Hellish Venus Might Have Been Habitable for Billions of Years

By -



Source:  By Shannon Hall, Scientific American

Excerpt: Venus is—without a doubt—Earth’s toxic sibling. Although both worlds are similar in size and density, our planetary neighbor has temperatures so high they can melt lead, winds that whip around it some 60 times faster than the planet itself rotates and an atmosphere that slams down with more than 90 times the pressure found on Earth’s atmosphere. But there have been a few tantalizing hints that billions of years ago Venus might have been more akin to Earth’s twin. ...But a few billion years ago a slightly fainter sun might have allowed for a relatively cool Venus, one where liquid water could have pooled in vast oceans that were friendly to life. A new study recently accepted in Geophysical Research Letters suggests that not only was Venus habitable in the distant past, it could have remained habitable for billions of years. Michael Way from NASA’s Goddard Institute for Space Studies and his colleagues applied the first three-dimensional climate model—the same computer simulations used to predict human-caused climate change on Earth—to early Venus. ...the results were clear—2.9 billion years ago the second rock from the sun could have had a balmy Earth-like temperature that hovered around 11 degrees Celsius. ...What allowed Venus to stay wet for so long? According to the models, clouds played a key role. They likely piled up on the dayside of the planet, acting as a bright shield that reflects incoming sunlight, and never formed on the nightside, letting heat radiate off into space.  ...This result has vast implications for the world of exoplanets. “The community should be careful about ignoring worlds that are very close to their stars, like Venus-type worlds,” Way says. If a few key characteristics such as an exoplanet’s topography and rotation rate are just right, then the inner edge of the habitable zone—the region in a solar system where conditions conducive to life can arise—will be closer to the host star than is usually thought....

http://www.scientificamerican.com/article/hellish-venus-might-have-been-habitable-for-billions-of-years/

Popular posts from this blog

Stellar remains of famed 1987 supernova found at last

By -
https://www.science.org/content/article/stellar-remains-famed-1987-supernova-found-last By DANIEL CLERY , Science.  Excerpt: When a nearby star exploded in 1987, it created the first supernova visible to the naked eye in 4 centuries and became one of the most intensely studied objects in space. Now, after more than 35 years of searching, researchers have finally discovered the cinder left behind. Using NASA’s new giant space telescope JWST, astronomers spotted  glowing gas at the center of the blast that can only have been energized by something hot and compact inside it , they report this week in Science. They believe a neutron star, all that remains of the shattered star, is responsible.... 
Read more

Planets around dead stars offer glimpse of the Solar System’s future—after the Sun swallows us up

By -
https://www.science.org/content/article/planets-around-dead-stars-offer-glimpse-solar-system-s-future-after-sun-swallows-us By JONATHAN O’CALLAGHAN , Science.  Excerpt: In about 5 billion years the Sun will balloon up into a red giant, consuming Mercury, probably Venus, and maybe even Earth. But even if the outer planets avoid being swallowed up, they might eventually get pulled in or ejected from the Solar System. A new discovery suggests they can survive intact. Using NASA’s JWST space telescope, astronomers have for the first time directly imaged planets on Solar System–like orbits around white dwarfs, the dead stars left after Sun-like stars swell into red giants and subside. The planets follow orbits resembling those of the giant planets in the outer Solar System—big enough for them to have escaped the inferno.... For GSS A Changing Cosmos chapter 1.
Read more

The Smallest Moon of Mars May Not Be What It Seemed

By -
https://www.nytimes.com/2023/04/25/science/mars-deimos-moon-photos.html By Jonathan O’Callaghan , The New York Times.  Excerpt: Deimos, the smaller of the two moons of Mars, might be a chip off the old block — quite literally. That’s the conclusion drawn by scientists in the United Arab Emirates, whose Hope orbiter — also called the Emirates Mars Mission and the country’s first interplanetary spacecraft — just snapped the best views of Deimos ever taken by human spacecraft. ... Mars has two irregularly shaped moons , and neither is mighty. Phobos, the larger of the two, is about 17 miles in diameter at its widest, and orbits closer to the red planet at an altitude of about 3,700 miles. Deimos is just nine miles across on its longest side, and completes an orbit of Mars every 30 hours at an altitude of 15,000 miles. The moons’ small size and quirky dimensions led to suggestions that they may be asteroids captured by Mars long ago. Not so, say researchers analyzing data recorded by Hope,
Read more