Astronomers using the Hubble Space Telescope discovered that the Black Hole (BH) at the center of the Milky Way probably swallowed its most recent load of cosmic gas around 6 million years ago. After the event, the BH ejected a huge bubble of gas weighing various millions of solar masses above and below the Milky Way´s core. The Fermi Bubbles, as these bubbles of gas, are known, were discovered in 2010 by NASA´s Fermi Telescope. Astronomers have been able to deduce the approximate age of the bubbles and the way in which came to exist by observing the northern bubble.
The Fermi Bubbles
These are two large portions of gas in the form of bubbles that extend below and above the galactic center of the Milky Way. They are thought to have been expelled by the black hole lying at the center of our galaxy and were discovered in 2010 by the Fermi Gamma-ray Space Telescope. These Fermi bubbles extend millions of light years above and below the galaxy and are formed of energetic gamma rays originating from the core of the Milky Way.
What is a black hole?
This is a very dense and compact region in space with a strong gravitational field that is so powerful that ay matter or light approaching it get pulled in by this force. Matter that gets trapped by the gravity of the BH spins around the BH until it gets swallowed.
Some of this matter is ejected creating two bubbles of gasses that extend on both sides; below and above the galactic core of the galaxy. A BH is believed to be the remnant of a massive star at its final stage of evolution.
How the age of this event was calculated
Scientists utilized Hubble´s Cosmic Origins spectrograph (COS), which examined the ultraviolet light coming from the luminous cores-quasars, of 47 distant galaxies.
They used this light to deduce the composition, speed and temperature of the gas within the enlarging bubble, resulting in a temperature of nearly 17,700° F. The elements silicon and carbon-two elements found in almost every galaxy and representing the remnants of stellar evolution, were detected inside the gaseous cloud. The cool gas was estimated to be travelling at 2 million miles/h, revealing an estimated age 6-9 million years for the bubbles.
