“Something like the diffuse glow of gamma ray background that permeates our Milky Way Galaxy could conceivably be evidence for dark matter,” researcher Mark Krumholz, a theoretical and computational astrophysicist at Australian National University, told The Daily Galaxy.
Maxwell Moe, astrophysicist, NASA Einstein Fellow, University of Arizona. Max can be found two nights a week probing the mysteries of the Universe at the Kitt Peak National Observatory.
The Milky Way Galaxy is the name given to our home in the cosmos. We have never imaged the Galaxy from the outside, only from our position in the solar system. As a result, much of what we know about the structure has to be inferred from clever and detailed studies. While there are many fast fact pages I can write about the Galaxy, within this article I have chosen four important ones for understanding our home location.
The Milky Way’s bulge is the ancient and crowded central hub of our Galaxy. It contains about one quarter of the total stellar mass of the Milky Way and has a very different stellar environment than our solar neighborhood. The stellar densities are on average over 10 times higher and include both very young but mostly very old stellar populations.
We’re kicking off the week with intriguing stories from our Universe beyond–from exoplanets in the ancient, densely populated bulge of the Milky Way to the mystery of eternal brown dwarfs to the soon approaching, long awaited launch of the iconic Hubble spacecraft’s successor.
Astronomers recently discovered a previously unrecognized spur of young stars and star-forming gas clouds sticking out of the Milky Way’s Sagittarius spiral arm –one of the most striking arms in our galaxy, noted for its young stars and beautiful nebula that connects to the major Orion arm that harbors our solar system. “Spiral arms in galaxies like the Milky Way typically form from long-lived spiral density waves that periodically cause a bunching up of stars and clouds in a regular symmetric pattern, like a pinwheel,” wrote astronomer Debra Elmegreen, president of the International Astronomical Union, in an email to The Daily Galaxy.
Something massive and mysterious is lurking in our home galaxy’s bulge. Or is it one of the estimated 100-billion objects known as brown dwarfs roaming the Milky Way? In 2017, astronomers used the light-warping effects of gravity to spot a massive object OGLE-2016-BLG-1190Lb using NASA’s infrared Spitzer Space Telescope, 13 times the mass of Jupiter and orbits a star about 22,000 light years away. This discovery of an absolutely massive planet residing in our galaxy’s “bulge” (image above) has scientists struggling to explain if it’s a huge unknown planet or a failed star.