According to the United States of America life scientific network reported, a new study confirms, the recently discovered hovering around the Milky Way Galaxy very dark small "Hobbit" Galaxy composed almost entirely of dark matter. Dark matter is a mysterious substance, scientists believe, it accounts for most of the mass of the universe, but with the existing equipment can not see it. The findings will be published in November 10th's "the Astrophysical Journal", it may help to uncover a long time giving astronomers a confused mass of the universe mystery, can explain such a small galaxies to form.
According to the interpretation of the universe in the development and evolution of "cold dark matter" model, large galaxies like our Milky way should be a group of hundreds of times "dwarf galaxies around". However, until recently, astronomers have found only 11 such "dwarf" galaxy. In order to explain the so-called "dwarf" not see this problem, theorists have suggested, most dwarf galaxies contain almost no stars, even if there are also quite a few, the opposite basically composed entirely of dark matter.
At the beginning of this year, the Sloan Digital Sky Survey team members announced, they have found 8 small galaxies very dark in the local group of galaxies, may belong to this strange "dark" Galaxy class. Because these new dwarf galaxies than known as big, Small Magellanic galaxies as much smaller, some scientists call them "Hobbit" galaxy.
Using the Keck 2 telescope in Hawaii, the United States California Institute of Joshua Simon and Canadian Hertz Berg Institute of astrophysics Marhler Gerhard conducted a follow-up study, calculation of its quality according to the "moving stars in the galaxy velocity hobbit". Two people are confirmed each galaxy measurement in the history of the smallest galaxies, than our galaxy 10000 times. They also found that, the galaxy is about 100 times the mass of the star alone from calculation. Simon said: "so the rest of the quality must be in some other substances."
Astronomers generally believe, most galaxies, including our Milky Way Galaxy than conventional material more dark matter, but these newly discovered "Hobbit" galaxy will this trend to the extreme. Simon said: "our study narrowed 'between the observation of cold dark matter' theory and the Milky Way dwarf galaxies were more and more of the gap, and let us understand the characteristics of these galaxies more."
W.M. Keck Observatory director Taft Amandlov says the new findings are significant. Not involved in the study of the Taft said: "this is to uncover 'invisible dwarf galaxies mystery' first step towards real." These new findings are so small that the galaxy is the question of how to form provides a possible explanation. According to the quality measure for "Hobbit" galaxies, the researchers speculate, issued by the formation of just a few hundred years after the big bang the first stars of the strong ultraviolet radiation may be all blown out from the hydrogen is still in the forming of the galaxy. While the hydrogen loss severely inhibited the formation of stars in the future, so that these galaxies become very dark or even a dark.
Simon estimates, scientists would need to find another 100 to 200 such galaxies to the final solution of difference between the number of predicted and observed galaxies. However, since the scientists predict a lot of dark matter galaxies do not contain any stars, it may prove difficult. Let these invisible galaxies "coming out" of a possible way is to find their influence on the Milky way. Simon said: "if you have hundreds of such galaxies orbiting the Milky Way orbit, you may think that they have an impact on the plane of our Milky way galaxy. The galaxy has a layer of tens of thousands of light-years away very thin disk of stars and gas. If it continues to be the dark material impact, each group has 1000000 solar masses so heavy, you might think it would affect the structure of the Milky way disk."
On the other hand, some scientists speculate, dark matter particles like their antimatter particles play the role of. When the regular matter and antimatter collide, they annihilate each other and produce large amounts of energy. Simon said: "the dark matter can do the same thing. You will think that this is a high energy gamma rays from these clumps of dark matter." Simon said, the future of Space Observatory, like the United States NASA is scheduled for the gamma-ray large area space telescope to start next year, can detect dark matter in these gamma rays.