(Press-News.org) Compared to its celestial neighbours Venus and Mars, Earth is a pretty habitable place. So how did we get so lucky? A new study sheds light on the improbable evolutionary path that enabled Earth to sustain life.
The research, published this week in Nature Geoscience, suggests that Earth's first crust, which was rich in radioactive heat-producing elements such as uranium and potassium, was torn from the planet and lost to space when asteroids bombarded the planet early in its history. This phenomenon, known as impact erosion, helps explain a landmark discovery made over a decade ago about the Earth's composition.
Researchers with the University of British Columbia and University of California, Santa Barbara say that the early loss of these two elements ultimately determined the evolution of Earth's plate tectonics, magnetic field and climate.
"The events that define the early formation and bulk composition of Earth govern, in part, the subsequent tectonic, magnetic and climatic histories of our planet, all of which have to work together to create the Earth in which we live," said Mark Jellinek, a professor in the Department of Earth, Ocean & Atmospheric Sciences at UBC. "It's these events that potentially differentiate Earth from other planets."
On Earth, shifting tectonic plates cause regular overturning of Earth's surface, which steadily cools the underlying mantle, maintains the planet's strong magnetic field and stimulates volcanic activity. Erupting volcanoes release greenhouse gases from deep inside the planet and regular eruptions help to maintain the habitable climate that distinguishes Earth from all other rocky planets.
Venus is the most similar planet to Earth in terms of size, mass, density, gravity and composition. While Earth has had a stable and habitable climate over geological time, Venus is in a climate catastrophe with a thick carbon dioxide atmosphere and surface temperatures reaching about 470 C. In this study, Jellinek and Matt Jackson, an associate professor at the University of California, explain why the two planets could have evolved so differently.
"Earth could have easily ended up like present day Venus," said Jellinek. "A key difference that can tip the balance, however, may be differing extents of impact erosion."
With less impact erosion, Venus would cool episodically with catastrophic swings in the intensity of volcanic activity driving dramatic and billion-year-long swings in climate.
"We played out this impact erosion story forward in time and we were able to show that the effect of the conditions governing the initial composition of a planet can have profound consequences for its evolution. It's a very special set of circumstances that make Earth."
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Philadelphia, PA, July 21, 2015 - Wet age-related macular degeneration (AMD) is the leading cause of severe vision loss in older individuals. AMD and other serious chronic eye problems that affect younger individuals result when fluid accumulates abnormally under or within the retina. A new study published in The American Journal of Pathology shows for the first time that the release of substances from mast cells may be a causal factor in this type of eye pathology, and inhibitors of this release may offer new ways to treat serous retinal detachment.
Mast cells are white ...
Quantum theory is one of the great achievements of 20th century science, yet physicists have struggled to find a clear boundary between our everyday world and what Albert Einstein called the "spooky" features of the quantum world, including cats that could be both alive and dead, and photons that can communicate with each other across space instantaneously.
For the past 60 years, the best guide to that boundary has been a theorem called Bell's Inequality, but now a new paper shows that Bell's Inequality is not the guidepost it was believed to be, which means that as the ...
July 2, 2015 - Feed and production input costs are the primary economic inputs of the cattle industry. As input costs increase, producers and cattle are asked to be more efficient to satisfy global food demands. Furthermore, the amount of land available for cattle production in the United States has decreased over the past 10 years. Improvements with marginal land and marginal-quality harvested feeds are being considered.
Three studies were recently published in the Journal of Animal Science that were highlighted at the Forages and Pastures Symposium at JAM in 2015 titled ...
DURHAM, N.C. -- People aren't the only ones who perform better on tests or athletic events when they are just a little bit nervous -- dogs do too. But in dogs as in people, the right amount of stress depends on disposition.
A new study by researchers at Duke University finds that a little extra stress and stimulation
makes hyper dogs crack under pressure but gives mellow dogs an edge.
The findings appear online in the journal Animal Cognition.
According to an idea in psychology called the Yerkes-Dodson law, a little stress can be a good thing, but only up to a point. ...
A class of drugs used to treat diabetes may be associated with protection against Parkinson's disease (PD), according to research published this week in PLOS Medicine. The study, conducted by Dr. Ruth Brauer, of the London School of Hygiene & Tropical Medicine, found a lower incidence of PD among people using a glitazone drug (either rosiglitazone or pioglitazone) to treat diabetes when compared to people who had used different treatments for diabetes.
The cohort study was conducted using data from the UK Clinical Practice Research Datalink, and compared individuals with ...
A type of drug used to treat diabetes may reduce the risk of developing Parkinson's disease, according to a new study published in PLOS Medicine.
The research, led by the London School of Hygiene & Tropical Medicine, found that diabetes patients taking glitazone antidiabetes drugs (either rosiglitazone or pioglitazone) had a 28% lower incidence of Parkinson's disease than people taking other treatments for diabetes who had never taken glitazones. [1]
Glitazones are a class of drug that activate the peroxisome proliferation-activated gamma (PPARγ) receptor, which ...
VANCOUVER, B.C. and DURHAM, N.C. - A Phase III, individually randomized trial has found conditional cash transfers for school attendance did not reduce the risk of HIV among high-school aged women in South Africa, investigators from the HIV Prevention Trials Network (HPTN) reported today at the 8th International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention in Vancouver, Canada.
The new finding is from HPTN 068, the first individually randomized study of young women conditioned on school attendance with an HIV incidence endpoint. In the trial, ...
An international panel of leading scientists is launching a new TripAdvisor-style website aimed at helping researchers choose better-quality research tools - and avoiding potentially serious errors in biomedical research.
In a 'call to action' published today (Tuesday), the international expert panel warns that many scientists are unwittingly using poor-quality chemical probes, leading to mistaken conclusions being drawn from research studies.
The expert panel - made up of researchers from non-profit research institutions and from biotechnology and pharmaceutical companies ...
July 2, 2015 - Porcine reproductive and respiratory syndrome virus (PRRSV) is the most widespread disease in the swine industry. In sows, PRRSV causes reproductive problems during gestation, including abnormal litters or abortions. Growing pigs with the disease will have respiratory problems and poor growth.
In 2012, Holtkamp and colleagues estimated the annual losses due to PRRSV to be a staggering $664 million in the U.S. alone. Producers on larger farms use vaccines and enhanced biosecurity measures to prevent eradicating an entire herd during a PRRSV outbreak. Unfortunately, ...
NEW YORK, July 21, 2015 -- A recent study conducted at Nathan S. Kline Institute for Psychiatric Research (NKI) and NYU Langone Medical Center implicates a new culprit in Alzheimer's disease development. The research reveals that ßCTF -- the precursor of the amyloid beta (Aß) peptide -- acts at the earliest stage of Alzheimer's to initiate a range of abnormalities leading to the loss of groups of neurons critical for memory formation. Results from the study are published online July 21, 2015 in the journal, Molecular Psychiatry, and the article has been selected ...
