According to experts, the Gregorian calendar was introduced to better reflect the time it takes Earth to orbit the Sun. But it is believed by many that as many as 11 days were lost from the year that was once determined by the Julian calendar.
Over time these lost days add up and now a conspiracy theory has cropped up which claims that we should actually be in the year 2012, not 2020.
In a since deleted tweet, scientist Paolo Tagaloguin reportedly said: “Following the Julian Calendar, we are technically in 2012. The number of days lost in a year due to the shift into Gregorian Calendar is 11 days. For 268 years using the Gregorian Calendar (1752-2020) times 11 days = 2,948 days. 2,948 days / 365 days (per year) = 8 years”.
Following this theory, June 21, 2020 would actually be December 21, 2012.
It may be recalled that in 2012, December 21 was proposed by some as the end of the world by conspiracy theorists.
https://nypost.com/2020/06/13/reading-of-mayan-calendar-suggests-end-of-the-world-is-next-week