Friday, June 29, 2018

Or, it might be an alien spaceship after all?

There's an abstract up at Nature about that interstellar visitor of last year, with the tantalising title:

Non-gravitational acceleration in the trajectory of 1I/2017 U1 (‘Oumuamua')
 
Here's the key part:
Here we report the detection, at 30σ significance, of non-gravitational acceleration in the motion of ‘Oumuamua. We analyse imaging data from extensive observations by ground-based and orbiting facilities. This analysis rules out systematic biases and shows that all astrometric data can be described once a non-gravitational component representing a heliocentric radial acceleration proportional to r−2 or r−1 (where r is the heliocentric distance) is included in the model. After ruling out solar-radiation pressure, drag- and friction-like forces, interaction with solar wind for a highly magnetized object, and geometric effects originating from ‘Oumuamua potentially being composed of several spatially separated bodies or having a pronounced offset between its photocentre and centre of mass, we find comet-like outgassing to be a physically viable explanation, provided that ‘Oumuamua has thermal properties similar to comets.
I know it's a long shot, but I guess it still leaves it open that it was an alien spaceship venting or trying to accelerate?

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