Period underwear offers a reusable and comfortable alternative to traditional menstrual products. Learn how to choose the safest options, and what to know about cost, comfort, and health. Period ...

Even if you’re not relying on a trusty cycle tracker, everyone has their sure-fire signs that their period is about to begin. Maybe you get a breakout or start to feel more sensitive. Me? I start to ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. The sensitive ...

Evolution of life forms on Earth. Sticker with ancient predecessor of fish. Jawless ostracoderm. Ordovician period of Paleozoic era. Cartoon flat vector illustration isolated on white background ...

Journal of Paleontology, Vol. 93, No. 6 (NOVEMBER 2019), pp. 1137-1158 (22 pages) End-Ordovician extinctions had a profound effect on shallow-water benthic communities, including the Crinoidea.

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Famously known for ...

Today, only the largest planets in the solar system have rings, but a new study suggests Earth may have been a ringed planet in the distant past. Scientists studying the geology of the Ordovician ...

Earth may once have had a vast ring system circling the planet, very similar to Saturn’s rings, according to a recent study. These rings seem to have formed around 466 million years ago, during a ...