Scaling: Why Giants Don't Exist

http://galileoandeinstein.physics.virginia.edu/lectures/scaling.html

by soundsop • 16 years ago

35 16 16 years ago

galileoandeinstein.physics.virginia.edu

tdmackey• 16 years ago

Dinosaurs and Google. 'nuff said.

I thought of Google when I read the article, when I got to the line about large animals being made possible by the development of the circulatory system.

It seems like there has to be a qualitative change to deal with scale. Moore's Law has multiplied computing power by a factor of roughly a million over 30 years. In most of the industry, that capacity has been eaten up by productivity enhancements. We have CPU cycles to burn, so we burn them in interpreted languages like Python and Ruby and IDEs like Eclipse, for some marginal increase in productivity.

Google chose to burn them by processing larger and larger data sets, instead. And there're certain emergent phenomena that occur as the data set gets bigger. Almost nothing in search or ads would work with the data available at desktop-scale.

The interesting thing is that by pushing on data size instead of productivity, Google's had to find other ways to scale productivity and the number of engineers in the organization. I've mentioned some of the public ones in a previous comment (http://news.ycombinator.com/item?id=1101443); there're some others that I don't think I can talk about. But I find this whole notion of where you allocate resources fascinating. There's this conventional wisdom of always putting them into developer productivity, but Google's succeeded because they sometimes (judiciously) choose to move them into processing more data and find other ways to work around the productivity hit that entails.

InclinedPlane2• 16 years ago

I've continued to be perplexed by the lack of other companies copying Google's revolutionary style of data center operations. It makes such a huge difference in Google's capabilities (and their bottom line), yet data center operations outside of Google haven't changed much in a decade.

roc• 16 years ago

While that bit may seem flippant, I also wonder about dinosaurs and scaling.

They don't seem to have half the supposed skeletal size that they 'should' according to simple scaling.

Mz• 16 years ago

My understanding is that the earth's atmosphere used to be far denser and the oxygen concentration far higher. This is what allowed giant roaches and the like to exist at one time. Dinosaurs evolved in a different world than we live in.

I'm not real up on this information -- it's my sons who are really interested in it, not me -- but this detail sticks with me because I used to really be bothered by giant spiders in movies. One day, while watching something on TV that talked about dinosaurs and other historical critters, they showed a very large spider and said "If this spider were alive today...(it would the size of a house cat or hunting house cats or something)" and I said "If it were alive today, it would be on life support." My sons cracked up. And I no longer get freaked by giant movie spiders. They can't exist in earth's current atmosphere, which is why they don't exist on earth today.

AngryParsley• 16 years ago

On Being the Right Size is in the same vein:

"You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes."

http://irl.cs.ucla.edu/papers/right-size.html

radley• 16 years ago

This topic was investigated many years ago and was known as "The Physics of Lilliput."

For those who are only familiar with Gulliver's Travels as a movie, the 18th century book also includes a visit to a land of giants (Brobdingnag) and other places (http://en.wikipedia.org/wiki/Gulliver%27s_Travels).

Thus the physics studied applied to both giants and mini-people (re: @AngryParsley).

(only reference I could find: http://www.brookscole.com/physics_d/templates/student_resour...)

jackchristopher• 16 years ago

The overall field is called allometry. Kleiber's Law is another reason behind our size and shapes: http://en.wikipedia.org/wiki/Kleiber%27s_law

"for the vast majority of animals, an animal's metabolic rate scales to the ¾ power of the animal's mass."

Apreche• 16 years ago

On a planet with lower gravity, the same rules would apply, but the ratio would differ. A much larger human could exist there with the same proportions as an Earth human.

Perhaps this is how Galactus exists. He lives in space, where there is effectively zero gravity. Thus, he can be gigantic without any problems.

subud• 16 years ago

On a related note, there are some geologists who believe the Earth has increased in volume/mass over millions of years:

http://en.wikipedia.org/wiki/Expanding_Earth

For instance, dinosaurs grew very large because the Earth was much smaller with less mass and gravity.

Scaling: Why Giants Don't Exist

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