The Hubble Space Telescope's Cosmic Origins Spectrograph (COS) probes Fermi Bubbles formed by a massive explosion at the center of the Milky Way.
The bubble was formed by a 3 million kilometers (km) per hour outburst from the Milky Way, which took place between 2.5 million and 4.0 million years back.
The gigantic eruption from the Milky Way spewed gas as well as other materials in two plumes at a likely speed of about 2 million miles per hour. The eruption's aftermath exists even today as a couple of gas clouds, which are 30,000 light years below and above the galactic plane's spiral.
Using data from NASA's Fermi Gamma-Ray Space Telescope, scientists discovered the structures only about five years back. Scientists have been observing the structure since then and with the help of Hubble Space Telescope they are able to get measurements of the composition and velocity of the lobes.
The scientists are also calculating the probable mass of the substance that was spewed out in the galaxy, which will help in understanding the reason of the galactic burst. The bubbles resemble the number "8" which is located at the center of the Milky Way.
Astronomers are using light from a quasar, a distant celestial object, to probe the Fermi Bubbles. Scientists suggest that while looking at the night sky, the bubbles may be there but as human eyes cannot detect x-rays, radio waves or gamma waves, the bubbles are not visible.
Andrew Fox, lead researcher of the study from the Space Telescope Science Institute in Baltimore, suggests that other galaxies also have similar outflow of gases and other materials. However, as other galaxies are far away, the bubbles appear to be smaller and difficult to examine.
"But the outflowing clouds we're seeing are only 25,000 light-years away in our galaxy. We have a front-row seat," says Fox.
The close proximity of the structure can enable scientists to estimate the size of the bubbles and their span in the sky.
The scientists suggest that COS has also detected the composition of the material that is being spewed in the gas clouds. Carbon, aluminum and silicon particles are detected, which suggests that the gas is rich in elements that are produced in a star and also represents fragments of a star formation.
The study suggests that this is the first research that has surveyed 20 faraway quasars whose light passes via gas inside or just outside the Fermi Bubbles.
Check out a video that describes the discovery of the bubbles in 2010.