Cosmologists Paul Steinhardt and Neil Turok liken the early history of the universe to a play in which the protagonists — matter and radiation — move across the stage according to the laws of physics. Astronomers are actors who arrived on the scene 13.7 billion years too late to know what happened. But that hasn’t stopped Steinhardt, Turok and other researchers from pondering whether the universe was born in a giant fireball around that time or might have existed before that. The modern-day notion of the cosmos’s tumultuous beginning — known as the Big Bang — has its root... (p. 22)

Waste heat, not exotic physics, is slowing two 1970s-era space probes down more than would be expected, a new study claims.

A high-energy blast has gone on for 11 days, puzzling astronomers as to its source.

MESSENGER spacecraft to capture more than 1,500 images in three days.

MESSENGER has radioed to Earth a new look at the first rock from the sun. (p. 9)

It will be the largest telescope ever launched into space, with a mirror that has about six times the light collecting area of Hubble’s. When the James Webb Space Telescope flies later this decade, its unparalleled infrared vision will record the flickers of the first stars and galaxies to light up the universe, in a mission that promises to rewrite astronomy textbooks. But for now, the 6.5-ton observatory has become a financial albatross for NASA. An independent investigative panel reported in November that the telescope, known by the acronym JWST, is running a minimum of $1.4 billion... (p. 22)

A new theory of planetary formation may explain variety seen in extrasolar searches. (p. 9)

A ground-based device would use light to push debris off a collision course.