Biosignatures & Paleobiology

Detecting Biospheres from Thermodynamic Disequilibrium in Planetary Atmospheres

Detecting Biospheres from Thermodynamic Disequilibrium in Planetary Atmospheres

Atmospheric chemical disequilibrium has been proposed as a method for detecting extraterrestrial biospheres from exoplanet observations.

Extrasolar Planets

Earth-like Tatooines From Star Wars May Be Common

Earth-like Tatooines From Star Wars May Be Common

Luke Skywalker's home in "Star Wars" is the desert planet Tatooine, with twin sunsets because it orbits two stars.

Extrasolar Planets

Hubble Search for Transit of the Earth-mass Exoplanet Alpha Centauri Bb

Hubble Search for Transit of the Earth-mass Exoplanet Alpha Centauri Bb

Results from exoplanet surveys indicate that small planets (super-Earth size and below) are abundant in our Galaxy. However, little is known about their interiors and atmospheres.

Mars

Curiosity Rover Finds Biologically Useful Nitrogen on Mars

Curiosity Rover Finds Biologically Useful Nitrogen on Mars

A team using the Sample Analysis at Mars (SAM) instrument suite aboard NASA's Curiosity rover has made the first detection of nitrogen on the surface of Mars from release during heating of Martian sediments.

SETI

Instrument Extends Search for Extraterrestrial Intelligence to New Realms

Instrument Extends Search for Extraterrestrial Intelligence to New Realms

Astronomers have expanded the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light. Their new instrument has just begun to scour the sky for messages from other worlds.

Extrasolar Planets

Calculations Show Planets in the Habitable Zone Around Most Stars

Calculations Show Planets in the Habitable Zone Around Most Stars

Astronomers have discovered thousands of exoplanets in our galaxy, the Milky Way, using the Kepler satellite and many of them have multiple planets orbiting the host star.

Habitable Zones & Global Climate

Habitability of Water Worlds

Habitability of Water Worlds

There are four different stable climate states for pure water atmospheres, as might exist on so-called "waterworlds".

Extrasolar Planets

Fourier Spectra From Exoplanets With Polar Caps and Ocean Glint

Fourier Spectra From Exoplanets With Polar Caps and Ocean Glint

The weak orbital-phase dependent reflection signal of an exoplanet contains information on the planet surface, such as the distribution of continents and oceans on terrestrial planets.

Oceanic Research

No Limit to Life in Deep Sediment of Ocean's Deadest Region

No Limit to Life in Deep Sediment of Ocean's Deadest Region

"Who in his wildest dreams could have imagined that, beneath the crust of our Earth, there could exist a real ocean...a sea that has given shelter to species unknown?"

Missions, Hardware, Software, & Sensors

Colorful Life-Form Catalog Will Help Discern If We're Alone

Colorful Life-Form Catalog Will Help Discern If We're Alone

While looking for life on planets beyond our own solar system, a group of international scientists has created a colorful catalog containing reflection signatures of Earth life forms that might be found on planet surfaces throughout the cosmic hinterlands.

Astrochemistry

Chemical Composition of tau Ceti and Possible Effects on Terrestrial Planets

Chemical Composition of tau Ceti and Possible Effects on Terrestrial Planets

tau Ceti (HD10700), a G8 dwarf with solar mass of 0.78, is a close (3.65 pc) sun-like star where 5 possibly terrestrial planet candidates (minimum masses of 2, 3.1, 3.5, 4.3, and 6.7 Earth masses) have recently been discovered.

More top stories from April.