May 26, 2016 | David F. Coppedge

More Challenges to Astrobiology

There aren’t likely as many places to live outside of Earth as earlier hoped.

Space weather report

Look at the plume rising from the Martian atmosphere in a photo posted by PhysOrg. What caused it? The latest theory is that the sun is to blame. It sent out a coronal mass ejection (CME) that lofted dust and ice grains in the atmosphere to higher levels. Earth is shielded from “space weather” by its strong magnetic field. The implications become obvious:

“A number of processes could be responsible, but if these plumes are indeed driven by space-weather disturbances, this adds an important angle to our understanding of how Mars may have lost much of its atmosphere in the past, changing from a warm, wet world and becoming the cold, dry, dusty place it is today,” says Dmitri Titov, Mars Express project scientist.

It’s rad out there

Space weather dims hopes for life on other planets and moons in our solar system. Nola Taylor Redd writes for Live Science, “Alien Life? Radiation May Erase Mars, Europa Fossils.” It’s not just that life would have a harder time emerging on an unprotected world; even if it did, she argues, we might never know.

The hunt for signs of alien life in the solar system may be much tougher than researchers had thought, thanks to the damaging effects of radiation.

Two separate studies suggest that galactic radiation would quickly degrade biological material on the surface of Mars and Jupiter’s ocean-harboring moon Europa, two of the prime targets in the search for past or present extraterrestrial life.

Earth’s biological material (both living and departed) would quickly degrade just as easily, were it nor for our protective atmosphere that shields the biosphere from high-energy galactic cosmic rays (GCRs). Most amino acids would degrade in 20 million years, a very brief time for hunters looking for ancient Martian life. But when wet, the materials degrade faster. “Water accelerated the degradation of the biomarkers, destroying some in as few as 500,000 years and all within 10 million years.” Instruments would have to be able to dig deeper than a meter, scientists estimate, to find evidence of life on Mars. Europa faces comparable radiation. Instruments might have to dig a dozen meters down to get below the decay zone.

Hot zones

Astrobiologists had hoped for numerous life-friendly planets around red dwarf stars, the most plentiful in the galaxy. A new study dims that hope, too. Planets within those stars’ habitable zones are likely to be too hot. “There may be far fewer potentially life-supporting alien planets out there than scientists had thought,” Mike Wall writes at Earth-size planets could hold onto their atmospheres longer than previously estimated. Sounds good, but the downside is that the thick atmospheres would be subject to a runaway greenhouse effect, scorching the planets’ surfaces. Science Daily explains:

Dr James Owen, Hubble Fellow and lead author of the study from the Institute for Advanced Studies in Princeton, said: “It was previously assumed that planets with masses similar to Earth would be habitable simply because they were in the ‘habitable zone’. However, when you consider how these planets evolve over billions of years this assumption turns out not to be true.

It was known previously that many of these planets are born with thick atmospheres of hydrogen and helium, making up roughly one percent of the total planetary mass. In comparison, the Earth’s atmosphere makes up only a millionth of its mass. The greenhouse effect of such a thick atmosphere would make the surface far too hot for liquid water, rendering the planets initially uninhabitable.

Another assumption was that X-rays from the star would strip down these initial atmospheres to safer levels. New models show that is not the case; Earth-size planets have enough mass to keep most of the gas for long periods of time. Smaller Mars-sized planets might work. That’s keeping hope alive. But it does point out that being in the ‘habitable zone’ is not a sufficient condition for habitability, and it renders a large pool of candidate planets disqualified.

“It was previously assumed” has brought the downfall of many a materialist’s hope. Notice again how reporters use passive voice verbs as cover. They should say, “Simple-minded materialistic evolutionary scientists assumed” this or that. Instead, they draw everybody into their circle of ignorance. We never assumed that. We assumed life was created on purpose by an intelligent Designer. We assume He knows how to build habitats for humanity. We don’t have to backtrack, because the evidence fits our assumptions.





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