Archives

May 2020


The existence of a planet the size of Earth around the closest star in the solar system, Proxima Centauri, has been confirmed by an international team of scientists including researchers from the University of Geneva (UNIGE).

In cells, protein is synthesized based on the genetic code. Each protein is coded by the triplet combination of chemicals called "nucleotides," and a continuous "reading" of any set of triplet codes will, after a multi-step process, result in the creation of a chain of amino acids, a protein.

Subduction of hydrous materials imposes great influence on the structure, dynamics, and evolution of our planet. However, it is largely unclear how subducting slabs chemically interact with the middle mantle.

The potential habitability of tidally locked planets orbiting M-dwarf stars has been widely investigated in recent work, typically with a non-dynamic ocean and without continents. On Earth, ocean dynamics are a primary means of heat and nutrient distribution.

The recent discovery of an Earth-sized planet (TOI-700 d) in the habitable zone of an early-type M-dwarf by the Transiting Exoplanet Survey Satellite constitutes an important advance.

The majority of potentially habitable exoplanets detected orbit stars cooler than the Sun, and therefore are irradiated by a stellar spectrum peaking at longer wavelengths than that incident on Earth.

Abridged: The interest towards searches for extraterrestrial civilizations (ETCs) was boosted by the discovery of thousands of exoplanets. We turn to the classification of ETCs for new considerations that may help to design better strategies for ETCs searches.

An instrument called SHERLOC will, with the help of its partner WATSON, hunt for signs of ancient life by detecting organic molecules and minerals.

The simulations show that the asteroid hit Earth at an angle of about 60 degrees, which maximised the amount of climate-changing gases thrust into the upper atmosphere.

We aim to confirm the presence of Proxima b using independent measurements obtained with the new ESPRESSO spectrograph, and refine the planetary parameters taking advantage of its improved precision.

Spectroscopic studies play a key role in the identification and analysis of interstellar ices and their structure. Some molecules have been identified within the interstellar ices either as pure, mixed, or even as layered structures.

In this work, we present the results of our investigation into the chemistry of Z- and E-cyanomethanimine (HNCHCN), both of which are possible precursors to the nucleobase adenine.

We present a model to study secularly and tidally evolving three-body systems composed by two low-mass planets orbiting a star, in the case where the bodies rotation axes are always perpendicular to the orbital plane.

To better understand and mitigate the health risks faced by astronauts from exposure to space radiation, we ideally need to be able to test the effects of Galactic Cosmic Rays (GCRs) here on Earth under laboratory conditions.

Why do carbon dioxide levels in the atmosphere wax and wane in conjunction with the warm and cold periods of Earth's past?

Before there were animals, bacteria or even DNA on Earth, self-replicating molecules were slowly evolving their way from simple matter to life beneath a constant shower of energetic particles from space.

Humans have been wondering whether we alone in the universe since antiquity.

We present four new secondary eclipse observations for the ultrahot Jupiter WASP-121b acquired using the Hubble Space Telescope Wide Field Camera 3.

Conventionally, a habitable planet is one that can support liquid water on its surface. Habitability depends on temperature, which is set by insolation and the greenhouse effect, due mainly to CO2 and water vapor.

After examining a dozen types of suns and a roster of planet surfaces, Cornell University astronomers have developed a practical model -- an environmental color "decoder" -- to tease out climate clues for potentially habitable exoplanets in galaxies far away.

Astronomers using the Subaru Telescope have determined that the Earth-like planets of the TRAPPIST-1 system are not significantly misaligned with the rotation of the star.

Complex organic molecules (COMs) are thought to form on icy dust grains in the earliest phase of star formation. The evolution of these COMs from the youngest Class 0/I protostellar phases toward the more evolved Class II phase is still not fully understood.

Terrestrial planets in temperate orbits around very low mass stars are likely to have evolved in a very different way than solar system planets, and in particular Earth.

Jupiter's moon Europa is a fascinating world. On its surface, the moon appears to be scratched and scored with reddish-brown scars, which rake across the surface in a crisscrossing pattern.

Measurements of the isotopic abundances in meteoritic amino acids have found enhancements of 2H/H, 15N/14N, and 13C/12C in the amino acids in the meteorites studied.

The oldest molecular fluids in the solar system could have supported the rapid formation and evolution of the building blocks of life, new research in the journal Proceedings of the National Academy of Sciences reveals.

The population of exoplanetary systems detected by Kepler provides opportunities to refine our understanding of planet formation.

Several recent observations of Mars have hinted that it might presently harbor liquid water, a requirement for life as we know it. However, in a new paper in Nature Astronomy, a team of researchers have shown that stable liquids on present-day Mars are not suitable environments for known terrestrial organisms.

A Southwest Research Institute scientist modeled the atmosphere of Mars to help determine that salty pockets of water present on the Red Planet are likely not habitable by life as we know it on Earth.

Upcoming biosignature searches focus on indirect indicators to infer the presence of life on other worlds. Aside from just signaling the presence of life, however, some biosignatures can contain information about the state that a planet's biosphere has achieved.

The goal of planetary protection is to control, to the degree possible, the biological cross-contamination of planetary bodies. Guidelines developed by the Committee on Space Research (COSPAR) are used by all spacefaring nations to guide their preparations for encounters with solar system bodies.

At the Endeavour Segment of the Juan de Fuca Ridge, about 350 kilometers (220 miles) northwest of Washington State, the seafloor is ripping apart.

Astrophysical measurements have shown that some stars have sufficiently high carbon-to-oxygen ratios such that the planets they host would be mainly composed of carbides instead of silicates.

Hydrostatic equilibrium is an excellent approximation for the dense layers of planetary atmospheres where it has been canonically used to interpret transmission spectra of exoplanets.

Because the geological carbon cycle regulates long term atmospheric oxygen concentrations, fluctuations in atmospheric O2 are typically attributed to an imbalance between the weathering of organic carbon (OC) and reduced sulfur on land, a sink of atmospheric O2, and the burial of OC and reduced sulfur in marine sediments, a source of O2.

In northern Chile's Atacama Desert, one of the driest places on Earth, microorganisms are able to eke out an existence by extracting water from the rocks they colonize.

Exoplanets residing close to their stars can experience evolution of both their physical structures and their orbits due to the influence of their host stars.

Whether there is life elsewhere in the universe is a question people have pondered for millennia; and within the last few decades, great strides have been made in our search for signs of life outside of our solar system.

With the discovery of a planetary system around TRAPPIST-1, there has been a surge of interest in ultracool dwarfs as potential planet hosts. Planetary systems around ultracool dwarfs represent our best chance of characterising temperate rocky-planet atmospheres with JWST.

Theory and observation for the search for life on exoplanets via atmospheric "biosignature gases" is accelerating, motivated by the capabilities of the next generation of space- and ground-based telescopes.

Life has had a dramatic impact on the composition of Earth's atmosphere over time, which suggests that statistical studies of other inhabited planets' atmospheres could reveal how they co-evolve with life.

The petroleum and coal models of the unidentified infrared emissions (UIE), sometimes referred also as unidentified infrared bands (UIBs) has been reviewed mainly based on the work of the authors with the inclusion of unpublished results.

Magnetic activity of the Sun and other stars causes their brightness to vary. We investigate how typical the Sun's variability is compared to other solar-like stars, i.e. those with near-solar effective temperatures and rotation periods.

The surface of Jupiter's moon Europa features a widely varied landscape, including ridges, bands, small rounded domes and disrupted spaces that geologists call "chaos terrain." Three newly reprocessed images, taken by NASA's Galileo spacecraft in the late 1990s, reveal details in diverse surface features on Europa.

The COVID-19 pandemic is a stark reminder that we move through a world shaped by unseen life. Bacteria, viruses, and other microscopic organisms regulate the Earth's vital functions and resources, from the air we breathe to all our food and most of our energy sources.

Giant elliptical galaxies are not as likely as previously thought to be cradles of technological civilizations such as our own, according to a recent paper by a University of Arkansas astrophysicist.

A study conducted by a team of national laboratory and NASA researchers has found that the environment of the International Space Station is affected by the microbial composition of the astronauts themselves.