# How often does Earth cross the galaxy regions with higher supernovae activity?

According to Summa Technologiae, a book by a Polish author Stanisław Lem that based his science fiction novels on scientific research of the era, the Earth crossed in the moment of forming of life the arms of the Galaxy, with high supernovae activity, which triggered life creation. Afterwards, it moved to regions with low supernovae activity, which enabled the preservation of existing life.

I'd like to test the validity of this claim against current research. How often does the Earth cross regions with higher concentrations of stars (and therefore, much greater chance of gamma burst wipe)? Additionally, how many times the probability of nearby supernova explosion is higher in that regions?

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Have you read the relevant Wiki article? It has some information on this that cites some reliable sources, though I have no idea how accurate their citation of the material is. If you've already read this and are satisfied with it, what additional information are you looking for beyond this? –  called2voyage Oct 8 '13 at 20:44
@called2voyage I'm more interested in Earth movement through galaxy and changing density of supernovae candidates connected with it –  Lukasz Oct 8 '13 at 20:52

Actually i read some where that in the entire time of humankind on earth, the earth has just covered 1/10th of a percent around the milky way galaxy, so assuming earth would survive that long and humankind would survive to witness it, i would say it would take billions-billions of year, before earth would move to closer to giant stars.

As for the supernova activity, humankind hasn't seen a supernova (excluding some theories), but our best bet to witness on would be Betelgeuse, it is already old for its size class and is expected to explode relatively soon (it may explode tomorrow or after a million years nobody knows exactly when) compared to its age.

So, i would say, we would be lucky if we witness a supernova in our lifetime.

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This question was not asking about within the human lifetime but within the entire lifetime of the Earth. Also, it would be helpful if you could give a better reference for where you got your information. Do you think you could track down where you read this? –  called2voyage Jan 14 at 14:22
Humankind has seen several supernovae in historical times. See en.wikipedia.org/wiki/History_of_supernova_observation The last observed supernova in the Milky Way was Kepler's Star in 1604, but since the rise of telescopy our observational capabilities have risen to the point of being able to observe them in other galaxies. Phil Plait, the Bad Astronomer gives the most likely next supernova as SBW1. See slate.com/blogs/bad_astronomy/2014/01/13/… –  Cyberherbalist Jan 14 at 17:05

The paper "Frequency of nearby supernovae and climatic and biological catastrophes" by Clark, McCrea, and Stephenson published in Nature estimates (at 50% probability) that the Solar System passes within 10 parsecs of a supernova every 100 million years. This supernova would be part of a 20-parsec strip in which an estimated 50 supernovae occur.

They do speculate that a connection between the Solar System passing through these regions and climatic and biological events (such as ice ages) is possible.

You can read the paper yourself for more details. It's only two pages and you can purchase 48 hour access for \$5 from Readcube.

Source:

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Do this paper deals with varying probability of meeting supernova depending on in which region of galaxy is the Solar System in given moment of its history? –  Lukasz Jan 14 at 17:53
@ŁukaszL. In brief, yes. It does not get into a lot of detail and there is no solid density/time information. You might, however, find their discussion of how they got to their estimate interesting. –  called2voyage Jan 14 at 17:54
Basically they figure Type II supernovae are usually localized to the arms of the Milky Way. –  called2voyage Jan 14 at 17:55
OK, but do they provide any calculations or estimations, how much more probable is to meet nearby supernova there? –  Lukasz Jan 14 at 18:04
I've given you all the end results: 50% probability of passing within 10 parsecs of one supernova every 100 million years, a supernova which is in a group of 50 supernovas in a 20-parsec region. The rest of the detail in in their methods, not their results. –  called2voyage Jan 14 at 18:05