60 Minute Question : Saturns Rings

Last night on the 60 Minutes segment on the Huygens mission, the
scientist in charge of imaging stated that the age of Saturns rings was
roughly 100 million years old and that they did not exist during the
age of the dinosaurs. How did we come to this knowledge? Have we done
any sampling of the rings and carbon dated them, or is this a SWAG on
her part?

BTW: SWAG = Scientific Wild A$$ Guess

Just curious

Matt

On 20 Jan 2005 10:23:20 -0800, wrote:

Last night on the 60 Minutes segment on the Huygens mission, the
scientist in charge of imaging stated that the age of Saturns rings was
roughly 100 million years old and that they did not exist during the
age of the dinosaurs. How did we come to this knowledge? Have we done
any sampling of the rings and carbon dated them, or is this a SWAG on
her part?

BTW: SWAG = Scientific Wild A$$ Guess

Neither by direct measurement, nor wild guessing. Ring systems are now thought
(by modeling) to be relatively unstable. Their presence depends on a variety of
factors, particularly gravitational resonances with moons.

I'm pretty sure that what was meant was that the ring system in anything like
its present form is relatively recent. There was probably a much less impressive
system in place for much longer.

BTW, 100 million years ago _was_ the age of dinosaurs, so I don't know what that
means to say the rings didn't exist then.

_________________________________________________

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

They seemed to imply (again this IS 60 Minutes) that the rings were
formed from a moon or comet that was captured and ripped apart in the
last 100 million years. As far as the timeline, she did state that
rings were NOT present during the age of the dinosaurs, but she may
have stated that the rings were LESS than 100 million years old. I just
thought I may have been unaware of a carbon dating experiment on
particles from the rings that was part of the Cassini mission. Of
course the imagination went wild with how one would accomplish this. Oh
well.

As far as modeling goes, how accurate are computer simulations in this
regard? What is their margin for error in creating a reverse timeline
from present day data?

On 20 Jan 2005 11:28:21 -0800, wrote:

They seemed to imply (again this IS 60 Minutes) that the rings were
formed from a moon or comet that was captured and ripped apart in the
last 100 million years. As far as the timeline, she did state that
rings were NOT present during the age of the dinosaurs, but she may
have stated that the rings were LESS than 100 million years old. I just
thought I may have been unaware of a carbon dating experiment on
particles from the rings that was part of the Cassini mission. Of
course the imagination went wild with how one would accomplish this. Oh
well.

As far as modeling goes, how accurate are computer simulations in this
regard? What is their margin for error in creating a reverse timeline
from present day data?

AFAIK the current thinking is that rings are formed from the breakup or
collisions of moons. Any given system is only stable over 100 million years or
so (not over billions of years).

I think the models are quite good at producing the features we see. I don't know
what the actual errors are. The point I'd take from this is that in terms of the
age of the Solar System, Saturn's ring system is fairly recent. Whether that
means 50 million years or 200 million I don't know, but it is a pretty safe bet
that it wasn't there a billion years ago.

_________________________________________________

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

wrote:
They seemed to imply (again this IS 60 Minutes) that the rings were
formed from a moon or comet that was captured and ripped apart in the
last 100 million years. As far as the timeline, she did state that
rings were NOT present during the age of the dinosaurs, but she may
have stated that the rings were LESS than 100 million years old.

My limited understanding of scientists' current hypotheses of how rings
are formed and maintained around gas giants is that it is a dynamic
process. The rings around gas giants are continually diminshing in
size due to the accretion of small particles into the interplanetary
solar system ecliptic. Small particles in the ring are accelerated
into the interplanetary ecliptic by centrifugal rotational forces.

The rings would dissipate in relatively short geologic periods, if they
are not renewed with new matter. The working hypothesis is that the
rings do not dissappear because they are continually renewed by the gas
giants capturing Kupier Belt objects. These small planetiods either
collide with each other, are ripped apart by tidal forces, or are
struck by inbound comets. The small fragments of the collisions then
renew the rings.

Colwell's 1994 computer simulations of ring structure suggest that the
materials in the rings may not be so old as the rings themselves, due
to this dynamic renewal process.

As far as modeling goes, how accurate are computer simulations in
this
regard?

This one I don't know.

I'll defer to Chris on whether stable rings have been present around
Saturn from most of the solar system's lifetime (due to continual
dynamic renewal) or whether they are more recent addition (on a
geologic time scale) to Saturn with a lifetime much shorter than the
life-time of the solar system.

My speculative guess would be (considering the relatively faint rings
around the other gas giants, Jupiter, Neptune and Uranus) that during
recent geologic times, rings around gas giants dissipate and are then
are recreated by newly captured Kupier Belt objects. The Kupier Belt
objects are flung inward when the solar system passes nearby stars or
tranverses large dark molecular clouds.

Enjoy - Canopus56

Colwell, J. E. (Dec. 1994) The disruption of planetary satellites and
the creation of planetary rings
Planetary and Space Science (ISSN 0032-0633), vol. 42, no. 12, p.
1139-1149
Bibcode: 1994P&SS...42.1139C
http://adsabs.harvard.edu/cgi-bin/np...6SS...42.1139C

Chapman, C. R.; Davis, D. R.; Weidenschilling, S. J.; Greenberg, R.
(Jan. 1983). Tidal Effects on Saturn Ring Particles: Implications for
Ring Evolution. LUNAR AND PLANETARY SCIENCE XIV, P. 95-96. Abstract.
Bibcode: 1983LPI....14...95C
http://adsabs.harvard.edu/cgi-bin/np...PI....14...95C

Canup, Robin M.; Esposito, Larry W. (March 1997). Evolution of the G
Ring and the Population of Macroscopic Ring Particles. Icarus, Volume
126, Issue 1, pp. 28-41.
http://adsabs.harvard.edu/cgi-bin/np...car..126...28C

On 20 Jan 2005 12:19:10 -0800, "canopus56" wrote:

I'll defer to Chris on whether stable rings have been present around
Saturn from most of the solar system's lifetime (due to continual
dynamic renewal) or whether they are more recent addition (on a
geologic time scale) to Saturn with a lifetime much shorter than the
life-time of the solar system.

My speculative guess would be (considering the relatively faint rings
around the other gas giants, Jupiter, Neptune and Uranus) that during
recent geologic times, rings around gas giants dissipate and are then
are recreated by newly captured Kupier Belt objects. The Kupier Belt
objects are flung inward when the solar system passes nearby stars or
tranverses large dark molecular clouds.

That's my understanding. The evidence would suggest that ring systems around gas
giants are common, and have probably been there for a long time. What is
interesting is that Saturn has such a large and complex system compared to the
other planets. I think it is this that is recent, and which probably won't
survive for more than a few tens or hundreds of millions of years. But it's a
good bet that some sort of ring system is going to be around for as long as
there is material to replenish it.

_________________________________________________

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

canopus56 wrote:
wrote:
They seemed to imply (again this IS 60 Minutes) that the rings were
formed from a moon or comet that was captured and ripped apart in
the
last 100 million years. As far as the timeline, she did state that
rings were NOT present during the age of the dinosaurs, but she may
have stated that the rings were LESS than 100 million years old.

The following science news excerpt also may be of interest:

Sci. Am. Science News. Dec. 20, 2004. Cassini Reports on an Evolving
Saturn.
http://www.sciam.com/article.cfm?cha...0483414B7FFE9F

"Larry W. Esposito of the University of Colorado at Boulder and his
colleagues employed the ultraviolet imaging spectrometer (UVIS) onboard
Cassini to measure the amount of hydrogen and oxygen present in the
Saturnian system. 'The evidence indicates that in the last 10 million
to 100 million years, fresh material probably was added to the ring
system,' Esposito says."

This would seem to imply that the rings were present during the upper
(65 to 98 million years ago) and possibly middle-lower Cretaceous
(99-144 million years ago), a time when dinosaurs were present.
- Canopus56

On 20 Jan 2005 10:23:20 -0800, wrote:

Last night on the 60 Minutes segment on the Huygens mission, the
scientist in charge of imaging stated that the age of Saturns rings was
roughly 100 million years old and that they did not exist during the
age of the dinosaurs. How did we come to this knowledge? Have we done
any sampling of the rings and carbon dated them, or is this a SWAG on
her part?

I can't comment on the age of Saturn's rings but I did want to make a
clarification about carbon dating. Carbon dating can only date things
back to about 50,000 years and then only things that were once alive,
on Earth, and then only those things that took carbon into their
system either directly (plants) or indirectly (eating plants). I
bring this up because most people know that there is a techinque
called "radiocarbon dating" that can be used to establish the age of
things. But very few people seem to understand how or why it works
and what its limitations are. More information can be found he

http://hyperphysics.phy-astr.gsu.edu...ar/cardat.html

There are other radioisotope dating methods as well which are suitable
for establishing dates of other things (ancient lavas for instance).
There may be one or more that would be suitable for Saturn's ring
material, I don't know. Radiocarbon is not the one though :-)

Hi Chris
I'm sure you know but for the others benifit, carbon
dating is only useful for organic molecules formed
in the earths atmosphere.
We have neither the reference point from the rings
to date against nor the nitrogen atmophere to create
the C14 from.
The concept of carbon dating on Titan has some possibilities
since the carbon mixtures are created in the atmosphere.
Still the half life of C14 might not be all that useful there
because I suspect the rate of change is too slow.
Just some thoughts.
Dwight

On 20 Jan 2005 17:21:03 -0800, wrote:

Hi Chris
I'm sure you know but for the others benifit, carbon
dating is only useful for organic molecules formed
in the earths atmosphere...

But there are many other radioisotope dating methods that _are_ suitable for
dating material such as might be encountered in Saturn's rings. All these
methods operate on the same basic principle as radiocarbon dating- that is,
measuring the ratio(s) between two or more isotopic species with different
half-lives. Of course, the mechanism that sets the initial ratio changes from
method to method. In the case of radiocarbon dating, it is the death of the
organism that starts the clock ticking- obviously not very useful for dating
rocks!

_________________________________________________

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