BryLog

Jupiter: Our Cosmic Protector? (via NY Times)

That’s Jupiter doing its cosmic job, astronomers like to say. Better it than us. Part of what makes the Earth such a nice place to live, the story goes, is that Jupiter’s overbearing gravity acts as a gravitational shield deflecting incoming space junk, mainly comets, away from the inner solar system where it could do for us what an asteroid apparently did for the dinosaurs 65 million years ago. Indeed, astronomers look for similar configurations — a giant outer planet with room for smaller planets in closer to the home stars — in other planetary systems as an indication of their hospitableness to life.

A Billion-Year Life Extension for Earth (via ScienceDaily)

Roughly a billion years from now, the ever-increasing radiation from the sun will have heated Earth into inhabitability; the carbon dioxide in the atmosphere that serves as food for plant life will disappear, pulled out by the weathering of rocks; the oceans will evaporate; and all living things will disappear.

Or maybe not quite so soon, say researchers from the California Institute of Technology (Caltech), who have come up with a mechanism that doubles the future lifespan of the biosphere—while also increasing the chance that advanced life will be found elsewhere in the universe….

Earth maintains its surface temperatures through the greenhouse effect. Although the planet’s greenhouse gases—chiefly water vapor, carbon dioxide, and methane—have become the villain in global warming scenarios, they’re crucial for a habitable world, because they act as an insulating blanket in the atmosphere that absorbs and radiates thermal radiation, keeping the surface comfortably warm.

As the sun has matured over the past 4.5 billion years, it has become both brighter and hotter, increasing the amount of solar radiation received by Earth, along with surface temperatures. Earth has coped by reducing the amount of carbon dioxide in the atmosphere, thus reducing the warming effect. (Despite current concerns about rising carbon dioxide levels triggering detrimental climate change, the pressure of carbon dioxide in the atmosphere has dropped some 2,000-fold over the past 3.5 billion years; modern, man-made increases in atmospheric carbon dioxide offset a fraction of this overall decrease.)

The problem, says Joseph L. Kirschvink, the Nico and Marilyn Van Wingen Professor of Geobiology at Caltech and a coauthor of the PNAS paper, is that “we’re nearing the point where there’s not enough carbon dioxide left to regulate temperatures following the same procedures.”

Kirschvink and his collaborators Yuk L. Yung, a Caltech professor of planetary science, and graduate students King-Fai Li and Kaveh Pahlevan, say that the solution is to reduce substantially the total pressure of the atmosphere itself, by removing massive amounts of molecular nitrogen, the largely nonreactive gas that makes up about 78 percent of the atmosphere. This would regulate the surface temperatures and allow carbon dioxide to remain in the atmosphere, to support life, and could tack an additional 1.3 billion years onto Earth’s expected lifespan…. (continues @ ScienceDaily)

Planet-forming Disk Discovered Orbiting Twin Suns (via Science Daily)

Astronomers have announced that a sequence of images collected with the Smithsonian’s Submillimeter Array (SMA) clearly reveals the presence of a rotating molecular disk orbiting the young binary star system V4046 Sagittarii. The SMA images provide an unusually vivid snapshot of the process of formation of giant planets, comets, and Pluto-like bodies. The results also confirm that such objects may just as easily form around double stars as around single stars like our Sun.

Raspberries and the Milky Way Galaxy were discussed on this past week’s episode of  Wait Wait…Don’t Tell Me and here is an article expanding upon it:

ASTRONOMERS searching for the building blocks of life in a giant dust cloud at the heart of the Milky Way have concluded that they taste vaguely of raspberries.

The discovery follows years of work by astronomers who trained their 30-metre Spanish radio telescope on the enormous ball of dust and gas in the hope of spotting complex molecules that are vital for life.

Finding amino acids in interstellar space is a holy grail for astrobiologists, as this would raise the possibility of life emerging on other planets after being seeded with the molecules.

In the latest survey, astronomers sifted through thousands of signals from Sagittarius B2, a vast dust cloud at the centre of our galaxy. While they failed to find evidence for amino acids, they did find a substance called ethyl formate, the chemical responsible for the flavour of raspberries. “It does happen to give raspberries their flavour, but there are many other molecules that are needed to make space raspberries,” Dr Arnaud Belloche, an astronomer at the Max Planck Institute for Radio Astronomy in Bonn, said.

Ethyl formate has another distinguishing characteristic: it also smells of rum.

While scouring their data, the team found evidence for the lethal chemical propyl cyanide in the same cloud. The two molecules are the largest yet discovered in deep space.

Dr Belloche and his colleague, Robin Garrod at Cornell University in New York, have collected about 4000 distinct signals from the cloud. “So far we have identified around 50 molecules in our survey, and two of those had not been seen before,” said Dr Belloche.

The results were presented yesterday at the European week of astronomy and space science at the University of Hertfordshire. Last year, the team came tantalisingly close to finding amino acids in space with the discovery of a molecule that can be used to make them, called amino acetonitrile.

The latest discoveries have boosted the researchers’ morale because the molecules are as large as the simplest amino acid, glycine. Amino acids are the building blocks of proteins and critical for complex life to exist anywhere in the universe. “I wouldn’t be surprised if we find an amino acid out there in the coming years,” Dr Belloche said….(continues @ The Sydney Morning Herald)