43 replies to this topic

[bison]

New research indicates that a large moon may not be needed to stabilize the rotational axis of a planet sufficiently to allow life to flourish. This claim has been heard a good deal in recent years. If it were so, it would sharply limit the number of otherwise Earth-like planets that could make good homes for complex forms of life. If the new research holds true, the number of possibly habitable planets will increase markedly.     http://www.physorg.c...uire-large.html

[scowl]

I don't think any study ever said that a large moon or even a highly stable axis is necessary for life. All we do know is that it doesn't hurt!

[bison]

scowl, on 02 December 2011 - 11:46 PM, said:

I don't think any study ever said that a large moon or even a highly stable axis is necessary for life. All we do know is that it doesn't hurt!

The article linked below, from Science Magazine's website, refers to the recent predominant conjecture about the near necessity of a large moon for planet stability, and why this was thought be so important for long term survival, particularly of complex forms of life. It also discusses the new work that renders this conjecture questionable. http://news.sciencem...eds-a-moon.html

Edited by bison, 03 December 2011 - 12:12 AM.

[sergeantflynn]

Here we go , girls and boys .  How long before our moon is towed around and used as a dump for space garbage ? When it gets full just point it towards  mars and light the touchpaper .

[sergeantflynn]

Here we go , girls and boys .  How long before our moon is towed around and used as a dump for space garbage ? When it gets full just point it towards  mars and light the touchpaper .

[Terra 333]

Then that means we can all pull up our pants now?  Today's science is so behind where it should be...partially because any idiot who has a paper published can push his own level of stupidity upon the masses. Just as in primitive time...we believe we are way smarter than we truly are. A moon necessary for life on a planet? We can never exceed the speed of light? What next?  We evolved from Apes?  Please....think!

[psyche101]

Terra 333, on 04 December 2011 - 09:09 PM, said:

Then that means we can all pull up our pants now?  Today's science is so behind where it should be...partially because any idiot who has a paper published can push his own level of stupidity upon the masses. Just as in primitive time...we believe we are way smarter than we truly are. A moon necessary for life on a planet? We can never exceed the speed of light? What next?  We evolved from Apes?  Please....think!

No it means science has been amended, that is what science is, the pursuit of knowledge, it is not a definition of knowledge. To imagine a thing does not mean it can be done.

And no, we are not claimed to have evolved from apes, science says we evolved alongside them.

[psyche101]

What does one classify as a "Large moon"? In larger instances, as per with Gas Giants, moons are where one would look for life.

[bison]

psyche101, on 04 December 2011 - 10:30 PM, said:

What does one classify as a "Large moon"? In larger instances, as per with Gas Giants, moons are where one would look for life.

Large enough, in comparison to its planet, to be able to supply the previously supposed stabilizing effect on that planet. The larger and closer in, the firmer the moon's hold on the planet's wandering rotation axis would be. If life is to be sought on the large moons of 'gas giant' (Jovian) planets, the significant roles would be reversed. The planet would eliminate any wandering tendency of the moons poles of rotation.

Edited by bison, 04 December 2011 - 11:34 PM.

[psyche101]

bison, on 04 December 2011 - 11:33 PM, said:

Large enough, in comparison to its planet, to be able to supply the previously supposed stabilizing effect on that planet. The larger and closer in, the firmer the moon's hold on the planet's wandering rotation axis would be. If life is to be sought on the large moons of 'gas giant' (Jovian) planets, the significant roles would be reversed. The planet would eliminate any wandering tendency of the moons poles of rotation.

So dependent on the body being orbited, and the ration between the two bodies then, but what is that ratio?

I wonder how big is big? 30%? 10% ?

Mass would be the deciding factor wouldn't it? So a small dense moon would have the same effect. Therefore you could have a very small dense moon doing what a larger moon with less mass does. Physical size would then be irrelevant.

They seem to be talking about mass, not physical size?

Edited by psyche101, 05 December 2011 - 12:24 AM.

[bison]

psyche101, on 05 December 2011 - 12:23 AM, said:

So dependent on the body being orbited, and the ration between the two bodies then, but what is that ratio?

I wonder how big is big? 30%? 10% ?

Mass would be the deciding factor wouldn't it? So a small dense moon would have the same effect. Therefore you could have a very small dense moon doing what a larger moon with less mass does. Physical size would then be irrelevant.

They seem to be talking about mass, not physical size?

  Well, the Earth's Moon has 1/81 the mass of Earth, and that's considered an unusually large ratio by a wide margin. Only Pluto's largest moon Charon exceed this,  at 1/9.  Yes, mass, not diameter is of  of the essence where gravity is concerned. In principle, a small dense moon would have the same gravitational effect as a large, less dense one.  As it actually turns out, large moons tend to be denser than small ones, so we wouldn't expect to see a very dense small one.

Edited by bison, 05 December 2011 - 03:09 AM.

[psyche101]

bison, on 05 December 2011 - 03:08 AM, said:

Well, the Earth's Moon has 1/81 the mass of Earth, and that's considered an unusually large ratio by a wide margin. Only Pluto's largest moon Charon exceed this,  at 1/9.  Yes, mass, not diameter is of  of the essence where gravity is concerned. In principle, a small dense moon would have the same gravitational effect as a large, less dense one.  As it actually turns out, large moons tend to be denser than small ones, so we wouldn't expect to see a very dense small one.

I think the title might be somewhat misleading then Large mass may not be necessary..... . I think this concept has been hypothesized before? I remember reading something a while back about proposed life on tidally locked planets, and some have felt there may be a Goldilocks zone of life around the rim. As has been proposed with the discoveries of Red Dwarf Systems. Interesting concept to say the least.

[DONTEATUS]

psyche101, on 05 December 2011 - 04:39 AM, said:

I think the title might be somewhat misleading then Large mass may not be necessary..... . I think this concept has been hypothesized before? I remember reading something a while back about proposed life on tidally locked planets, and some have felt there may be a Goldilocks zone of life around the rim. As has been proposed with the discoveries of Red Dwarf Systems. Interesting concept to say the least.

My money is on life will find a way to be in the most strange places we have yet to even Imagine !
Moons or not we just need to start really Looking . Stop all this non-sence about Money and research funding !
Just Do it ! Its our only chance to survive this world !

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[27vet]

How else do you get lunatics?

[DieChecker]

bison, on 02 December 2011 - 03:08 AM, said:

New research indicates that a large moon may not be needed to stabilize the rotational axis of a planet sufficiently to allow life to flourish. This claim has been heard a good deal in recent years. If it were so, it would sharply limit the number of otherwise Earth-like planets that could make good homes for complex forms of life. If the new research holds true, the number of possibly habitable planets will increase markedly.     http://www.physorg.c...uire-large.html

I've yet to read the link, but first guess... I'd say not necessary. After all the Earth supports life deep in the crust, at the bottom of the oceans and in radioactive pools. Situations that would kill most creatures in seconds support other life just fine.

Is it a big help here on Earth, sure. But look at Mars and Venus. Little to no wobble that I know of. The Moon if anything is probably sustaining the axial wobble that the Earth does have.

Edit: I'd say that a Magnetic field is ten times more necessary.

Edited by DieChecker, 05 December 2011 - 07:07 PM.