I've decided to learn the history of the earth, starting with the Paleoproterozoic era which is as far back as I can find. Now, everyone find me one fact about this era, and you're not allowed to use wiki.
I heard a bird cry, sharp and free. My name is Jordan.
Yes, every 50,000 years the day becomes one second longer.
In the Paleoproterozoic era, the moon was very much closer to the earth and tides had an enormous effect. But since then, the moon has gradually receded from the earth and so the length of day is changing only very slowly.
The earliest era (or eon) is the Hadean when the earth was formed (4600 to 3900 million years ago). The most significant event in that eon occurred when a Mars sized body, called Theia, crashed into the earth and formed the moon.
The American billion does make sense really, and the old British billion is dead in the water.
I only realized recently that all the ***-illion words you hear bandied about do make some sort of sense with the same prefixes used for multiple births (triplets, quadruplets, quintuplets, ...) counting the groups of three digits before the hundreds, tens, and units:
thousand = 1,000 million = 1,000,000 (from the Roman mile meaning 'one thousand' - i.e. a thousand thousands) billion = 1,000,000,000 trillion = 1,000,000,000,000 (three groups of '000' to count the number of thousands) quadrillion = 1,000,000,000,000,000 (four groups) quintillion = five groups sextillion = six groups septillion = seven groups
...and then it goes oct, non, dec, and so on up to increasingly useless words for big numbers where it's much easier to say something like 'ten to the fifteen'.
...so each of the -illion words is for a number a thousand times bigger than the one before, starting with million as 'a thousand thousands.'
Are we ready to move on to the Neoarchean era yet? I think that was the one with the first proper photosynthesising plants causing the atmosphere to have abundant oxygen for the first time.
Oxygen was a waste product of the photosynthesis process and it was originally very poisonous and toxic to living things - but as the concentration of oxygen gradually built up, life had to learn to accommodate it and eventually came to depend on it.
Oxygen is still a very dangerous and reactive gas, of course: it allows things to catch fire! It's just that we're so used to it and so dependent on it that we don't realize how weird it is. If we find evidence of oxygen on other worlds we can be confident that there is life there. In the absence of life any oxygen would quickly be used up (quickly in the astronomical or geological context) as it reacts with virtually everything so ends up bound in various types of rock and minerals.