Jupiter had major collisions with a comet 10 years ago this week. This week Jupiter had another major collision, probably from a comet. With this interesting fact in mind, is there a higher probability, than what is commonly given, that Earth could have a major impact from a comet or asteroid? Within the past ten years, Earth has also had a couple of lunar distance close calls with asteroids that were not detected until they where very close, by astronomical standards. Sincerely, J. David Baxter baxman2@q.com
Actually it was 15 years ago. -C. On Wed, Jul 22, 2009 at 9:51 AM, BAXTER J DAVID Owner <baxman2@q.com> wrote:
Jupiter had major collisions with a comet 10 years ago this week. This week Jupiter had another major collision, probably from a comet. With this interesting fact in mind, is there a higher probability, than what is commonly given, that Earth could have a major impact from a comet or asteroid? Within the past ten years, Earth has also had a couple of lunar distance close calls with asteroids that were not detected until they where very close, by astronomical standards.
Sincerely,
J. David Baxter
baxman2@q.com
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David has a valid question and though I'm no expert, I'll try to answer to the best of my limited knowledge. Jupiter would have a much higher probability of large impacts due to: (1) Its much larger mass makes it quite literally a bigger target. (2) Its position closer to the source of most comets, i.e. the Oort cloud and the Kuiper belt, makes it more likely to encounter such objects. Probabilities and averages don't give a true picture of what could happen. For example, I'm always annoyed at the nightly TV weather forecasts when they use the term "normal" to describe the average temperature for a given day. A temperature a few degrees above or below the average is not abnormal. Similarly, when we predict impacts that may occur on average, say, every 1000, 10,000 or 10 million years, it is no predictor of a non-average impactor. We are simply a random target for whatever may come our way. The interesting coincidences of this latest Jupiter impact are just that, coincidences, and are no predictor of what may occur to Earth today, tomorrow, next year, or next millennium. Hope this helps, but I hope more that I'm not way off base. Kim
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy- bounces@mailman.xmission.com] On Behalf Of BAXTER J DAVID Owner Sent: Wednesday, July 22, 2009 9:52 AM To: Utah Astronomy-Digest Subject: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability
Jupiter had major collisions with a comet 10 years ago this week. This week Jupiter had another major collision, probably from a comet. With this interesting fact in mind, is there a higher probability, than what is commonly given, that Earth could have a major impact from a comet or asteroid? Within the past ten years, Earth has also had a couple of lunar distance close calls with asteroids that were not detected until they where very close, by astronomical standards.
Sincerely,
J. David Baxter
baxman2@q.com
Even with weathering and erosion, there is a good statistical sampling of impacts on the land area of earth. We can infer impact probabilities for the Earth from evidence in-hand. The oceans toss a bit of uncertainty into the mix. Jupiter doesn't retain impact scars long; the atmosphere sweeps away the evidence in a matter of days or weeks. Events such as these can help bolster models of Jovian impact frequencies, but probably have little or no effect on the numbers as far as earth goes. Kim is right- if you're a planet, your location in the solar system largely determines just how vulnerable you are to impacts. Jupiter and the outer planets are the size they are because they have been exposed to a much greater inventory of raw materials, either by initial accretion from the solar nebula, or later impact. On Wed, Jul 22, 2009 at 9:53 PM, Kim <kimharch@cut.net> wrote:
David has a valid question and though I'm no expert, I'll try to answer to the best of my limited knowledge.
Jupiter would have a much higher probability of large impacts due to: (1) Its much larger mass makes it quite literally a bigger target. (2) Its position closer to the source of most comets, i.e. the Oort cloud and the Kuiper belt, makes it more likely to encounter such objects.
Probabilities and averages don't give a true picture of what could happen. For example, I'm always annoyed at the nightly TV weather forecasts when they use the term "normal" to describe the average temperature for a given day. A temperature a few degrees above or below the average is not abnormal. Similarly, when we predict impacts that may occur on average, say, every 1000, 10,000 or 10 million years, it is no predictor of a non-average impactor. We are simply a random target for whatever may come our way. The interesting coincidences of this latest Jupiter impact are just that, coincidences, and are no predictor of what may occur to Earth today, tomorrow, next year, or next millennium.
Hope this helps, but I hope more that I'm not way off base.
Kim
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto: utah-astronomy- bounces@mailman.xmission.com] On Behalf Of BAXTER J DAVID Owner Sent: Wednesday, July 22, 2009 9:52 AM To: Utah Astronomy-Digest Subject: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability
Jupiter had major collisions with a comet 10 years ago this week. This week Jupiter had another major collision, probably from a comet. With this interesting fact in mind, is there a higher probability, than what is commonly given, that Earth could have a major impact from a comet or asteroid? Within the past ten years, Earth has also had a couple of lunar distance close calls with asteroids that were not detected until they where very close, by astronomical standards.
Sincerely,
J. David Baxter
baxman2@q.com
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BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o) Combat soldiers are fond of saying that you never hear the one (bullet) that gets you...
Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended. I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected. Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events. In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events. So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due". DT --- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
Hi Daniel, But isn't it true that in the situation you site, say the chance is one in 100, that in a century there's a good chance it will happen? To turn your example around, I'd be willing to bet you won't flip 10 heads in a row. Thanks, Joe --- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote: From: daniel turner <outwest112@yahoo.com> Subject: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:16 PM Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended. I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected. Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events. In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events. So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due". DT --- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
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Daniel, I totally agree with your appraisal. Statistics may show the number of significant astroid impacts per hundred years. But a period of lower than average doesn't mean a higher than average frequency of impacts anytime soon. But looking at this as applied to Joe Bauman's comment about the Yellowstone Super Volcano this are a bit different. It is well documented that the YSV has a periocity rate of about 620K years. I believe that the last major event was about 620-640K years ago. Based on this, it is quite likely that the YSV will blow it's stack in the near geologic future. Probably not in our lifetime but perhaps in the next 5K years and almost certainly within the next 50K years. Just a thought. Rodger Fry ----- Original Message ----- From: "Joe Bauman" <josephmbauman@yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Thursday, July 23, 2009 7:22 PM Subject: Re: [Utah-astronomy] Statistical mythbusting. Hi Daniel, But isn't it true that in the situation you site, say the chance is one in 100, that in a century there's a good chance it will happen? To turn your example around, I'd be willing to bet you won't flip 10 heads in a row. Thanks, Joe --- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote: From: daniel turner <outwest112@yahoo.com> Subject: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:16 PM Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended. I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected. Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events. In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events. So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due". DT --- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
Roger: There may be a common factor relating volcanic erruption events to a schedule, like it takes a certain amount of time to load the canon for the next shot, but this isn't true for asteroid impacts. Meteor showers are related events tied to the orbit of a parent comet or asteroid. Tunguska events are not so related. Their parent bodies were disrupted so long ago that their orbits are fully random as far as we can determine. DT --- On Thu, 7/23/09, Rodger C. Fry <rcfry@comcast.net> wrote:
From: Rodger C. Fry <rcfry@comcast.net> Subject: Re: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 6:39 PM Daniel, I totally agree with your appraisal. Statistics may show the number of significant astroid impacts per hundred years. But a period of lower than average doesn't mean a higher than average frequency of impacts anytime soon.
But looking at this as applied to Joe Bauman's comment about the Yellowstone Super Volcano this are a bit different. It is well documented that the YSV has a periocity rate of about 620K years. I believe that the last major event was about 620-640K years ago. Based on this, it is quite likely that the YSV will blow it's stack in the near geologic future. Probably not in our lifetime but perhaps in the next 5K years and almost certainly within the next 50K years.
Just a thought.
Rodger Fry ----- Original Message ----- From: "Joe Bauman" <josephmbauman@yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Thursday, July 23, 2009 7:22 PM Subject: Re: [Utah-astronomy] Statistical mythbusting.
Hi Daniel, But isn't it true that in the situation you site, say the chance is one in 100, that in a century there's a good chance it will happen? To turn your example around, I'd be willing to bet you won't flip 10 heads in a row. Thanks, Joe
--- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote:
From: daniel turner <outwest112@yahoo.com> Subject: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:16 PM
Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended.
I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected.
Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events.
In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events.
So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due".
DT
--- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
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Daniel, I couldn't agree with you more on this one. Each asteroid is its own event and unrelated to the previous or subsequent events. Your anology of "loading the canon" for a volcanic eruption is good and reasonable reletive predictions can be made by looking at the periocity rate of previous events. I know that I don't loose sleep at night worrying about the next asteroid strike or volcanic eruption. Rodger ----- Original Message ----- From: "daniel turner" <outwest112@yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Thursday, July 23, 2009 7:57 PM Subject: Re: [Utah-astronomy] Statistical mythbusting. Roger: There may be a common factor relating volcanic erruption events to a schedule, like it takes a certain amount of time to load the canon for the next shot, but this isn't true for asteroid impacts. Meteor showers are related events tied to the orbit of a parent comet or asteroid. Tunguska events are not so related. Their parent bodies were disrupted so long ago that their orbits are fully random as far as we can determine. DT --- On Thu, 7/23/09, Rodger C. Fry <rcfry@comcast.net> wrote:
From: Rodger C. Fry <rcfry@comcast.net> Subject: Re: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 6:39 PM Daniel, I totally agree with your appraisal. Statistics may show the number of significant astroid impacts per hundred years. But a period of lower than average doesn't mean a higher than average frequency of impacts anytime soon.
But looking at this as applied to Joe Bauman's comment about the Yellowstone Super Volcano this are a bit different. It is well documented that the YSV has a periocity rate of about 620K years. I believe that the last major event was about 620-640K years ago. Based on this, it is quite likely that the YSV will blow it's stack in the near geologic future. Probably not in our lifetime but perhaps in the next 5K years and almost certainly within the next 50K years.
Just a thought.
Rodger Fry ----- Original Message ----- From: "Joe Bauman" <josephmbauman@yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Thursday, July 23, 2009 7:22 PM Subject: Re: [Utah-astronomy] Statistical mythbusting.
Hi Daniel, But isn't it true that in the situation you site, say the chance is one in 100, that in a century there's a good chance it will happen? To turn your example around, I'd be willing to bet you won't flip 10 heads in a row. Thanks, Joe
--- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote:
From: daniel turner <outwest112@yahoo.com> Subject: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:16 PM
Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended.
I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected.
Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events.
In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events.
So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due".
DT
--- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
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Asteroid impacts probably happen at random intervals, but over time, there's a likelihood verging on certainty that another one will hit. There's a difference between frequency and the chance that it eventually will happen. A look at how many such events have happened in the last 10,000 years at least gives us something to go on as far as predicting the odds of its happening in the next 10,000. If our world had never been hit we probably wouldn't worry about it. If it was hit by a big asteroid every century, that might give us more concern. -- just a thought. --- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote: From: daniel turner <outwest112@yahoo.com> Subject: Re: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:57 PM Roger: There may be a common factor relating volcanic erruption events to a schedule, like it takes a certain amount of time to load the canon for the next shot, but this isn't true for asteroid impacts. Meteor showers are related events tied to the orbit of a parent comet or asteroid. Tunguska events are not so related. Their parent bodies were disrupted so long ago that their orbits are fully random as far as we can determine. DT --- On Thu, 7/23/09, Rodger C. Fry <rcfry@comcast.net> wrote:
From: Rodger C. Fry <rcfry@comcast.net> Subject: Re: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 6:39 PM Daniel, I totally agree with your appraisal. Statistics may show the number of significant astroid impacts per hundred years. But a period of lower than average doesn't mean a higher than average frequency of impacts anytime soon.
But looking at this as applied to Joe Bauman's comment about the Yellowstone Super Volcano this are a bit different. It is well documented that the YSV has a periocity rate of about 620K years. I believe that the last major event was about 620-640K years ago. Based on this, it is quite likely that the YSV will blow it's stack in the near geologic future. Probably not in our lifetime but perhaps in the next 5K years and almost certainly within the next 50K years.
Just a thought.
Rodger Fry ----- Original Message ----- From: "Joe Bauman" <josephmbauman@yahoo.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Thursday, July 23, 2009 7:22 PM Subject: Re: [Utah-astronomy] Statistical mythbusting.
Hi Daniel, But isn't it true that in the situation you site, say the chance is one in 100, that in a century there's a good chance it will happen? To turn your example around, I'd be willing to bet you won't flip 10 heads in a row. Thanks, Joe
--- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote:
From: daniel turner <outwest112@yahoo.com> Subject: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:16 PM
Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended.
I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected.
Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events.
In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events.
So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due".
DT
--- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
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Joe, you are correct. Talking about the odds of an impact occurring during a specific interval is, well, pointless, but the geologic cratering impact record does give us an idea of how often these things happen on earth over enormous timescales. I think Daniel and Rodger are correct in reasoning that the chances of it happening anytime soon, or even out to imaginable times in the future as measured in human terms, can't be predicted. There have even been recent computer model studies demonstrating that the inner planets orbital integrity isn't robust over very long timescales, and the earth has a not insignificant chance of being hit by an errant Mercury or Mars one day. Personally, I am more worried about getting hit by someone texting while driving, than an asteroid. I would welcome a near-miss by a very small meteorite, however. On Thu, Jul 23, 2009 at 9:28 PM, Joe Bauman <josephmbauman@yahoo.com> wrote:
Asteroid impacts probably happen at random intervals, but over time, there's a likelihood verging on certainty that another one will hit. There's a difference between frequency and the chance that it eventually will happen. A look at how many such events have happened in the last 10,000 years at least gives us something to go on as far as predicting the odds of its happening in the next 10,000. If our world had never been hit we probably wouldn't worry about it. If it was hit by a big asteroid every century, that might give us more concern. -- just a thought.
Joe: A chance yes, a certainty no. There may be one strike in some centuries and more than one in other centuries, even a string of dry centuries for no apparent reason. The nature of the events are unrelated. There is no convention of Tunguska size objects where they all decide whose turn it is to smack into earth. They don't have calendars. It's a myth imposed by people's expectations. And of course you can sell a lot of papers if you suceed in frightening a lot of people, or in a more modern example, drive up the hit rate on a conspiracy theory website and your advertisers will give you more money. But the truth lies elswhere. DT --- On Thu, 7/23/09, Joe Bauman <josephmbauman@yahoo.com> wrote:
From: Joe Bauman <josephmbauman@yahoo.com> Subject: Re: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 6:22 PM Hi Daniel, But isn't it true that in the situation you site, say the chance is one in 100, that in a century there's a good chance it will happen? To turn your example around, I'd be willing to bet you won't flip 10 heads in a row. Thanks, Joe
--- On Thu, 7/23/09, daniel turner <outwest112@yahoo.com> wrote:
From: daniel turner <outwest112@yahoo.com> Subject: [Utah-astronomy] Statistical mythbusting. To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 7:16 PM
Kim recently was brave enough to take on a common misconception about the concept of what is normal. More of this needs to be done and I hope that no one becomes offended.
I would like to address the concept that the earth is "due" for a Tunguska size impact event. Frontrunner train arrivals can be considered to be "due" because each train is part of a coordinated system of schedules and operators communicating with a central dispatcher who keeps things running as expected.
Impact events are not subject to a dispatcher with a schedule to keep, they are independent events. Let's assume that the odds of getting hit are once every 100 years. Then the olds of a hit during any one year are 1 in 100. That is true for all years; the year before Tunguska, the year after Tunguska, the year OF Tunguska, and this year, more than a century after Tunguska. The odds on each year are the same: 1 in 100. That's the way statistical odds work for unrelated events.
In a coin flip example, if you happen to toss heads three times in a row the odds of doing so on the next flip is 50%. If you manage to toss 10 consecutive heads in a row, the odds on the next flip are still 50%. That's because the coin is just a lump of metal without any memory of recent events or expectations of future events.
So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due".
DT
--- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you... _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
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You're tilting at the wrong windmill, Daniel. Since you quoted my post, I'm assuming you are addressing my statement as well as Kim's. Planetary scientists and astronomy popularizers are the ones pushing this idea; the same scientists who are publicly rallying for a more complete inventory of earth-orbit-crossing objects. They are the ones you need to write your letter of objection to. Or the media who give them a platform, I suppose. I'm sure they'd love to play semantic games with you. On Thu, Jul 23, 2009 at 7:16 PM, daniel turner <outwest112@yahoo.com> wrote:
I would like to address the concept that the earth is "due" for a Tunguska size impact event. So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due".
--- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you...
As Clint Eastwood's character Harry Callaghan said "do you feel lucky?", in our lifetimes the chances Yellowstone Volcano erupting and a asteriod/meteor impact are outside possibilities, but both will happen.
How many times has the earth had impacts in the past? How many volcanic eruptions? Of course many more major super volcanic eruptions and a major eruption is more likely to occur before an impact event, but look at the moon and recently Jupiter and it seems an impact will occur in the future. Lets hope we are lucky enough to miss out on it. I recall, like Chuck said, the Astronomical community is the group pushing the idea that an impact is a certain. Can such a relatively rare event even have statistics even applied to it? Erik You're tilting at the wrong windmill, Daniel. Since you quoted my post,
I'm assuming you are addressing my statement as well as Kim's.
Planetary scientists and astronomy popularizers are the ones pushing this idea; the same scientists who are publicly rallying for a more complete inventory of earth-orbit-crossing objects.
They are the ones you need to write your letter of objection to. Or the media who give them a platform, I suppose. I'm sure they'd love to play semantic games with you.
On Thu, Jul 23, 2009 at 7:16 PM, daniel turner <outwest112@yahoo.com> wrote:
I would like to address the concept that the earth is "due" for a Tunguska size impact event. So as far as Tunguska is concerned, you should go out and buy a bunch of green bananas with the full confidence that you have plenty of time for them to ripen. Impact events are never "due".
--- On Thu, 7/23/09, Chuck Hards <chuck.hards@gmail.com> wrote:
From: Chuck Hards <chuck.hards@gmail.com> Subject: Re: [Utah-astronomy] Asteroid or Comet Collision With Earth Probability To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, July 23, 2009, 5:21 PM BTW, for the worriers among us, some scientists feel that the earth is overdue for a "nuclear" sized impact; one big enough to cause major disruptions or even mass extinction. Thus the current emphasis on finding and cataloging objects that cross earth's orbit. (Get busy, Patrick!) ;o)
Combat soldiers are fond of saying that you never hear the one (bullet) that gets you...
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
participants (7)
-
BAXTER J DAVID Owner -
Chuck Hards -
daniel turner -
erikhansen＠TheBlueZone.net -
Joe Bauman -
Kim -
Rodger C. Fry