[Salvation]

Video I

Video II

[Bidimus1]

The goldilocks zone is a small place indeed.

That Life might exist on planets not like earth is of course a possibility, who 100 years ago would have thought the deep sea vent ecology could exist ?

[Salvation]

Monsignor Pope Ping!

[JimRed]

Since the universe goes on forever, this rare occurrence may only consist of hundreds of trillions of inhabited planets. God’s wonders!

[Robert A Cook PE]

Well, you only need one place. One Eden for life to begin as we know it.

He never did promise us more than one.

[stocksthatgoup]

Could we exchange our Pope for a Catholic?

[posterchild]

I’d be curious to learn more about the reasoning behind 4.

There may well be other ways of achieving a ‘goldilocks zone.’ Imagine a description of a modern automobile and declaring all it’s attributes as the ideal way to provide transport just because that is the prevalent example we have.

[Ransomed]

“It would appear that for complex life to be sustained, many factors must come together in just the right way. The sheer number of these factors sharply decreases the number of possible Earth-like planets, despite the many billions of galaxies and stars.”

Seem like all this is only true if the hypothetical life is exactly like the only extant organic life we know of, us. So I’m not sure we can say how rare something is or not based on an example of the one place we know of where it occurs.

Freegards

[Delta 21]

Expand your mind to try to grasp and comprehend how our God tossed out the entire universe like so many marbles from the hand of a child into the sand. Then made this one especially just to hold his children.

[Rebel_Ace]

Some of the points are easily observable in both our and extra solar systems. For example:

"For suns to spawn Earth-like planets they must have sufficient “metallicity,” which is necessary for the formation of terrestrials rather than gaseous planets."

This has been observed in extra solar star forming regions.

"Earth is in a “habitable zone” within the galaxy as well. Closer to the center of galaxies, radiation and the presence of wandering planetoids make life there unlikely."

Fair point, but if you create a "donut shape" around the center of the Milky Way, delineating this habitable zone, there are lots and lots of stars to consider.

"Earth’s orbit around the sun is an almost perfect circle rather than the more common “eccentric” (elongated) ellipse."

The orbits of Venus and Mars are also highly circular. So are the orbits of most of the others in our solar system. So, just in our neck of the woods, we are something like 6 out of 8.

"Earth’s axis is tilted just enough relative to its orbital plane to allow seasonal variations that help complex life but not so tilted as to make those variations too extreme."

Mars is currently tilted at the nearly the identical angle. Again, just in our Solar System, we are 2 for 8.

"Earth exists in a disk-shaped spiral galaxy (the Milky Way) rather than in an elliptical (spheroid) galaxy. Spiral galaxies are thought to be the only type capable of supporting life."

No reason is given for this assumption. If a DISK shaped galaxy has a donut shaped habitable zone, then a SPHERE shaped galaxy should have a Spherical Shell shapped habitable zone.

"Our sun is just the right kind of star, putting out a fairly steady amount of energy. Other types of stars are more variable in their output and this variance can utterly destroy life or cause it to be unsustainable due to the extremes caused."

Red Dwarfs also fall into the category of steady producers of energy, and they have the added advantage of being much, MUCH longer lived.

Just a few things to consider when pondering how rare the Earth is. Also, keep in mind what a tiny, tiny, really, really tiny fraction of the galaxy we have had any real kind of look at.

[PIF]

If you hold up your thumb to the sky at night, you block the light from a trillion galaxies; If you hold up a grain of sand to the sky at night, you block the light from a billion galaxies.

How many thumbs does it take to completely block the night sky around the entire globe of the Earth? Compute the total number of galaxies in the universe. Hint: find a number above 70 billion trillion.

Multiply that number times the average number of stars in a galaxy (300,000,000) to get the total number of stars in the universe.

Assume each star has only 1 planet; assume that only 20% of all plants are in the carbon cycle habitable zone; assume that of those planets only 1 percent currently have intelligent life: how many planets is that?

Assume you have a starship capable, for arguments sake, of Warp Nine and can stop instantaneously: how long will it take the ship to visit all the planets which currently have intelligent life?

Discuss how the number of planets with intelligent life will change during the course of the trip. And discuss whether or not you will have to visit and revisit all the stars that exist by the time you finish visiting them all the first time.

[Moonman62]

The Rare Earth position matches observations, at least up to this point.

[butlerweave]

What if Earth type planets are the worst type to live on and habitable planets are completely different ? It’s always about us

[TruthInThoughtWordAndDeed]

Rare. As in non-existant.

[wardaddy]

This is not news

They just hate admitting it

[MrB]

Rare? How about UNIQUE.

Even given a 1/10th chance for every factor necessary for “an Earth” to exist,

the odds become higher than the number of atoms in the universe.

[yefragetuwrabrumuy]

Issac Asimov wrote a collection of non-fiction essays published in a book entitled The Tragedy of the Moon (1973).

In it is both an essay called The Triumph of the Moon, and The Tragedy of the Moon. In Triumph, he notes all the many and myriad ways the Moon has contributed to life on Earth and making and keeping the Earth habitable.

In Tragedy, he notes how men have used the Moon as justification for doing evil.

[backwoods-engineer]

Right on, Earth is very likely rare, maybe unique.

See Ward and Brownlee's book "Rare Earth", and Gonzales' book, "Privileged Planet."

[Heartlander]

The human world stands about midway between the infinitesimal and the immense. The size of our planet is near the geometric mean of the size of the known universe and the size of the atom. The mass of a human being is the geometric mean of the mass of the earth and the mass of a proton. A person contains about 10²⁸ atoms, more atoms than there are stars in the universe... In our 150 pounds of protoplasm, in our three pounds of brain, there may be more operational organization than there is in the whole of the Andromeda Galaxy. The number of associations possible among our 10 billion neurons, and hence the number of thoughts humans can think, may exceed the number of atoms in the universe...
- Excerpt from: A Look at the Fine-Tuned Universe

[Slyfox]

Thank you for this post.

[onedoug]

The Privileged Planet