MadSci Network: Astronomy |
G'day! While it is possible that all the stars of magnitude 5.0 and less within a 100 light-year have been mapped (that is, the ones visible to the naked eye), it is definite that all the stars within 100 light-years have NOT been mapped. Dunno if you were interested in astronomy back in 1996, but it was about that time that the first extra-solar planets were being tracked. About that same time a big argument emerged over a new type of observed stellar body called a brown dwarf. The argument essentially was about the largest size one of these brown dwarves could be and still be technically called a planet (1 to 10 times the size of Jupiter is still a planet, 10- 80 times the size of Jupiter are brown dwarves, larger objects than this tend to ignite into stars). Brown dwarves do not emit very much light at all. In fact, the way that the one circling Gliese 229 (one of the first, I think) was detected was the light from the parent star reflecting off the brown dwarf. Others have been detected blocking the view or bending light around other more-visible stellar objects. The Orion Nebula is supposed to have quite a number of brown dwarves. More and more reports are coming in which state that there are lots and lots of these brown dwarves, and that they could account for some of the matter supposedly missing from the universe. From this, it's easy to conclude that there are free-standing brown dwarves out there, quite possibly with their own miniature solar systems (much like Jupiter), and that their near-lightlessness would make them practically impossible to detect with modern astronomical equipment. So, the answer to your question is quite definitely NO (at least for most of this century). And there's also rogue planets (spun off from dying nova stars) and really big dead space rocks (asteroids and planetoids) out there that are so cold they can't even be detected unless they cross the path of something else that was visible. That's not really part of an answer to your question, but they're out there too. I hope this helps you somewhat. Good luck to you! Steve Cartoon Former Internet Software Engineer, Edmark.com
Try the links in the MadSci Library for more information on Astronomy.