Titan exploration

[rlb2]

<font color="orange">Now you would have the opportunity for tidal warming of both the hypothetical earth-like moon, and Titan! Two warm moons orbiting Saturn - now that would be something.<font color="white"><br /><br />Great deduction. Terraforming Titan by changing its orbit. Now thats a good introduction to start another thread. If they don't find any vocanoes there then when do we start. <br /><br />See you there.<br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[remcook]

rlb2: why would Earth steal some atmosphere from Saturn in the Titan position? Why isn't the moon stealing atmosphere from the Earth?

 

[rlb2]

<font color="orange">Why isn't the moon stealing atmosphere from the Earth? <font color="white"><br /><br />There are several reasons. First and most important is that the moon is to close to the sun to retain any atmosphere, because its gravitational field is to week to hold even CO2 because the kinetic energy of the heated gas is faster than escape velocity of the moon. The second reason is that the moon never had a global magnetic field therefore it couldn’t prevent the solar wind and Earths magnetosphere from stripping it away. The moon was over 5 time’s larger (diameter) in the night sky after it was formed because it was much closer to Earth then. It is currently receding away from us and may leave Earths gravitational pull within another billion years. <br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[remcook]

those are all reasons why the moon cannot retain an atmosphere. But why isn't the moon stripping away some of the Earth's atmosphere? Or is it? <br /><br />Could you explain your hypothesis again about the stripping of atmospheres due to tidal interactions? Do you have any references or examples?<br /><br />And what does density have to do with it?

 

[rlb2]

This is a long winded reply to your questions.<br /> <br />Where to begin. <br /><br />Let me begin by saying after studying this question a bit I have come to the conclusion of – poor baron Earth if its present size was to become a victim of being placed around any one of the gas giants in our solar system. The only hope Earth would have of growing is to steal the ring material away from Saturn, then its atmosphere. At Titans distance from Saturn the only hope of doing this is by tidal forces. If Earth was much closer in to Saturn then there could be an interesting interaction between the two competing bodies.<br /> <br />If the Earth was a satellite of Saturn unless it takes enough mass away from Saturn then it may never become a threat. Titans distance from Saturn is over 1,200,000 kilometers. The earth gravitational reach, counteracting Saturn’ would be approximately 100,000 kilometer, anything in this range would be drawn towards the Earth but may not necessarily end up in Earths orbit. This is small compared to Saturn because it’s a spherical property, gravitations inverse square law, if two objects have the same gravitational pull at there surface then the larger diameter spherical object would win out. This is true with Saturn. I first made a blunder by just looking at the gravity when the gravity for both was taken from there respective surfaces, that’s not right to assume. Don’t know exactly where Saturn’s is, but its spherical radius is approximately ten times larger than Earths. In other words if Saturn’s mass was condensed down to what Earths diameter was then its surface gravity would be approximately 100 times more than Earth, (10^2). Because Saturn’s mass is spread out more it has a much larger affect on the fabric of space time. <br /><br />It’s a combination of factors that could add to the mass of the Earth.<br /><br />One is any free gas within its reach would be free for earth to take. Its colder at Saturn’ distance from the sun, so Earth can retain hydr <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[remcook]

"Because Saturn’s mass is spread out more it has a much larger affect on the fabric of space time. "<br /><br />Outside Saturn, Saturn's gravity field is the same, whether it would have been the size of the Earth or not. Even better, Saturn can be modelled by a mass of no size (a point source). For distance larger than Saturn's radius, this point source has the same effect as Saturn itself (assuming Saturn is spherical).<br /><br />"<br />At one time Titan may have been a smaller version of a gas giant. Who knows what we may be seeing of Titan is the remnants of a dieing gas giant. What we may find on the surface is to a lesser extent, what may be at the core of these other gas giants……… "<br /><br />I wonder if you'd find anyone who would agree on this <img src="/images/icons/wink.gif" />

 

[titanian]

On that point, I noted that the density of Neptune for instance, supposed to be a gas giant was quite the same as the density of numerous satellites in the outer solar system.<br />Now, there would be a huge and deep atmospheric layer on those gas giants.That implies that the interior is much denser so that the global density of the gas giant is over 1 g /cm3.

 

[remcook]

good point. Titan's mean density is only 3 times as large as Saturn's and 4 times as small as the Earth's. If you would strips a gas giant from its light atmosphere, the density would be much larger than Titan's.

 

[alokmohan]

Double KBO we should say.

 

[rlb2]

<font color="orange">I wonder if you'd find anyone who would agree on this <font color="white"><br /><br />I don't know, right now I know of one person who does, unless he finds something else to changes his mind.<br /><br />I think out loud before I reach a conclusion that I care to backup, when free to do so. This is called brainstorming, loosely getting ideas on how to solve a problem. This is a good place to do that, we don't have to worry about our reputation or credentials interfering with the process of extracting out what you think the truth is. This is how great discoveries are made.<br /><br />Here is a just released article from space.com about the two gas giants, Jupiter and Saturn and how they have different cores. It kind of fits into our discussions here. <br /><br /> http://space.com/scienceastronomy/planet_formation_040720.html</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

<font color="orange">That implies that the interior is much denser so that the global density of the gas giant is over 1 g /cm3.<font color="white"><br /><br />Density of water is 1 g / cm3 at 39.2 f. Density of Ice is less than water that’s why it floats, however after 0 f the density of water ice goes up the colder it gets. Saturn and Jupiter is made mostly of hydrogen.<br /><br /> Here is the run down of the planets mean density.<br /><br />Mercury 5.4<br />Venus 5.3<br />Earth 5.5<br />Mars 3.9<br />Jupiter 1.3 may not have a rocky core<br />Saturn 0.7 has a rocky core<br />Uranus 1.2 has a molten rocky core <br />Neptune 1.56 has a molten rocky core<br />Pluto 0.7 to 0.8 not completely known. <br /><br /><br />A density example of our planets, to get a point across only, is the old instructional example of how Saturn’s density was so low at 0.7 g/ cm3 that if you found a body of water large enough Saturn would float in it. I wouldn't use that as an instructional tool myself because they are so many other factors to consider in that example but it helps make a point.<br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

<font color="orange">Outside Saturn, Saturn's gravity field is the same, whether it would have been the size of the Earth or not. Even better, Saturn can be modelled by a mass of no size (a point source). <font color="white"><br /><br />Classical physics inverse square law uses spherical definitions of forces such as gravity and atmospheric pressure. If you use a point source, center of gravity, then you would need to consider that if Saturn’s volume was compressed down to the same diameter as Earths its gravitational field would be approximately 100 times stronger than Earths is at its surface.<br /><br />If two gravitational fields are the same on there surface the larger volume mass gravitation would dissipate less than the smaller one, as a result can extend farther out. Saturn’s pull on Earth at Titans distance from its surface is approximately 1/400 of Saturn’s gravitational field. On the other hand Earths pull on Saturn at the same distance would be approximately 1/36,000 of its surface gravitational field. <br /><br />This means that if Earth still had its oceans the pull on it from Saturn is so great that the ocean tides would move across most of its land mass.<br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[remcook]

tidal forces are not a consequence of only the direct pull of gravity at the surface. The tidal acceleration is caused by the difference in pull between the surface and the acceleration of the centre of mass of the planet (the Earth in this case):<br /><br />http://csep10.phys.utk.edu/astr161/lect/time/tides.html<br /><br />on the same note...the Moon is more accelerated by the Sun than by the Earth! (TRY IT!)

 

[remcook]

"If you use a point source, center of gravity, then you would need to consider that if Saturn’s volume was compressed down to the same diameter as Earths its gravitational field would be approximately 100 times stronger than Earths is at its surface. " <br /><br />Why would you want to compress Saturn to the size of the Earth? If you would do that, indeed the surface gravity would be larger. But what is the relevance to the discussion?

 

[alokmohan]

I also dont understand why he is after poor saturn and compress it for nothing.

 

[titanian]

Like every genius, you can have sometimes surprising reasoning.I have another question in that gender: what would be the size of a tellurian planet having the same density as Earth and the same mass as Saturn?<br />If rlb2 says that Titan could be the remnant of a gas giant of which a big part of the atmosphere has been stolen by Saturn, that means Saturn could have an internal structure similar to the internal structure of satellites orbiting around it.The core would have a density about 2 g / cm3 and we could postulate by deduction how deep is the Saturn atmosphere.

 

[remcook]

OK then, the radius of the completely hypothetical planet.<br /><br />volume of a sphere is given by:<br /><br />V = 4/3 pi r^3<br /><br />mass saturn: 5.685 e 29 gram<br />density : say- 2 g /cm3<br /><br />r^3 [cm] = 5.685 e 29 * 3 / (2*pi*4)<br /><br />r = 40776 km (more than half the size of saturn)<br /><br />Now, where was this going again?

 

[titanian]

So, Saturn has a mass similar to a tellurian planet the same density as Earth 80000 km across.The gas giant are not only made of helium and hydrogen, it is certain.<br />Thank you for this original calculation!

 

[rlb2]

<font color="orange"> Outside Saturn, Saturn's gravity field is the same, whether it would have been the size of the Earth or not. Even better, Saturn can be modelled by a mass of no size (a point source). For distance larger than Saturn's radius, this point source has the same effect as Saturn itself (assuming Saturn is spherical).<font color="white"> <br /><br />That’s not right. Saturn’s gravity changes much less over distance than Earth does. Again it’s a spherical thing, inverse square law, basic classical physics.<br /><br />Here is a picture maybe this will help. <br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[remcook]

"Saturn’s gravity changes much less over distance than Earth does"<br /><br />True. Where do I state otherwise? What I am saying is that Saturn's gravity field at point outside Saturn itself can be described by a point source (Newton's gravitation, basic classical physics).

 

[remcook]

Regarding your picture...<br /><br />you have made the false assumption that the gravitational acceleration on Saturn's "surface" is 1 g. Let me demonstrate:<br /><br />We all know Newton's law of gravitation:<br /><br />F = GMm/r^2 <br /><br />Combined with Newton's second law, this gives:<br /><br />F = ma =GMm/r^2<br /><br />so, a=GM/r^2<br /><br />The Earth accelerates Saturn by:<br /><br />a = GMe/d^2<br /><br />Me = mass of the Earth<br />d = distance Earth centre - Saturn centre<br /><br />What you have done is write the acceleration as follows:<br /><br />a = GMe/Re^2 *(Re/d)^2<br /><br />Which is perfectly valid. Re is the Earth radius by the way.<br /><br />The first term, GMe/Re^2 is the gravitational acceleration at the Earth surface, which is indeed equal to "g".<br /><br />so, it says: a = g *(Re/d)^2<br /><br />This is also what your picture says.<br /><br />But now for Saturn. Saturn's pull on the Earth is given by:<br /><br />a = GMs/d^2<br /><br />Ms is Saturn's mass. This can again be rewritten as:<br /><br />a = GMs/Rs^2 *(Rs/d)^2<br /><br />Only now the first term (GMs/Rs^2) is equal to the gravitational acceleration at Saturn's "surface". This pull is NOT equal to "g"!

 

[yruc]

<blockquote><font class="small">In reply to:</font><hr /><p> originally posted by rlb2. <br />If the Earth was .... snip....This is small compared to Saturn because it’s a spherical property, gravitations inverse square law, if two objects have the same gravitational pull at there surface then the larger diameter spherical object would win out. This is true with Saturn. I first made a blunder by just looking at the gravity when the gravity for both was taken from there respective surfaces, that’s not right to assume. Don’t know exactly where Saturn’s is, but its spherical radius is approximately ten times larger than Earths. ...snip.. <p><hr /></p></p></blockquote><br /><br />Not sure if this is what you were looking for here. But they measure the surface of Gas Giants at where the gravity is = to earths which for Saturn is at its cloud tops.<br /><br />If not what you were refering to then sorry for interjecting.<br /><br />Yruc

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Not sure if this is what you were looking for here. But they measure the surface of Gas Giants at where the gravity is = to earths which for Saturn is at its cloud tops. <p><hr /></p></p></blockquote><br /><br />No, I don't think that's correct. I suppose it might coincidentally be true, but the definition I've seen is surface = altitude where the pressure is 1 atm (same as Earth at sea level), which is admittedly pretty arbitrary. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[rlb2]

Titans glow. <br /><br />I posted a larger image of this finding weeks ago. If you wear night goggles on Titan all you would see would be bright lights if you don't have a good filter. In other words the surface isn't in complete darkness if your vision is in the inferred; in fact it may be in complete lightness. Ha - Another prediction that is reality.<br /><br /><font color="orange">The Sun-illuminated fluorescent glow of methane throughout Titan's upper atmosphere -- revealing the atmosphere's immense thickness and extending more than 435 miles (700 kilometers) above the surface, was expected. However, the nighttime glow, persistently shining over the night side of Titan, initially surprised scientists. <br /><br />These images are as if you were seeing Titan through alien eyes. Titan glows throughout the near-infrared spectrum. If you were an alien it would be hard to get a good night's sleep on Titan because the light would always be on," said Baines. <font color="white"><br /><br />http://space.com/scienceastronomy/cassini_lightning_040805.html</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

Bump Just for continued and updated discussion. <div class="Discussion_UserSignature"> Ron Bennett </div>