Spotted: Mysterious Cosmic Gas Bubbles
By Vincent Liu
Recently, some cosmic gas bubbles, called Fermi bubbles, were seen for the first time in visible light. They have always been there, but the light they emit was not previously visible to the human eye. “At least, it hadn’t been until now.” (Science News for Students). The hydrogen gas inside the bubbles “was electrically charged, or ionized. That ionization made the gas glow in colors our eyes can see” (Science News for Students)
Scientists are currently studying the origin of the Fermi bubbles. Some people say it is the result of the black hole at the center of the galaxy messily gobbling up matter, and some say it is emissions caused by bursts of stars forming. Scientists do have a lead, though. Inside the bubbles, the motion of the expanding gas is altering the apparent wavelength of its light. The color changes according to the direction the gas is traveling in. According to science news, “material closer to the solar system is traveling toward it, appearing bluer, and more distant gas is moving away, appearing redder.” (Science News). The wavelength shift allowed researchers to find the gas’s velocity at one location within the bubbles. Using the Wisconsin H-Alpha Mapper telescope, or WHAM, researchers found that the gas flowed outward at approximately 220 KPS (kilometers per second). The estimate matched with a measurement made using UV (ultraviolet) light. By recording the measurements of different locations, the researchers hope to more fully map out the velocity of the gas. “What that can tell us is how, over time, the energy output from the Fermi bubbles has changed. That’ll really be able to nail down more about the origin,” astronomer Dhanesh Krishnarao said. Through this process, scientists hope to uncover more about the origin of the Fermi bubbles.