massive compact halo objects have been detected by microlensing
an invisible compact object passing in front of a distant source causes a temporary spike in the light curve by gravitational lensing---the brightening might last a couple of days
this was written about in the late 1990s when...
I was just playing with this little doo-hickey http://www.phy.ntnu.edu.tw/java/circularMotion/circular3D_e.html and was wondering; How is it that Jupiter and Neptune remain in orbit even as large as they are? Is it their mass and that the Suns gravity has THAT much of an influence on them?
If the sun becomes a black hole, all the planets in the solar system will stil be orbiting the sun as usual, but would there be any alteration in their orbit trajectories? And would the gravitational influence be stronger on the planets?
If so, what is the relationship between the density of...
Two questions:
1) When in 2004 is the Cassini probe due to reach Saturn/Titan ?
2) Are there any missions being planned or that have been proposed (cost permitting :wink:) to any of the three outer planets (Uranus, Neptune and Pluto) in the not too distant future?
Browsing through my physics book...
The book defines velocity as the limit(t->0) [Δx/Δt], which of course makes sense. An acceleration can occur in two ways: either the speed (speed= ||v||) changes or the direction of the velocity changes. Centripetal acceleration (||a|| is...
I've just talked with someone who informed me of a T.V. special, that dealt with the discovery of two planets, that move in perpendicular orbits - relative to the other nine planets. Is this true, or was I right in assuming that it was ridiculous?