravity.  Muscular atrophy, could cause other issues if one didn't have the strength to perform the necessary tasks of life.

Human infants in the first couple of months might adapt well to space life as they have minimal strength.  However, there would also be little stimulus to get stronger.  Over time it is likely they would develop extremely weak muscles, osteoporosis at a very young age.  As a toddler, they may not learn to walk.  And, may not ever develop a sense of balance which could possibly preclude ever learning to walk.

In a Zero-G environment, the adaptations may not be harmful, especially if supplemented with resistance training.

The infant would likely have severe problems if it returned to earth at age 4 or greater.
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
The effects of weightlessness in space ?
« Reply #2 on: 23/12/2010 01:46:11 »
I'm probably flogging a dead horse here, but, when you are in a lowish orbit around the Earth, you are still subject to pretty much the same force of gravitational attraction towards the Earth that you had when you were standing on the Earth's surface.

All this stuff about Zero G, microgravity, etc., etc., is a load of misleading baloney.

You are only "weightless" because the molecules that make up your mass have nothing to react against, and that, as Clifford points out, can create some serious problems for the human body over time.
 

Offline CliffordK

  • Neilep Level Member
  • ******
  • Posts: 6321
  • Thanked: 3 times
  • Site Moderator
    • View Profile
The effects of weightlessness in space ?
« Reply #3 on: 23/12/2010 02:55:13 »
You are only "weightless" because the molecules that make up your mass have nothing to react against

In "Earth Orbit", your are falling towards the earth at the same rate as the earth's gravitational pull (Centripetal acceleration due to gravity along with forward momentum).  It would be no different than having an endless elevator that falls at 1G.

NASA is able to simulate a Zero-G (or if they wish a low-G) environment using their "Vomit Comet".

http://en.wikipedia.org/wiki/Vomit_Comet

Essentially it is/was an airplane that would decrease its upward acceleration, and tip downwards to give the sensation of about 20 seconds of Zero-G.

Earth is also essentially experiencing a Zero-G freefall towards the sun.

All our space probes such as Voyager and Pioneer are also decelerating towards the sun at a rate that would make them seem to experience Zero-G on the space probe.

I suppose that is what you're saying.
If you could stop "dead in space" and burn rockets to maintain your position.  Then you would feel a positive gravity pull, unless you happened to be stopped in a Lagrange point.
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
The effects of weightlessness in space ?
« Reply #4 on: 23/12/2010 06:54:40 »
You are only "weightless" because the molecules that make up your mass have nothing to react against

In "Earth Orbit", your are falling towards the earth at the same rate as the earth's gravitational pull (Centripetal acceleration due to gravity along with forward momentum).  It would be no different than having an endless elevator that falls at 1G.

NASA is able to simulate a Zero-G (or if they wish a low-G) environment using their "Vomit Comet".

http://en.wikipedia.org/wiki/Vomit_Comet

Essentially it is/was an airplane that would decrease its upward acceleration, and tip downwards to give the sensation of about 20 seconds of Zero-G.

Earth is also essentially experiencing a Zero-G freefall towards the sun.

All our space probes such as Voyager and Pioneer are also decelerating towards the sun at a rate that would make them seem to experience Zero-G on the space probe.

I suppose that is what you're saying.
If you could stop "dead in space" and burn rockets to maintain your position.  Then you would feel a positive gravity pull, unless you happened to be stopped in a Lagrange point.

Yes. I agree Clifford. It's the terminology that I object to simply because it confuses some people into believing that humans in low orbit have somehow escaped from gravity, which, of course, is nonsense. If they did, they would fly off tangentially and, presumably, go into orbit around the Sun. 

There is nothing very magical about Zero G either. You don't need the Vomit Comet to experience it. Jumping up in the air is quite sufficient.

But the one that really gets me going (in case you didn't notice :D) is the term microgravity. There's nothing micro about it.

"Ooo! Look at me! I jumped six inches off the ground and now I'm in microgravity."

(Sorry about the rant.)
 

The Naked Scientists Forum

The effects of weightlessness in space ?
« Reply #4 on: 23/12/2010 06:54:40 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums