"In the nanoseconds that followed, the capsule imploded and released a neutron yield of nearly 3x10^15, or approximately 8,000 joules of neutron energy..."
[...]
"These promising returns were the result of a laser experiment that delivered 1.7 megajoules (MJ or million joules) of ultraviolet light..."
More numbers: https://en.wikipedia.org/wiki/National_Ignition_Facility#NIF...
1.7 megajoules is about 400 kilocalories, or a king size Kit Kat bar. This is the energy of a car going 140 miles per hour. This is about 7 cents of AC power.
Wow. How can those two things be equivalent? I know there's a lot I don't know about physics...
But yes, the comparison is supposed to be to put in natural contexts, and so this is flawed example since we don't really live in space.
2) think about all the things you could do in the hour or so that a king sized Kit Kat bar could keep you energized;
3) visualize the trillions of cell-sized actuations required to perform each step of each task previously listed, and the neural computation required to organize these actions;
4) compare that with the relative simplicity of turning wheel axels to propel a car down the road;
5) marvel at the power of a Kit Kat bar powering the magnificent machine that is you.
140 mph is not a small number; to the power of two it's rather large. Now multiply the result by the mass of a car, which is still pretty huge even halved.
A racing car barreling down the speedway packs a hell of a punch.
Well, a kitkat bar actually has a decent amount of energy in it. Very roughly, the same energy as the same mass of wood, or gasoline. Chemical fuels don't vary too much in terms of energy density. They stay within the same order of magnitude, at most.
And yes, food is chemical fuel.
Probably only a straight-up chemical fuel like gasoline or methane packs more punch per gram.
The energy density of Kit Kat is 22 MJ/Kg (5.2 Kcal/g) http://www.wolframalpha.com/input/?i=%28Kit+Kat+calories+to+...
TNT has 2.8 MJ/Kg in an explosion and 4.2 MJ/Kg in a combustion. It has too much Carbons. In an explosion, it doesn’t react with the oxygen in the air, because it’s too fast. There is an interesting discussion in http://en.wikipedia.org/wiki/Trinitrotoluene#Energy_content
In general, the explosives have to explode without using the Oxygen in the air, so they have a lot of Oxygen and Nitrogen atoms inside. The fuels for slow combustions can have almost only Carbon and Hydrogen atoms to store the energy more efficiently and get the Oxygen from the air.
Nitroglycerin has less Carbons, so has more energy density. Mixed in dynamite has 7.5 MJ/Kg and alone has 6.4 MJ/Kg (Is this correct? I expected a bigger value).
I found a list of these values for a wide range of materials. In particular it says that green wood has 10 MJ/Kg, air dry wood has 15 MJ/Kg and oven dry wood has 20 MJ/Kg. http://physics.info/energy-chemical/
Other values: Gasoline ~45 MJ/Kg, Methane 55.5 MJ/Kg, Hydrogen 142 MJ/Kg
assuming ~4000lb[1] car, 140mph ~= 62.6m/s,
0.5*m*v*v = 0.5 * (4000*0.454) * 62.6^2 = 3.5E6Joules[2]
~= 830kcal
Which is still only 2 kitkats :)
The other potentially confusing thing (judging by the sibling comments here) is that this isn't the energy required to accelerate an actual car from 0 to 140mph. It's the kinetic energy embodied in a car traveling at that speed. Wind & tyre resistance losses, engine/transmission, etc, etc. It's really the (upper bound of the) amount of energy you could expect it to impart if it hit something, or the amount of heat the brakes would need to dissipate to stop it.
Finally, for all those commenting on how much energy there appears to be in a kitkat, consider the famous E=MC^2, and just how staggeringly huge that C^2 term really is (9E16J/kg, if you're wondering) Getting all that out in a usable form, however, is left as an exercise for the reader.
[1] http://www.nytimes.com/2004/05/05/business/05weight.html
http://hypertextbook.com/facts/2000/YanaZorina.shtml
[2] http://www.wolframalpha.com/input/?i=0.5+*+%284000+*+0.454%2...
Anyone who has used a treadmill at the gym will recognize that it's a lot of work to burn off 400 calories. Not enough to get a car up to 140 MPH because the body isn't 100% efficient.