Well, sure, on a few of them. And then what? Could be quite a leap for single-celled organisms to evolve into something resembling a flying insect. Given how successful insects have been on our planet, why would life evolve into anything more complex?

I'm actually not too worried that we're the only example of life in the universe. Instead I'm more worried that the galaxy is filled with planets containing nothing but slime mold.

It would be pretty trippy to think about. A planet not unlike our own in terms of atmosphere, water content, temperature, etc, and it's all slime mold. Entire mountains, covered in mold. Rolling hills of mold. Valleys thick with mold. Mold everywhere.

Ours may very well be the only planet in the universe where life evolved to one day ponder the possibility of a universe filled with mold. Multiverses and Moldyverses.

So, who knows, we may take it upon ourselves to spread life and make the universe less moldy.

I am more worried that humans are destroying this planet and ecosystem at an exponential rate, no external cause needed.

https://www.theguardian.com/environment/2014/sep/29/earth-lo...

Insects are actually very eolutionarily complex if you think about it. It’s much more logical for a single celled organism to develop say a membrane than a carapace. Especially since single celleds start in an ocean to our knowledge.

True but no one knows how likely life is to start up from raw materials in the first place.

It would also need to reach a balance with its planet and not simply eat up all the resources and die out.

> It would also need to reach a balance with its planet and not simply eat up all the resources and die out.

Like we're kinda doing?

Humans are far from dying out and incredibly resilient. Things like climate change are not really about the human race surviving, more the scale and quality at which we continue to live. Both important but very different things.

I was speaking more to the resource utilization part of the statement, but sure: technically, there will probably still be humans left, in places, if we keep going at the rate we are.

If we're (as a species) lucky, that number might even exceed the minimum viable population.

The individuals in that circumstance probably won't feel very lucky, though.

I once saw a paper that calculated the probability distribution for the number of planets with intelligent life, using estimates from other papers and the best data currently available. IIRC, the conclusion was that it's likely that we're alone in the galaxy, and not that unlikely that we're alone in the universe.

IIRC, many low-probability events were in the development of simple life, so life itself might be surprisingly thin too.

Do you have a link to this paper?

Life got going on Earth very early on, now perhaps it was a lucky fluke, but it happened early.

When you consider that there are perhaps 100 Billion stars in a typical galaxy, and in the observable universe there are perhaps 200 billion to 2 trillion galaxies, for me personally, I can only conclude that the universe is teeming with life.

Lets say Earth was a 1 in a million, that still means there are perhaps 1000 planets in our galaxy which contain life. Now if you multiply that by the number of galaxies you end up with billions.

Now intelligent life is a whole different beast, it could be that within a single galaxy civilisations come and go at different periods and never exist at the same time. Civilisations which are in different galaxies will find it extremely hard to contact each other.

Could it be this talk? http://www.jodrellbank.manchester.ac.uk/media/eps/jodrell-ba...

That looks like it.

> The number of Earth-like planets capable of supporting life is thought to exceed the number of grains of sand on our planet.

I believe the popular statement is more towards 'There are more stars in the universe than grains of sand on all beaches of earth.'

Once you bring in inland sand deposits etc this would probably not be true given the estimate (I've read but there must be other) of stars to beach sand grains is fairly close given the scope.

And as for planets, I'm not sure the ratio of 'earth like' planets to star ratio in the universe but would suspect this to be less than 1:1 given in the milky way this averages a less than 2 earth like planets for every 10 stars.

It's such a great analogy. Its the closest as I can come to understanding the scale of the universe we live in.

Familiarize yourself with the Fermi Paradox. http://fermisparadox.com/

The Fermi Paradox deals with intelligent life (aliens) capable of being detected by other intelligent life (us). Life itself, however simple, is likely extremely abundant - there is even some inconclusive evidence that life once existed on Mars.

The fact of intellegent life arising somewhere else in the universe is statistically guaranteed. However, the sheer physical vastness of space and the timeframes that an intelligent species may be solvent mean that two separate intelligent species arising next to each other at the same time is almost a statitical impossibility. What the fermi paradox strongly supports is that faster than light/deep space travel in our little corner of the universe has not been figured out yet.

> The fact of intellegent life arising somewhere else in the universe is statistically guaranteed.

We have insufficient data from which to make that conclusion to any reasonable degree of certainty.

We also have an insufficient definition of “intelligent life” to even enable gathering such data.

Somone had to be first. Why not us.