On 24 October Mercury stops and starts moving backwards. Over the next few weeks you will read somewhere that this is the time to sign nothing, buy no phones, book no flights and tell nobody what you think. Worth saying straight away: that is not how it works, and it never was.

Where the panic comes from

Mercury goes retrograde three times a year, about sixty days in total. It is the most frequent and most visible astrological event on the calendar, which has made it the only one everybody knows by name. Something that comes round every four months and already has a sinister reputation quickly turns into an explanation for everything: the train is late because of it, you argued with someone because of it, the file failed to save because of it.

That season of breakdowns does not exist in the tradition. No text describes three yearly windows in which objects break and agreements collapse. What does exist is far more modest and far more useful: an indication of rhythm.

What actually happens

A retrograde planet does not really move backwards. We watch it from an Earth that is moving too, and the effect is the one you get on a train when the carriage on the next platform seems to slide backwards while it is yours pulling away. What changes is apparent speed: Mercury slows, stops, retraces the same stretch of zodiac and then crosses it a third time. A loop like that lasts about forty days.

Retrograde motion does not weaken the function and does not spoil it. It changes its direction, from outward to inward. Mercury is the part of you that thinks, understands and puts things into words. When it slows, the weight shifts from the act of communicating to the process of thinking, and you take less interest in what is objective, shared, and meant to be put on the table with somebody else.

That is a change of pace, not a fault. And the planet crossing the same degrees three times has one precise consequence: whatever it touches, it touches three times. A conversation you left open comes back round. Not because the sky decided so, but because in these weeks your attention works better backwards than forwards.

What is actually worth doing

Tidy up what you have already started. This is a good time to reread, correct, close old business, pick up a piece of writing you had set aside, get back to someone you left mid-conversation. Rest your mind rather than loading it: these are the weeks when heavy external commitments and forced company cost you more than usual.

There is no need to postpone a signature or a purchase. A decision that is ripe stays ripe with Mercury retrograde; one that is not was not ripe last month either. The only sensible precaution is the one that always applies, which is to read it over before you send it.

The guide to retrogrades and nodes lays out the mechanism in full, with the durations of the other planets and the reason a fast planet, once it stops, can weigh more than Jupiter.

Where it reaches you

The sign Mercury retrogrades in is the same for everybody, so it says nothing about you. What does say something is the house of your birth chart the dwelling falls in: that is where these forty days concentrate. Mercury, going retrograde every four months, tends to insist on three or more houses, usually of the same element.

To see it you need your date, time and place of birth, and it takes a minute. From then on you stop reading Mercury retrograde as news about everyone, and start reading it as a few weeks that concern you.