Michelle Starr

Every atom of matter in the Universe is built around a nucleus. It's a tightly packed bundle of protons and neutrons that makes up the atomic core, defines its elemental identity , and contains most of its mass.

For those living in the shadow of mental health conditions such as PTSD, anxiety, and depression , finding a way forward can sometimes feel impossible – especially when conventional treatments have offered little succor.

IC 1101 is much bigger than previous estimates suggested. (C. Marrero de la Rosa et al.; data: Isaac Newton Telescope (INT/ING))

Sometime in Earth's distant past, nearly 4 billion years ago, our planet's earliest lifeforms somehow coalesced from primordial chemistry.

The desert sands of Egypt have been dry for thousands of years.

A molecular illustration of the crowded interior and cell envelope of Escherichia coli. (David S. Goodsell, The Scripps Research Institute)

To replicate information, life usually has fairly straightforward ways of doing things. To copy DNA, you generally use DNA as a template.

When the batteries die in your TV remote, you might start rummaging around your desk clock for a replacement.

It does so many different things. It acts as an anesthetic, painkiller, dissociative drug, hallucinogen, and unusually fast-acting antidepressant.

Even 'empty'space is seething with quantum fluctuations. (Quardia/iStock/Getty Images Plus)