The discussion revolves around the presence of a supermassive black hole at the center of the Milky Way galaxy and its relationship with a bar of stars that is oriented at a 45-degree angle to the galaxy's main plane. Participants explore the implications of these structures coexisting and the dynamics involved in their interactions.
Participants generally agree that the large distances between the supermassive black hole and the bar of stars allow for their coexistence, but there remains uncertainty regarding the specific dynamics and evolutionary processes involved.
The discussion touches on the complexities of galactic structures and the challenges of observing the galaxy's center, which may introduce limitations in understanding the interactions between the black hole and the bar of stars.
Milky Way’s central structure seen with fresh clarity
new infrared survey that claims to be the most comprehensive structural analysis of our galaxy confirms previous evidence for a central bar of stars.
The bar is embedded in the center of the galaxy's spiral arms and cuts across the heart of it all where a supermassive black hole resides. The survey found that the bar is longer than thought and sits at a sharp angle to the galaxy's main plane.
"This is the best evidence ever for this long central bar in our galaxy," said Ed Churchwell, a University of Wisconsin-Madison professor of astronomy.
The challenge
If you've ever been fortunate enough to see the Milky Way in the night sky, then you can appreciate the frustration astronomers face trying to probe the galaxy's center.
The milky swath of stars visible under a dark, rural, summertime sky represents a fraction of the millions upon millions of stars that crowd the center of the galaxy. We sit on the outskirts, looking in. Seeing through the glow to determine the galaxy's structure is hard.
Even more challenging is peering through all the dust between here there.
The survey was done with NASA's Spitzer Space Telescope, which records infrared light. All objects that emit any heat can be seen in infrared, and this wavelength penetrates dust, so the new survey revealed light from tens of millions of stars hidden to optical telescopes.
Bigger than expected
The bar is made of relatively old and red stars, the survey shows. It is about 27,000 light-years long, or roughly 7,000 light-years longer than previously thought. Churchwell's team also found that the bar is oriented at about a 45-degree angle relative to the main plane of the galaxy, in which the Sun and the other spiral-arm stars orbit.
A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers).
Other stars exist outside the galaxy's main plane. The Milky Way, like many galaxies, is surrounded by a sparsely populated spherical halo of stars. The main galactic disk is about 100,000 light-years wide, and the Sun sits about 26,000 light-years from the center.
Bars are fairly common in large spiral galaxies, but some do not have them. Astronomers had glimpsed ours and were not sure if it was in fact a bar or perhaps an ellipse.
What is the source of your confusion?Echo 6 Sierra said:I was reading on Space.com about our galaxy and it said that there is a bar of stars, mostly old and red, at the center and at a 45 degree angle from the plane the rest of us are on. In addition to this there is a super-massive black hole. How can the BH be there and the bar of stars, let alone, at a 45?
Echo 6 Sierra said:How can the BH be there and the bar of stars, let alone, at a 45?
Echo 6 Sierra said:So, it's the enormous distances between the objects that keeps everything okey-doke, right?