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APOD Robot
- Otto Posterman
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by APOD Robot » Mon Dec 11, 2023 5:05 am
Solar Minimum versus Solar Maximum
Explanation: The surface of our Sun is constantly changing. Some years it is quiet, showing relatively few sunspots and active regions. Other years it is churning, showing many
sunspots and throwing frequent
Coronal Mass Ejections (CMEs) and
flares. Reacting to
magnetism, our Sun's surface goes through periods of relative calm, called Solar Minimum and relative unrest, called Solar Maximum, every 11 years. The
featured video shows on the left a month in late 2019 when the
Sun was near
Solar Minimum, while on the right a month in 2014 when near
Solar Maximum. The video was taken by NASA's
Solar Dynamic Observatory in far
ultraviolet light. Our
Sun is progressing again toward
Solar Maximum in 2025, but displaying even now a surface with a
surprisingly high amount of activity.
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Ann
- 4725 Å
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by Ann » Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it is still darn quiet for a star of its class!
Phil Plait of SYFY wrote:
Astronomers have determined that, on average, the Sun is quieter than other stars magnetically, and it's not clear why...
(T)he scientists who did the new research turned to the Kepler observatory, which for three years stared at a single spot in space to look for exoplanets, planets orbiting other stars. It did this by taking frequent brightness measurements of 150,000 stars, looking for dips in brightness when planets passed in front of them, making mini-eclipses. And that means Kepler got a lot of brightness measurements of the stars, which is perfect for this study...
In the end they wound up with long-term Kepler data for 365 solar-type stars. They also had a group of over 3,500 stars that were very much like the Sun but for which no rotation period was known. Then they compared the changes in those stars' brightness with the Sun's.
What they found is surprising:
The Sun is much quieter than other stars like it! While the Sun's median brightness variation is 0.07%, the other stars had a median of 0.36%, five times higher! That's even twice as much as the Sun's maximum variation of 0.2%.
Ann
Last edited by Ann on Tue Dec 12, 2023 5:25 am, edited 1 time in total.
Color Commentator
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VictorBorun
- Captain
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Post
by VictorBorun » Mon Dec 11, 2023 6:38 am
Ann wrote: ↑Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class!
Phil Plait of SYFY wrote:
Astronomers have determined that, on average, the Sun is quieter than other stars magnetically, and it's not clear why...
(T)he scientists who did the new research turned to the Kepler observatory, which for three years stared at a single spot in space to look for exoplanets, planets orbiting other stars. It did this by taking frequent brightness measurements of 150,000 stars, looking for dips in brightness when planets passed in front of them, making mini-eclipses. And that means Kepler got a lot of brightness measurements of the stars, which is perfect for this study...
In the end they wound up with long-term Kepler data for 365 solar-type stars. They also had a group of over 3,500 stars that were very much like the Sun but for which no rotation period was known. Then they compared the changes in those stars' brightness with the Sun's.
What they found is surprising:
The Sun is much quieter than other stars like it! While the Sun's median brightness variation is 0.07%, the other stars had a median of 0.36%, five times higher! That's even twice as much as the Sun's maximum variation of 0.2%.
Ann
what are the "365 solar-type stars"? Are they of the same mass and age, or do they share Sun's metallicity too?
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Ann
- 4725 Å
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Post
by Ann » Mon Dec 11, 2023 6:42 am
VictorBorun wrote: ↑Mon Dec 11, 2023 6:38 am
Ann wrote: ↑Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class!
Phil Plait of SYFY wrote:
Astronomers have determined that, on average, the Sun is quieter than other stars magnetically, and it's not clear why...
(T)he scientists who did the new research turned to the Kepler observatory, which for three years stared at a single spot in space to look for exoplanets, planets orbiting other stars. It did this by taking frequent brightness measurements of 150,000 stars, looking for dips in brightness when planets passed in front of them, making mini-eclipses. And that means Kepler got a lot of brightness measurements of the stars, which is perfect for this study...
In the end they wound up with long-term Kepler data for 365 solar-type stars. They also had a group of over 3,500 stars that were very much like the Sun but for which no rotation period was known. Then they compared the changes in those stars' brightness with the Sun's.
What they found is surprising:
The Sun is much quieter than other stars like it! While the Sun's median brightness variation is 0.07%, the other stars had a median of 0.36%, five times higher! That's even twice as much as the Sun's maximum variation of 0.2%.
Ann
what are the "365 solar-type stars"? Are they the same mass and age, or do they share Sun's metallicity too?
Out of 150,000 stars, the scientists picked the 365 ones that were the most Sunlike in terms of temperature, metallicity, chemical composition, surface gravity and rotation. These magnetism of these stars was compared with the magnetism of the Sun.
Ann
Color Commentator
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VictorBorun
- Captain
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by VictorBorun » Mon Dec 11, 2023 1:07 pm
Ann wrote: ↑Mon Dec 11, 2023 6:42 am
VictorBorun wrote: ↑Mon Dec 11, 2023 6:38 am
Ann wrote: ↑Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class!
Ann
what are the "365 solar-type stars"? Are they the same mass and age, or do they share Sun's metallicity too?
Out of 150,000 stars, the scientists picked the 365 ones that were the most Sunlike in terms of temperature, metallicity, chemical composition, surface gravity and rotation. These magnetism of these stars was compared with the magnetism of the Sun.
Ann
That's quite alarming! We can be well heading to a more active Sun's age
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MelvzLuster
- Ensign
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by MelvzLuster » Mon Dec 11, 2023 2:52 pm
Our Sun's age is 4.6 billion years and is predicted to go bigger in the year 3937, so we better prepare now for our future's sake. Correct!
Cmdr. Melvyn M. Lusterio
NASA's Space Commander-Engineer
USS Victory NCC 1967
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Bird_Man
- Ensign
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by Bird_Man » Mon Dec 11, 2023 5:08 pm
Ann wrote: ↑Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class!
Phil Plait of SYFY wrote:
Astronomers have determined that, on average, the Sun is quieter than other stars magnetically, and it's not clear why...
What they found is surprising:
The Sun is much quieter than other stars like it! While the Sun's median brightness variation is 0.07%, the other stars had a median of 0.36%, five times higher! That's even twice as much as the Sun's maximum variation of 0.2%.
Ann
What would be the effect to life on Earth if the Sun's activity was more typical? Is this unique quality of the Sun one of the reasons life, as we know it, exists on Earth?
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Chris Peterson
- Abominable Snowman
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Post
by Chris Peterson » Mon Dec 11, 2023 6:59 pm
MelvzLuster wrote: ↑Mon Dec 11, 2023 2:52 pm
Our Sun's age is 4.6 billion years and is predicted to go bigger in the year 3937, so we better prepare now for our future's sake. Correct!
Uh... no.
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johnnydeep
- Commodore
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by johnnydeep » Mon Dec 11, 2023 7:35 pm
Chris Peterson wrote: ↑Mon Dec 11, 2023 6:59 pm
MelvzLuster wrote: ↑Mon Dec 11, 2023 2:52 pm
Our Sun's age is 4.6 billion years and is predicted to go bigger in the year 3937, so we better prepare now for our future's sake. Correct!
Uh... no.
Yeah, I did a few searches using "year 3937" and "sun" and came up empty. This sure sounds like some unfounded religious or pseudo-science "prediction", but I'm curious where the OP got it from. "Bigger" could also mean different things: a lot more sunspots, more coronal mass ejections, significantly warmer, or actually larger in diameter. But changes in any of those over the next 1900 years, outside of the normal 22 year cycle - let alone
predictable changes - are highly unlikely.
[ EDIT: it is amusing that 39.37 is approximately the number of inches in a meter: 39.37008 ]
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}
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johnnydeep
- Commodore
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by johnnydeep » Mon Dec 11, 2023 8:10 pm
Bird_Man wrote: ↑Mon Dec 11, 2023 5:08 pm
Ann wrote: ↑Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class!
Phil Plait of SYFY wrote:
Astronomers have determined that, on average, the Sun is quieter than other stars magnetically, and it's not clear why...
What they found is surprising:
The Sun is much quieter than other stars like it! While the Sun's median brightness variation is 0.07%, the other stars had a median of 0.36%, five times higher! That's even twice as much as the Sun's maximum variation of 0.2%.
Ann
What would be the effect to life on Earth if the Sun's activity was more typical? Is this unique quality of the Sun one of the reasons life, as we know it, exists on Earth?
Well, I would think that the largest effect would be an increased number or magnitude of coronal mass ejections (CME's). But from what I understand, CME's, although they can fry power lines and electronics on Earth's surface and in orbit, they would not affect evolving life or even the transient surface environment much. Am I wrong?
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}
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Chris Peterson
- Abominable Snowman
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- Joined: Wed Jan 31, 2007 11:13 pm
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Post
by Chris Peterson » Mon Dec 11, 2023 11:03 pm
johnnydeep wrote: ↑Mon Dec 11, 2023 8:10 pm
Bird_Man wrote: ↑Mon Dec 11, 2023 5:08 pm
Ann wrote: ↑Mon Dec 11, 2023 5:35 am
The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class!
Ann
What would be the effect to life on Earth if the Sun's activity was more typical? Is this unique quality of the Sun one of the reasons life, as we know it, exists on Earth?
Well, I would think that the largest effect would be an increased number or magnitude of coronal mass ejections (CME's). But from what I understand, CME's, although they can fry power lines and electronics on Earth's surface and in orbit, they would not affect evolving life or even the transient surface environment much. Am I wrong?
I think in terms of life the most important factors are an increase in charged particles reaching the ground, and the temperature variation created by the greater variation in brightness. A strong magnetic field like our is very protective, but not 100%. If more were thrown our way, more would affect life.
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johnnydeep
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by johnnydeep » Mon Dec 11, 2023 11:48 pm
Chris Peterson wrote: ↑Mon Dec 11, 2023 11:03 pm
johnnydeep wrote: ↑Mon Dec 11, 2023 8:10 pm
Bird_Man wrote: ↑Mon Dec 11, 2023 5:08 pm
What would be the effect to life on Earth if the Sun's activity was more typical? Is this unique quality of the Sun one of the reasons life, as we know it, exists on Earth?
Well, I would think that the largest effect would be an increased number or magnitude of coronal mass ejections (CME's). But from what I understand, CME's, although they can fry power lines and electronics on Earth's surface and in orbit, they would not affect evolving life or even the transient surface environment much. Am I wrong?
I think in terms of life the most important factors are an increase in charged particles reaching the ground, and the temperature variation created by the greater variation in brightness. A strong magnetic field like our is very protective, but not 100%. If more were thrown our way, more would affect life.
Ok, on the potential DNA disruption - mutations - of more charged particles, but perhaps more mutations could
positively affect life by hastening evolution?
As for brightness variation, the example graph is showing less than a 1% variation. Would that really make much of a difference?
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}
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Chris Peterson
- Abominable Snowman
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by Chris Peterson » Mon Dec 11, 2023 11:59 pm
johnnydeep wrote: ↑Mon Dec 11, 2023 11:48 pm
Chris Peterson wrote: ↑Mon Dec 11, 2023 11:03 pm
johnnydeep wrote: ↑Mon Dec 11, 2023 8:10 pm
Well, I would think that the largest effect would be an increased number or magnitude of coronal mass ejections (CME's). But from what I understand, CME's, although they can fry power lines and electronics on Earth's surface and in orbit, they would not affect evolving life or even the transient surface environment much. Am I wrong?
I think in terms of life the most important factors are an increase in charged particles reaching the ground, and the temperature variation created by the greater variation in brightness. A strong magnetic field like our is very protective, but not 100%. If more were thrown our way, more would affect life.
Ok, on the potential DNA disruption - mutations - of more charged particles, but perhaps more mutations could
positively affect life by hastening evolution?
As for brightness variation, the example graph is showing less than a 1% variation. Would that really make much of a difference?
An increased mutation rate would impact life. Hard to define "better" or "worse" in this context. It's worse if you go extinct, it's better if you're a new species!
A 1% variation is significant enough to have an effect, although it's less than the variation induced by the non-zero eccentricity of our orbit. The real question, I think, isn't what the median values are but what the actual extremes are over millions of years. If these more active stars are transiently a LOT more active, that could be a big deal for life.
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johnnydeep
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Post
by johnnydeep » Tue Dec 12, 2023 12:01 am
Chris Peterson wrote: ↑Mon Dec 11, 2023 11:59 pm
johnnydeep wrote: ↑Mon Dec 11, 2023 11:48 pm
Chris Peterson wrote: ↑Mon Dec 11, 2023 11:03 pm
I think in terms of life the most important factors are an increase in charged particles reaching the ground, and the temperature variation created by the greater variation in brightness. A strong magnetic field like our is very protective, but not 100%. If more were thrown our way, more would affect life.
Ok, on the potential DNA disruption - mutations - of more charged particles, but perhaps more mutations could
positively affect life by hastening evolution?
As for brightness variation, the example graph is showing less than a 1% variation. Would that really make much of a difference?
An increased mutation rate would impact life. Hard to define "better" or "worse" in this context. It's worse if you go extinct, it's better if you're a new species!
A 1% variation is significant enough to have an effect, although it's less than the variation induced by the non-zero eccentricity of our orbit. The real question, I think, isn't what the median values are but what the actual extremes are over millions of years. If these more active stars are transiently a LOT more active, that could be a big deal for life.
Ok, got it - thanks.
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}