Neil deGrasse Tyson explains why the heck we have leap days
Neil deGrasse Tyson sat down with comedian Chuck Nice to give an entertaining and informative explanation of our calendar's biggest head scratcher.

Neil deGrasse Tyson explains why we have a Leap Year.
While Neil deGrasse Tyson might usually break down the more complex mysteries of our universe, he also has a knack for discussing the mundane in a way that makes it every bit as interesting.
On a recent episode of the StarTalk Podcast, where the popular astrophysicist chats about “everything under the sun; Or rather under the universe!” Tyson sat down with comedian Chuck Nice to break down how and why Leap Day came to be.
“People seem to be mystified by it. A day just shows up on the calendar,” Tyson told Nice.
But really, there’s nothing all that mystical about it. We know a year consists of 365 revolutions around the sun, aka a “year.” However, “there's no law in the heavens that requires” a year to consist of exactly 365 revolutions.
In reality, a year is 365 revolutions…plus one-fourth. Or six hours.
Tyson then pondered, “so what are you gonna do with the six hours?” Which brought on a pretty intriguing concept: a rotating New Year’s celebration. Celebrating at the standard midnight one year, followed by a 6am celebration the following year, then midnight again, and so on.
“That’d be kinda dope,” Nice and Tyson agreed.
But regardless, we don’t do that. Instead, in ancient Rome, which used the Julian calendar, they “pocketed” the extra six hours and technically celebrated New Year’s early. When 24 hours accrued every 4 years, they’d give an extra day to the”month that needed it most,” i.e. February.
But here’s the thing: Ancient Romans didn't know that it actually takes “a little less” than 365 for the Earth to go around the sun, Tyson explained. Therefore days that should have been “reckoned” were not, causing key moments of the calendar to keep shifting. The spring equinox, for instance, which was originally on March 21st, continuously moved up a day.
Neil deGrasse Explains Why We Have Leap Days
This became more of a glaring problem in the Late 16th century, when the religious holiday of Easter, which closely followed the spring equinox, had gotten dangerously close to Passover on the calendar.
So, Pope Gregory XIII had his team of scientists (aka the Jesuits) rectify the situation and account for the skipped days.
The result? October got 10 of its days swiped that year, and we got the Gregorian calendar commonly used today. Which, like the Julian calendar, adds a day to the calendar every 4 years, except when the year is divisible by 100 and not divisible by 400.This is what makes the year 2000 so remarkable, Tyson told Nice. It was an incredibly rare “century year” that met the parameters needed to be a leap year. 1900, 1800, 1700 couldn't claim that.
And perhaps this is the most amazing part of all: the Jesuits were able to figure all of this out “without a telescope,” Tyson said.
Leap Years might feel a bit wonky, arbitrary even. But really, it’s a nod to human ingenuity. The concept of time is such a complex, almost incomprehensible aspect of existence. It’s extraordinary that we have been able to even come up with a measuring system, albeit an imperfect one, in the first place.
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There's a reason why some people can perfectly copy accents, and others can't
Turns out, there's a neurodivergent link.
A woman in black long sleeve shirt stands in front of mirror.
Have you ever had that friend who goes on vacation for four days to London and comes back with a full-on Queen's English posh accent? "Oooh I left my brolly in the loo," they say, and you respond, "But you're from Colorado!" Well, there are reasons they (and many of us) do that, and usually it's on a pretty subconscious level.
It's called "accent mirroring," and it's actually quite common with people who are neurodivergent, particularly those with ADHD (Attention Deficit Hyperactivity Disorder). According Neurolaunch, the self-described "Free Mental Health Library," "Accent mirroring, also known as accent adaptation or phonetic convergence, is the tendency to unconsciously adopt the accent or speech patterns of those around us. This linguistic chameleon effect is not unique to individuals with ADHD, but it appears to be more pronounced and frequent in this population."
Essentially, when people have conversations, we're constantly "scanning" for information—not just the words we're absorbing, but the inflection and tone. "When we hear an accent, our brains automatically analyze and categorize the phonetic features, prosody, and intonation patterns," writes Neurolaunch. For most, this does result in copying the accent of the person with whom we're speaking. But those with ADHD might be more sensitive to auditory cues. This, "coupled with a reduced ability to filter out or inhibit the impulse to mimic…could potentially explain the increased tendency for accent mirroring."
While the article explains further research is needed, they distinctly state that, "Accent mirroring in individuals with ADHD often manifests as an unconscious mimicry of accents in social situations. This can range from subtle shifts in pronunciation to more noticeable changes in intonation and speech rhythm. For example, a person with ADHD might find themselves unconsciously adopting a Southern drawl when conversing with someone from Texas, even if they’ve never lived in the South themselves."
People are having their say online. On the subreddit r/ADHDWomen, a thread began: "Taking on accents is an ADHD thing?" The OP shares, "My whole life, I've picked up accents. I, myself, never noticed, but everyone around me would be like, 'Why are you talking like that??' It could be after I watched a show or movie with an accent or after I've traveled somewhere with a different accent than my 'normal.'
They continue, "Apparently, I pick it up fast, but it fades out slowly. Today... I'm scrolling Instagram, I watch a reel from a comedian couple (Darcy and Jeremy. IYKYK) about how Darcy (ADHD) picks up accents everywhere they go. It's called ADHD Mirroring??? And it's another way of masking."
(The OP is referring to Darcy Michaels and his husband Jeremy Baer, who are both touring comedians based in Canada.)
Hundreds of people on the Reddit thread alone seem to relate. One comments, "Omfg I've done this my whole life; I'll even pick up on the pauses/spaces when I'm talking to someone who is ESL—but English is my first language lol."
Sometimes, it can be a real issue for those around the chameleon. "I accidentally mimicked a waitress's weird laugh one time. As soon as she was out of earshot, my family started to reprimand me, but I was already like 'oh my god I don’t know why I did that, I feel so bad.'"
Many commenters on TikTok were shocked to find out this can be a sign of ADHD. One jokes, "Omg, yes, at a store the cashier was talking to me and she was French. She's like 'Oh are you French too? No, I'm not lol. I'm very east coast Canada."
And some people just embrace it and make it work for them. "I mirror their words or phrase! I’m 30. I realized I start calling everyone sweetie cause my manager does & I work at coffee shop."