Cosmology

The oldest group of terrestrial worlds now known formed some 11.2 billion years ago, more than six billion years before our sun and planets. Clara Moskowitz reports

 

The crew of STS-51-L: Front row from left, Mike Smith, Dick Scobee, Ron McNair. Back row from left, Ellison Onizuka, Christa McAuliffe, Greg Jarvis, Judith Resnik.

Intriguing data from an event in 2007 hints at an exomoon forming around a giant planet in a youthful star system 420 light years from Earth.

In 1990, NASA's Voyager 1 spacecraft briefly looked back from its journey out of the solar system, capturing a view of the faraway Earth. Carl Sagan called it the "pale blue dot." From more than 6 billion kilometers away, beyond the orbit of Pluto, it seemed remarkable that our planet was even visible.

Scientists must now decide whether the anomalous signal is truly exotic or has a more mundane provenance

I’ve always been an Edgar Allan Poe fan, so much so that I even watched the horrifying—not in a good way–2012 film The Raven.

I remember battling sleepiness as I slouched in a large lecture hall, squinting to make out the writing on the blackboard during my freshman introductory physics course in college.

NASA's planet-hunting Kepler spacecraft finds two worlds that have sizes and orbits similar to ours
 

Books and recommendations from Scientific American

New image shows the star’s system shares features with our own

Simulations suggest Venus could have once harbored seas of supercritical carbon dioxide

From humanity’s first, flawed foray to the surface of a comet to the celebrated discovery of (and less celebrated skepticism about) primordial gravitational waves, 2014 has brought some historic successes and failures in space science and physics.