Arpanet.Guest@CMU-10A@sri-unix (07/30/82)
Concerning the question of objects A and B, and the time it takes B to realise that A is gone, consider the following (lightly though!) Given that recently (50+ years) we have compiled some accurate astronomical data, does it not follow that we could take a known event of stellar proportions such as a nova or supernova and track it out to it's corresponding actions on the red/blue shift of a nearby star and thus measure the time delay? Since the distance to nova A is known, and the distance to star B is known, and thus the distance between them, the earth-object times are known and thus of no importance, and the object-object time becomes the control. If the change is very slight, which is very likely, do we have a means of accurate measurement? Would the space telescope provide the nessecary level of discretion? This is my first attempt at net communication, and I can only hope that somehow it will get through. Greg Maples n900gs0t@cmua gmm@mit-mc,ai
REM@MIT-MC@sri-unix (08/02/82)
From: Robert Elton Maas <REM at MIT-MC> It is my understanding that most supernovas are rather symmetrical. Since an object that is symmetric has the same gravitational force at a given distance from its center of mass regardless of the radial distribution of the mass, providing the distance is greater than the radius of the object (distance from center to furthest part of its mass), a supernova would cause no gravitational effect on another object until after the outer parts of the star that exploded had passed the other object, by which time that object would be knocked about by physical impact, masking the change in gravitational force. An asymmetrical explosion would cause a net change in gravitational force at distances beyond the radius of the explosion, but computing just what this change might be as we look at a 2-dimensional telescope image of the supernova from a distance of many light years, would be too difficult. We might see the gravitational effect on the other object and not know whether our observed supernova did it or not (perhaps a dark star collided with it, perhaps some other gravitational wave did it, ...). I doubt we can predict the gravitational change accurately enough to confirm or refute it by our observations of that other object.