After I read Joe’s blog I went over and read Sheena’s. In reading her article on ‘Light from the darkness’ I realized I have missed a step (or 10) along the way in my understanding of black holes. On TV when ever someone is discussing black holes they always emphasize that the gravity in the black hole is so intense that not even light can escape from it. So, how do we get these radio jets escaping from a black hole as depicted in the galaxy Centaurus A? Jim
Hi Jim. I'm certainly no expert, but I understand that an awful lot can happen to matter as it approaches the event horizon, and these processes account for the energetic jets and other phenomena observed within the regions near a black hole. I'm reminded of a short story by SF author Larry Niven where the hero encounters tidal forces near a massive object (I believe it was an anti-matter star) that nearly destroyed him and his spacecraft. The manufacturers of the craft's hull had to make good on an unconditional warranty to replace the hull, but did not readily comprehend the tidal phenomenon because in their world there was no Earth-Moon analogue to relate to. At least that's how I remember the story from about 35 years ago. Kim -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Jim Gibson Sent: Friday, January 30, 2009 8:01 AM To: Utah Astronomy Subject: [Utah-astronomy] Black holes leak? After I read Joe?s blog I went over and read Sheena?s. In reading her article on ?Light from the darkness? I realized I have missed a step (or 10) along the way in my understanding of black holes. On TV when ever someone is discussing black holes they always emphasize that the gravity in the black hole is so intense that not even light can escape from it. So, how do we get these radio jets escaping from a black hole as depicted in the galaxy Centaurus A? Jim _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com No virus found in this incoming message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.15/1923 - Release Date: 1/29/2009 7:13 AM No virus found in this outgoing message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.16/1925 - Release Date: 1/30/2009 7:37 AM
Good memory, Kim. That was a General Products #2 hull, IIRC. The company was owned by Pierson's Puppeteers. It may have been a Beowulf Shaeffer story, memory is dim now, but the hull survived the encounter as did Shaeffer. He moved to the center of gravity of the hull just in time to avoid being flattened into a thin film at the extreme tip of the hull from tidal forces. When Niven came to town about 30 years or so, he met with planetarium staff because I think they were presenting a show based on one of his stories; there was also a sci-fi con going on at the time. I was asked to do a painting of the Ringworld in glow-in-the-dark paint, for the occassion, and it was placed on display in the Black Light Gallery for a while. 2009/1/30 Kim <kimharch@cut.net>
I'm reminded of a short story by SF author Larry Niven where the hero encounters tidal forces near a massive object (I believe it was an anti-matter star) that nearly destroyed him and his spacecraft. The manufacturers of the craft's hull had to make good on an unconditional warranty to replace the hull, but did not readily comprehend the tidal phenomenon because in their world there was no Earth-Moon analogue to relate to. At least that's how I remember the story from about 35 years ago.
So after attending last night's excellent F.O.S. lecture at the U on emerging solar photovoltaic technology, I came away a little troubled by something that I realized in the course of the lecture. I post this by way of trying to better understand things, so if I'm wrong in what I'm thinking here, please one or more of you correct me. It occurred to me that we are publicly funding (taxes, NSA grants, etc.) university-level research that in turn is being copyrighted and commercialized by the individuals receiving the grants for personal gain. I recognize that their hard work and creativity certainly deserves to be rewarded, but shouldn't scientific breakthroughs funded by taxes become public domain, available to any and all enterprising talent to bring said technologies to market (at a far more rapid pace than could said individual, who certainly wouldn't be excluded, and in fact have a head-start due to his/her intimate understanding of the emerging technology)? Aren't we the venture capitalists in that sense, entitled to share in the profit? Or is the profit that cool new things come to market? I'm interested in hearing your thoughts on the subject... /R
Well, my memory obviously doesn’t hold a candle to yours. However, I do also remember that the protagonist then blackmailed the Puppeteers, about whose home world almost nothing was known by outsiders. Larry Niven was never my favorite author, but I really liked Ringworld. Where is your painting now? I'd be interested to see it. -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Friday, January 30, 2009 10:06 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] Black holes leak? Good memory, Kim. That was a General Products #2 hull, IIRC. The company was owned by Pierson's Puppeteers. It may have been a Beowulf Shaeffer story, memory is dim now, but the hull survived the encounter as did Shaeffer. He moved to the center of gravity of the hull just in time to avoid being flattened into a thin film at the extreme tip of the hull from tidal forces. When Niven came to town about 30 years or so, he met with planetarium staff because I think they were presenting a show based on one of his stories; there was also a sci-fi con going on at the time. I was asked to do a painting of the Ringworld in glow-in-the-dark paint, for the occassion, and it was placed on display in the Black Light Gallery for a while. 2009/1/30 Kim <kimharch@cut.net>
I'm reminded of a short story by SF author Larry Niven where the hero encounters tidal forces near a massive object (I believe it was an anti-matter star) that nearly destroyed him and his spacecraft. The manufacturers of the craft's hull had to make good on an unconditional warranty to replace the hull, but did not readily comprehend the tidal phenomenon because in their world there was no Earth-Moon analogue to relate to. At least that's how I remember the story from about 35 years ago.
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://gallery.utahastronomy.com Visit the Wiki: http://www.utahastronomy.com No virus found in this incoming message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.16/1925 - Release Date: 1/30/2009 7:37 AM No virus found in this outgoing message. Checked by AVG. Version: 7.5.552 / Virus Database: 270.10.16/1925 - Release Date: 1/30/2009 7:37 AM
Jim: The fireworks associated with giant black holes takes place in the accretion disk which is outside of the event horizon. The strong gravity of the hole is just like gravity anywhere it goes on out decreasing in strength by the inverse square law. In the accretion disk thing get pretty exciting because things get there by falling down a deep deep gravity well and their velocity or kinetic energy gets converted to heat when everything gets closer and closer together. A lot of heat. DT --- On Fri, 1/30/09, Jim Gibson <jimgibson00@yahoo.com> wrote:
From: Jim Gibson <jimgibson00@yahoo.com> Subject: [Utah-astronomy] Black holes leak? To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Friday, January 30, 2009, 7:00 AM After I read Joe’s blog I went over and read Sheena’s. In reading her article on ‘Light from the darkness’ I realized I have missed a step (or 10) along the way in my understanding of black holes. On TV when ever someone is discussing black holes they always emphasize that the gravity in the black hole is so intense that not even light can escape from it. So, how do we get these radio jets escaping from a black hole as depicted in the galaxy Centaurus A? Jim
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Has Hawking radiation been disproved? Or is is still accepted that black holes can evaporate by losing thermal energy via quantum effects? This assumes that infalling material doesn't offset themal loss; any black hole with an accretion disk is not decreasing in mass.
Thanks Daniel, Seems like I just saw on Nova where Stephen Hawking’s theory has not been disproven yet about some kind of separation of particles as matter approaches the event horizon. Sorry I can’t be more specific about the details. I guess he was the first to bring quantum mechanics into the big picture and show a relationship. Kind of a first step towards a unified theory which has eluded him for over 20 years. I misunderstood the article and thought the radio jet was coming from within the black hole; something I thought was a no no. It was a beautiful picture though. Jim --- On Fri, 1/30/09, daniel turner <outwest112@yahoo.com> wrote: From: daniel turner <outwest112@yahoo.com> Subject: Re: [Utah-astronomy] Black holes leak? To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Friday, January 30, 2009, 3:16 PM Jim: The fireworks associated with giant black holes takes place in the accretion disk which is outside of the event horizon. The strong gravity of the hole is just like gravity anywhere it goes on out decreasing in strength by the inverse square law. In the accretion disk thing get pretty exciting because things get there by falling down a deep deep gravity well and their velocity or kinetic energy gets converted to heat when everything gets closer and closer together. A lot of heat. DT --- On Fri, 1/30/09, Jim Gibson <jimgibson00@yahoo.com> wrote:
From: Jim Gibson <jimgibson00@yahoo.com> Subject: [Utah-astronomy] Black holes leak? To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Friday, January 30, 2009, 7:00 AM After I read Joe’s blog I went over and read Sheena’s. In reading her article on ‘Light from the darkness’ I realized I have missed a step (or 10) along the way in my understanding of black holes. On TV when ever someone is discussing black holes they always emphasize that the gravity in the black hole is so intense that not even light can escape from it. So, how do we get these radio jets escaping from a black hole as depicted in the galaxy Centaurus A? Jim
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participants (5)
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Chuck Hards -
daniel turner -
Jim Gibson -
Kim -
Richard Tenney