Thread: Star Probe
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Old 7th Nov 2018, 12:40
  #17 (permalink)  
ORAC
Ecce Homo! Loquitur...
 
Join Date: Jul 2000
Location: Peripatetic
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One of the points in the paper is that th “tumbling” is an artefact of the tracking radar/telescope and a similar signature would be given from the ticking of a light sail across the solar wind.

”...... have shown that the observed non-gravitational acceleration of ‘Oumuamua, may be explained by Solar radiation pressure. This requires a small mass-to-area ratio for ‘Oumuamua of (m/A) ≈ 0.1 g cm−3.........

While our scenario may naturally explains the peculiar acceleration of ‘Oumuamua, it opens up the question what kind of object might have such a small mass-to-area ratio? The observations are not sufficiently sensitive to provide a resolved image of ‘Oumuamua, and one can only speculate on its possible geometry and nature. Although periodic variations in the apparent magnitude are observed, there are still too many de- grees of freedom (e.g., observing angle, non-uniform reflectively, etc.) to definitely constrain the geometry. The geometry should not necessarily be that of a planar sheet, but may acquire other shapes, e.g., involving a curved sheet, a hollow cone or ellipsoidal, etc.......

Known Solar System objects, like asteroids and comets have mass-to-area ratios orders of magnitude larger than our estimate for ‘Oumuamua. If radiation pressure is the accelerating force, then ‘Oumuamua represents a new class of thin interstellar material, either produced naturally,through a yet unknown process in the ISM or in proto-planetary disks, or of an artificial origin.

Considering an artificial origin, one possibility is that ‘Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment. Lightsails with similar dimensions have been designed and constructed by our own civilization, including the IKAROS project and the Starshot Initiative.......

This would account for the various anomalies of ‘Oumuamua, such as the unusual geometry inferred from its lightcurve, its low thermal emission, suggesting high reflectivity, and its deviation from a Keplerian orbit without any sign of a cometary tail or spin-up torques”......



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