Stars in the milky way?

I've heard a good comparison for the number of stars in our Milky Way

If you filled an Olympic swimming pool with sand, there would be the same number of stars in the galaxy as there is grains of sand in the pool.

That's alot of stars !!

I've heard a good comparison for the number of stars in our Milky Way

If you filled an Olympic swimming pool with sand, there would be the same number of stars in the galaxy as there is grains of sand in the pool.

That's alot of stars !!

Yeah but it'd be a pig to clean it back out. And the filters would probably be wrecked.

not directly related but in a seperate incarnation as a teacher/lecturer im constantly reinventing distance scale factors. Im always thrown by galactic sizes but not by Cosmological ones. what do I mean?
Well given a Sun the size of your fist (10cm = sol) I reckon a solar system would form about the size of a building or small campus with an inner solar system the size of a large hall. (1 AU= 100 sols = 10m) On that scale the nearest star is about half way round the Earth.( 250,000 AU =25,000 km~ 1Pc)

And so I hit a wall because on that scale, the Moon is 20 Pc the Sun about 1000 Pc. The Galactic Core (15,000 Pc) is way out near Neptune. Actually this isnt bad since we could put the Galactic core at the Sun and the visible Galaxy might fit innside the Kuiper Belt.

Anyway the Universe is much easier as i see it. If you take the Galaxy to be your fist. (1 million Ly = 1 metre) Given about 14 giga Years for the age of the universe that is about 150 billion Ly in size. Which is about the distance to the Sun! So the universe isnt really that big at all

No doubt my comfort is because I used the same solar System scaling factor. Don't we have this anthrocentric habit of comparing everything to us?

4 billion would be far too light.

Yes, slip of the brain there. (I was wondering who would be the first to spot the deliberate mistake ) I obviously meant from 100 to 400 billion, not 1 to 4.

I've heard a good comparison for the number of stars in our Milky Way

If you filled an Olympic swimming pool with sand, there would be the same number of stars in the galaxy as there is grains of sand in the pool.

That's alot of stars !!

Yeah but it'd be a pig to clean it back out. And the filters would probably be wrecked.

Pass me the shovel, I'm digging my way outa here !

I see in this month's S@N that they reckon star formation is at ~4 solar masses of gas condensing into stars each year.
As the average star is less massive than the Sun, that ~= 7 stars per year.

The Milky Way has so far converted ~90% of it's gas content into stars.

Est.'d stellar death is at ~2 high mass stars going supernova each CENTURY :shock: , with one planetary nebula from a low mass star each year.

So => star birth rate > star deaths.

I would have thought the rates might all have been a bit higher....