Comments on: Stars and Sand Grains http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/ Explore science, nature and environment stories from Northern California and beyond with KQED’s multimedia series Fri, 10 Feb 2012 05:38:00 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Rvaldez4108 http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-25006 Rvaldez4108 Tue, 03 Jan 2012 09:08:00 +0000 http://www.kqed.org/quest/blog/?p=957#comment-25006 Oops...I was trying to recall the numbers but more acurrately, it would be: first two grains, half-mile, third grain representing furthest star in milky galaxy, 125 miles, fourth in Andromeda - 3,125 miles and finally, fifth representing furthest star in the universe, 17.5 million miles away. Or 700 times around the Earth. At the size of a grain of sand - pretty impressive. Oops…I was trying to recall the numbers but more acurrately, it would be: first two grains, half-mile, third grain representing furthest star in milky galaxy, 125 miles, fourth in Andromeda – 3,125 miles and finally, fifth representing furthest star in the universe, 17.5 million miles away. Or 700 times around the Earth. At the size of a grain of sand – pretty impressive.

]]> By: Rvaldez4108 http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-25005 Rvaldez4108 Tue, 03 Jan 2012 08:06:00 +0000 http://www.kqed.org/quest/blog/?p=957#comment-25005 So I next asked her to imagine that two of the grains we held in our hand (one representing our sun and one the nearest star) were placed at proportional distances from each other. She'd have to walk the grain a half-mile down the beach. I was doing the numbers in my head so they're very rough. If we took a third grain representing the furthest star in our galaxy, she'd have to walk 13.5 miles. Take a fourth representing a star in Andromeda, and she'd have to fly 338 miles away. Take a fifth representing the furthest star and she'd have to be 1.9 million miles away. She lost interest at 338 miles. ;) So I next asked her to imagine that two of the grains we held in our hand (one representing our sun and one the nearest star) were placed at proportional distances from each other. She'd have to walk the grain a half-mile down the beach. I was doing the numbers in my head so they're very rough. If we took a third grain representing the furthest star in our galaxy, she'd have to walk 13.5 miles. Take a fourth representing a star in Andromeda, and she'd have to fly 338 miles away. Take a fifth representing the furthest star and she'd have to be 1.9 million miles away. She lost interest at 338 miles. ;)

]]> By: Rvaldez4108 http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-25004 Rvaldez4108 Tue, 03 Jan 2012 06:49:00 +0000 http://www.kqed.org/quest/blog/?p=957#comment-25004 This is so cool! One of the best summaries I've seen on the subject of sand grains versus star counts. Mind boggling until you mention the water molecules being 3000x! But your's is one of the few with depth defined. I told my daughter about this "fact" last summer when we were at the beach and she said "but how deep?". Oops...I hadn't read that anywhere. This is so cool! One of the best summaries I've seen on the subject of sand grains versus star counts. Mind boggling until you mention the water molecules being 3000x! But your's is one of the few with depth defined. I told my daughter about this "fact" last summer when we were at the beach and she said "but how deep?". Oops…I hadn't read that anywhere.

]]> By: fatalflaw http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-24970 fatalflaw Thu, 15 Dec 2011 05:57:00 +0000 http://www.kqed.org/quest/blog/?p=957#comment-24970 http://www.youtube.com/watch?v=7wwZ2OQ8WNA http://www.youtube.com/watch?v=7wwZ2OQ8WNA

]]> By: George Whaley http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-11713 George Whaley Fri, 02 Oct 2009 16:57:03 +0000 http://www.kqed.org/quest/blog/?p=957#comment-11713 I take your point about considering only beaches. It is clearly an important difference as many instances of this question being discussed do fail to make the distinction. In any case the visible universe is only a fraction of the (unknowable?) total so the universe may well win out. I take your point about considering only beaches. It is clearly an important difference as many instances of this question being discussed do fail to make the distinction.
In any case the visible universe is only a fraction of the (unknowable?) total so the universe may well win out.

]]> By: Ben Burress http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-11712 Ben Burress Fri, 02 Oct 2009 14:50:20 +0000 http://www.kqed.org/quest/blog/?p=957#comment-11712 There are many ways to slice and dice this calculation. In my own, I was confining my example to only the sand of Earth's beaches (not deserts), and taking every opportunity to use conservative estimates for the variables. But the point of my estimation was not so much to try to calculate how many grains of sand there are, but demonstrate the number of stars in the Universe. Even if you regard my conservative beaches with their coarse sand grains, the fact is, that's a heck of a lot of sand! And if my (maybe unrealistically) conservative sand sum is in the ballpark of the Universal star-sum, as long as I've achieved mind-boggledom, I'm satisfied.... There are many ways to slice and dice this calculation. In my own, I was confining my example to only the sand of Earth's beaches (not deserts), and taking every opportunity to use conservative estimates for the variables. But the point of my estimation was not so much to try to calculate how many grains of sand there are, but demonstrate the number of stars in the Universe. Even if you regard my conservative beaches with their coarse sand grains, the fact is, that's a heck of a lot of sand! And if my (maybe unrealistically) conservative sand sum is in the ballpark of the Universal star-sum, as long as I've achieved mind-boggledom, I'm satisfied….

]]> By: George Whaley http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-11711 George Whaley Fri, 02 Oct 2009 12:32:39 +0000 http://www.kqed.org/quest/blog/?p=957#comment-11711 This longstanding issue has been discussed again recently (on BBC)and notwithstanding many web pages giving calculations I am deeply distrusting of the maths. I have just measured (roughly) some garden sand and reckon it at 100 grains per mm^3. 10^22 (stars) = 100x1000^3x1000^3x100 =100 km^3 of garden sand. The sandy region of the Sahara desert (alone) is some 2.5 million km^2 which is 2500 km^3 or 25 universes per metre depth. As to the rest of the world's deserts, beaches... Or have I missed something? This longstanding issue has been discussed again recently (on BBC)and notwithstanding many web pages giving calculations I am deeply distrusting of the maths. I have just measured (roughly) some garden sand and reckon it at 100 grains per mm^3. 10^22 (stars) = 100×1000^3×1000^3×100 =100 km^3 of garden sand.
The sandy region of the Sahara desert (alone) is some 2.5 million km^2 which is 2500 km^3 or 25 universes per metre depth.
As to the rest of the world's deserts, beaches…

Or have I missed something?

]]> By: Ben Burress http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-11710 Ben Burress Mon, 27 Apr 2009 22:32:02 +0000 http://www.kqed.org/quest/blog/?p=957#comment-11710 And even after doing the math, part of me still can't believe it. This was reinforced recently as I sat on a beach in Half Moon Bay, surveyed all that sand, and just could not get my belief in gear. There's another sand and star scale mind game that goes like this: If all the stars in the sky that we can see with our eyes (without a telescope) were stand grains, they would fill a thimble. All of the stars in the Milky Way Galaxy would fill a wheelbarrow. To represent all the stars in the visible universe this way, you would have to haul in the sand with a train, one boxcar-ful per second, 24 hours a day for 3 years.... And even after doing the math, part of me still can't believe it. This was reinforced recently as I sat on a beach in Half Moon Bay, surveyed all that sand, and just could not get my belief in gear.

There's another sand and star scale mind game that goes like this: If all the stars in the sky that we can see with our eyes (without a telescope) were stand grains, they would fill a thimble. All of the stars in the Milky Way Galaxy would fill a wheelbarrow. To represent all the stars in the visible universe this way, you would have to haul in the sand with a train, one boxcar-ful per second, 24 hours a day for 3 years….

]]> By: Jim Fisher http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-11706 Jim Fisher Tue, 10 Feb 2009 05:10:56 +0000 http://www.kqed.org/quest/blog/?p=957#comment-11706 I've been meaning to calculate this ever since I first read the "sand in the beaches" statement in Carl Sagan's "Cosmos." Thanks for saving me the time. I've been meaning to calculate this ever since I first read the "sand in the beaches" statement in Carl Sagan's "Cosmos."

Thanks for saving me the time.

]]> By: Jonas Kulland http://science.kqed.org/quest/2008/11/21/stars-and-sand-grains/#comment-11707 Jonas Kulland Wed, 04 Feb 2009 21:35:35 +0000 http://www.kqed.org/quest/blog/?p=957#comment-11707 Mindblowing indeed! Thanks for the perspective. Mindblowing indeed!
Thanks for the perspective.

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