Comet 21P/Giaccobini-Zinner just made its closest pass to Earth and also made its Solar perihelion on the same day (Sept 10) which is roughly one month ahead of the annual Draconids meteor shower (Oct 9). In both 1933 and 1946 these same circumstances also occurred and there were reportedly 1000s of meteors per hour in those years - meteor storms.

Question - I know the expert forecasts are not calling for more than 20 or so per hour based on some reference data about debris streams, but is there any chance that they may be wrong this year in their forecasts? Could the favorable circumstances this year plus a new debris stream result in a meteor storm surprise next week?

  • $\begingroup$ Simple answer for "is there a chance of 'x' happening" is yes..... Of course there is a chance, so there could be more than predicted. I don't have the knowledge on this particular subject to give a conclusive answer though, but usually they give pretty conservative estimates $\endgroup$
    – MCG
    Commented Oct 3, 2018 at 12:07
  • $\begingroup$ Thanks. I suspect it as well. I am only hoping that there might be someone who knows about the detail of how they "predict" (or is that "forecast"). If a prediction is essentially only "safe" baseless fodder, then don't bother. How do they monitor comet dust streams anyway? $\endgroup$
    – user22542
    Commented Oct 3, 2018 at 12:15
  • $\begingroup$ Not too sure on that one, hence not writing a complete answer. If I get time, I'll have a dig around on the internet tonight to see if I can find anything $\endgroup$
    – MCG
    Commented Oct 3, 2018 at 13:13
  • $\begingroup$ I doubt the comet was directly responsible for the showers, but rather a coincidence with a dense patch of space dust in the overall Draconids source stream. $\endgroup$ Commented Oct 3, 2018 at 16:03
  • $\begingroup$ A mathematical "model" is not a true predictive tool - they should not make statements of prediction if they don't have actual data to support the statement. They do make such statements. They talk about 21P dust streams like they can monitor them with a telescope. Of that - I am skeptical. I am just asking to see if anyone has some information that I could not find online. As I understand it, the "geometry" of this years comet passage (just 30 days prior) is very similar to 1933 and 1946. Those two events were both in the year of the passage also - not one of the 6 years in between. $\endgroup$
    – user22542
    Commented Oct 3, 2018 at 20:54

1 Answer 1


Earthsky discusses this.

There isn't a storm every perihelion, and predicting meteors is tricky, as we can't observe the meteoroids in space, we don't know if the Earth will pass through a dense patch or not.

Key quote "How many Draconid meteors will you be able to catch? No one expects a Draconid storm this year, but one can always hope!"

  • $\begingroup$ No, it isn't the perihelion, and the distance from the earth's orbital path is always the same. It is, though, a statistical wonder that the comet reached its closest point to both the Earth and the Sun (perigee and perihelion) on the same day (I am amazed). I am asking the question, looking for hard facts. I am not finding any - only continual downplaying of the event - given the nature of this particular meteor shower. Your first statement sounds like they truly don't know - which is probably correct. I will be watching if I can - because of the similarities with 1933 and 1946. $\endgroup$
    – user22542
    Commented Oct 3, 2018 at 20:44

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