Questions on observational astronomy, optics, and astrophysics. Specializing in the evolution of stars, variable stars, supernovae, neuton stars/pulsars, black holes, quasars, and cosmology.
I was a professional astronomer (University of Texas, McDonald Observatory), lecturer at the Adler Planetarium, professor of astrophysics, and amateur astronomer for 42 years. I have made numerous telescopes, and I am currently building one of the largest private observatories in Canada.
StarDate, University of Texas, numerous Journal Publications
B.A. Physics and Astronomy M.Sc. Physics Ph.D. Astrophysics
Hello Antero, A recent study published in the "Monthly Notices of the Royal Astronomical Society" ( http://mnras.oxfordjournals.org/content/448/4/3608) suggest that, on average, there are 1 to 3 planets
Hi Srijan, The answer to your question can be very involved, and I'm not sure how mathematical you'd like the answer. For now, time is dilated (compressed) outside a non-rotating spherical mass
Hi Mika, Almost but not quite. Many speculate that the Magellanic Clouds were barred spirals before being disrupted by the Milky Way. But galactic evolution is still an area with many unanswered questions
Hi Luca, This is a very difficult question to answer, for three main reasons: 1) We don't know the current size of the universe, or even how to define "size", since it probably is not spherical and
Hi Michael, This question requires a lengthy answer. But the confusion lies, I think, in the published "distance" of 13 billion light-years away. Please read "Why the Light Travel Time Distance should