Some comment I read ages ago convinced me that the real Ultimate Question is “pick a number, any number.” The two bits of evidence for this are paraphrased below.

Marvin talking to the mattress: “I’m roughly a billion times smarter than you. For example, pick a number. Any number.” Mattress: “Ummmm…seven?” Marvin: “Wrong. You see?”

Arthur, while aboard the Heart of Gold, says, “I’m disappointed we never figured out that Ultimate Question business.” Eddie the ship’s computer immediately after says, “Pick a number, any number!”

Given the abilities of each of those characters, it’s a plausible theory. It’s also how the author chose the Answer, so at least at a meta level it is true.

More specifically, Marvin claimed to have a brain the size of a planet.

Adams alluded elsewhere to how the march of technology had brought about galactic scale advances in miniaturisation and exponential growth in the capability of technology.

When deep mind designed the earth she probably used the state of the art for that time however many billions of years ago, but Marvin being a more modern device is far more powerful and can do the same calculations trivially.

Furthermore he always claims to be depressed because despite his eminence nobody will listen to what he says, which is indeed ”pick a number any number” which is probably what DNA said to himself when he selected it.

A tangential question that has always bothered me is "How do you get to Alpha Centauri". Or to put it another way, I can probably set off to Alpha Centauri using today's technology. My corpse would arrive there probably in 130,000 years. Give or take an order of magnitude (I've not run the numbers properly). Now I'm extremely confident that the human race in the next 100 years could design a craft that would be able to travel to Alpha Centauri in less than 129,900 years. So. How do I get to alpha centauri? Just a vaguely interesting question that bothers me.

Or to put it another way, how pissed off would you be when you set off to alpha centuri and you arrive to find your bloody grandson vaping and listening to Lil Nas x.

> My corpse would arrive there probably in 130,000 years

It is infinitely improbable that you would arrive instantly and alive.

Or could just turn to the ol janx spirit ;-)

Except that "pick a number, any number" is not a question.

But it does require an answer.

Yeah but that was because the program running on Earth was corrupted by the presence of the Golgafrinchans arriving in prehistoric times, thus corrupting the output.

That was a bit of retcon though - I remember Adams saying it was just a random number he saw on a fridge, or something equally inconsequential.

wouldn't six by nine be 54? Is this one just soaring over my head?

That's the joke within the joke. Without giving away the plot of the book in question, it's incorrect for a reason.

That's the joke. Everyone in the book thought it was THE ANSWER - but it wasn't. It was wrong.

I think it's a bit more subtle than that, it's not clear if the answer is wrong, the question is wrong, or both are correct and the universe is wrong (although the story does hint towards one in particular being wrong).

Spoiler alert: Try 6 by 9 in base13.

But that isn't a spoiler alert, since it is a coincidence that the author didn't intend.

It's not by nine

The ultimate question of life, the universe, and everything is indeed asking what is 6 multiplied by 9. (42 of course, as any well-read high school student could tell us.)

It's unclear. It's proceeded by a discussion that the question may have been garbled. So we're left with two possibilities:

1) The ultimate question was 6 * 9 = ? and the universe makes no sense at all.

2) The ultimate question was 6 * 7 = ? and the universe has no deeper meaning.

Both are possible, and the ambiguity suggests he wanted to say both.

Have you ever read the source material? If not, you should, and if you have, you still should, since that was a quote