* Jupiter is good protection for Earth against some comets, but new simulations suggest it is not all that benevolent:
Jupiter’s role seems confused. It definitely sends asteroids and comets our way and, in any given year, more than 90 percent of all objects crossing Earth’s orbit are asteroids, so the protection Jupiter provides us from long period comets, or by eventually removing short period comets, is of lesser importance. Hence Jupiter is not the friend that it has been perceived to be. However, things could be far worse: were Jupiter to have a mere 20 percent of its mass, the impact rate would skyrocket. Obviously for any denizens on a planet in the target zone this is bad news, but in the grand scheme of things are impacts a positive or negative factor on the overall evolution of life on a planet across billions of years?* Some scientists still have grand plans for a maglev rail track to space. The report sounds half plausible when it is talking about a cargo system (the track can run up the side of a mountain and cost about $20 billion - which is only a few years of NASA budget), but it sounds a bit loopy when it comes to the human rated system:
According to their plans, the Generation 2 magnetically levitated track would run about 1,609 km (1,000 miles) long, heading upward to an altitude of about 20 km (12 miles). While the track would be securely tethered to the ground, it would be held in mid-air completely by magnetic levitation. The entire track would be enveloped in a vented vacuum tunnel to avoid sonic shock waves that result from the spacecraft's hypersonic speeds of up to 9 km/sec (5.6 miles/sec). Once it exits this track, the spacecraft would be in position to reach LEO.Sounds a tad implausible, no? But the guys talking about this (see the Startram website) are not nutters. Just wildly optimistic, by the sounds.
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