Abstract: In this paper we claim that the most likely surprise visit from an epoch-ending NEO (near-Earth object) is one arriving from the Oort Cloud on a radial track toward the Sun, rather than co-orbiting with the Earth. We assume the Breakthrough Starshot laser has been funded and used to launch small photon sails into space with light pressure. Given this, we show that using this laser to ablate the surface of an oncoming comet core can generate enough force to slow the object enough to avoid an epoch-ending collision with Earth. These NEO’s are dark: the low reflectivity of a “dirty iceball” approaching Earth is so low that the NEO will not be detected until it has approached to within 0.35 AU of Earth, but with a velocity that gives about two weeks to react. We assume it is 1km in diameter, with the density of water. Detection depends on raster-scanning the sky to find the solar-illuminated object. Given 100GW from Breakthrough Starshot applied during that period, we show that a collision can be avoided, by slowing the NEO just enough that the Earth passes the collision point prior to predicted collision
Keywords: Death asteroid, Laser propulsion, NEO, Breakthrough starshot, Laser ablation
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