#before present

BC has AD.

BCE has CE

what does BP have? Its been a few years since the 1950s

Hmmm, I would propose either 2000 or 2050 as the new benchmark. Although anchoring the BP method in a Western dating system still has the same problems as BCE/CE. The dates 1950, 2000, or 2050 are still based in a system that counts time by marking the supposed death of Jesus.

For sure, Anon!

BP means number of years Before Present (with the present being defined as 1950). It tends to be used for larger increments of time, especially when you get into the deep past.

The BC/AD and BCE/CE systems both use the (approximate) date of the birth of Jesus as their start date, and the further you get from that date, the less useful it becomes.

Gabriel Sierra, Before Present

installation view at Kunsthalle Zürich 2015 photo: THOMAS STRUB

Today, I learned about the "Before Present" time scale, which is used in geology—specifically carbon dating. However, the "present" in the time scale is not defined as "whatever day the test took place," but rather specifically as January 1, 1950.

There are a few reasons for this. First, informally, with the amounts of time we're generally talking about for carbon dating, 65 years or so is usually well outside the realm of necessary precision. Second, that date is more or less when radiocarbon dating became practical. Third, and most interestingly, radiocarbon dating of stuff formed since 1950 is generally considered unreliable because the ratios of different carbon isotopes in the atmosphere were artificially altered by widespread testing of nuclear weapons in the '50s.