Glowing planets: A "derrr" moment

[Stainless]

I've just been watching on the BBC a documentary called "Do we really need the moon?"

Since it's for general consumption, it's understandably fairly simple. However, having said that, it's probably one of the better documentaries I've seen in a while.

Anyway, during the documentary the presenter points out that just after the moon formed, it and the earth would have been luminous glowing objects.

There's a clip of the simulation here.

Anyway, I knew this already, but it reminded me of it, and I thought of how this could be used to add a little colour to a Traveller game.

Another point the presenter makes is the truly massive tide we would have if the moon was 20X closer to the planet. Basically, only a relatively small amount of land will be habitable. Another point I knew, but it's reminded me to include it in future Traveller games.

Anyway, I just thought I'd share what is a very interesting and nicely produced documentary.

 

[Gee4orce]

I was fairly good - the animation of the collision that created the moon was excellent.

There were some factual errors though - I'll be kind and say they were gross oversimplifications. eg. It stated that high tide occurs when the moon moves overhead, but in reality that's an illusion: it's the earth that's turning under the moon.

But on the whole, it was worth watching. It does make one wonder that maybe life requires a rotationally stable planet - which either limits it to a double planet like the earth/moon, or to moons of gas giants

 

[BP]

To clarify - that is also a simplification - the earth and the moon orbit about their barycenter (located inside the Earth - for now*).

Additionally, the idealized model where high tide occurs is also an over simplification (the earth's 'surface' being quite irregular for one) - most places have 2 high/low tides per day, but some, only one. Tidal bulges are slightly ahead on earth due to our rotation and the phase of the tidal flow can be out of phase.

On another note, the Sun also causes tidal bulging (though much lower) - during full/new moons (~2x per month) the sun and moon forces 'combine' causing higher/lower tides (the spring tides). This means even planets without moons and 'double planet' systems can still have tidal bulging re: assisting the development of life.

[* - note: in some billions of years, the moon will be farther from earth and the center of gravity will lie outside the earth (also, more commonly the accepted definition of a double-planet system ).]

 

[Nuclear Fridge Magnet]

[* - note: in some billions of years, the moon will be farther from earth and the center of gravity will lie outside the earth (also, more commonly the accepted definition of a double-planet system ).][/quote]

If I'm around then, I'll take some pictures...

This reminds me of the BBC series a few years ago regarding early space probes to Mars and Venus. How we -- as a species -- took our preconceptions and expected another world to obey them.

I recall the wonder I felt at learning about the metallic 'snow' icecaps on Venus... :shock:

 

[AndrewW]

[* - note: in some billions of years, the moon will be farther from earth and the center of gravity will lie outside the earth (also, more commonly the accepted definition of a double-planet system ).]

Or it could happen the moon will part ways with the earth (Space 1999...).

 

[BP]

Oops - should have written 'might' instead of 'will'.

Could be the Moon or Earth suffers another fate before then...