The planet moves in space all the time, of course, but the times that people actually get up off their bums and give it a shove in one direction or another are rare.
Humans have a mixed history of doing things en masse - for every example of a peaceful uprising there is a Kristallnacht to remind us we do appalling things too. But the Arab Spring of 2011 seemed to be all good.
Deposing dictators - check. Popular uprising - check. Largely peaceful - check. Captured by people with smartphones - checkety check.
It hit a stumbling block in Libya, and again in Bahrain and Syria where the bad men had time to realise what was coming down the pipe, and get their tanks in a row. But in Egypt the bad man was so surprised by the strength of feeling in a largely middle-class population that in the end he capitulated. He was arrested, and has been in court to answer for decades of crimes.
A bloodless, righteous coup. What wonderful stuff! Well done the human race.
Except democracy is not a natural state, and in the vacuum which followed the peaceful siege of Tahrir Square the generals regrouped, and then the fundamentalists got enough of a toehold among a disaffected and disappointed population that the first elections saw them into parliament.
Where, this week, they've all decided to be a bit worse than the bad man they got rid of.
There have been stories about new laws allowing men to have sex with their dead wives which aren't actually true, but the laws which are being suggested are just as icky and wrong.
During Hosni Mubarak's dictatorial regime lots of bad things happened, but because he was a crazy there was some accidental good stuff too. One of them was that women were allowed the right to seek a divorce or separation from their husband, under an Islamic law called Khula.
She had to reimburse him for whatever he provided her during the marriage (bit cheeky if she can't work) but he has to pay for the children, and they can remain with her for seven years after which point they can live with whatever parent they choose.
No-one in their right mind divorces willy-nilly - especially if they have to repay him for all the crap jewellery he bought - but it enabled women who were abused, beaten or otherwise mistreated to get themselves and their children out. Before that law, it took 10 to 15 years, the husband could refuse, and even after divorce the wife often had to remain living with her ex for financial and social reasons.
Egypt's new rulers want to end that right. It wants to remove Egypt from international treaties on women's rights, remove the quota for female representatives in parliament, and make it legal to marry a girl of 14.
It didn't say that on the side of the tin, did it? 'Contents: one Arab Spring. May spring backwards in time by eight centuries.'
Egypt's National Council for Women (have we got one of those? I'm not sure we do) has kicked off and is campaigning against the changes, which are being backed by hard-right religious groups with names like Coalition for the Family. Coincidentally that's exactly what the same kind of loons in the US call themselves; Mitt Romney has more in common with the Muslim Brotherhood than he'd like to admit.
But what if it actually happens? What if, all across the Arab world, the single bad men who were in charge have been replaced with groups of bad men all egging each other on to see how medieval they can be? That's not just going to affect women or minorities, that's going to be World War III.
You might think, 'well, that's Egypt, can't happen here'. But this week we've got anti-abortion activists accusing the British Pregnancy and Advisory Service of genocide, we've got a tied vote in the House of Lords because half of them couldn't be bothered to take part in legal aid reforms which means poor people won't be able to seek civil injunctions against violent partners, and the only female who meets with universal national approval is one who doesn't speak.
This week I was invited to meet a group of 14-year-old girls as part of a project teaching them about what professions and role models are available to them. It was great fun, but most of them were stunned that I swore, told them to fight for the things they believed in, and said the celebrities they're all taught to look up to were idiots in real life. When I told them Justin Bieber thinks 'rape happens for a reason' I think I broke their hearts, but it needed to be done.
Democracy, freedom, and rights, don't just fall out of the sky like rain. They're a wall you have to build with backbreaking labour and toil in order to keep yourself safe from those who want to take it all away. Women's rights are just one brick in there, along with things like freedom of speech, voting rights, and protection of children. But if you start taking bricks out the whole lot comes down.
And it needs regular maintenance if it's not all going to wash away some day.
The trouble with springs is that they're often quite rainy.
Brollies out, ladies.