![]() ![]() The trapped heat caused more water to evaporate, which put more water in the atmosphere, which trapped more heat, and round and round it went in a vicious greenhouse cycle. The combination of increased heat and increased exposure to high-energy radiation set in motion Venus' downward, hellish spiral.Īs Venus lost its oceans, the water vapor in the atmosphere trapped heat. The more time that Venus spent closer to the sun, the worse it suffered.Įven worse, the closer Venus was to the sun, the more it was susceptible to ultraviolet radiation blasts from solar flares, which were especially prominent when our sun was a young upstart. The problem is that radiation intensity increases rapidly for even small inward shifts in orbital position. If Venus got sent into a highly elliptical orbit due to the presence of Jupiter in the early days of the solar system, it spent some of its year far away from the sun (nice and cool) and some of its year way too close for comfort.Īll told, the researchers calculate, Venus may have suffered from more heat exposure than is healthy. Poor Venus suffered a worse fate, however. Indeed, some deep-time climate variations are directly connected to changes in our eccentricity.īut still, despite the occasional frozen moment, Earth has been able to hang on to its water. We already know from studies of Earth's own history that variations in our planet's eccentricity (due to, you guessed it, gravitational tweaks and tugs from the other planets) triggered ice ages and glaciation events. If you're a planet trying to hold on to your liquid water oceans, an eccentric orbit is a real pain in the neck. Our solar system: A photo tour of the planets If Venus had great liquid water oceans (which we suspect it did, since Venus and Earth are about the same size and had similar formation histories), then the tides on the oceans could have provided enough friction to stabilize the orbit of that planet into a nice, steady circle.īut that elongation of the orbit due to Jupiter may have had another catastrophic consequence: It could have hastened the transformation of Venus from tropical wetland to hellish nightmare. Since Venus no longer has that great of an eccentricity, something must have happened to circularize its orbit, and the authors of the paper suggest that it was ocean tides. Its eccentricity (the measure of how elliptical an orbit can get) is only 0.007, meaning that at closest approach Venus is 66.5 million miles (107 million kilometers) from the sun, and at its farthest it's … 67.7 million miles (109 million km) from the sun.īut according to a recent paper appearing in the preprint journal arXiv, if Jupiter happened to migrate inward closer to the sun, it could have tugged Venus into an extremely elliptical orbit, creating an eccentricity of up to 0.3. Currently, Venus has one of the most perfectly circular orbits in the entire solar system. ![]() The mass of that planet is so great - it's 2.5 times more massive than all the other planets combined - that any little shift in its orbit pulls and plucks on anything else in the solar system. Either way, a dancing Jupiter caused havoc for the inner planets. ![]()
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