From their recent 10Q for investors, they list a revenue of $7.8 billion for "Google Network" in revenue for the preceding 3 months before September 30, 2022 [1] There are 90 days in 3 months, so their revenue for a day is approximately

$7.8 billion / 90 days = ~$87 million/day

$87 million / 24 hours = ~$3.64 million/hour

$3.64 million / 60 minutes = ~$60,740 thousand/minute

$60,740 thousand / 60 seconds = ~$1,012/second

And, depending on their agreements with their advertising partners, they might be liable for some of the profits lost by their partners.

[1] https://abc.xyz/investor/static/pdf/20221025_alphabet_10Q.pd...

edit: It was initially using the wrong row, it should be correct now.

It doesn't look like it's affecting their search ads (or if it is, it's not fully down for them), so not the full advertising revenue of GOOG. But it's still likely tens of millions per hour.