Explain xkcd: It's 'cause you're dumb.
All matter in the universe (heavier than lithium-7) was created through nuclear fusion of hydrogen atoms inside stars over the 13.8 billion years that have gone by since the Big Bang. A detailed explanation (for the lay man) of this process is available in this article about Making Atoms.
From this article (and from the wiki article on Big Bang) it is clear that our universe began not only with hydrogen. Although the majority of atoms produced by the Big Bang were hydrogen, lots of helium and traces of lithium were also produced. Actually about 25% of the mass in the universe comes from helium created shortly after the Big Bang. In stars, however, helium is also created directly from hydrogen atoms. So it would have been enough to just start out with hydrogen in the early universe. Given enough time, all the other elements would have been created inside these originally hydrogen-only stars. To make elements heavier than helium some of the elements created by hydrogen, will have to fuse subsequentially. And in order to make elements heavier than iron, a supernova explosion is needed. But in either case it is still products of hydrogen that fuse together.
In many countries, food products must have their ingredients displayed somewhere on their packaging. Because all the ingredients in any food are either hydrogen or heavier atoms created through stellar nuclear fusion from hydrogen over time, the ingredients of any items can technically be described fully as only being made from hydrogen and time. Thus this label would be the universal label. A pun on two of the meanings of the word universal. Any food is of course universal as in a part of the universe. But the label can also be a universal label as in a common label for all food or any other product in the universe, as well as the universe itself for that matter.
The title text first makes it clear that this works both for any grocery as well as any non-grocery, which as described above simply means anything else. It then goes on to making a pun on the words thyme (a herb) and time, as the two words are homophones. "H" is the chemical symbol for hydrogen thus completing the pun by noticing that the word "thyme" can be made by adding the letter "h" to "tyme" which would be a homophone even closer to the word time.
Randall previously made a joke on the fact that thyme and time are homophones in 282: Organic Fuel.
- Hydrogen, Time
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I think Randall may be going for another pun with the title text, as "H" is the chemical symbol for hydrogen.--Dangerkeith3000 (talk) 15:42, 19 October 2012 (UTC)
I suspect that without Helium and a little Lithium we wouldn't even be here discussing this. These were both formed independently of Hydrogen shortly after the BB and without them the first stars would have been huge and short-lived...18.104.22.168 14:34, 19 October 2012 (UTC)
- ... in other words, with the addition of time... -- IronyChef (talk) 13:44, 20 October 2012 (UTC)
But you can make matter using energy, therefore, you only need energy and time! Ray
The label's missing energy. Just saying. Davidy22 (talk) 04:34, 19 October 2012 (UTC)
- But isn't it somehow contained in the hydrogen? I don't know squat about quantum physics, so I'm probably wrong. 22.214.171.124 04:49, 19 October 2012 (UTC)
- Actually, the amount of energy in any grocery or non-grocery (even in explosives) is significally lower that the amount of energy in hydrogen used for their creation. Sure, you need energy to grow crops, but where does that energy come from? Hydrogen fusion in Sun - which is first step of creating the carbon the crop is from (not the same crop, of course). -- Hkmaly (talk) 09:12, 19 October 2012 (UTC)
So when Mussolini made the trains run on thyme he was really making them run on hydrogen and time?--Pmakholm (talk) 08:18, 19 October 2012 (UTC)
I think this is the smallest xkcd comic ever. :-)
--126.96.36.199 09:43, 19 October 2012 (UTC)
It's also the first in a long time to make me laugh out loud! Steve B.
I suspect Randall was influenced by this quote: "Given enough time, hydrogen starts to wonder where it came from, and where it is going", attributed to Edward R. Harrison. --Prooffreader (talk) 10:58, 19 October 2012 (UTC)
Actually, I'm not sure you can make antimatter with just regular hydrogen.
--188.8.131.52 11:24, 19 October 2012 (UTC)
- Why would food contain antimatter? --Kronf (talk) 12:21, 19 October 2012 (UTC)
I think I've spotted my first Randall mistake. Using this ingredient list, The amount of time must exceed the amount of hydrogen (unless the product is hydrogen) thus Time should be listed first on the label. — Comment by 14:09, 19 October 2012 (talk) Anthingy (please sign your comments)
- Which units are you using? How do you relate a cup full of Time and a day full of Hydrogen? 184.108.40.206 18:20, 19 October 2012 (UTC)
- In Norway (and I guess most other countries where producers must list them) ingredients are sorted by weight, and I guess time doesn't weigh anything but in a metaphorical sense. --Buggz (talk) 08:39, 22 October 2012 (UTC)
- Even if time weighs nothing, isn't Hydrogen lighter than air at 1 atmosphere? That would give it a negative weight, so it should be listed last.220.127.116.11 04:05, 18 November 2012 (UTC)
- There's a significant difference between having negative weight and being positively buoyant in Earth atmosphere. Weight is simply the acceleration caused by gravity (9.8 m/s^2, here on Earth) multiplied by mass (.0899 g for each litre of hydrogen). Hydrogen has mass (and therefore weight); time doesn't. --LiteralPhilosopher 18.104.22.168 11:45, 26 November 2012 (CST)
- Time has a whole lot of wait. -- 22.214.171.124 (talk) (please sign your comments with ~~~~)
Yes, that may be a mistake, but the FDA website mentions "predominance by weight." I'm not sure how time would compare to hydrogen in that respect. Also I translated thyme = H+time = tHime. --126.96.36.199 14:25, 19 October 2012 (UTC)
- Also, it's not Randall's first mistake, he made some in the last comic. ??? 14:31, 19 October 2012 (UTC)
- Implying the above commentor is Randall. 188.8.131.52 15:15, 19 October 2012 (UTC)
Time is not a proper ingredient like hydrogen. It is permitted in Randall's ingredient list by cartoon license.
"Because all matter was originally created through stellar nuclear fusion from hydrogen over time"
Nuclear fusion only explains the creation of all elements up to iron. Heavier elements are created by other processes:
- The fusion of heavier elements is still fusion, even if it takes a supernova to make it happen. Nothing in the cartoon suggests that only the fusion reactions found in stable stars apply, and even more complicated processes (fusion+fission, whatever) involves matter that ultimately has a hydrogen pedigree. (I am, however, intrigued by the comment about helium and lithium in the early universe. I have some of those around here somewhere.) 184.108.40.206 21:02, 19 October 2012 (UTC)
At the risk of nitpicking: The present composition of the universe is about 75% dark energy, 20% dark matter, and 5% baryons, i. e., hydrogen, helium, and everything else. In the early universe, the dark energy was less important. And in the very early universe, before the formation of elements or even subnuclear particles, there were just quantum fluctuations of some primordial field. Space, time, and energy are related by gravity. So maybe, if quantum gravity is ever figured out, it will turn out all you need is a fluctuation in time. But all this spoils the herbal pun.
--220.127.116.11 21:29, 19 October 2012 (UTC)
 Universe / Universal
I also think universal is the adjective for universe.
So the label has universal use and specifies universal origin.
--18.104.22.168 23:08, 19 October 2012 (UTC)
This label has now been applied to every poster of the cosmos in my current school. This applies to both the poster as an item and the subject matter of the image. DruidDriver (talk) 22:22, 22 January 2013 (UTC)
"A detailed explanation of this process is available here"
An obvious rebuttal is found here: http://biblehub.com/job/38-4.htm
There again, of course, merely not being around (and lacking mastery of universal physics).... I used Google News BEFORE it was clickbait (talk) 15:37, 16 January 2015 (UTC)