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Image of the Day: Enigma of Hypergiant Stars Solved
Andromeda's Supermassive Black Hole: "Mystery of the Rings of Ancient Red and New Blue Stars"
The Hubble Space Telescope image at the bottom of the page centers on the 100-million-solar-mass black hole at the hub of the neighboring spiral galaxy M31, or the Andromeda galaxy, the only galaxy outside the Milky Way visible to the naked eye and the only other giant galaxy in the local group. This is the sharpest visible-light image ever made of the nucleus of an external galaxy. The event horizon, the closest region around the black hole where light can still escape, is too small to be seen, but it lies near the middle of a compact cluster of blue stars at the center of the image.
The compact cluster of blue stars is surrounded by the larger "double nucleus" of M31, discovered with the Hubble Space Telescope in 1992. The double nucleus is actually an elliptical ring of old reddish stars in orbit around the black hole but more distant than the blue stars. When the stars are at the farthest point in their orbit they move slower, like cars on a crowded freeway. This gives the illusion of a second nucleus.
The blue stars surrounding the black hole are no more than 200 million years old, and therefore must have formed near the black hole in an abrupt burst of star formation. Massive blue stars are so short-lived that they would not have enough time to migrate to the black hole if they were formed elsewhere.Astronomers are trying to understand how apparently young stars were formed so deep inside the black hole's gravitational grip and how they survive in an extreme environment.
The fact that young stars are also closely bound to the central black hole in our Milky Way galaxy suggests this may be a common phenomenon in spiral galaxies.
Tod R. Lauer of the National Optical Astronomy Observatory in Tucson, Ariz., assembled the image below of the nuclear region by taking several blue and ultraviolet light exposures of the nucleus with Hubble's Advanced Camera for Surveys high-resolution channel, each time slightly moving the telescope to change how the camera sampled the region. By combining these pictures, he was able to construct an ultra-sharp view of the galaxy's core.
The Daily Galaxy via NASA's Goddard Space Flight Center
Image Credit: This image of the Andromeda galaxy was taken on Jan. 13, 2001, with the WIYN/KPNO 0.9-meter Mosaic I by T. Rector, University of Alaska in Anchorage.
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Posted on November 03, 2012 at 09:47 AM | Permalink
Just to get an idea of the distances we are talking about, if we had an FTL drive that was roughly 125 million times as fast as the speed of light--fast enough to take us to Alpha Centauri in roughly one second--it would take us, using that same drive, more than 10 weeks to get to Andromeda. And hundreds of years to reach neighboring super-clusters.
Jack Butler |
There's a factual error in this article. The author states that M31 is the "only galaxy outside the Milky Way visible to the naked eye and the only other giant galaxy in the local group."
In fact, the Large and Small Magellanic Clouds are both visible to the naked eye and are both irregular galaxies in the local group (and satellites of the Milky Way). Some people can also see M33, the Triangulum Galaxy, under very good and very dark sky conditions, which is also a separate galaxy in the local group. Depending on your definition, it could be called a giant galaxy, and the Milky Way and M31 could be called more average galaxies, particularly when compared to true Giant galaxies like M87.
John Haynes |
And at the '' Speed of Mind '' we can be there in an instant
preston |
Like any modern day galaxy the age of ours and the age of Andromeda, they got the size they are by acquiring other galaxies, hence the dichotomy in star age in concentrated "zones". An older galaxy with older stars merges with a younger galaxy such as ours or Andromeda and bingo, you've got a nice mix of star age types. It used to be puzzling until it was discovered that galaxies our size got that way by merging with smaller ones. The Magelanic clouds are examples of mergers or fragments resulting from mergers or a bit of both, according to modern theory and findings. Modern theory often is laid to the wayside when new theories emerge so physics/astronomy is always changing/dynamic. It's cool to live in an era of such discoveries and rediscoveries, the dawn of physics actually. Think what we'll know in 1000 or 10,000 years (given mankind survives and accumulates knowledge at present rate)...and the technology. It's possible we can achieve speeds near C or way beyond right now, but the military isn't divulging it...only possible mind you given all the UFO sightings and testimony by former Scunk works people. What to believe? Posted by:
Charley |