Possible exomoon spotted

This will be amazing, if proved true. 

http://www.nature.com/news/why-astronomers-reluctantly-announced-a-possible-exomoon-discovery-1.22377

Obviously this must be photometric statistical analysis, but the fact that the technology is reaching a resolution sufficient that such a thing can even be discussed!... This makes me more confident that evidence of intelligent life may be found in the lifetimes of our children! The same increases in resolution must be occurring in Radio-Astronomy as well.

I mean, it's no great leap, after confirming that at least half of all stars have planets, that moons are equally ubiquitous.... but Intelligent life?! -- WOW. That day will be the most important day in the history of humanity since that bitch Eve talked Adam into eating an apple!

After reading "Rare Planet" and "What if we had no Moon" I am strongly leaning towards we are the only intelligent life in the universe.  I understand there are like 5x10**23 stars, but even then the requirements it takes for intelligent life is so remote.  This is one of those things I can never be proven right on, only wrong. 

But why would you think it is less than say 1 in a trillion?

The book Rare Earth is fascinating and I do recommend it (By Peter Ward and Donald Brownlee).  At the start they summarize some are the factors why earth is rare:

Right Distance from star - Habitat for complex life.  Liquid water near surface, far enough to avoid tidal lock

Right Planetary Mass - Retain atmosphere and ocean.  Enough heat for plate techtonics.  Solid/molten core.

Plate techtonics - CO2 - silicate thermostat.  Build up land mass.  Enhance biotic diversity.  Enable magnetic field.

Right mass of star - Long enough lifetime.  Not too much ultraviolet.

Jupiter like neighbor - Clear out comets and asteroids.  Not too close, not too far

Ocean - Not too much not too little.

Stable planetary orbits - Giant planets do not create orbital chaos

Large moon - Right distance. Stabilizes tilt

The right tilt - Seasons not too sever

Atmospheric properties - Maintenance of adequate temperature, composition and pressure for plants and animals

Right kind of Galaxy.  Enough Heavy elements.  Not small, elliptical or irregular.

Giant impacts - Few giant impacts.  No global sterilizing impacts after an initial period

Biological evolution - Successful evolutionary pathway to complex plants and animals

Right position in Galaxy - Not in center, edge or halo

The right amount of carbon - Enough for life, not enough for runaway greenhouse

Evolution of oxygen - Invention of photosynthesis.  Not too much or too little.  Evolves at the right time

Wild cards - Snowball earth. Cambrian explosion. Inertial interchange event

The book goes into detail on why these make the chance of intelligent extra terrestrials unlikely.

The book What If We Had No Moon explains the very unlikely way we got our moon and how different life would be (if it happened at all) without a moon.  Bottom line, even with relatively small changes in the moon, like size, we have it would be next to impossible to develop past the stone age.

There is also a much deeper book titled "Improbably Planet" by Hugh Ross that mentions a lot more criteria and is geared more for the person educated in the sciences.  However, the first two books were written by atheists.  The Hugh Ross book was written by a committed Christian.  I didn't mention his book initially because it could be viewed that he was biased. 

The above is what is required for human life. There could be other intelligent life that can survive in different conditions.

And in an infinite universe, other life is a certainty

Hawk,  If the universe had a beginning and is expanding, then it is not infinite.  Second, all life forms must be carbon based.  Arsenic or anything else on the periodic table do not allow binding nearly as well as carbon. 

The observable universe is expanding. Who knows, maybe the universe is just a hole in a giant block of cheese

If you meant science doesn't know what the universe is expanding into, then we agree.  My point was to challenge the word "infinite" in your post #6.

Firstly, though observing one is a great milestone, it seems pretty obvious moons are two a penny.  We have a solar system which is littered with them. The Moon is relatively very big though (though not as relatively big as Charon) which makes its effect larger.

Planets don't seem to need a Moon to stabilise their axis. Mars and Venus do fine (Mars' tilt is almost the same as Earth's, Venus' is virtually 180 degrees, which is pretty much the same as 0 degrees in effect).

The Moon's greatest achievement is probably helping life from the ocean, by creating large tidal regions in which life could exist partially evolved for land. Even so, leaving the ocean was quite tough and took quite a while, so without it, who knows if it would have happened.

I don't consider Charon a "true" moon.  Most moon form when the planet is forming.  Our moon was most likely formed 80 million years later when a Mars sized body collided with earth at a 45 degree angle and the debris outside the Roche Limit formed the moon.  This is why our moon is abnormally large.

According to the writers of Rare Earth the large moon serves three purposes.  Two you mentioned.  The other is that the moon slows the earths rate of rotation.   When the earth was formed the day was only six hours long.  When the dinosaurs roamed it was 22 hours long. 

The Rare Earth authors argue that "This (the earths) angle is nearly constant for hundreds of millions of years because of gravitational effects of the moon.  Without the moon, the tilt angle would wander in response to the gravitational pulls of the sun and Jupiter...Without a large moon, Earths spin axis might vary by as much as 90 degrees.  Mars, a planet with the same spin rate and axis tilt, but no large moon, is believed to have exhibited changes to its tit axis of 45 degrees or more".

The planets tilt affects seasons and climate.

' 

Well, you have to consider Charon a moon or part of a double (minor) planet. It has a very long term stable orbit. Whether Pluto had a moon at some earlier part of its life is another matter, but Pluto-Charon could be as old as the Earth-Moon system, and was possibly formed from a collision, like the Earth-Moon system. I still think it is amazing that this minor planet has 4 other little moons, so far from the Sun.

Unlike our Moon, Charon has large quantities of water and many of the organic chemicals needed for life.

Interesting to note that if the barycentre of the Earth-Moon system were outside of Earth, and that of the Pluto-Charon system were outside Pluto, they would be considered binary planets (or binary dwarf planets, in the case of Pluto-Charon.

The barycentre of Pluto-Charon is outside of the body of Pluto, I recall. So by that definition it is a double dwarf planet.

So it is!

Life, even on earth, thrives in conditions which we humans cannot live in.

I wonder if there could be a planet in our solar system with everything necessary for chemical energy based life (like the candidate earliest life on Earth, living in hydrothermal vents). Such life is independent of the Sun (as long as there is the heat to keep water liquid, which is feasible with any planet big enough and with enough radioactive elements to be mostly molten, like the Earth.