Cows are expensive. Cow meat, in particular, is resource-intensive. That’s what worries people who look at population growth trends. Meat needs a lot of resources to grow, specially cows and such. And global demand for beef will continue to increase as people climb out of poverty and seek more efficient sources of nutrition. Someone on Quora asked about the cost of growing crickets compared to the cost of growing cows for beef, and this particular answer had some numbers. Alex Drysdale, CEO of Changing What We Eat writes the following:
Crickets are approximate 20x more efficient overall as a food source compared to beef.
They grow 13 x faster (6wks vs 18m) than cattle, on 2000 x less land (0.0125 acres vs 25 acres), with 2000 x less water and 13 x less feed.
I wanted to find the equivalent amounts of each animal to produce the same protein, so I calculated a few things.
How many crickets would it take to grow a cow’s beef worth of protein?
Disclaimer: I have not added sources to this, I just did quick Google searches for numbers that seemed reasonable and rounded extremely variable ones. I might add better sources in the future.
How much protein does an average cow have?
Let’s take a big cow that reaches an adult weight of 680 kilos. 43% of the cow’s weight is meat for consumers. That is 292.4 kgs of beef. 1 kilogram of beef has an average of 154 grams of protein. (depending on the cut)
292.4 kgs of beef therefore contains 45 kilograms of protein. This is, roughly, an estimate of what an average cow that weight would have.
How many crickets does one need to produce 45 kgs (1 cow’s worth) of protein?
1 kilogram of crickets contains about 129 grams of protein. Dividing that by 2.86, we know that there are 45 grams of protein in 349.6 grams of crickets. 45 - 349 600 4.5 - 34 960 0.45 - 3 496 0.045 - 349.6 Multiplying (4.5 x 10^-2) and 10^3, we get 45 kilos, and the corresponding amount of crickets needed to produce that is 349 kilos. That is a third of a tonne! If an average 6-week old cricket (adult) weighs give or take 385 grams, it means that we need about 910 crickets to match the protein content of a cow’s worth of beef.
How much water is needed to grow that cow versus all the crickets?
A cow, on a normal day might need about 26.5 litres of water, depending on temperature. On hot days it might need twice as much! Over 77 weeks, which is the 18 months a cow takes to grow full-sized, this consumption amounts to 14 283.5 litres of water. A cricket consumes about 2000 times less water than a cow, according to Drysdale above. This is about 0.0135 litres daily, or 13.5 mililitres (grams). 910 crickets, drinking 13.5 grams of dat H20 stuff amounts to 12 litres a day. Over the course of 6 weeks, the time it takes for them to grow from pinheads to adult-sized crickets, this adds to 504 litres. If we take Drysdale’s figure of a two-thousandth the water intake of a cow, but adjust for equivalent protein output, the more accurate number is a 1/28 the water input. Let that sink in. This means that in 7% it takes to raise a cow, and with 3.5% of the water used. Our dependence on meats from vertebrates is a heavy burden on ecosystems and takes up a lot of energy, which drives currently a lot of emissions into the atmosphere. It contributes to droughts (I am looking at you, California), and it means land is cleared. It also serves as a distraction. Who gives two monkeys’ if the beef is organic? Or freerange? Those points are on very shaky ground here. Seriously.
A while back I stumbled across the following video, and the conundrum in it resurfaced in my thoughts later and I presented it to a few friends. It provided an interesting hour or two at the college cafeteria for discussion, and tons of disagreements.
One person in particular suggested the following:
The speed of the information traveling through the plank would approach the speed of light (c) as the bonds joining the atoms in the plank become 'stiffer', and if you had a completely rigid atomic structure, the plank's other end would move nearly instantaneously as the information traveled faster than light. The whole structure would move in unison if we reached complete stiffness, as there is no room for contraction waves and every particle moved at the same time.
The first part of this is correct as described in the following formula for the speed of sound:
(from Wikipedia) Where:
E is a coefficient of stiffness, the bulk modulus (or the modulus of bulk elasticity for gases),
The speed of sound decreases with density p and increases with bulk modulus (stiffness), which in solids is Y, Young's modulus.. The question then is, what is the highest that E can be?
The transfer of this movement through the plank is a pressure wave that moves the atoms within. When an atom is pushed, its electrons create a force against the electrons of the neighbouring atom, moving it and causing eventually the whole system to be displaced when the movement reaches the end of the plank. Diamond, the hardest bulk material known to man, has a speed of propagation of 1200 m/s (as opposed to air's speed of about 340. This is because diamond is not very elastic at all and it has the density of carbon. However, dealing with a theoretical material with total stiffness, we run into a problem.
Faster than light or near instant?
Can infinitely high bulk modulus allow sound to surpass c, the speed of light? Is this property possible? Firstly, atoms have a limit
on their bonds' rigidity; and there are reasons why infinite bulk modulus does not make sense.
A completely rigid system would mean that the initial atom would not be able to move in relation to the one next to it, with no relative change in distance between them, and no push exerted. This means all the energy would be absorbed and none would be transferred onto the next atom. Clearly this is a problem. It might seem counter-intuitive but the idea of completely stiff atomic bonds does not make sense since atoms need at least some degree of movement in order to act on nearby atoms.
The idea is a lazy one because it doesn't explain how atoms could transfer energy to each other. Infinite stiffness does not make sense and could allow one to decide its outcome as anything because it is undefined. Dividing infinity by a finite number and taking its square root will give you an undefined answer.
This model ignores the restrictions of our current model of the universe, and therefore the current model of the universe cannot tell us anything useful about it. Ok, so if instant movement does not make sense by definition, we need to consider the next issue issue: the possibility of information traveling faster than c, the speed of light. Tachyons are the only exception to this rule and as far as science has seen, they do not exist. Furthermore, other areas of astronomy can shed some light on this, as this passage I quote from here, about the largest theoretical size of neutron stars before they collapse into black holes:
Since the conditions in a neutron star are very difficult to duplicate on
Earth, nobody is exactly sure just how big a neutron star can be. One
indirect argument is based on the fact that as a neutron star becomes more
massive, it must become stiffer to maintain itself, and the speed of sound
through the star increases accordingly. Above six solar masses, the speed of
sound exceeds that of light, which is ruled out by Einstein's theory of
relativity.
Six solar masses is only an upper bound on the size of a neutron star. More
practical calculations estimate the upper limit as three solar masses. No
objects confirmed as neutron stars are known that are larger than two solar
masses; the mass is typically about 1.35 solar masses.
At the speed of light, or below?
Once we discard the possibility of faster-than-light sound-waves, one begins to wonder; what is the speed of a force? This might sound strange, but firstly, the energy is transferred from one end of the plank to the other through electromagnetic force that, as mentioned before, keeps atomic and subatomic particles apart. According to the standard model and the theory of relativity, forces travel at the speed of light, so the weak and strong nuclear forces, gravity and electromagnetism are not instantaneous as may be perceived in the small scales in which we might perceive them.
In the link above, the following possibilities are explored by some people:
Plasma: matter in this state goes by slightly different mechanics, and bulk modulus would be the energy associated with electron degeneracy, and the guesstimated speed would reach about 500,000 m/s. (100 times slower than light).
Neutron stars: electron degeneracy is followed by neutron degeneracy which makes matter collapse onto itself. This causes the bulk modulus to rise exponentially (as predicted by my friend). To quote the result:
"At
that point, information from the center of the star can barely reach
the edge, whether it's light or sound, so the local speed of sound at a
neutron star just about to become a black hole would probably be just
about light speed.
References:
I used no references and I also don't know what I am talking about.
Please do not substitute this answer for medical advice."
The distance the electromagnetic forces communicate movement through is not the space between the atoms (atoms are mostly empty space);
it's the space between the electromagnetic fields of the electrons that
interact with each other. That space is VERY CLOSE to a light year long
in our experiment. The whole process of movement includes this space
plus the distance particles (which can't be completely rigid) must
travel to influence one another. In theory, as long as the formula used to calculate it does not provide
undefined answers, none of the parameters stray off the current model of the
universe we understand and the answer reaches c but isn't equal to it, there would be little reason to dismiss claims
of the possibility that some materials may be able to transmit at
almost such speeds. The best example I could find was in this following paper that concludes that evaluating equations at different densities for neutron stars all yield values for the speed of sound inferior to c.
Wait a minute! What about black holes?
Most of the theory before this deals with matter before it collapses into black holes. Most mathematical models explaining spacetime and force break down when they deal with black holes since they consist of matter that has collapsed further than a neutron star would have and has become so compressed it ceases to have actual volume.
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