I tell my kids stories at night. Sometimes they are good enough stories to re-tell here.
They can see the Milky Way at its most magnificent from their large, south-pointing, low-light-pollution 2nd-story windows. They ask about the stars.
"What's a star, Mum?"
"A star is just like a sun but a lot further away so it looks much smaller. And some stars aren't single suns, but a whole mass of suns a very very very long way away called a galaxy. And some are planets of our own solar system, reflecting the light of our own sun."
"How do you tell which one is which?"
"Well you have to learn about the skies. But if the star is in this section here (point to the bright spray of the Milky Way) it's probably a star. And if it's over there (south-west) it's probably a galaxy. And if it's really bright it might be a planet."
"Did people always know what stars were? When in history did they work it out?"
(precocious flippin' 5 yr old! *sigh*,)
Here starts the story, in grownup words this time.
The name Milky Way comes from Greek mythology, same as Galaxy comes from the same root as lactation.
Here is my favourite pre-Christian, (pre-Greek) creation story amalgum, from fragments of memory of mythology, which wouldn't hold up to any decent research but makes me smile anyway. (Come to think of it, maybe it's Hopi Indian. I'll look it up and edit this post.)
The Sky, the mother of everything, fell in love with the father Sun and they had children, the Earth, the Moon, (and the other inner planets, if you accept the assumption that this amalgum pre-Christian society had half-decent proto-astronomy)
She had so much milk for her child(ren) that it sprayed all over her dress, creating the Milky Way.
But the Sun and the Sky could not get along. The Sun was too bright, the Sky took up too much space.
Ultimately, they decided to split the care of their child Earth into Day and Night.
The Sky also helped her daughter the Earth deliver life, flowing out of the ground in a vast river and filling the land and the sea with all living things. (Can't remember which was the Earth's partner. It's not the Moon, he was her brother.)
So then a couple of weeks ago, we borrowed Carl Sagan's Cosmos ep 1&2.
There is a rather good section on the origins of life, at roughly 48 minutes.
Sagan stands next to a large glass bulb full of gases supposedly in abundance before plants evolved, took over and started messing with things.
Electrical arcs (simulating lightning) were generated through the chamber.
After an unspecified length of film on the cutting room floor, a fabulous brown sludge of proto-amino-acids started running down the walls of the chamber.
He put this forward as evidence that self-replicating organic molecules can appear on any planet with something close to the right atmosphere & a bit of atmospheric turbulence. I was convinced (enough to do a bit more reading & get more convinced, anyway).
Check out this very readable article on Google Scholar. It puts forward four theories from the body of literature for the origin of life and talks about their plausibility and likelihood. It's short but my version is shorter.
It all sounds complicated, but truly, consider the endogenous theories alongside the miscellaneous mythology story above. I propose that the longer scientific language tells largely the same story, just a little differently.
My two older kids loved that story. They told me I should write it down.
I hope you liked it too.
Sleep well, my invisible readers.
Lexskigator
They can see the Milky Way at its most magnificent from their large, south-pointing, low-light-pollution 2nd-story windows. They ask about the stars.
"What's a star, Mum?"
"A star is just like a sun but a lot further away so it looks much smaller. And some stars aren't single suns, but a whole mass of suns a very very very long way away called a galaxy. And some are planets of our own solar system, reflecting the light of our own sun."
"How do you tell which one is which?"
"Well you have to learn about the skies. But if the star is in this section here (point to the bright spray of the Milky Way) it's probably a star. And if it's over there (south-west) it's probably a galaxy. And if it's really bright it might be a planet."
"Did people always know what stars were? When in history did they work it out?"
(precocious flippin' 5 yr old! *sigh*,)
Here starts the story, in grownup words this time.
The name Milky Way comes from Greek mythology, same as Galaxy comes from the same root as lactation.
Here is my favourite pre-Christian, (pre-Greek) creation story amalgum, from fragments of memory of mythology, which wouldn't hold up to any decent research but makes me smile anyway. (Come to think of it, maybe it's Hopi Indian. I'll look it up and edit this post.)
The Sky, the mother of everything, fell in love with the father Sun and they had children, the Earth, the Moon, (and the other inner planets, if you accept the assumption that this amalgum pre-Christian society had half-decent proto-astronomy)
She had so much milk for her child(ren) that it sprayed all over her dress, creating the Milky Way.
But the Sun and the Sky could not get along. The Sun was too bright, the Sky took up too much space.
Ultimately, they decided to split the care of their child Earth into Day and Night.
The Sky also helped her daughter the Earth deliver life, flowing out of the ground in a vast river and filling the land and the sea with all living things. (Can't remember which was the Earth's partner. It's not the Moon, he was her brother.)
So then a couple of weeks ago, we borrowed Carl Sagan's Cosmos ep 1&2.
There is a rather good section on the origins of life, at roughly 48 minutes.
Sagan stands next to a large glass bulb full of gases supposedly in abundance before plants evolved, took over and started messing with things.
Electrical arcs (simulating lightning) were generated through the chamber.
After an unspecified length of film on the cutting room floor, a fabulous brown sludge of proto-amino-acids started running down the walls of the chamber.
He put this forward as evidence that self-replicating organic molecules can appear on any planet with something close to the right atmosphere & a bit of atmospheric turbulence. I was convinced (enough to do a bit more reading & get more convinced, anyway).
Check out this very readable article on Google Scholar. It puts forward four theories from the body of literature for the origin of life and talks about their plausibility and likelihood. It's short but my version is shorter.
- Exogenous, ie a "banana skin thrown from a passing spacecraft". Totally untestable, at least until we invent interstellar transport and go ask them if they dropped a banana skin on our planet about 4 Bn yrs ago.
- Endogenous and atmospheric, from gases + electricity. like Urey & Miller demonstrated in 1953 and Sagan filmed in 1980, except that they might have gotten the primitive earth's atmosphere wrong, so on to the next theory
- Endogenous, aquatic. Some magic around some funky hydrothermal vents, where clay or something protected the tiny volatile proto-proteins (lol) from boiling alive, or
- RNA from we don't know where. Possibly atmospheric. Proposed mechanism requires UV light.
There is another one in the literature, - Meteorite bombardment literally vibrating some replicating organic molecules of life into existence. Also hard to test & probably not necessary since 2, 3, and 4 are quite plausible enough for me. Anyone got a spare planet to propel some meteors at, and we can see if you get a nice brown amino sludge?
It all sounds complicated, but truly, consider the endogenous theories alongside the miscellaneous mythology story above. I propose that the longer scientific language tells largely the same story, just a little differently.
- The Sky (atmosphere) interacted with the Sun (whose heat & light generated the required atmospheric turbulence, and also sent UV radiation if that turns out to be necessary)
- and this interaction seeded RNA on earth (atmosphere, hydrothermal vent, who's pickin?)
- which then flooded simple replicating RNA from a few discrete places to fill the entire Earth, evolving into the life we know.
- The Sky had enough milk for all of her children, in fact her breasts were so full that they sprayed it right through the galaxy. (Sagan's film proposes highly probable extrasolar life, arising from similar mechanisms on other planets).
- The stars in the sky are there to remind us that the Sky (both in terms of our Earth's atmosphere, and the whole galaxy & visible universe) is probably a very fecund place.
My two older kids loved that story. They told me I should write it down.
I hope you liked it too.
Sleep well, my invisible readers.
Lexskigator
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