Popular astrophysicist and cosmologist Neil deGrasse Tyson has caused quite a stir on social media after a series of irreverent tweets that poked fun at the treatment of Dec. 25 as a sacred Christian holiday.

“QUESTION: This year, what do all the world’s Muslims and Jews call December 25th? ANSWER: Thursday … On this day long ago, a child was born who, by age 30, would transform the world. Happy Birthday Isaac Newton b. Dec 25, 1642 … A Pagan holiday (BC) becomes a Religious holiday (AD). Which then becomes a Shopping holiday (USA).”

While most appeared to enjoy his remarks, many on Twitter lashed out, declaring his comments “disrespectful to Christians,” and that “Jesus created the science you cherish so much.” Another said that “everyone finds God eventually, you will too.” Many others demanded an apology, according to the Christian Science Monitor.

Tyson has 3 million followers on Twitter, so it is not surprising his comments received such widespread attention. He and popular television scientist Bill Nye have often clashed publicly with Creationists.

His comments on Newton were retweeted more than 72,000 times. The day after Christmas, he doubled down on his comments, asking readers to imagine a world in which “we are all enlightened by objective truths rather than offended by them.”

He then went on Facebook to express amazement at the response to his Newton tweet. He also corrected the record on Newton’s actual birthdate, which was more likely on Jan. 4, 1643, due to the fact that the Gregorian Calendar had not yet been adopted by Great Britain and thus people were probably celebrating Christmas a little later than on the modern date of Dec. 25.

Neil deGrasse Tyson is currently the Frederick P. Rose Director of the Hayden Planetarium at the Rose Center for Earth and Space. He is also a research associate in the department of astrophysics for the American Museum of Natural History. He is also formerly the television host for the science program NOVA ScienceNow on PBS, which he hosted from 2006 to 2011.

Since 2009, he has been hosting a weekly radio show called Star Talk, and this year hosted “Cosmos: A Spacetime Odyssey” television series, which is a sequel to Carl Sagan’s “Cosmos: A Personal Voyage,” which ran in 1980.