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virtualcomposer
11-21-2008, 02:02 PM
I know there is some sort of atmosphere on Mars and know that sound cannot travel without a medium to react with it. So the question is, if I was on Mars and took a baseball bat and hit a gong, would there be sound? Would I hear it in my space suit? Also if I were to hit something out in open space, since there is no air in space but there is in my space suit, would I hear the clank of a hammer?

ericsmith
11-21-2008, 02:26 PM
I would assume that you'd hear it on mars. It might sound different than on earth, as the sound waves are traveling through a different composition.

In space, the complete vacume would eliminate any sound, even though there's air in your suit.

What counts is that when the hammer hits the gong, it will create a vibration. If there's something directly in contact with the gong (like air or water), then that will also vibrate, and that vibration will cascade through the medium until it vibrates your ear drum, which your brain will translate into "sound". If there's nothing in contact with the gong, then there's no way for the vibration energy to transfer outward and ultimately to your ear.

The only exception would be that if you're holding the hammer, some of that vibration will transfer directly through your arm and you might "hear" some form of hit.

Eric

virtualcomposer
11-21-2008, 02:53 PM
So where does the energy go then if it can't dissapate in the air? Does this make the object more suseptible to breaking? Are the waves stuck on the object?

Stooch
11-21-2008, 03:01 PM
the object vibrates as it always does.. except tis vibrations arent causing a sympathetic reaction.

on mars there is a thin atmosphere, so sound will travel but poorly.

cresshead
11-21-2008, 03:07 PM
"in space no one can hear you scream" from Alien

virtualcomposer
11-21-2008, 03:19 PM
the object vibrates as it always does.. except tis vibrations arent causing a sympathetic reaction.

on mars there is a thin atmosphere, so sound will travel but poorly.

Is there a site that would explain what would happen to a human if on another planet without a suit. I like science facts like that. I've always wondered how long a person would last if they took a deep breath on Mars. Is it toxic or the fact that there is only 3 percent oxygen and I'm not even sure about that fact.

ericsmith
11-21-2008, 03:20 PM
So where does the energy go then if it can't dissapate in the air? Does this make the object more suseptible to breaking? Are the waves stuck on the object?

Well, if you really look at the scenario completely, you'll see it's not quite so simple.

Let's take the hammer and gong example. The first question to ask is, what's the gong attached to? If the answer is nothing, then hitting it will cause it to move away from the blow of the hammer when hit. It will continue in motion until something acts upon it to change it's motion (inertia). On the other hand, let's assume it's attached to something with significant mass. It will still move away from the hammer, but the kinetic energy sent into it by the hammer will be distributed amongst the greater mass, making the reactive motion less (as measured in speed) by that ratio. Along those lines, that energy will transfer across the entire mass until it equalizes, but the kinetic energy will stay in the object until something else comes in contact with it for that energy to transfer into.

Ultimately, the vibrating will probably slowly transfer into more of a linear and rotational movement, as the energy distributes itself out into the entire mass.

There's no reason that this process would make the object more susceptable to breakage, however.

Eric

Stooch
11-21-2008, 03:37 PM
Is there a site that would explain what would happen to a human if on another planet without a suit. I like science facts like that. I've always wondered how long a person would last if they took a deep breath on Mars. Is it toxic or the fact that there is only 3 percent oxygen and I'm not even sure about that fact.

the person would get asphyxiated pretty quickly. on some planets your tissues would melt due to acids, on some you would get crushed by the atmospheric pressure alone. for example jupiter is all gas, if you were to go "sea level" equivalent of earth, you would experience an effect similar to being at the bottom of our ocean (the sound will get transmitted nicely, on the plus side). you would need a little bit more than a suit to survive there.

then there is the huge and constant electrical activity, causing almost non stop arcing. then there are the hot or cold planets. mars for example will give you frostbite almost instantly. while some planets are the opposite, its like stepping into an oven. basically its a whole cournicopia of ways to die.

dont even get me started on unshielded planets that are bombarded with high energy radiation. an atmosphere with a working magnetic field is too easy to take for granted. Without one, we would be obliteraded by the solar wind annually.

hrgiger
11-21-2008, 06:28 PM
Your eyes would bug out of your heads and you would convulse terribly. In fact, you would look like you were some kind of animatronic doll. But you would return to normal as soon as oxygen was returned with no adverse side effects. Didn't you guys watch the end of total recall, geesh?

cresshead
11-21-2008, 06:38 PM
totall recall....yeah i must pick that up on DVD...was a fun film...love the line
'consider that a divorce'

cresshead
11-21-2008, 06:48 PM
if you were on>

1. Venus you'd be listening to your Skin cooking!...plenty of atmosphere on venus but it's 400deg C...ie like a hot gas oven..has nr same gravity as earth.

2.on titan [moon that orbit's around saturn] when they dropped the probe
they also recorded sounds from titan on the way down...titan has a thick atmosphere so you CAN hear sounds..it is rather chilly though at around
- 150dec C ...it's 10% gravity of earth

3.on mars the atmosphere is around 1% of the earth's pressure so VERY thin and also pretty cold..much colder than the earth's antarctic in their winter
but can get up to 27deg c and coldest at -143deg c

virtualcomposer
11-21-2008, 06:53 PM
So if it was that cold on mars then hitting a rock should shatter it and everything would be brittle right? Also I thought nothing got colder then absolute zero.

cresshead
11-21-2008, 06:58 PM
So if it was that cold on mars then hitting a rock should shatter it and everything would be brittle right? Also I thought nothing got colder then absolute zero.

yeah to understand what absolute zero is in simple terms it's when atoms stop moving...

it is absolute and is −273.15 C.

virtualcomposer
11-21-2008, 07:02 PM
So is space absolute zero? If so how do space ships and suits keep from freezing?

Jarno
11-21-2008, 07:04 PM
Rocks tend to be solid, so they don't change in any way when frozen, because they can't freeze in the first place. So no, just because a rock is cold does not make it shatter more easily. Organic material with a significant liquid component which does freeze however are a different story.

And nothing gets colder than absolute zero. Absolute zero is -273.15 degrees Centigrade, or -459.67 Fahrenheit.

---JvdL---

cresshead
11-21-2008, 07:17 PM
So is space absolute zero? If so how do space ships and suits keep from freezing?

it depends WHERE in space you are...

a thing to keep in mind is that SOUND needs something to transmit thru...like an atmosphere/wood/metal...

HEAT on the other hand can be transmitted in a vaccum like in space...we 'the earth' get all our heat from the light coming from the sun which is our nearest star at over 90+million miles from the earth and has 'space' to transmit that heat/light toward us...

'light' get a bit complicated to explain what exactly it is.....as it can be understood as particles or a waveform....

IMI
11-21-2008, 07:56 PM
Light is heat and heat is light. It's all part of the electromagnetic spectrum, of which only a small portion is considered visible. Visible to human eyes, that is.

I've always been under the assumption that because of that, all the wavelengths of the electromagnetic spectrum behave as light.

Or is that wrong? Wavelength aside, is there any physical difference between a gamma particle and a visible photon?

ericsmith
11-21-2008, 08:00 PM
HEAT on the other hand can be transmitted in a vaccum like in space...we 'the earth' get all our heat from the light coming from the sun which is our nearest star at over 90+million miles from the earth and has 'space' to transmit that heat/light toward us...

This point is quite obviously true, but it does make me scratch my head. I remember learning in chemistry that heat is basically defined as atoms vibrating.

I always figured that energy from the sun came in the form of light (photon particles) and radiation (also particles).

But the fact is, things in space tend to freeze, so obviously, the heat is dissapating into the void. I'm very curious to understand the mechanics of that now.

I guess my high school education wasn't completely on point in other areas as well. I remember quite clearly being told that zero kelvin (absolute zero) was somewhere around -2200 F. But that's not what I'm finding after a quick google search.

Makes ya' go hmm....

Eric

IMI
11-21-2008, 08:08 PM
This point is quite obviously true, but it does make me scratch my head. I remember learning in chemistry that heat is basically defined as atoms vibrating.

I always figured that energy from the sun came in the form of light (photon particles) and radiation (also particles).

But the fact is, things in space tend to freeze, so obviously, the heat is dissapating into the void. I'm very curious to understand the mechanics of that now.

I guess my high school education wasn't completely on point in other areas as well. I remember quite clearly being told that zero kelvin (absolute zero) was somewhere around -2200 F. But that's not what I'm finding after a quick google search.

Makes ya' go hmm....

Eric

Heat can be created by friction - that's one way. But consider simply standing in the sunlight. It's warm, but no friction causing it. It's heat energy which is a part of the electromagnetic spectrum you're feeling. You would see it with an infrared camera.

As for the light cooling as it travels, it's just getting dissipated. Far as I know, none of those particles or waves ever actually "burn out", just get so far spread apart their effects are little to nothing. And considering our universe's "edges" are defined by that very expansion of light, it lends credibility to the theory that it is always expanding, and light never goes away once "created".

I think I remember reading once that absolute zero is a physical impossibility, as absolute zero is the point where all motion stops. I think there are places in the universe very close to absolute zero, but I don't think they've proved it's anything more than a theory, and used as a "starting point" for the Kelvin scale more than anything.

TripD
11-21-2008, 08:24 PM
Light is heat and heat is light. It's all part of the electromagnetic spectrum, of which only a small portion is considered visible. Visible to human eyes, that is.

I've always been under the assumption that because of that, all the wavelengths of the electromagnetic spectrum behave as light.

Or is that wrong? Wavelength aside, is there any physical difference between a gamma particle and a visible photon?

Just the amount of energy within it.

TripD
11-21-2008, 08:28 PM
Some interesting tidbits about heat. 3 ways it can be transmitted:

Radiation, conduction and convection. The ability of an substance to conduct heat makes a big practical difference to us. You can peek into your mom's oven and poke the cake she is baking without any harm... if your quick.
But don't even think of touching the metal rack. Both are at the same temperature, but the metal conducts it's heat waaaaay faster!

ericsmith
11-21-2008, 09:17 PM
Heat can be created by friction - that's one way. But consider simply standing in the sunlight. It's warm, but no friction causing it. It's heat energy which is a part of the electromagnetic spectrum you're feeling. You would see it with an infrared camera.

Well, that doesn't quite answer it though. Light is particles (photons), so heat could be created by one particle striking another. Also, the sun is basically just a huge ball of heavy radioactive material, so it's spewing out fissioned protons, or neutrons, or something like that. I'm not that savvy with nuclear physics, but I know that heavy metals like Uranium or Plutonium tend to fissure into lead, and there is a release of a spare proton or something like that. So ultimately, nuclear radiation is another way that energy can dissapate via a particle.

But if you have a warm body in an empty space, what kind of particles are emitted that dissapate heat? If heat is indeed the vibration of atoms, how is that vibration transfered away from the body if there is nothing to transfer it to?

I wonder if perhaps inert forms don't dissapate heat in space, but only organic, because moisture and gas is expelled or something.

If someone has a clearer picture on the actual mechanics of heat (ie. am I wrong about the whole "vibrating atom" thing) and therefore it's dissapation in a vaccum, I'm curious to know.

Eric

ericsmith
11-21-2008, 09:30 PM
Okay, after a bit of research, I think I get it. As long as wikipedia can be trusted, that is...

All mass that is not at a temperature of absolute zero radiates electromagnetic energy. And light is simply a form of electromagnetic energy that occilates within a certain frequency range. But photons are emitted in any electromagnetic energy, whether it lies within the range classified as "light" or not.

So the bottom line is, any mass that contains heat emitts photons, whether visible or not.

That sounds logical, at least up to the point where they say that a photon is a particle that has no mass, and exhibits wave–particle duality. I'm not sure how to wrap my head around that one.

Eric

Riff_Masteroff
11-21-2008, 10:52 PM
'sounds' like some here have been watching far too many hollywood movies

In fact sound can and is transmitted through 'empty' space. I have read that in Scientific American. Check this URL for reference:

http://www.space.com/scienceastronomy/mystery_monday_030922.html

JeffrySG
11-21-2008, 11:26 PM
If you want to see some great Science lectures from an MIT professor, head on over to:
http://ocw.mit.edu/OcwWeb/Physics/8-01Physics-IFall1999/VideoLectures/index.htm
Very cool teacher, with a ton of hands on examples.

Some other links too:
http://web.mit.edu/physics/facultyandstaff/faculty/walter_lewin.html

this was a great one on sound...
http://mitworld.mit.edu/video/168/

SplineGod
11-22-2008, 02:32 AM
Is there a site that would explain what would happen to a human if on another planet without a suit. I like science facts like that. I've always wondered how long a person would last if they took a deep breath on Mars. Is it toxic or the fact that there is only 3 percent oxygen and I'm not even sure about that fact.

You would be eaten by hostile aliens.
You would also be very unlikey to take a deep breath on mars period. :)

cresshead
11-22-2008, 06:48 AM
You would be eaten by hostile aliens.
You would also be very unlikey to take a deep breath on mars period. :)

i wouldn't call the chinese 'hostile aliens'...:D

they're more probably going to be the first on mars from earth as the u.s.a. seems to be pulling back on spending money for exploring our solar system...

can you imagine the day the chinese flag is planted on mars and the usa is kicking it's heals in the dirt back on earth?

i think the second space race [to the moon and then mars] will find the usa on it's back foot as china can 'afford' to push
without any concern for the people's thoughts on 'spending'

biliousfrog
11-22-2008, 07:48 AM
i wouldn't call the chinese 'hostile aliens'...:D

they're more probably going to be the first on mars from earth as the u.s.a. seems to be pulling back on spending money for exploring our solar system...

can you imagine the day the chinese flag is planted on mars and the usa is kicking it's heals in the dirt back on earth?

i think the second space race [to the moon and then mars] will find the usa on it's back foot as china can 'afford' to push
without any concern for the people's thoughts on 'spending'

Their flag would fit nicely on the planets surface, red and stars...quite suitable me thinks :D

You'd need to watch out for mini-sasquatch...or are they sand-people?
http://www.planetary.org/blog/article/00001305/

IMI
11-22-2008, 08:00 AM
Good. Let China go to Mars first. Let them spend the money to terraform it for the rest of us. ;)

cresshead
11-22-2008, 08:41 AM
hey wouldn't care too much on 'who' as long as someone gets there before 2050!

Matt
11-22-2008, 09:11 AM
Not Mars, but Jupiter

http://www.youtube.com/watch?v=e3fqE01YYWs

IMI
11-22-2008, 09:15 AM
hey wouldn't care too much on 'who' as long as someone gets there before 2050!

Why? Just to say we did it? Maybe I'm missing something, but Mars just doesn't do it for me. I'm more into the idea of exploring Jupiter's moons than stupid ol' Mars. ;)

cresshead
11-22-2008, 09:29 AM
mars is the most 'habitable' for a human colony...as it has water and used to have oceans of water...
a great place to start a human colony...expanding our race outward from earth.

well here's my top destinaions for extended/new exploration>>

titan> go back and have a balloon fly over it and have a few probes/landers/rovers poke about this truly amazing moon.
europa> probe to land on it and maybe a probe to swim in it's ice covered ocean
mars> people on it...make a permanent base/colony
moon> permantent manned base/colony..we should be there now not floating 200 miles above the earth.
mercury> lander/rover on the sun/night boarder
venus> have a few moore robust landers head there.
saturn>...that planet and it's moons are very enticing..more so than jupeter for me a jupiter is so hostile a place with it's huge radiation output from the planet that can knock out probes near it.

also i'm waiting for the probes sent out to Vesta and Ceres..love to see what the're all about with some hi res imaging as the probes fly by.

IMI
11-22-2008, 09:42 AM
Ah, I see. You're more of a Let's-colonize-and-expand kind-of-guy.
I'm not real concerned about that, since I kinda like it here just fine. ;)
I'm more interested in exploring the more hostile places anyway - places which might have more of that weird quantum stuff going on, places with serious extremes.
Titan, though, I agree with. Stephen Baxter wrote a great fiction about traveling to the place I read a few years ago.

Stooch
11-22-2008, 03:06 PM
http://www.youtube.com/watch?v=m5lnavfxZWo&feature=related