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Venus May Have Been the First Habitable Planet In Our Solar System, Study Suggests (theguardian.com)
An anonymous reader quotes a report from The Guardian: Venus is often referred to as Earth's evil twin, but conditions on the planet were not always so hellish, according to research that suggests it may have been the first place in the solar system to have become habitable. The study, due to be presented this week at the at the American Astronomical Society Meeting in Pasadena, concludes that at a time when primitive bacteria were emerging on Earth, Venus may have had a balmy climate and vast oceans up to 2,000 meters (6,562 feet) deep. Michael Way, who led the work at the Nasa Goddard Institute for Space Studies in New York City, said: "If you lived three billion years ago at a low latitude and low elevation the surface temperatures would not have been that different from that of a place in the tropics on Earth," he said. Crucially, if the calculations are correct the oceans may have remained until 715m years ago -- a long enough period of climate stability for microbial life to have plausibly sprung up. "The oceans of ancient Venus would have had more constant temperatures, and if life begins in the oceans -- something which we are not certain of on Earth -- then this would be a good starting place," said Way. With an average surface temperature of 462C (864F), Venus is the hottest planet in the solar system today, thanks to its proximity to the sun and its impenetrable carbon dioxide atmosphere, 90 times denser than Earth's. At some point in the planet's history this led to a runaway greenhouse effect. Way and colleagues simulated the Venusian climate at various time points between 2.9 billion and 715 million years ago, employing similar models to those used to predict future climate change on Earth. The scientists fed some basic assumptions into the model, including the presence of water, the intensity of the sunlight and how fast Venus was rotating. In this virtual version, 2.9 billion years ago Venus had an average surface temperature of 11C (52F) and this only increased to an average of 15C (59F) by 715m years ago, as the sun became more powerful. Details of the study are also published in the journal Geophysical Research Letters.
reminds me of the one-shot manga Hotel (where global warming on Earth turns it basically into Venus).
Well, they either smoked a hell of a lot, or they had civilization and burned up wood and all their fossil fuels, leading to the runaway greenhouse effect the article mentions.
Wouldn't it be ironic if humanity is searching the vastness of space with the most powerful telescopes for extraterrestrial intelligence, all the while the remnants of a fallen civilization reside on the planet right next to us, somewhere under layers of dirt and dust?
What a gloomy, foreboding picture that makes.
Perhaps they sent probes and robots to Earth, like we do to Mars, and life on Earth is the descendant of the microorganisms that made the trip on them.
Well, they either smoked a hell of a lot, or they had civilization and burned up wood and all their fossil fuels, leading to the runaway greenhouse effect the article mentions.
While Venus serves as an interesting example of the greenhouse effect, the liklihood of that happening on earth is pretty slim indeed.
Wouldn't it be ironic if humanity is searching the vastness of space with the most powerful telescopes for extraterrestrial intelligence, all the while the remnants of a fallen civilization reside on the planet right next to us, somewhere under layers of dirt and dust?
It better be made of pretty tough stuff! Venus isn't a material friendly place. I think the longest lasting Venera probe made it for two hours. Pretty much anything that we make would be dissolved fairly quickly.
What a gloomy, foreboding picture that makes.
Perhaps they sent probes and robots to Earth, like we do to Mars, and life on Earth is the descendant of the microorganisms that made the trip on them.
While an interesting thought experiment about Venus harboring oceans and possibly life, What I would be interested in is working our way backwards to find out what caused the extremely dense atmosphere, and what made it the concentration that it is. I do not see that as the future of earth, because I don't think we have enough CO2.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Although that's certainly how some people will try to spin it. Venus' atmosphere is theorized to have begun much like Earth's. The crucial difference was its proximity to the sun caused its water to mostly turn into vapor, instead of remain as a liquid. This (1) contributed to the greenhouse effect - water vapor is the biggest greenhouse gas contributor on Earth despite only a tiny fraction of our water being in vapor form, and (2) rose above heavier CO2 thus shielding it from being lost into space or being broken apart into its elements by solar radiation (Venus has almost no magnetosphere to protect it).
So Venus' CO2 was allowed to build up instead of being lost to space, eventually leading to the enormous pressures Venus has today. Mars's atmosphere has a similar composition (both are 96% CO2), but due to its weaker gravity and lack of water vapor, most of Mars' CO2 was lost into space giving Mars a surface atmospheric pressure only 0.6% that of Earth's. Venus' surface pressure by contrast is 92 times Earth's atmospheric pressure at sea level. CO2's critical point is at 73.9 bar (atmospheres) and 31 C, above which the difference between the gas and liquid phases disappears. So the CO2 "atmosphere" on Venus' surface is more like a sea of CO2 fluid (the Venera landers didn't even use parachutes for the final descent - they gently floated down using nothing but hull drag). You basically have the greenhouse effect of the CO2 gas, compressed into the higher density of liquid CO2. All made possible by excess water vapor early in Venus' early history.
Earth's early atmosphere was also nearly the same as on Mars and Venus. But Earth retained liquid water, which was able to dissolve most of the CO2, creating the "habitable" conditions for life we have today. So it's actually liquid vs gaseous water which is the key difference, not CO2 levels. In fact Venus' present atmosphere is theorized to actually be much more hospitable. In the past when water vapor was still present, temperatures there were probably twice what they are today.