Category Astronomy/Space

This scene from NASA’s Mars rover Opportunity shows “Wharton Ridge,” which forms part of the southern wall of “Marathon Valley” on the rim of Endeavour Crater. The ridge’s name honors the memory of astrobiologist Robert A. Wharton (1951-2012). The scene is presented in approximately true color. Credits: NASA/JPL-Caltech/Cornell/Arizona State Univ.

Opportunity Mars rover will drive down a gully carved long ago by a fluid that might have been water, according to the latest plans for the 12-year-old mission. No Mars rover has done that before. The longest-active rover on Mars also will, for the first time, visit the interior of the crater it has worked beside for the last 5 years. These activities are part of a 2-year extended mission that began Oct...

Stock image. A new study presents the first measurements of the changing strengths of oxygen emission lines from the present day and back to 12.5 billion years ago. Credit: © robert / Fotolia

A new study casts light on how young, hot stars ionize oxygen in the early universe and the effects on the evolution of galaxies through time. It presents the first measurements of the changing strengths of oxygen emission lines from the present day and back to 12.5 billion years ago. The strength of doubly ionized oxygen increases going back in time, while the strength of singly ionized oxygen increases up to 11 billion years ago and then decreases for the remaining 1 to 2 billion years.

The cause of the two different evolutions is due to the changing physical conditions inside star-forming galaxies...

Stephanie Olson and Tim Lyons next to an image of visualizations of sulfate concentrations (top) and methane destruction (bottom) from their biogeochemical model of Earth’s ocean and atmosphere roughly one billion years ago.

For at least a billion years of the distant past, planet Earth should have been frozen over but wasn’t. Scientists thought they knew why, but a new modeling study from the Alternative Earths team of the NASA Astrobiology Institute has fired the lead actor in that long-accepted scenario. Humans worry about greenhouse gases, but between 1.8 billion and 800 million years ago, microscopic ocean dwellers really needed them. The sun was 10 to 15% dimmer than it is today – too weak to warm the planet on its own...

This four-panel graphic illustrates how the binary-star system V Hydrae is launching balls of plasma into space. Credit: NASA, ESA, and A. Feild (STScI)

NASA’s Hubble Space Telescope has detected superhot blobs of gas, each twice as massive as the planet Mars, being ejected near a dying star. The plasma balls are zooming so fast through space it would take only 30 minutes for them to travel from Earth to the moon. This stellar “cannon fire” has continued once every 8.5 years for at least the past 400 years, astronomers estimate. The fireballs present a puzzle to astronomers, because the ejected material could not have been shot out by the host star, V Hydrae, a ed giant, 1,200 light-years away, which has probably shed at least half of its mass into space during its death throes...