A pair of spiral galaxies
Click for full image.
Another cool image to herald in the weekend! The photo to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and shows a pair of spiral galaxies about 800 million light years away.
The smaller galaxy is superimposed on the larger one, which is a type of active galaxy called a Seyfert galaxy.
Seyfert galaxies are named for astronomer Carl K. Seyfert who, in 1943, published a paper about spiral galaxies with very bright emission lines. Today we know that about 10% of all galaxies may be Seyfert galaxies. They belong to the class of “active galaxies” – galaxies that have supermassive black holes at their centers accreting material, which releases vast amounts of radiation. The active cores of Seyfert galaxies are at their brightest when observed in light outside the visible spectrum. The larger galaxy in this pair is a Type II Seyfert galaxy, which means it is a very bright source of infrared and visible light.
In other words, both of these galaxies emit a lot of radiation in the infrared, radio, and X-rays due to activity taking place at the supermassive black holes believed to be at their cores.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Click for full image.
Another cool image to herald in the weekend! The photo to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and shows a pair of spiral galaxies about 800 million light years away.
The smaller galaxy is superimposed on the larger one, which is a type of active galaxy called a Seyfert galaxy.
Seyfert galaxies are named for astronomer Carl K. Seyfert who, in 1943, published a paper about spiral galaxies with very bright emission lines. Today we know that about 10% of all galaxies may be Seyfert galaxies. They belong to the class of “active galaxies” – galaxies that have supermassive black holes at their centers accreting material, which releases vast amounts of radiation. The active cores of Seyfert galaxies are at their brightest when observed in light outside the visible spectrum. The larger galaxy in this pair is a Type II Seyfert galaxy, which means it is a very bright source of infrared and visible light.
In other words, both of these galaxies emit a lot of radiation in the infrared, radio, and X-rays due to activity taking place at the supermassive black holes believed to be at their cores.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Image of IC 4271, also known as Arp 40.
Image of IC 4271, also known as Arp 40,
When galaxies collide do they pass through each other since individual stars are so far apart? Will the galaxy center black holes be more likely to be attracted to each other and combine than the individual stars would be? The gravitational waves that scientist are now detecting, are they from the merging of run of the mill black holes? Or galaxy center black holes?
Steve Richter: To answer your questions:
1. The stars do not touch when galaxies collide or merge. Too far apart.
2. The black holes may collide and merge however.
3. Such a merger would produce gravitational waves that would be detected today. As would a stellar sized black hole. It just depends on the sensitivity of the detector.
Steve Richter,
The stars may not collide, but the galaxies may not merely pass through each other but may undergo dramatic changes due to the odd gravitational forces, and some of the orbiting stars may be flung into the intergalactic void. Below is a brief video about such collisions:
https://rumble.com/v10ew32-44.colliding-galaxies-james-webb-space-telescope-science.html (4 minutes)