Lots of new scientific results in the past couple of weeks feed directly into the central questions of astrobiology – from the search for life, to the environment of interplanetary and interstellar space, and the grand cosmological terrain we find ourselves in.
No Methane For Mars
The latest measurements of atmospheric methane on Mars, made in-situ by the Tunable Laser Spectrometer onboard the Curiosity rover, peg it at less than 1.3 parts per billion. This is in stark contrast to earlier claims, from telescopic studies, of concentrations as high as 45 parts per billion in certain locations, with seasonal variation. Methane could be a key indicator of the metabolic activity of microorganisms, as it is here on Earth. The lack of a detection is not yet definitive proof that earlier measurements were in error, but it certainly calls them into some doubt.
Voyager’s Magnetic Puzzle
Now it’s clear that Voyager 1 has indeed passed into the interstellar medium, one of the next puzzles is why the configuration of magnetic fields around the spacecraft have not shifted very significantly. The expectation had been for a magnetic change in this transition to the region outside the Sun’s electromagnetic dominance. There may be more surprises in store.
A study of the configuration of the great cracks and creases adorning Jupiter’s icy moon Europa suggests that the patterning seen is evidence that the satellite tilts – its spin axis pointing away from a ‘straight’ up and down orientation by a mere degree or so. This small change could explain the distribution of stresses across Europa’s icy crust (due to Jupiter’s gravitational tides) – and it could be happening over days and months. It could also tell us something about the longevity of Europa’s long speculated interior ocean. A mission to Europa could help resolve this question.
A Vast Galactic Belch
The supermassive black hole at the center of our galaxy has long been thought a quiet and relatively diminutive object (a mere 4.3 million times the mass of the Sun). But, in recent years, evidence has been accumulating that it does occasionally tear up passing matter and generate a great outpouring of energy – radiation and fast moving particles. Now another observation could add to these clues – the ethereal glow of radiation from the Magellanic Stream may be an echo of just such an episode some 2 million years ago, one that could have produced the great ‘Fermi Bubbles’ reported earlier. The impact on our remote backwoods area of the Milky Way might have been small, but we don’t know for sure. Across the history of the galaxy such events could have played an influential role in setting the character of the stellar population, and ultimately the environment our solar system formed from.
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