Today’s Tough Trivia question is History, deep history:

When we measure human life spans, we talk about decades. When we measure the lives of countries, we talk about centuries. But when we talk about the history of the planet, we’re talking about geologic time. We divide geologic time into Eons, which are subdivided into eras, which are themselves subdivided into Periods. The cruel questioner in me wants to say “name the Periods,” but I have some mercy. I’m going to give you the Eons, Eras, and Periods. Your job is to put the Periods in the correct Eras (with bonus points for listing them in order).

The Phanerozoic Eon is broken into the Cenozoic (current), Mesozoic, and Paleozoic Eras. The Proterozoic Eon was broken into the Neoproterozoic, Mesoproterozoic, and Paleoproterozoic Eras). Before the Proterozoic was the Archean Eon, broken into the Neoarchean, Mesoarchean, Paleoarchean,and Eoarchean Eras, but we don’t divide that Eon into Periods, so you can ignore it.

Here are the Periods in alphabetical order (some of which we subdivide into Epochs): Calymmian, Cambrian, Carboniferous (Mississippian and Pennsylvanian), Cretaceous, Cryogenian, Ectasian, Ediacaran, Jurassic, Neogene (Miocene and Pliocene), Devonian, Ordovician, Orosirian, Paleogene (Paleocene, Eocene, and Oligocene), Permian, Quaternary (Pleistocene and Holocene), Rhyacian, Siderian, Silurian, Statherian, Stenian, Tonian, and Triassic.

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Friday’s question was:

There is one specific feature or quality that puts these people on the same list, these people and only these people. What is that thing which brings them together? Bonus points if you can also list them in the proper order of their placement on this list (rather than the simple alphabetical order in which they are presented here). Anousheh Ansari, Richard Garriott, Guy Laliberte, Gregory Olsen, Mark Shuttleworth, Charles Simonyi, and Dennis Tito.

The answer is:

They are all the people who have paid to be and then actually travelled into space:

Dennis Tito (April 28–May 6, 2001)

Mark Shuttleworth (April 25–May 5, 2002)

Gregory Olsen (October 1–10, 2002)

Anousheh Ansari (September 20–29, 2006)

Charles Simonyi (April 7–21, 2007)

Richard Garriott (October 12–24, 2008)

Charles Simonyi (second flight, March 26–April 8, 2009)

Guy Laliberte (September 30–October 11, 2009)

As of the date of this writing, there are at least 11 more space tourists scheduled to fly, starting in September.

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Ian’s Tough Trivia is a daily feature of this blog (Monday’s category is History; Tuesday is Arts; Wednesday is Science; Thursday is Entertainment; and Friday is Grab Bag). Each day, I post a tough question, as well as the answer to the previous day’s question. Simply comment on this post with your answer. I’ll approve the comments after the next question is posted. Sure, you can probably find the answers by searching the web, but what’s the fun in that?

And if you’ve got a favorite trivia question—or even just a topic for which you’d like to see a question—let me know! Reader participation is warmly encouraged.