Centauri Dreams 6 Nov 2019, 17:36 UTC We often think of Jupiter as a mitigating influence on asteroid or comet strikes in the inner system, its gravity changing the trajectories of potential impactors. That would make gas giants a powerful determinant of the survivability of Earth analogues, at least in terms of habitability. While we continue to investigate the question, it’s interesting to consider the damage a gas giant on an elliptical orbit might do to habitable zone planets. Stephen Kane (UC-Riverside), working with Caltech astronomer Sarah Blunt, decided to find out what would happen if, in their modeling, they introduced an elliptical gas giant into the system of an Earth twin.
Astrobiology Magazine 6 Nov 2019, 16:49 UTC Sulfur chemistry was vital for early anaerobic life in the Archean eon, over 2.5 billion years ago
Bad Astronomy 6 Nov 2019, 14:00 UTC The exoplanet LHC 3844b is what we call a super-Earth: With a diameter of roughly 17,000 km it's roughly 30% bigger than our own beloved home world. But habitable it most definitely ain't: Although it orbits a relatively cool red dwarf star, it's so close — just 950,000 km from the star, less than three times the distance of the Moon from Earth! — it gets cooked by the heat.
SciTech Daily 6 Nov 2019, 09:33 UTC The glow of the Milky Way — our galaxy seen edgewise — arcs across a sea of stars in a new mosaic of the southern sky produced from a year of observations by NASA’s Transiting Exoplanet Survey Satellite (TESS). Constructed from 208 TESS images taken during the mission’s first year of science operations, completed on July 18, the southern panorama reveals both the beauty of the cosmic landscape and the reach of TESS’s cameras.
Sky and Telescope 6 Nov 2019, 03:25 UTC Through the fall and winter of 2017, a team of astronomers used a baker’s dozen of telescopes distributed around the globe to follow a star in the constellation Taurus. Now, they’re reporting that the data they collected that winter has confirmed the existence of a Neptune-mass planet in the outskirts of our galaxy.
Universe Today 5 Nov 2019, 20:24 UTC Ever since astronomers realized that the Universe is in a constant state of expansion and that a massive explosion likely started it all 13.8 billion years ago (the Big Bang), there have been unresolved questions about when and how the first stars formed. Based on data gathered by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and similar missions, this is believed to have happened about 100 million years after the Big Bang.
Starts With a Bang! 5 Nov 2019, 14:01 UTC Back in the 17th century, Isaac Newton put forth the first comprehensive theory of gravity that worked: the law of universal gravitation. All objects with mass attracted all others with an instantaneous force determined by the distances between all pairs of objects (or particles). But when we discovered Special Relativity, and the fact that different observers would disagree about what those distance values were, we knew it couldn’t be the full story. When Einstein put forth General Relativity in 1915, it truly heralded a revolution in physics. Masses didn’t just gravitate; all forms of energy did. Space and time weren’t fixed and absolute, but tied together as spacetime, with properties relative to each observer. And spacetime curves and evolves based on all the matter and energy present within it. Only, when Einstein first applied it to the entire Universe, a huge problem arose. That’s where the story begins.