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developmental biology

Cells Form Into ‘Xenobots’ on Their Own

March 31, 2021

Embryonic cells can self-assemble into new living forms that don’t resemble the bodies they usually generate, challenging old ideas of what defines an organism.

A graphic showing that changing any of the digits of 505, 447 turns it into a composite number
prime numbers

Mathematicians Find a New Class of Digitally Delicate Primes

March 30, 2021

Despite finding no specific examples, researchers have proved the existence of a pervasive kind of prime number so delicate that changing any of its infinite digits renders it composite.

Spheres representing black holes, with small ones on top, large ones on the bottom, and one midsize example in the middle.

Long-Missing Midsize Black Hole Flashes Into View

March 29, 2021

Black holes seemed to come only in sizes small and XXL. A new search strategy has uncovered a black hole of “intermediate” mass, raising hopes of more to come.

Insights puzzle

Finding Zen in the Art of Puzzle Solving

March 26, 2021

Readers used their Zen-like puzzle solving skills to discover hidden insights.

A mosaic of five microscope images of igneous rocks. The rocks are dappled with blue, pink, orange and multicolor inclusions.

Scientists Pin Down When Earth’s Crust Cracked, Then Came to Life

March 25, 2021

New data indicating that Earth’s surface broke up about 3.2 billion years ago helps clarify how plate tectonics drove the evolution of complex life.

Orange hills (polaritons) against a black background. Below each hill, an arrow points to an angular position on a circle.

The Near-Magical Mystery of Quasiparticles

March 24, 2021

The zoo of spontaneously emerging particlelike entities known as quasiparticles has grown quickly and become more and more exotic. Here are a few of the most curious and potentially useful examples.

A graphic showing improvements in the speed of matrix multiplication

Matrix Multiplication Inches Closer to Mythic Goal

March 23, 2021

A recent paper set the fastest record for multiplying two matrices. But it also marks the end of the line for a method researchers have relied on for decades to make improvements.

Illustration of researchers trying to reconstruct the shape of an epidemic curve from its distorted shadow on the floor.

Chasing the Elusive Numbers That Define Epidemics

March 22, 2021

Most modeling efforts during the COVID-19 pandemic have sought to address urgent practical concerns. But some groups aim to bolster the theoretical underpinnings of that work instead.

The zoologist Arik Kershenbaum of the University of Cambridge and his dog.

Why Extraterrestrial Life May Not Seem Entirely Alien

March 18, 2021

The zoologist Arik Kershenbaum argues that because some evolutionary challenges are truly universal, life throughout the cosmos may share certain features.