September Astronomy News |
Written by Nathaniel Whitehead | |
It has been a while since our last astronomy news update and many a discovery has been made in interim. Of course there is an update on the Phoenix Lander that is revealing ever more mysteries on the Martian surface and bringing never before images of Martian clouds. As well new studies put an upper limit on the size of black holes, research has shown that all the dwarf galaxies around our own Milky Way appear to have the same mass (regardless of luminosity), a new minor-planet has been found inside the orbit of Neptune, the SDSS survey has discovered that there appears to be no dark matter in the cosmic voids found in the large scale structure of the Universe, and a recent Hubble image has shed some light on extra-galactic magnetic fields. All that and a little more in this edition of the cosmic wire….. Phoenix Update:The Phoenix craft had dominated the headlines of most local and national newscasts, but as is usual it soon faded from the front pages, but that doesn’t speak to importance of the data and images being returned from the Martian polar frontier, for they have only increased in measure as of late. So the Lander has given us incredible images of ice in the Martian artic, and now it has given us images of clouds lazily floating above the latest robotic outpost on the red planet. The images are striking not for their alien aesthetic, but rather for the lack of it, for they look very much like something you would see on our own planet. As well the Lander has been hard at work conducting test on the Martian soil to try and determine the amount of water locked inside and just how much water is being cycled from the surface to the atmosphere and vice-versa, one of the instruments onboard (it looks like a robot fork) is used to test the electrical conductivity of the soil around the Lander site and what it found is most curious, it found nothing….zip…..nadda and that is most intriguing because other instruments show that there is minimal amount of water in the atmosphere and it was thought this would condensate in the evening and sublimate in the morning, meaning that the instrument should find some, though little was expected, electrical conductivity. All this will be figured out in due time of course and we will just have to wait and see what happens. There are also images just released of clumps of material adhering to the leg struts on the craft, ones that have been growing and were not seen there previously. There are several theories as to what the material is, could be ice, or mud, or salt, or…..well you get the idea, they haven’t exactly figured that one out either but give them time and they will. With Phoenix there is a steady trickle of information going out to the public but the major discoveries don’t happen every day, but that certainly doesn’t mean they won’t, and in fact Phoenix has already returned invaluable data from the Martian wilderness. So stay tuned for more on this most exciting mission. For more information visit the Phoenix Lander’s website at the following link; http://phoenix.lpl.arizona.edu/
Black Hole Upper Mass Limit: To read more and see our original source visit the following link; Stars or Not, They Seem the Same: If you live or have ever been to the southern hemisphere than you might have turned you eyes skyward and seen the striking Magellanic clouds, dwarf galaxies that lay very close to our own Milky Way and the two Magellanic clouds are only a few of the more than twenty orbiting our galaxy. Research into these dwarfs has revealed some startling data. One would think that the more luminous dwarfs, the ones with more stars, would be larger in terms of mass but new research indicates other wise. And what is the reason for this conclusion, dark matter, what else. The study has shown that regardless of the luminosity the dwarfs all share the same approximant mass, around 10 million solar masses and studies on the nature of dark matter have shown that the minimum mass for dark matter that will allow for stars to form into galaxies is around the 10 million solar masses found in the masses of so many Milky Way satellites. So the research is saying that some of the small satellites could very well be dark matter dominated in terms of the their mass (within a 300 parsec central region). Though no formal conclusions have been reached in the mystery of the mass scale of these small galaxies the research will go on and could give us yet more insight into that mysterious and enigmatic stuff; dark matter. For more information on this study please visit the following site and our original source; http://arxiv.org/abs/0808.3772
New Minor Planet: No Dark Matter in Cosmic Voids: When one looks at the large scale views of the Universe certain structures emerge in the picture, where massive clusters of galaxies form what are called filaments and voids. The filaments are vast tracts of galaxy clusters and super clusters stretching out for millions of light years like a cosmic web, in between those filaments are the voids, which are nearly empty spaces stretching for millions of light years themselves. This structure has been thought to have been seeded in the very early Universe, having been pulled together over time by the slow workings of gravity into the web that we see today. For a while there were questions on just how empty these voids really are, well recent studies done using data collected by the Sloan Digital Sky Survey has begun to answer that question, and what is emerging is that the voids really are almost totally empty. Using models made possible from the ‘standard’ theory of cosmology the observations from the survey were compared with the predictions of the model and viola, they match, almost spot on. The observations showed voids as large as 75 million light years across and this is on par with what the ‘standard’ model predicts, and they are not only devoid of normal matter (the stuff that reacts with light and that we are made out of) they are also lacking any dark matter and this is noteworthy find. In fact it is the dark matter that engenders the structure seen in the cosmos, not the way we find it today but the way it was distributed in the very early (primordial) universe. Over time gravity pulled the dark matter into larger structures thus allowing the normal (baryonic) matter to fall into the already condensed clumps of dark matter. This is what allowed for galaxy formation and ultimately the largest structures of super clusters of galaxies. This research is not only very interesting but very important for determining the validity of models of the universe like the ‘standard’ cosmological model, and the best part is that its ability to explain has only been enhanced by actual observation. For more information on this story and to read our original source follow the link given below; http://www.sdss.org/news/releases/20080817.vpf_final.html “The Magnetic Monster”: |