Could a human walk on Titan's surface?

Allison Kirkpatrick wrote:
What about on Mars, without a spacesuit?

Warmest temperatures on Mars are something like +40F (+4C) as I recall.
Could a human at one of these warm locations take a big gulp of air
inside the spaceship and run outside holding his breath for a few
seconds, then run back inside, without getting killed? Assuming no dust
storms, volcanoes, etc. are in progress at the time, of course. What
would kill him, if anything?

For a few seconds, probably. The atmospheric pressure, even down in
the canyons, is pretty low--on the order of 10 or 20 millibars, as I
recall. But even so, it doesn't seem that it could be worse than
exposure to space in LEO. While I wouldn't risk it with any other
alternative, it seems likely that if need be, a human could withstand
several seconds of exposure to such conditions.

The things I'd be worried about would be lack of atmospheric pressure
and oxygen, rather than temperature. Obviously, a human being could
withstand 40 F temperatures for a long time, even clothed ordinarily.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

wrote:
What about on Mars, without a spacesuit?

Warmest temperatures on Mars are something like +40F (+4C) as I recall.
Could a human at one of these warm locations take a big gulp of air
inside the spaceship and run outside holding his breath for a few
seconds, then run back inside, without getting killed? Assuming no dust
storms, volcanoes, etc. are in progress at the time, of course. What
would kill him, if anything?

Didn't you see "Mars Attacks"?
Seriously (not!) I'd just complain to the newspaper company. Tell the
boy to get it closer to the porch. :-)

Don't exhale. At that pressure, you would lose O2 from your blood
through your lungs. You'd pass out faster trying to breath than you
would if you held even a small amount of air in your lungs.

Shawn

"Szaki" wrote in message
...
-290F deg? Not very long, if Huygens survived only a few hours.
JS

True, not just cold, but contact to draw off heat. Being in a cold near
vacuum is one thing. Being in contact with cold air/liquid/solids makes it a
lot harder to maintain your heat.

Clear Skies

Chuck Taylor
Do you observe the moon?
Try http://groups.yahoo.com/group/lunar-observing/

Are you interested in understanding optics?
Try http://groups.yahoo.com/group/ATM_Optics_Software/

************************************


"RichA" wrote in message
...
Given current spacesuit technology, how long
could a person survive on the surface
of that moon?
-Rich

Brian Tung wrote:

For a few seconds, probably. The atmospheric pressure, even down in
the canyons, is pretty low--on the order of 10 or 20 millibars, as I
recall. But even so, it doesn't seem that it could be worse than
exposure to space in LEO. While I wouldn't risk it with any other
alternative, it seems likely that if need be, a human could withstand
several seconds of exposure to such conditions.

The things I'd be worried about would be lack of atmospheric pressure
and oxygen, rather than temperature. Obviously, a human being could
withstand 40 F temperatures for a long time, even clothed ordinarily.

I got the impression the OP was asking whether it was physically
possible to stand on the surface of Titan. IOW- Would it support a man's
weight. I heard recently that the surface is thought to be spongy.

Martin Brown wrote:
Brian Tung wrote:

Michael Barlow wrote:

I brought and read many books to work all relating to the different
sciences of astronomy and physics and someone asked a question about space,
I don't recall the specific question but it mentioned the vacuum of space.

You're both right--just in different ways.

Although, strictly speaking, space is not a vacuum, it is a hell of a
lot emptier than what we consider a very hard vacuum here on the Earth.
Interstellar space density is on the order of atoms per tens of cc.
Even in the solar system, it's on the order of atoms or perhaps tens
of atoms per cc. We cannot, as far as I know, achieve such vacuums with
our current technology.

We can, but not for very long. I was surprised to see how much the very
best terrestrial vacuum had improved since I was last involved.

Apparently itis now of the order of 1000 atoms/cm^3 or about what you
get in orbit 1000km above the Earth's surface. 10^10 atoms/cm^3 was
bleeding edge terrestrial hard vacuum not all that long ago (and is
still good enough for most production semicon chip lines).

I'm also impressed. That's close to the density of the emitting regions
in many emission nebulae and galactic nuclei. Who'd have thought?
Now to work out how big a tank of that almost-nothing it would take
to produce detectable [O III] emission. Cue the quotation from
Asimov's _Currents of Space_ about the loose grip on sanity held
by anyone who spends time studying material which is so
nearly nothing...

Bill Keel

It would be very cold there and you would need an extra heavy coat.

"starman" wrote in message
...
Brian Tung wrote:

For a few seconds, probably. The atmospheric pressure, even down in
the canyons, is pretty low--on the order of 10 or 20 millibars, as I
recall. But even so, it doesn't seem that it could be worse than
exposure to space in LEO. While I wouldn't risk it with any other
alternative, it seems likely that if need be, a human could withstand
several seconds of exposure to such conditions.

The things I'd be worried about would be lack of atmospheric pressure
and oxygen, rather than temperature. Obviously, a human being could
withstand 40 F temperatures for a long time, even clothed ordinarily.

I got the impression the OP was asking whether it was physically
possible to stand on the surface of Titan. IOW- Would it support a man's
weight. I heard recently that the surface is thought to be spongy.

Saturn, and therefore Titan, are about 10 astronomical units away
from the Sun. They
therefore get about 1 percent of the light that the Earth does.

I've often wondered how a very small percentage of broad daylight (like
1%) could still be some thousands of times brighter than a night
illuminated by a full Moon. Just today it occurred to me that the
constriction of our pupils in daylight gives us a very false sense of
how bright the day really is. We've all experienced walking out of the
eye doctor's office after having our pupils dilated. That's how bright
the sun really is, *painfully bright*.

Out on Titan, our pupils would simply dilate appropriately in that
dimmer "daylight" to let us see better. They would probably still not
dilate to the full 6-7 mm that they do at night; if they did, even the
relatively small amount of sunlight at that distance could be painful!
Cheers,
Ritesh

On 20 Jan 2005 13:25:02 -0800, "Axel" wrote:

Saturn, and therefore Titan, are about 10 astronomical units away
from the Sun. They
therefore get about 1 percent of the light that the Earth does.

I've often wondered how a very small percentage of broad daylight (like
1%) could still be some thousands of times brighter than a night
illuminated by a full Moon. Just today it occurred to me that the
constriction of our pupils in daylight gives us a very false sense of
how bright the day really is. We've all experienced walking out of the
eye doctor's office after having our pupils dilated. That's how bright
the sun really is, *painfully bright*.

Out on Titan, our pupils would simply dilate appropriately in that
dimmer "daylight" to let us see better. They would probably still not
dilate to the full 6-7 mm that they do at night; if they did, even the
relatively small amount of sunlight at that distance could be painful!
Cheers,
Ritesh

Most of our ability to deal with varying brightness comes from the retina, not
the pupil. In most people, the full range of pupil size only accommodates a
factor of about 10 in brightness- not even 3 magnitudes. People with problems
that cause permanently dilated pupils actually don't have any major problems
with full sunlight.

BTW, the numbers Brian is talking about are absolute- that is, he isn't talking
about perceived brightness, but actual brightness as it would be measured with a
light meter.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Chris L Peterson wrote:
BTW, the numbers Brian is talking about are absolute- that is, he
isn't talking about perceived brightness, but actual brightness as it
would be measured with a light meter.

That's right. Ritesh, as far as I could tell, was wondering, with the
absolute numbers as far apart as they are, how the Titan daytime sky
could possibly be bright enough to see by. It really is surprising to
me sometimes how great the eye's dynamic range is, when you include the
visual processing system. It's rather remarkable.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

I guess we're making too much of a problem from Titan's -180=B0C...
Look, people survived in Antarctic -80=B0C, which is already 105=B0C
below human normal. It may well be possible to enhance an arctic suit
for such needs, maybe with some simple heating. There's definitely no
use resorting to full-scale space-suits. Atmospheric pressure on Titan
is 1.6 bar (that is 60% higher that on Earth), so it will only be
necessary to add oxygen baloons and a breathing mask. All parts of the
body should surely be covered, but there's no danger of being exposed
to space vacuum or really bad poison gases. Titanian suit should be far
more effecient and long-lasting and much cheaper than all those suits
used in moonwalks etc.