Sometimes, bad luck and/or bad timing can make an already bad day worse. If you’re already late to work, that’s a prime time to blow a tire during your commute. If you’re a dinosaur living 66 million years ago in an already fragile ecosystem, that’s apparently the perfect time for a massive asteroid to strike Earth and eradicate your entire existence. That’s the latest from a study conducted by researchers at the University of Edinburgh, who say that had the asteroid struck a little earlier or a little later, the dinosaurs would have likely survived the impact.

“The dinosaurs were victims of colossal bad luck. Not only did a giant asteroid strike, but it happened at the worst possible time, when their ecosystems were vulnerable,” said Dr. Steve Brusatte of the Edinburgh School of GeoSciences.

If you travel back 69 or so million years, a few before the asteroid struck, you’d find a world in upheaval. Climate change was having a massive impact, including increased volcanic activity, increased sea levels and wild temperature swing. Those factors all conspired to severely weaken the dinosaur food chain, as there was decreased diversity among the herbivores at the bottom.

The 10km-wide asteroid that struck what is now Mexico only served to accelerate those weaknesses. The ensuing environmental changes would have wiped out the dinosaur kingdom rapidly, leaving only flying dinos to survive and eventually evolve into modern birds. They just might have survived had the impact come earlier, when the population was healthier, or later, when they’d had time to evolve and adapt to the changing climate.

The researchers arrived at their conclusions by studying specimens in the North American fossil record, painting a picture of how dinosaurs were evolving in the millennia leading up to the impact. They hope that future studies in Spain and China will reinforce their findings and shed even more light on what was an unquestionably dark time (for dinosaurs).

“Our new findings help clarify one of the enduring mysteries of science,” said Dr. Brusatte.