Archives de catégorie : sciences-general

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!

Contamination of the Arctic reflected in microbial metagenomes from the Greenland ice sheet

by A.L. Hauptmann et al., July 11, 2017

Globally emitted contaminants accumulate in the Arctic and are stored in the frozen environments of the cryosphere. The microbial potential to degrade anthropogenic contaminants, such as toxic and persistent polychlorinated biphenyls, was found to be spatially variable and not limited to regions close to human activities.

Why there are so many species of tropical trees and other organisms

by Washington University in St-Louis, June 29, 2017 in ScienceDaily

If aliens sent an exploratory mission to Earth, one of the first things they’d notice — after the fluffy white clouds and blue oceans of our water world — would be the way vegetation grades from exuberance at the equator through moderation at mid-latitudes toward monotony at higher ones. We all learn about this biodiversity gradient in school, but why does it exist?

Le sol, un héritage méprisé

par Ales Bartos, 16 février 2017

Étant très marginalisées sur le champ médiatique, les problématiques liées aux sols échappent largement à l'attention du public. Pourtant, la pollution et l'érosion des sols fait annuellement baisser la capacité des sols de produire des aliments en qualité et quantité suffisantes pour nourrir une population mondiale croissante. Cet article tente d'ouvrir des pistes vers une meilleure gestion des sols, physique et réglementaire, s'inscrivant dans les logiques du développement durable.