![]() There are other issues as well, such as that it would require a complete rethinking of our models of the galactic magnetic field."įixsen agrees wholeheartedly. "The primary reason is that it would make our galaxy completely unlike any similar spiral galaxy, which as far as we can tell do not exhibit the sort of giant, spherical, radio-emitting halo extending far beyond the galactic disk that would be required. "However, I would say that this explanation does seem to be less likely. "I wouldn't quite say that scientists have largely ruled out the possibility of the radio synchrotron background originating from our galaxy," said Jack Singal, an assistant professor of physics at the University of Richmond in Virginia, who recently led a workshop on the matter. Īll About Space magazine takes you on an awe-inspiring journey through our solar system and beyond, from the amazing technology and spacecraft that enables humanity to venture into orbit, to the complexities of space science. This article is brought to you by All About Space. "The space roar is similar to this expected signal, but there doesn't seem to be six times more galaxies in the distant universe to make up the difference, which could point to something new and exciting as the source." "It has been known since the late 1960s that the combined radio emission from distant galaxies should form a diffuse radio background coming from all directions," Kogut told All About Space in an email. But because the "space roar" is caused by synchrotron radiation, a type of emission from high-energy charged particles in magnetic fields, and because every source has the same characteristic spectrum, pinpointing the origin of this intense signal is difficult. Scientists call the signal "radio synchrotron background" - background being an emission from many individual sources and blending together into a diffuse glow. "The signal also has a frequency spectrum, or 'color,' that is similar to radio emission from our own Milky Way galaxy." "It's a diffuse signal coming from all directions, so it is not caused by any one single object," said Al Kogut, who headed the ARCADE team at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The latter became apparent rather quickly. Since then, scientists have looked to see where the radiation is coming from while looking to describe the properties of the signal. So the surprise was gradually revealed over months." That said, the impact was still huge. "It then took months of data analysis to first separate instrumental effects from the signal and then to separate galactic radiation from the signal. "While it might make a good movie to see us surprised when we see the light meter pop over to a value six times what was expected, we actually spent years getting ready for our balloon flight and a very busy night taking data," said NASA scientist Dale J. It was then that the intensity of one particular signal became apparent, albeit over many months. By looking at all of the "light" and comparing it to a blackbody source, ARCADE was able to see the combination of many dim sources. ![]() This was different from typical radio telescopes, which observe and contrast two points in the sky. ARCADE was able to make "absolutely calibrated zero-level" measurements, which means it was measuring the actual brightness of something in real physical terms rather than relative terms. ![]()
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