In case you live under a rock, there's been some huge news in the physics world: On Thursday, scientists finally confirmed long-swirling rumors that they'd detected gravitational waves for the first time. But we heard it first from a picture of a cake.

Reporters (myself included) waited with bated breath as scientists prepared to take the stage at the National Press Club in D.C. Most of us knew the news that was coming, because we'd been told details under embargo — a promise not to share the story before a 10:30 a.m. Eastern time reveal. Scientists and universities often let journalists have the news a little early so we have time to report out stories on the subject.

But embargo breaks happen all the time: Weeks ago, when scientists announced the best-ever evidence for a hidden ninth planet at the edge of the solar system, the story went up three hours early because of some confusion about the time zone. When huge news breaks early, other outlets are left scrambling to decide whether to publish before the promised time. It's a controversial thing and annoying as heck, but we won't get into that now.

So it's not surprising that a couple of outlets went live a few minutes early, especially given the fact that rumors about gravitational waves have been circulating for months. What is surprising is the leak that prompted them to pull the trigger.

The leak came from a cake.

Somebody caked the embargo.

And here's the best part: This is actually the second time she's broken an embargo with a cake.

The cake-tweeting culprit is Erin Lee Ryan, a research associate at the University of Maryland who works at NASA's Goddard Space Flight Center.

"It was September of 2013, and someone had brought cake," Ryan recalled to The Post on Thursday. The lab would have coffee chats every Monday and Friday to discuss science, but cake was an anomaly.

"I was like, yes, there's cake at the coffee thing! So I tweeted it. That's how we'd get people from other labs to come over, by telling them we had food," Ryan said.

But the cake actually featured a picture of a scientific result that was embargoed for another two hours. Because scientists aren't typing up articles about their colleagues' findings and broadcasting them out into the world, they don't usually have to be aware of embargo times or think about what constitutes breaking them. But in the age of Twitter, that can become a problem.

"A couple hours later, I got a phone call from my boss, like 'where are you, do you know what's going down right now?' " Ryan said. "I mean, they weren't happy about it."

But in the end, her tweet actually got more attention than the press release that got tweeted out later.

"They told me to maybe chill with the tweeting for a week or so," she said — but she didn't get in trouble.

Fast forward to Thursday morning, when Goddard scientists received another embargoed confection — and Ryan tweeted it with 16 minutes to go until the press conference. Ryan was aware of the 10:30 a.m. announcement, but didn't realize an embargo was still active when the cake arrived. She and her colleagues were even told to take pictures of the cake, Ryan said in an email. She didn't think tweeting the picture would break an embargo, even if there was one.

On the one hand, Ryan was right in thinking her cake tweet was probably harmless: Physicists had been talking about the findings announced Thursday for weeks. It's not like Ryan tweeted a picture of the official paper. But the definitive language on the cake — paired with the timing, just minutes before the press conference, and the fact that it came from a NASA employee — made it seem like more than just another rumor.

At least one outlet seems to have taken the cake as a serious embargo break, and went ahead with publishing.

"When I saw all the retweets I just thought, oh no," Ryan said, laughing. "I mean, this is the second time I've wound up tweeting a cake before an embargo!"

In her defense, she says, this is what science is like: It's hard not to want to share the exciting results of your peers. Or news of free food.

And Ryan was extremely excited about the gravitational wave detection, which she counts as one of the coolest things she's ever seen published.

Since we know you're wondering, we asked Ryan what she thought of the cake, too. "It was very tasty," she said.

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