Archives

August 2020


We present an overview of the GOTHAM (GBT Observations of TMC-1: Hunting Aromatic Molecules) Large Program on the Green Bank Telescope.

A new study finds that Earth's water may have come from materials that were present in the inner solar system at the time the planet formed -- instead of far-reaching comets or asteroids delivering such water. The findings published Aug. 28 in Science suggest that Earth may have always been wet.

The detectability of exoplanets and the determination of their projected mass in radial velocity are affected by stellar magnetic activity and photospheric dynamics.

Imagine microscopic life-forms, such as bacteria, transported through space, and landing on another planet. The bacteria finding suitable conditions for its survival could then start multiplying again, sparking life at the other side of the universe.

The atmospheres of temperate planets may be regulated by geochemical cycles. Silicate weathering provides essential negative feedback to the carbonate-silicate cycle (carbon cycle) to maintain temperate climates on Earth and possibly on Earth-sized temperate exoplanets.

An international team of researchers has discovered a new group of Chlamydiae - Anoxychlamydiales - living under the ocean floor without oxygen.

The origin of life on Earth is a topic that has piqued human curiosity since probably before recorded history began.

The growth time scales of planetary embryos and their formation process are imperative for our understanding on how planetary systems form and develop.

A nearby star, the host of two (and possibly three) planets, was initially thought to be quiet and boring.

The development of habitable conditions on Earth is tightly connected to the evolution of its atmosphere which is strongly influenced by atmospheric escape.

New observing capabilities coming online over the next few years will provide opportunities for characterization of exoplanet atmospheres. However, clouds/hazes could be present in the atmospheres of many exoplanets, muting the amplitude of spectral features.

Tidal Disruption Events (TDEs) are characterized by the emission of a short burst of high-energy radiation. We analyze the cumulative impact of TDEs on galactic habitability using the Milky Way as a proxy.

UNSW Science Professor Rick Cavicchioli is an expert in microbes and why they are so important - just last year, he led an urgent call for the world to stop ignoring this 'unseen majority' in Earth's biodiversity and ecosystem when addressing climate change.

Recent observations of the potentially habitable planets TRAPPIST-1 e, f, and g suggest that they possess large water mass fractions of possibly several tens of wt% of water, even though the host star's activity should drive rapid atmospheric escape.

The discovery of potentially habitable planets around the ultracool dwarf star Trappist-1 naturally poses the question: could Trappist-1 planets be home to life?

During a 2012 expedition to Antarctica, a team of Japanese and Belgian researchers picked up a small rock that appeared coal black against the snow white. Now known as meteorite Asuka 12236, it was roughly the size of a golf ball.

In their first follow-up to a high-profile 2017 study which showed microbes in Antarctica have a unique ability to essentially live on air, researchers from UNSW Sydney have now discovered this process occurs in soils across the world's three poles.

Most effort in origins of life research is focused on understanding the prebiotic formation of biological building blocks.

We investigate the prospects for the past or current existence of habitable conditions deep underneath the surfaces of the Moon and Mars as well as generic bound and free-floating extrasolar rocky objects.

Combining isotopic constraints from meteorite data with dynamical models of planet formation proves to be advantageous in identifying the best model for terrestrial planet formation.

The question of whether life exists beyond the Earth is one of humanity's most fundamental questions. Future NASA missions, for example, aim to examine the ice moons of Jupiter and Saturn, which may potentially shelter life in the liquid oceans underneath the thick layer of ice, on the ground.

A new study from The University of Texas at Austin is helping scientists piece together the ancient climate of Mars by revealing how much rainfall and snowmelt filled its lake beds and river valleys 3.5 billion to 4 billion years ago.

Earth-sized planets in the habitable zones of M dwarfs are good candidates for the study of habitability and detection of biosignatures.

One of the major goals for astronomy in the next decades is the remote search for biosignatures (i.e.\ the spectroscopic evidence of biological activity) in exoplanets.

Imagine reading by the light of an exploded star, brighter than a full moon - it might be fun to think about, but this scene is the prelude to a disaster when the radiation devastates life as we know it.

There is compelling evidence for subsurface water oceans among the three outer Galilean satellites, and evidence for an internal magma ocean in the innermost moon, Io. Tidal forces from Jupiter periodically deform these bodies, causing heating and deformation that, if measured, can probe their interior structures.

If you could dive down to the ocean floor nearly 540 million years ago just past the point where waves begin to break, you would find an explosion of life--scores of worm-like animals and other sea creatures tunneling complex holes and structures in the mud and sand--where before the environment had been mostly barren.

"I'm fascinated with life, and that's why I want to break it." This is how Betül Kaçar, an assistant professor at the University of Arizona with appointments in the Department of Molecular and Cellular Biology, Department of Astronomy and the Lunar and Planetary Laboratory, describes her research.

A key component when forecasting what the Earth's climate might look like in the future is the ability to draw on accurate temperature records of the past.

A few years ago, geologist Abderrazak El Albani and his team at the Institut de chimie des milieux et matériaux de Poitiers (CNRS/Université de Poitiers) discovered the oldest existing fossils of multicellular organisms in a deposit in Gabon

The Red Planet has fascinated humans for millennia, especially for the last few centuries, and particularly during the Space Age. The nagging suspicion of extant Martian life is both fed by, and drives the many space missions to Mars and recent detections of large, seasonal volumes of atmospheric methane have re-fuelled the discussion.

We outline a flagship-class mission concept focused on studying Titan as a global system, with particular emphasis on the polar regions.

Keith's note: I have known John Rummel for 35 years. I first worked with him at the old Life Science Division at NASA Headquarters. He has made an indelible mark on NASA's search for life in the universe. Please consider making a donation to help out John and his family in this time of need.

Atmospheric studies of spectroscopically accessible terrestrial exoplanets lay the groundwork for comparative planetology between these worlds and the Solar System terrestrial planets.

The Kepler Space telescope has uncovered around thirteen circumbinary planets (CBPs) that orbit a pair of stars and experience two sources of stellar flux.

In the study of planetary habitability and terrestrial atmospheric evolution, the divergence of surface conditions for Venus and Earth remains an area of active research.

The discovery of hydrothermal vents - where volcanoes at the seafloor produce hot fluid exceeding 350 degrees Celsius, or 662 degrees Fahrenheit, fundamentally changed our understanding about Earth and life in the 1970s. Yet, life at and underneath the seafloor is still very much a mystery today.

Orbital geophysical investigations of Enceladus are critical to understand its energy balance. Mapping Enceladus' gravity field, improving the accuracy of the physical libration amplitude, and measuring Enceladus' tidal response would provide critical constraints on the internal structure, thus establishing a framework for assessing Enceladus' long-term habitability.

Any search for present or past life beyond Earth should consider the initial processes and related environmental controls that might have led to its start.

In a publication in Nature Communications last Friday, NIOZ scientists Nina Dombrowski and Anja Spang and their collaboration partners describe a previously unknown phylum of aquatic Archaea that are likely dependent on partner organisms for growth while potentially being able to conserve some energy by fermentation.

A critical question in the search for extraterrestrial life is whether exoEarths are Earth-like, in that they host life that progressively oxygenates their atmospheres roughly following Earth's oxygenation history.

Beneath the icy shell encasing Enceladus, a small icy moon of Saturn, a global ocean of liquid water ejects geyser-like plumes into space through fissures in the ice, making it an attractive place to investigate habitability and to search for extraterrestrial life.

We analyze the formation and evolution of terrestrial-like planets around solar-type stars in the absence of gaseous giants. In particular, we focus on the physical and dynamical properties of those that survive in the system's Habitable Zone (HZ).

Insights and technology gleaned from creating a carbon-measuring instrument for Earth climate studies is being leveraged to build another that would remotely profile, for the first time, water vapor up to nine miles above the Martian surface, along with wind speeds and minute particles suspended in the planet's atmosphere.

NASA astronaut and Expedition 63 Commander Chris Cassidy works inside the International Space Station's Harmony module servicing microbial DNA samples for sequencing and identification.

In this work we address the problem of estimating the probabilities of causal contacts between civilisations in the Galaxy. We make no assumptions regarding the origin and evolution of intelligent life. We simply assume a network of causally connected nodes.

Taking advantage of a total lunar eclipse, astronomers using NASA's Hubble Space Telescope have detected Earth's own brand of sunscreen - ozone - in our atmosphere.

In SETI, when searching for "beacons" -- transmissions intended for us and meant to get our attention -- one must guess the appropriate frequency to search by considering what frequencies would be universally obvious to other species.

The key goals of the astrobiology community are to identify environments beyond Earth that may be habitable, and to search for signs of life in those environments. A fundamental aspect of understanding the limits of habitable environments and detectable signatures is the study of where such environments can occur.

We observed the 2019 January total lunar eclipse with the Hubble Space Telescope's STIS spectrograph to obtain the first near-UV (1700-3200 Å) observation of Earth as a transiting exoplanet.

All the chemical elements in the universe, except for hydrogen and most of the helium, were produced inside stars. But among them there are a few (carbon, nitrogen, oxygen, sulphur and phosphorus) which are particularly interesting because they are basic to life as we know it on Earth.

We present a new investigation of the habitability of the Milky Way bulge, that expands previous studies on the Galactic Habitable Zone.

As Carl Sagan famously said, "We're made of star stuff" -- but how do stars distribute their essential "stuff" for life into space? NASA's telescope on an airplane, SOFIA, is finding some answers by watching pulsating stars as they expand and contract, almost like beating hearts.

A large number of the valley networks scarring Mars's surface were carved by water melting beneath glacial ice, not by free-flowing rivers as previously thought, according to new UBC research published today in Nature Geoscience.

One of the proposed scenarios for the origin of life is the primordial RNA world, which considers that RNA molecules were likely responsible for the storage of genetic information and the catalysis of biochemical reactions in primitive cells, before the advent of proteins and DNA.

Our solar system has one habitable planet -- Earth. A new study shows other stars could have as many as seven Earth-like planets in the absence of a gas giant like Jupiter.

Recent studies of the effects on the Earth's atmosphere by astrophysical sources, such as nearby gamma-ray bursts or supernovae, have shown that these events could lead to severe changes in atmospheric composition.

LOUPE, the Lunar Observatory for Unresolved Polarimetry of the Earth, is a small, robust spectro-polarimeter with a mission to observe the Earth as an exoplanet. Detecting Earth-like planets in stellar habitable zones is one of the key challenges of modern exoplanetary science.

We estimate the expected magnitudes of the Schumann resonance fields immediately after the Chicxulub impact and show that they exceed their present-day values by about 5×104 times.

Understanding the atmospheres of exoplanets is a milestone to decipher their formation history and potential habitability. High-contrast imaging and spectroscopy of exoplanets is the major pathway towards the goal. Directly imaging of an exoplanet requires high spatial resolution.