# What is the order in numbers of the following

What is the order, in numbers, of the following. (To put it very mildly, all numbers will be very approximate.)

Stars in the sky of the observable universe (A billion galaxies with a billion stars each).
Drops of water in the earth’s oceans.
Grains of sand on earth.
Micro-organisms on earth
Leaves on earth’s trees

Seems like a google-able list to me.

This isn’t right; there are a lot more galaxies than that and they definitely contain much more than a billion stars on average.

IIRC it’s something like 500 billion galaxies with 500 billion stars, on average*, with considerable error bars of course.

• I think the average is pulled up considerably by a few huge galaxies which contain tens of trillions of stars.

Steven Estes, I have contacted you by PM to indicate that you should reduce the number of threads you are starting every day. Since you have chosen to ignore this, I am going to start closing your threads. Please start no more than two threads a day, and wait until some of your questions have fallen off the first page before starting new threads.
From the Registration Agreement:

Colibri
General Questions Moderator

Since no new threads have been opened recently, I am reopening this one. Since the answers require speculation, I am moving this to IMHO.

Colibri
General Questions Moderator

The list is interesting, but not so much that I would try to tackle the math myself, so I googled. Source URLs included below, I rounded all numbers to an even power of 10 (which shouldn’t matter at this level of granularity.)

Viruses 1 x 10[sup]31[/sup]
Bacteria 1 x 10[sup]30[/sup]
Drops 1 x 10[sup]25[/sup]
Stars 1 x 10[sup]24[/sup]
Grains 1 x 10[sup]18[/sup]
Leaves 1 x 10[sup]17[/sup]

Your source gives the size of a drop of water as 1 cubic centimeter. Other sources I’ve checked say that it’s 1/20th of a milliliter. A millimeter of water is 1 cubic centimeter of water, according to sources I’ve checked. So the sources I’ve checked say that there are twenty times as many drops as you’ve indicated. Thus there are 1 x 10^26 drops of water, not 1 x 10^25 (rounding to the nearest order of 10, as you do), assuming my sources are correct.