Planetary scientists speculate that Venus was much more like Earth billions of years ago. However, it lost its water sometime in the past and became a sweltering-hot world.
Venus was doomed from the beginning, according to a recent paper, but it may have accelerated its journey to hell by the gravitational power of none other than the solar system's greatest bully: Jupiter.
The early solar system was a Wild West in its entirety: lawless and unpredictable. Astronomers now firmly suspect that the giant worlds did not form in their current orbits. In the forming and sculpting of orbits in the asteroid belt and in the propagation of the ice remains beyond Neptune's orbit, we can recognize this. It is evident from the series of gravitational hints from the holdovers of the development of the solar system that the giant planets first developed further away, then moved closer to the sun inwardly.
We don't have a good picture of just how the migration arose, however. In certain simulations, over the span of hundreds of millions of years, Jupiter slowly edges closer, followed by Saturn and the rest. But Jupiter nearly hops to the orbit of Mars in other versions before slinking back to its present location.
In any case, Jupiter's dance created mayhem on the inner planets. The mass of the planet is so big that every little change in its orbit draws and plucks on everything else in the solar system. It is 2.5 times more massive than all the other planets together.
Take Venus, for instance. Venus actually has one of the most precisely circular orbits in the solar system as a whole. Its eccentricity (the indicator of how elliptical an orbit can get) is just 0.007, which means that Venus is 66.5 million miles from the sun at the nearest approach, and at its furthest ... 67.7 million miles from the sun.
It may have tugged Venus into a highly elliptical orbit if Jupiter happened to shift inward near to the sun, producing an eccentricity of up to 0.3.
Since Venus no longer has an eccentricity so great, something must have happened to circularize its orbit, and the paper's authors say that it was ocean tides. If Venus had great oceans of liquid water (which we believe it did, because Venus and Earth are around the same size and had identical histories of formation), then the ocean tides may have produced ample momentum to settle the planet's orbit into a steady ring.
But the Jupiter-related elongation of the orbit could have had another disastrous result: it may have intensified the transition of Venus from a lush wetland to a hellish nightmare.
The water vapor in the atmosphere captured heat as Venus lost its oceans. The trapped heat caused more water to evaporate, putting more water in the atmosphere, trapping more heat, and in a vicious greenhouse cycle, round and round it went. With no liquids to lubricate the joints of Venus, plate tectonics halted, allowing carbon dioxide to leak into the atmosphere, locking its fate in dramatically.
The phenomenon is described in a paper titled "Could the Migration of Jupiter have Accelerated the Atmospheric Evolution of Venus?," appearing in the preprint journal arXiv.
