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# Which Is Greater, The Number Of Sand Grains On Earth Or Stars In The Sky?

Mon 17 Sep, 2012 09:59 am
Which Is Greater, The Number Of Sand Grains On Earth Or Stars In The Sky?
September 17, 2012
by Robert Krulwich - NPR

Here's an old, old, question, but this time with a surprise twist. The question is — and I bet you asked it when you were 8 years old and sitting on a beach: Which are there more of — grains of sand on the Earth or stars in the sky?

Obviously, grains and stars can't be counted, not literally. But you can guestimate.

Science writer David Blatner, in his new book Spectrums, says a group of researchers at the University of Hawaii, being well-versed in all things beachy, tried to calculate the number of grains of sand.

They said, if you assume a grain of sand has an average size and you calculate how many grains are in a teaspoon and then multiply by all the beaches and deserts in the world, the Earth has roughly (and we're speaking very roughly here) 7.5 x 1018 grains of sand, or seven quintillion, five quadrillion grains.

That's a lot of grains.

OK, so how about stars? Well, to my amazement, it turns out that when you look up, even on a clear and starry night, you won't see very many stars. Blatner says the number is a low, low "several thousand," which gives the sand grain folks a landslide victory. But we're not limiting ourselves to what an ordinary stargazer can see.

Our stargazer gets a Hubble telescope and a calculator, so now we can count distant galaxies, faint stars, red dwarfs, everything we've ever recorded in the sky, and boom! Now the population of stars jumps enormously, to 70 thousand million, million, million stars in the observable universe (a 2003 estimate), so that we've got multiple stars for every grain of sand — which means, sorry, grains, you are nowhere near as numerous as the stars.

So that makes stars the champions of numerosity, no?

Ummm, no. This is when Blatner hits us with his sucker punch. Yes, he says, the number of stars in the heavens is "an unbelievably large number," but then, very matter-of-factly, he adds that you will find the same number of molecules "in just ten drops of water."

Say what?

Let me repeat: If you took 10 drops of water (not extra-big drops, just regular drops, I'm presuming) and counted the number of H2O molecules in those drops, you'd get a number equal to all the stars in the universe.

This is amazing to me. For some reason, when someone says million, billion or trillion, I see an enormous pile of something, a grand scene, great sweeps of desert sand, twirling masses of stars. Big things come from lots of stuff; little things from less stuff. That seems intuitive.

But that's wrong. Little things, if they're really little, can pile up just like big things, and yes, says Blatner, water molecules "really are that small."

So next time I look up at the sky at all those stars, I will be impressed, of course, by the great numbers that are out there. But I will remind myself that at the other end of the scale, in the nooks and crannies of the physical world, in the teeniest of places, there are equally vast numbers of teenier things.

We are surrounded by vastness, high and low, and either way, as Blatner's book says, we "can't handle the biggitude."

PHOTOS

http://www.npr.org/blogs/krulwich/2012/09/17/161096233/which-is-greater-the-number-of-sand-grains-on-earth-or-stars-in-the-sky
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Type: Discussion • Score: 8 • Views: 2,748 • Replies: 15

farmerman

3
Mon 17 Sep, 2012 12:49 pm
@BumbleBeeBoogie,
now ya made me lose count

65 437 097 002 291.....,65 437 097 002 292....
0 Replies

Lustig Andrei

2
Mon 17 Sep, 2012 06:31 pm
@BumbleBeeBoogie,
Love that word "biggitude." Whole article is worth that word alone.
oralloy

0
Mon 17 Sep, 2012 09:13 pm

Infinite universe = infinite stars.

Finite planet = finite grains of sand.
Ceili

2
Mon 17 Sep, 2012 10:29 pm
@oralloy,
Finite? Sand is constantly being made, from sea shells to the mountains eroding, not to mention all the broken bottles.. Why didn't they count all the sand at the bottom of the seas?
farmerman

2
Tue 18 Sep, 2012 05:30 am
@Lustig Andrei,
From the infinitive, "Embiggen"

0 Replies

raprap

1
Tue 18 Sep, 2012 06:32 am
@Ceili,
I used this as a word problem in an HS senior AP Chemisty class.

Quote:
Assume all sand paticles are an uniform 5 micron spheres, and knowing that the close packing of spheres is an optimal 60%, How many grains of sand would make a sphere the size of the earth.

Express this number in equivalent moles of sand grains.

I used this question to give my students a feeling of the size of a molecule and the magnititude of a mole.

Rap

0 Replies

1
Tue 18 Sep, 2012 06:55 am
@BumbleBeeBoogie,
I thought "stars" because logically there can only be a finite number of grains of sand as the earth is so big. Whereas the universe is infinite therefore the number of stars would be infinite.
0 Replies

1
Tue 18 Sep, 2012 06:56 am
@oralloy,
say thought process...
0 Replies

1
Tue 18 Sep, 2012 06:56 am
@Ceili,
But there is finite land mass - whereas the universe space-wise is infinite - also stars are continously being created ....
0 Replies

imans

-1
Tue 18 Sep, 2012 08:18 am
@BumbleBeeBoogie,
when truth exist then infinite small or infinite big dont matter, that is why u never heard of what a star did or sand

truth is abstract existence since it is in freedom conception of its value while it was objective to conceive, moron believers in god looovvv to ****

yea u love to **** too good for u and him and her and it all lovers of **** united as one **** u
0 Replies

JLNobody

1
Wed 19 Sep, 2012 11:37 pm
@BumbleBeeBoogie,
After a certain point size (large or small) in both space and time becomes meaningless to me.
Befuddled
imans

0
Thu 20 Sep, 2012 12:28 am
@JLNobody,
while size is all what matters from where it is the source of all means
which prove the fake u r as well as the violater of any spacetime

get down forever fucked, it is the end
imans

-1
Thu 20 Sep, 2012 12:33 am
@imans,
only through size concept reality mean the truth

but when the size is true then it stops to mean it as a matter of fact reality

small size mean freedom in truth
big size mean facts in truth

truth is existence freedom, so facts superiority before free superior moves

**** u
0 Replies

MontereyJack

2
Thu 20 Sep, 2012 01:00 am
Want another number to think about?

There are around six trillion human cells in your body.

There are around SIXTY trillion non-human cells (bacteria, fungi, etc.) in your body. In other words, the vast majority of you is not human. I'm not either. It's like that famous New Yorker cartoon of two dogs looking at a computer monitor, and one says to the other "No one can tell you're really a dog on the internet." No one can tell you're mostly an alien on the internet.
Cyracuz

1
Thu 20 Sep, 2012 05:52 am
@MontereyJack,
The human parts is the alien bit..
0 Replies

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