Archives

November 2013


We have had pretty nice weather the last two days so we have taken advantage of it with a fair amount of work. Today we put up the tripod that will support the new met station I am deploying here at Lake Obersee.

The weather today was quite nice. While a bit windy, it was sunny all day which was a nice change of pace.

Astrobiology Hearing on Capitol Hill

A House Science Committee hearing titled "Astrobiology: Search for Biosignatures in our Solar System and Beyond" will be held on Wednesday, 4 December.

The biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime.

Today's weather is a major improvement over what we have seen the last two weeks while in Antarctica.

You may have thought that NASA's Kepler spacecraft was finished. Well, think again. A repurposed Kepler Space telescope may soon start searching the sky again.

Rain as acidic as undiluted lemon juice may have played a part in killing off plants and organisms around the world during the most severe mass extinction in Earth's history.

Ancient Minerals: Which Gave Rise to Life?

Life originated as a result of natural processes that exploited early Earth's raw materials. Scientific models of life's origins almost always look to minerals for such essential tasks as the synthesis of life's molecular building blocks or the supply of metabolic energy.

Much like the Grand Canyon, Nanedi Valles snakes across the Martian surface suggesting that liquid water once crossed the landscape, according to a team of researchers who believe that molecular hydrogen made it warm enough for water to flow.

Charged dust grains in the atmospheres of exoplanets may play a key role in the formation of prebiotic molecules, necessary to the origin of life. Dust grains submerged in an atmospheric plasma become negatively charged and attract a flux of ions that are accelerated from the plasma.

Evolution can Select for Evolvability

Evolution does not operate with a goal in mind; it does not have foresight. But organisms that have a greater capacity to evolve may fare better in rapidly changing environments. This raises the question: does evolution favor characteristics that increase a species' ability to evolve?

Researchers from Bern have developed a method to simplify the search for Earth-like planets: By using new theoretical models they rule out the possibility of Earth-like conditions, and therefore life, on certain planets outside our solar system -- and limit their search by doing so.

My research team and I are now camped on the shores of Lake Obersee, a few km NE of Lake Untersee in the mountains of Queen Maud Land.

Derek Lovley's lab at UMass Amherst show for the first time that one of the most abundant methane-producing microorganisms on Earth makes direct electrical connections with another species to produce the gas in a completely unexpected way.

An international team of researchers led by Ralf Tappert, University of Innsbruck, reconstructed the composition of the Earth's atmosphere of the last 220 million years by analyzing modern and fossil plant resins.

Possible Climates on Terrestrial Exoplanets

What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance to optimize future telescopic observations, or to assess the probability of habitable worlds.

On the Radius of Habitable Planets

The conditions that a planet must fulfill to be habitable are not precisely known. However, it is comparatively easier to define conditions under which a planet is very likely not habitable.

Planet Packing in Circumbinary Systems

The recent discovery of planets orbiting main sequence binaries will provide crucial constraints for theories of binary and planet formation.

Reconstructing the rise of life during the period of Earth's history when it first evolved is challenging. Earth's oldest sedimentary rocks are not only rare, but also almost always altered by hydrothermal and tectonic activity.

Biosignatures Across Space and Time

This meeting will to bring together astronomers, geologists, biologists and other interested scientists to share interdisciplinary approaches to detect signs of life on early Earth and other celestial bodies (including exoplanets) and to elucidate the environmental limits and origins of life.

Material from the surface of a planet can be ejected into space by a large impact, and could carry primitive life forms with it.

A rare, recently discovered microbe that survives on very little to eat has been found in two places on Earth: spacecraft clean rooms in Florida and South America.

The Kepler space telescope has detected transits of objects as small as the Earth's Moon, and moons as small as 0.2 Earth masses can be detected in the Kepler data by transit timing and transit duration variations of their host planets.

Recent observations have shown the presence of extra-solar planets in Galactic open stellar clusters, as in the Praesepe (M44). These systems provide a favorable environment for planetary formation due to the high heavy-element content exhibited by the majority of their population.

This shows the relative sizes of the orbits and planets in the multi-transiting planetary systems discovered by Kepler up to Nov. 2013. The colors simply go by order from the star (the most colorful is the 7-planet system KOI-351). The terrestrial planets of the Solar System are shown in gray.

Clay May Have Been The Birthplace of Life

Clay, a seemingly infertile blend of minerals, might have been the birthplace of life on Earth. Or at least of the complex biochemicals that make life possible, Cornell University biological engineers report in the Nov. 7 online issue of the journal Scientific Reports, published by Nature Publishing.

The ongoing searches for exoplanetary systems have revealed a wealth of planets with diverse physical properties. Planets even smaller than the Earth have already been detected, and the efforts of future missions are placed on the discovery, and perhaps characterization, of small rocky exoplanets within the habitable zone of their stars.

Eclipsing systems, such as transiting exoplanets, allow one to measure the mean stellar density of the host star under various idealized assumptions. Asterodensity Profiling (AP) compares this density to an independently determined value in order to check the validity of the assumptions and ultimately extract useful information on the nature of the target system.

Please join us in welcoming science historian Steven J. Dick as he begins his term today as the second Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology in the John W. Kluge Center at the Library of Congress. He will be in residence for one year.

We present the results of a search for potential transit signals in four years of photometry data acquired by the Kepler Mission. The targets of the search include 111,800 stars which were observed for the entire interval and 85,522 stars which were observed for a subset of the interval.

We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes and interferometrically determined radii to refine their effective temperatures, luminosities, and metallicities.

he proportions of oxygen, carbon and major rock-forming elements (e.g. Mg, Fe, Si) determine a planet's dominant mineralogy. Variation in a planet's mineralogy subsequently affects planetary mantle dynamics as well as any deep water or carbon cycle.

NASA's Kepler spacecraft, now crippled and its four-year mission at an end, nevertheless provided enough data to complete its mission objective: to determine how many of the 100 billion stars in our galaxy have potentially habitable planets.