Archives de catégorie : sciences-general

Mars: Oxygen-rich, life-supporting liquid water?

by California Institute of Technology, October 22, 2018 in ScienceDaily


A team led by scientists at Caltech and the Jet Propulsion Laboratory (JPL), which Caltech manages for NASA, has calculated that if liquid water exists on Mars, it could — under specific conditions — contain more oxygen than previously thought possible. According to the model, the levels could even theoretically exceed the threshold needed to support simple aerobic life.

That finding runs contrary to the current, accepted view of Mars and its potential for hosting habitable environments. The existence of liquid water on Mars is not a given. Even if it is there, researchers have long dismissed the idea that it might be oxygenated, given that Mars’s atmosphere is about 160 times thinner than that of Earth and is mostly carbon dioxide.

Ancient Mars had right conditions for underground life, new research suggests

by Brown University, September 24, 2018 in ScienceDaily/EPSL


A new study shows evidence that ancient Mars probably had an ample supply of chemical energy for microbes to thrive underground.

“We showed, based on basic physics and chemistry calculations, that the ancient Martian subsurface likely had enough dissolved hydrogen to power a global subsurface biosphere,” said Jesse Tarnas, a graduate student at Brown University and lead author of a study published in Earth and Planetary Science Letters. “Conditions in this habitable zone would have been similar to places on Earth where underground life exists.”

New research shows that ancient Mars likely had ample chemical energy to support the kinds of underground microbial colonies that exist on Earth.
Credit: NASA / JPL

BBC tells journalists that IPCC is God, can not be wrong –”No debate allowed”

by JoNova, September 8, 2018


Lets all bow to the IPCC — a modern God that shalt not be questioned. The Holy Sacred Climate Cow!

The IPCC is an unaudited and unaccountable foreign committee. Not only are no scientists paid to check its findings, now the publicly mandated BBC is making sure none of their journalists will check its findings either.

Carbonbrief has a copy of the BBC new internal guidance on how to report climate change.

In April, the UK regulator, Ofcom, found the BBC was guilty of not sufficiently challenging Lord Lawson, a skeptic. So in response the BBC now promises they will never sufficiently challenge the IPCC. That’s “false balance” for you.

Direct evidence of surface exposed water ice in the lunar polar regions

by Shaui Li et al., August 20, 2018 PNAS


We found direct and definitive evidence for surface-exposed water ice in the lunar polar regions. The abundance and distribution of ice on the Moon are distinct from those on other airless bodies in the inner solar system such as Mercury and Ceres, which may be associated with the unique formation and evolution process of our Moon. These ice deposits might be utilized as an in situ resource in future exploration of the Moon.

Integrated genomic and fossil evidence illuminates life’s early evolution and eukaryote origin

by Holly C. Betts et al., August 20, 2018 in NatureEcology&Evolution


We derive a timescale of life, combining a reappraisal of the fossil material with new molecular clock analyses. We find the last universal common ancestor of cellular life to have predated the end of late heavy bombardment (>3.9 billion years ago (Ga)). The crown clades of the two primary divisions of life, Eubacteria and Archaebacteria, emerged much later (<3.4 Ga), relegating the oldest fossil evidence for life to their stem lineages. The Great Oxidation Event significantly predates the origin of modern Cyanobacteria, indicating that oxygenic photosynthesis evolved within the cyanobacterial stem lineage. Modern eukaryotes do not constitute a primary lineage of life and emerged late in Earth’s history (<1.84 Ga), falsifying the hypothesis that the Great Oxidation Event facilitated their radiation…

The Medusae Fossae Formation as the single largest source of dust on Mars

by L. Ojha et al., July 20, 2018 in NatureCommunications (open access)


Transport of fine-grained dust is one of the most widespread sedimentary processes occurring on Mars today. In the present climate, eolian abrasion and deflation of rocks are likely the most pervasive and active dust-forming mechanism. Martian dust is globally enriched in S and Cl and has a distinct mean S:Cl ratio. Here we identify a potential source region for Martian dust based on analysis of elemental abundance data …

Invisible Scientific Debates Accomplish Nothing

by Donna Laframboise, April 23, 2018 in ClimateChangeDispatch


SPOTLIGHT: After the Intergovernmental Panel on Climate Change (IPCC) report was released in 2007, its dramatic findings of species extinction were repeatedly emphasized by chairman Rajendra Pachauri.

BIG PICTURE: When it examined the question of species extinction, the 2007 IPCC report relied heavily on a single piece of research – a Nature cover storypublished early in 2004. Written by Chris Thomas and 18 others, this was the source of Pachauri’s claim that climate change threatened 20 to 30% of the world’s species.

Clear as mud: Desiccation cracks help reveal the shape of water on Mars

by Geological Society of America and in Geology, April 19,2018 in ScienceDaily


.pdf of the article

In early 2017 scientists announced the discovery of possible desiccation cracks in Gale Crater, which was filled by lakes 3.5 billion years ago. Now, a new study has confirmed that these features are indeed desiccation cracks, and reveals fresh details about Mars’ ancient climate.

“We are now confident that these are mudcracks,” explains lead author Nathaniel Stein, a geologist at the California Institute of Technology in Pasadena. Since desiccation mudcracks form only where wet sediment is exposed to air, their position closer to the center of the ancient lake bed rather than the edge also suggests that lake levels rose and fell dramatically over time.

Scientists discover first super salty subglacial lakes in Canadian Arctic

by University of Alberta, April 11, 2018 in ScienceDaily


Super salty water beneath ice could serve as a terrestrial analogue for a habitat for life on other planets.

An analysis of radar data led scientists to an unexpected discovery of two lakes located beneath 550 to 750 meters of ice underneath the Devon Ice Cap, one of the largest ice caps in the Canadian Arctic. They are thought to be the first isolated hypersaline subglacial lakes in the world.

Science is Not Truth

by Donna Laframboise, April 4, 2018 in ClimateChangeDispatch


SPOTLIGHT: As the influence of religion has waned, we’ve placed science on a pedestal – mistaking it for an oracle of truth.

BIG PICTURE: Richard Harris has written a startling book about the state of medical research. The preface to Rigor Mortis: How Sloppy Science Creates Worthless Cures, Crushes Hope, and Wastes Billions includes a warning about scientific naivety:

Most of science is built on inference rather than direct observation…Science progresses by testing ideas indirectly, throwing out the ones that seem wrong…Gradually, scientists build stories that do a better job of approximating the truth.

Earth’s stable temperature past suggests other planets could also sustain life

by Anthony Watts,  April 3, 2018 in WUWT


Theories about the early days of our planet’s history vary wildly. Some studies have painted the picture of a snowball Earth, when much of its surface was frozen. Other theories have included periods that would be inhospitably hot for most current lifeforms to survive.

New research from the University of Washington suggests a milder youth for our planet. An analysis of temperature through early Earth’s history, published the week of April 2 in the Proceedings of the National Academy of Sciences, supports more moderate average temperatures throughout the billions of years when life slowly emerged on Earth. (…)

Mars’ oceans formed early, possibly aided by massive volcanic eruptions

by University of California-Berkeley, March 19, 2018 in ScienceDaily


A new theory about how oceans and volcanoes interacted during the early history of Mars supports the idea that liquid water was once abundant and may still exist underground. Geophysicists propose that the oceans originated several hundred million years earlier than thought, as the volcanic province Tharsis formed, and that greenhouse gases enabled the oceans. The theory predicts smaller oceans, more in line with estimates of water underground and at the poles today.

On Science and Nonscience

by Neil Lock, January 11, 2018 in WUWT


What is science?

According to Webster’s, science is: “knowledge or a system of knowledge covering general truths or the operation of general laws.”

The way I see it, science is a method of discovering truths. For the idea to make any sense at all, though, we need first to agree that scientific truth is objective. Now, a particular truth or fact may of course be unknown, or poorly understood, or wrongly apprehended, at a particular time. But in science, one man’s truth must be the same as another’s. (…)

Carbon isotopes, Part 2 : The Delta Notation

by David Kirtley, December 28, 2017, in SkepticalScicence


In Part 1, we learned about carbon isotopes: how 14C forms in the atmosphere, how different isotopes move through the Carbon Cycle, and how isotopic measurements reveal clues about our changing climate. In this post we will look at how measurements of changing isotopic ratios are described.

(…)

Check out this NOAA link for more. And if you have more time check out the entire series on isotopes. I can’t recommend it enough!