board77

This was inspired by something TW said in the meaning of life thread; that our planet is just right for life, including being not too big or too small. That set my imagination going about what the world would be like if the Earth was significantly bigger or smaller than at present.

I suppose you could ask two questions - could intelligent life have formed on a different sized Earth, and assuming it could, how would human society be different?

It just got me thinking how strange it would be if, for example, it took 150 hours to fly to the other side of the world instead of 15. How much more strange and exotic that would make those distant lands! But then I imagine those who had to travel our world by boat instead of plane got a similar sort of feeling due to the length of the voyage.

Very interesting indeed Iavas! I can't imagine how much PTO I'd have to take to get to those exotic far off places Of course the first thing I thought would be how long it would take to overpopulate and even larger earth.

What if the earth expanded right now? What do you suppose folks would do then?

I honestly don't think it would change much of anything. We wouldn't know the diffrerence unless it happened now, and even if it did happen now we would just adjust and move on.

Iavas, I don't know if you are a scifi reader? One amazingly good book is called "Dragon's Egg" and it is about life evolving - intelligent life - on a neutron star. The author is a physicist. It's wonderful, one of the best scifi books I've ever read in over 50 years of reading.

What I like about it is, it is NOT a "stand-in" for Earth, written to put forth the guy's philosophy in a thinly veiled parable. Far from it. It creates a truly alien world, and truly alien beings, but they are interesting and lovable and fun, too.

Give it a try, if you haven't. I recommend it without hesitation.

That sounds really interesting, vison. I'll have to give it a look.

Meril36 wrote:

That sounds really interesting, vison. I'll have to give it a look.

Dragon's Egg, by Robert Forward.

Interesting idea, Iavas, and like you mentioned, the earth at least seems a lot smaller than it did just a few hundred years ago. I'm guessing it will seem much smaller still in another 50.

If the earth was drastically smaller than the earth today, my first thought would be that there would be fewer diversity of races. We'd all at least look more similar to each other. Same idea would apply if the earth was much larger - there would be a higher number of physical variations between races.

Vison, if I recall correctly that book was the subject of your first ever TORC post. Good book

As that book makes clear, gravity would be an important factor on how life develops. Presumably on a larger planet (with probably higher atmospheric pressure) there would be squatter lifeforms - but also geographical features would be flattened out, I guess, so overall life might not be too different. Larger planets might have longer days though.

The tilt of the planet leads to more or less intense seasons ... (Let me see what spring is like on Jupiter and Mars is a bad song lyric, because Jupiter has no tilt and therefore no seasons ).

I would suggest the big variable is temperature, however. We are a goldilocks planet, not too hot, not too cold for liquid water to cycle.

Relatively small changes may have unexpected impacts. Eg I read recently that Earth's winds are stronger than they used to be when there was open ocean at the Earth's poles, because the Antarctic continent and the enclosed Arctic ocean now both serve to trap cold air at the poles, leading to less even mixing with warmer air in the tropics. Stronger winds and storms result from this rearrangment of the continents, which may have led to the extinction of those large fragile gliding pterodactyls, for example.

Wilko wrote:

Vison, if I recall correctly that book was the subject of your first ever TORC post. Good book.

You remembered that? My word. I scarcely know what to say!

I thought I said something to offend the Xhen.

Well, everything I say offends the Xhen, anyway............



It WAS a good book. One of my top 10. No kidding.

Gravity is the first thing that springs to mind – had human life developed on a moon-sized planet, we’d all be 11 metres (33ft) tall (IIRC). Also, a larger planet would have presumably given rise to more diversity of life. A smaller planet would have a thinner atmosphere, while a larger one would have a thicker one. I’m not sure exactly what affect that would have on the development of life.

As Wilko pointed out, more of a tilt would given more severe seasons – somewhere like Europe or the Northern US could experience tropical summers and artic winters. This would be a hindrance to life, and force the development of hardy life forms. I imagine such rapid changes would also lead to more severe weather. No tilt would lead to no seasons – migratory animals would be rare and the poles probably uninhabited.

A hotter or colder planet would also have some affect. As far as I know, liquid water is essential to any life form that we know can exist (there may be a different sort of life in another part of the galaxy). This means that there must be liquid water somewhere on the planet – be it contained at the poles (a hot planet) or around the equator (a cold planet). Our Earth seems to be around the cooler end of the spectrum – we have plenty of ice, but no ocean or sea water that’s much over 30 degrees C. Life forms would then develop accordingly.

A colder planet would also be drier, locking up water around the poles. A hotter planet would be wetter, and also have more stormy weather. A colder planet would have more desert.

This has always been a fun part of astronomy\physics\biology.

Also consider: if the Earth were slighty farther away from the sun, or if the sun were dimmer. The orbit - the ecliptic, the eccentricity. The frequency of orbit and\or revolution.

Imagine people on a not-so-hot Venus, for example. The sun rises for weeks (in the wrong direction to boot).

My personal favorite is the scenario where intelligent life develops on a planet and also the moon(s). They can see eachother building up (the view must be spectacular at night - to see each other's cities glow on the dark-side of the planet) and are close-enough to one day meet each other. They might meet via radio first, figure out eachother's language and help each other develop the technology to visit in person.

Makes for awesome artwork.

wilko185 wrote:

Here ya go vison

Vison,
The book you describe sounds kinda like Hal Clement's Mission of Gravity Here's a snippet of someone's review of it:

Quote:

First published in 1953, this book was the progenitor of the modern 'hard' SF sub-genre. Using only the known science of the day, it imagined a world so wildly different from our everyday experience that it dazzles the mind, showing just how wild the universe really can be.

The world is Mesklin, a very large planet that rotates on its axis in just eighteen minutes, leading to gravitational forces of 700 gravities at the poles, and just 3 gees at the equator. But this is just the first of the items that make the world unique: its average temperature is a toasty -160 degrees Celsius; a methane/ammonia atmospheric composition that at these temperatures act much like water on Earth - phasing between solid, liquid, and gaseous forms; a wildly ecliptic orbit and planetary axial tilt that has strange consequences for the weather. Now add an intelligent native life form that is fifteen inches long and just three inches tall, looking very much like an overgrown millipede with pinchers, an Earth probe stranded at one of the poles that Terran scientists would very much like to retrieve for the data it contains about high gravity environments, and you have the ingredients for a great scientific adventure story.

A very, very fascinating book. But then, all of Hal Clement's are.

I remember Mission of Gravity too and was preparing to mention it until I saw Maria's post. I believe there was a sequel but I haven't read it.

Just imagine the privilege of seeing vison burst forth in all her glory! Thanks Wilko.