Enceladus

THEO Concept Mission: Testing the Habitability of Enceladus's Ocean

THEO Concept Mission: Testing the Habitability of Enceladus's Ocean

Saturn's moon Enceladus offers a unique opportunity in the search for life and habitable environments beyond Earth, a key theme of the National Research Council's 2013-2022 Decadal Survey.

Biosignatures & Paleobiology

Using Clouds to Map Life

Using Clouds to Map Life

Clouds may seem like distant, ephemeral features that have little to do with life on Earth. In fact, they affect everything from the viability of ecosystems, to how much carbon plants absorb, to the reproductive success of reptiles.

Extrasolar Planets

Three Potentially Habitable Worlds Found Around Nearby Ultracool Dwarf Star

Three Potentially Habitable Worlds Found Around Nearby Ultracool Dwarf Star

Astronomers using the TRAPPIST telescope at ESO's La Silla Observatory have discovered three planets orbiting an ultracool dwarf star just 40 light-years from Earth.

Habitable Zones & Global Climate

Temperature Constraints for Complex Life

Temperature Constraints for Complex Life

In an effort to derive temperature based criteria of habitability for multicellular life, we investigated the thermal limits of terrestrial poikilotherms, i.e. organisms whose body temperature and the functioning of all vital processes is directly affected by the ambient temperature.

Biosignatures & Paleobiology

Hypotheses for Near-surface Exchange of Methane on Mars

Hypotheses for Near-surface Exchange of Methane on Mars

The Curiosity rover recently detected a background of 0.7 ppb and spikes of 7 ppb of methane on Mars. This in situ measurement reorients our understanding of the Martian environment and its potential for life, as the current theories do not entail any geological source or sink of methane that varies sub-annually.

Biosignatures & Paleobiology

Debris Disks and the Search for Life in the Universe

Debris Disks and the Search for Life in the Universe

Circumstellar debris disks are the extrasolar analogues of the asteroid belt and the Kuiper belt. They consist of comets and leftover planetesimals that continuously collide and produce circumstellar dust that can be observed as infrared excess or in resolved imaging.

Astrogeology

Effects of Mg/Si on Exoplanetary Refractory Oxygen Budget

Effects of Mg/Si on Exoplanetary Refractory Oxygen Budget

Solar photospheric abundances of refractory elements mirror the Earth's to within ~10 mol% when normalized to the dominant terrestrial planet-forming elements Mg, Si and Fe. This allows for the adoption of Solar composition as an order-of-magnitude proxy for Earth's.

Astronomy

Hiding in the Sunshine: The Search for Other Earths

Hiding in the Sunshine: The Search for Other Earths

We humans might not be the only ones to ponder our place in the universe. If intelligent aliens do roam the cosmos, they too might ask a question that has gripped humans for centuries: Are we alone?

Astrobiology (general)

Are We Alone? Setting Some Limits to Our Uniqueness

Are We Alone? Setting Some Limits to Our Uniqueness

Are humans unique and alone in the vast universe? This question-- summed up in the famous Drake equation--has for a half-century been one of the most intractable and uncertain in science.

Extrasolar Planets

Giant Planets in the Habitable Zone

Giant Planets in the Habitable Zone

We report the discovery of three new substellar companions to solar-type stars, HD191806, HD214823, and HD221585, based on radial velocity measurements obtained at the Haute-Provence Observatory.

Astrochemistry

Herschel Detects Oxygen in the beta Pictoris Debris Disk

Herschel Detects Oxygen in the beta Pictoris Debris Disk

The young star beta Pictoris is well known for its dusty debris disk, produced through the grinding down by collisions of planetesimals, kilometre-sized bodies in orbit around the star.

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