For my May 2019 diary, go here.

Diary — June 2019

John Baez

June 1, 2019

Still snarling after 40,000 years, the head of a giant Pleistocene wolf was just found in the permafrost of Yakutia, east of Siberia! Its fur, fangs and brain are intact.

Last year they found the cub of a cave lion! It's about 50,000 years old, but it died at the age of one month.

Cave lions, Panthera spelaea, lived in Europe, Russia, Central Asia and Alaska. They went extinct 13,000 years ago, near the end of the last glacial cycle.

These animals lived in the mammoth steppe, the world's largest biome from 120,000 to 12,000 years ago. There are just a few small patches of it left, like this nature reserve at the border of Mongolia and Tuva:

As the permafrost melts due to global warming, people are finding amazing things! For example, a team of scientists dissected this 42,000-year-old foal, found well-preserved blood in it, and want to clone it:

To learn more read The Siberian Times. Also click on the pictures. If we cloned some of these Pleistocene animals, we could do some 'rewilding', as described in my September 12, 2007 diary entry.

June 29, 2019

Because Bellard's formula for pi is a sum of terms with big powers of 2 in the denominators, it's good when you want to compute some binary digits of pi without computing all the earlier ones! It's similar to the earlier Bailey–Borwein–Plouffe formula, but it's more efficient for computing individual binary digits of pi.

Bellard's proof is pretty simple.

For my July 2019 diary, go here.


© 2019 John Baez
baez@math.removethis.ucr.andthis.edu

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