What's up in


Illustration of a hanging mobile with "Planet 9" weighing down 2015 BP519's orbit, thus tilting it.
planetary science

A New World’s Extraordinary Orbit Points to Planet Nine

Astronomers argue that there’s an undiscovered giant planet far beyond the orbit of Neptune. A newly discovered rocky body has added evidence to the circumstantial case for it.

Photo of Large Magellan Cloud rotating clockwise.
Abstractions blog

What Astronomers Are Learning From Gaia’s New Milky Way Map

A roundup of some of the most important discoveries gleaned so far from the Gaia space observatory’s new map of the galaxy.

Art for "Three Decades Later, Mystery Numbers Explained"
Abstractions blog

Three Decades Later, Mystery Numbers Explained

Zeta values seem to connect distant geometric worlds. In a new proof, mathematicians finally explain why.

Lede art for "A Radically Conservative Solution for Cosmology’s Biggest Mystery": This Hubble image shows RS Puppis, a type of variable star known as a Cepheid variable. As variable stars go, Cepheids have comparatively long periods— RS Puppis, for example, varies in brightness by almost a factor of five every 40 or so days. RS Puppis is unusual; this variable star is shrouded by thick, dark clouds of dust enabling a phenomenon known as a light echo to be shown with stunning clarity. These Hubble observations show the ethereal object embedded in its dusty environment, set against a dark sky filled with background galaxies.
Abstractions blog

A Radically Conservative Solution for Cosmology’s Biggest Mystery

Two ways of measuring the universe’s expansion rate yield two conflicting answers. Many point to the possibility of new physics at work, but a new analysis argues that unseen errors could be to blame.

Lede art for "Troubled Times for Alternatives to Einstein’s Theory of Gravity"

Troubled Times for Alternatives to Einstein’s Theory of Gravity

New observations of extreme astrophysical systems have “brutally and pitilessly murdered” attempts to replace Einstein’s general theory of relativity.

Gif illustration for "Machine Learning’s ‘Amazing’ Ability to Predict Chaos"
chaos theory

Machine Learning’s ‘Amazing’ Ability to Predict Chaos

In new computer experiments, artificial-intelligence algorithms can tell the future of chaotic systems.

Illustration for "Ultra-Accurate Clocks Lead Search for New Laws of Physics"
experimental physics

Ultra-Accurate Clocks Lead Search for New Laws of Physics

Atomic clocks are letting physicists tighten the lasso around elusive phenomena such as dark matter.

Illustration for "Trouble Detected in Infamous Dark Matter Signal"
dark matter

Trouble Detected in Infamous Dark Matter Signal

Independent scientists have cast serious doubt on a claimed detection of dark matter.

Illustration for "Mathematicians Explore Mirror Link Between Two Geometric Worlds"

Mathematicians Explore Mirror Link Between Two Geometric Worlds

Decades after physicists happened upon a stunning mathematical coincidence, researchers are getting close to understanding the link between two seemingly unrelated geometric universes.