3243: Crystal Gazing

2026-05-08T18:17:06Z

2A02:21B4:9E01:1400:38D0:50D4:7A74:73EE: /* Explanation */

{{comic
| number = 3243
| date = May 8, 2026
| title = Crystal Gazing
| image = crystal_gazing_2x.png
| imagesize = 281x397px
| noexpand = true
| titletext = 'Beyond that lies a vale of fire through which my vision cannot penetrate' is the kind of fun thing geologists, heliophysicists, and early universe cosmologists have a lot of opportunities to say.
}}

==Explanation==
{{incomplete|This page was created over 4.54 billion nanoseconds ago. Don't remove this notice too soon.}}

A geologist dressed up as a wizard announces - in archaic language befiting his costume - that he has determined the age of the earth by analysing zircon. Zircon is a crystal with the formula ZrSiO4. During its formation it can incorporate Uranium instead of Zirconium in its lattice - but no lead. However Uranium decays (via several intermediates) into lead. Thus a sufficiently old Zircon crystal will contain some lead, allowing geologists to calculate its age. This method is especially reliable since Uranium 238 decays into Lead 208 with a half life of 4.5 billion years while Uranium 235 decays into Lead 207 with a half life of 0.7 billion years. This allows geologists to determine the age even if some lead was lost from the crystal.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}

A character in wizard garb with long beard and hair talks to Cueball. To the left of the wizard is a chart with two lines intersecting.

"By gazing into my crystals of zircon, I have divined the date of the hour of fire marking the limit of this world's existence.

4.54 billion years ago, the beginning was nigh!"

Text below comic: Geochronologists are just reverse prophets of doom.

{{comic discussion}}<noinclude>

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3243: Crystal Gazing