Surface gravity on Mars

A couple of questions is inspired by the recent manned Mars simulation that's in progress.

1. As I understand it, 0 gravity is harmful to human physiology. Is Mars's reduced gravity equally as harmful too, or is it one of those things where it sufficient without the need for aggressive countermeasures (like vigorous exercise & dietary modifications/meds)?

2. The level of Mars's surface gravity is said to be at around the midpoint between the moon's gravity and Earth's. What exactly would that be like? can you describe a few of the phenomena you would encounter in day to day living --- like would walking be different? If your pencil falls off your desk while you're working, what happens to it? can you jump off taller objects without any problems?

 

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Isn't Mars' gravity .6 that of Earth's? I am not going to Wiki it- the OP should have. Things will be moving more slowly, that's all. Watch astronauts on the moon- they all look like they're moving in slow motion- that is the effect of the moon's gravity.

 

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The Martian gravity is only ~40% of Earth's vs ~16% on the moon, so you could jump about twice as far on Mars as you could on Earth.

The apparent slow motion has probably more to do more with the pressurized space suits then the gravity, but it is true you accellerate slower so there is that effect, but I don't recall an astronaut ever getting high enough in a jump so that would be noticable, but you can clearly see the effects when they drop the hammer and feather for instance.

http://video.google.com/videoplay?docid=6926891572259784994#

Astronauts in weightless conditions for long periods of time can lose significant amounts of bone and muscle mass even if they exercise a lot and so far we don't know if the gravity on Mars is strong enough to avoid this. A satellite to help explore this issue, with White Mice in a revolving container to simulate Martian gravity was cancelled due to lack of funding.

Arthur

 

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Correct, you start losing bone mass rather quickly without gravity. There are other physiological changes as well that harm the body.

Sice there's little atmosphere on Mars you'll be bombarded by radioactive particles when your outside your protected living quarters. You''ll need to supply your own oxygen as well since there's none there.

 

Wow they took a feather (organic material) to the moon I wonder if they would still do that today or perhaps in the future on mars.

But it would be pretty safe at night and with phobos having 2/3 the apparent size of our full moon it won't be pitch dark either

 

That's 2/3 the angular diameter which works out to 0.44 the area. Now add in that Phobos' albedo is 0.58 that of the Moon and that sunlight is 0.44 times as intense at Mars' distance than it is at Earth's and you end up with Phobos providing ~11% of the illumination of a full Moon.

And that's when Phobos is full and directly overhead. Since Mars' radius is a significant fraction of the the radius of Phobos' orbit, this drops to ~5.5% when Phobos is near the horizon. This means its illumination will vary with its passage and its maximum brightness will vary with the lattitude from which it is observed.

 

You might be right there 11% of 0.27 lux isn't much to see by, still night missions might still help to reduce radiation exposure

 

They took food as well just as they will when they go to Mars, what is the big deal? :shrug:

 

Their could be bacteria on it for starters Like on the surveyor 3 lander where bacteria survived for years on the lunar surface.

I'm sure that if you dropped a exthremophile at the right place preferably near the base where waste heat could perhaps melt some water (astonauts are sure to move ice near their base and their are plenty of salts in the martian soil so the lifeforms could potentially stay alive for years contaminating the area around it.

That is the biggest reason I can think of

 

They also left their human waste on the moon as well. When they take off from the moon to return to Earth they leave everything that they used up behind. Think about that cotamination if a meteor hits one of the 10 landing craft and its contents are spewn all over the place!

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Yeah your making jokes now but as long as terraforming and colonisation are impossible the search of life will be the main (official) reason to visit mars, to that end it's better to keep organic material and whatever life that is on it away from the enviroment

 

I was referring to the effects from gravity in particular. I just wanted to see a few examples of the gravitational behaviors of things you'd be likely to encounter living there.
Dealing with the nastier aspects of the environment are a given (its super cold, radioactive, etc).... my questions take for granted those problems already being taken care of, and what normal life would be like. Let's assume the colony lives in a gigantic sealed-environment type compound.

Pencil falling off the desk was one. Normally here on earth, the pencil falls, bounces once or twice, then possibly rolls for a short distance. On mars, am I going to end up having to chase my pencil all the way across the room?

If I'm running a sink full of water to do dishes, will the behavior of the splashing water be dramatically different (will i be forced to wear a bib when I'm scrubbing LOL). What about boiling water on the a stove....are lids going to become crucial?

I dunno --- those are the kinds of things I'm wondering about.

 

Some effects of reduced gravity.

An improved standing high jump. Improved vertical leap for basketball players. An athlete weighs less & his muscles can supply the same vertical force. Not sure about the effects on the running high jump.

The broad jump & 100 meter dash would suffer. Horizontal force for running depends on friction with the ground & is proportional to the weight of the athlete. Mass of the athlete (resistance to force) is the same on the earth, Mars, Luna, and/or when weightless in a space station. On some surfaces, spiked shoes would partially or fully (?? here) restore the amount of horizontal force an athlete could apply.

Note that when weightless, spiked shoes would not help much, if at all. In a nearly weightless environment, they would result in only restoring a small percentage of the possible horizontal force.

Some SciFi author described an inexperienced astronaut seriiously injuring himself by building up speed using hand rails in a space ship corridor. When he came to a right turn, he could not slow down enough to avoid a painful collison with a wall. He did not realize that his mass/inertia was the same as always, even though he was weightless.

You could hit a golf ball farther on Luna. ?? As far as indicated by theoretical calculations ?? Not sure about the latter.​

 

With no air resistance you could hit it MUCH further than that.

Arthur

 

Then your figure is wrong.

The ball is hit with the SAME velocity/angle in both situations, but because of the lower gravity the ball is in flight much longer on the moon and because there is no air resistance on the moon to slow it down, the horizontal velocity remains constant during this much longer flight time, while the horizontal speed of the ball on the earth decreases from the moment it leaves the club.

http://scienceblogs.com/startswithabang/2010/10/could_you_really_hit_a_golf_ba.php

This example shows a golfer who could hit ~300 yds on the earth would hit it about 40 times further on the moon.

Arthur

 

Well then your answer was just silly.

This is SCI forums remember?

You can't just pretend there is no air resistance on the Earth.

Which is why your answer was more than a magnitude off.

Arthur