Yes, the statement regarding the drifting of the stars was rather vague and unsubstantiated!
What about these six painted dots above the large bull (Taurus?) in the Lascaux cave paintings?
Could ancient humans have been depicting the Pleiades? https://skyandtelescope.org/observing/meet-the-pleiades-the-seven-sisters/#:~:text=The stars of the Pleiades are gravitationally bound.,traffic all moving together at the speed limit.
I was interested to learn elsewhere that the Pleiades, having an estimated age of only about 100 million years, was born long after the Jurassic dinosaurs had passed into history.
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That would explain my confusion on this in my last post.
I'm discovering late in life that astronomy is like any other are of study (I've found this true of two areas I know a little better than astronomy, engineering and mathematics), if you don't know the history, you can't know everything about it.
No doubt, some of the ancients were highly impressive. Galileo had only a tiny 30mm x 30 telescope and a sketch pad but discovered wonders. Tycho Brahe had only his eyes but a meticulous observation and note taking which allowed Kepler to derive elliptical orbits.
William Herschel and his long-suffering sister Caroline spent many chilly nights in Walcot Street in Bath observing the skies around March 1781 and finding Uranus, which definitely looked fuzzy in his telescope:
It was near Zeta Taurus (The sqiggly thing near the Crab Nebula M1) at this date:
I have done the math, and Uranus which is currently south of the Pleiades, period 84 years siderial, will be back near this point in 2033. Zeta and Beta (Elnath), aka the horns of the bull, were called the Gate of the Ecliptic in ancient times, and when a planet crossed it, you could conveniently calculate things.
Another possible explanation of this six or seven sisters thing is that Pleione above Atlas is a variable rapidly rotating star with a dust disk which affects visibility:
https://en.wikipedia.org/wiki/Pleione_(star)
The other six bright stars are all above magnitude 4. Well, that's my theory! 😀
William Herschel and his long-suffering sister Caroline spent many chilly nights in Walcot Street in Bath observing the skies around March 1781 and finding Uranus, which definitely looked fuzzy in his telescope:
It was near Zeta Taurus (The sqiggly thing near the Crab Nebula M1) at this date:
I have done the math, and Uranus which is currently south of the Pleiades, period 84 years siderial, will be back near this point in 2033. Zeta and Beta (Elnath), aka the horns of the bull, were called the Gate of the Ecliptic in ancient times, and when a planet crossed it, you could conveniently calculate things.
Another possible explanation of this six or seven sisters thing is that Pleione above Atlas is a variable rapidly rotating star with a dust disk which affects visibility:
https://en.wikipedia.org/wiki/Pleione_(star)
The other six bright stars are all above magnitude 4. Well, that's my theory! 😀
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My younger son's pal left earlier after demonstrating his 'Seestar S50' smart astronomical telescope to me.
https://www.seestar.com/
He simply sat the Seestar S50 out in the garden and, from the warmth of our living room, instructed it via a smartphone app to locate then track the Pleiades and stack images of the star cluster
The sky was too hazy tonight to warrant completing the stacking, but he was able to show us his previous impressive images of the star cluster, as well as other astronomical features he had imaged, including the Horsehead Nebula.
This magical piece of kit can be purchased for around £540, but may not suit those amateur astronomers who, like Steve, prefer to do it all the hard way!
https://www.seestar.com/
He simply sat the Seestar S50 out in the garden and, from the warmth of our living room, instructed it via a smartphone app to locate then track the Pleiades and stack images of the star cluster
The sky was too hazy tonight to warrant completing the stacking, but he was able to show us his previous impressive images of the star cluster, as well as other astronomical features he had imaged, including the Horsehead Nebula.
This magical piece of kit can be purchased for around £540, but may not suit those amateur astronomers who, like Steve, prefer to do it all the hard way!
My worst enemies are the weather and light pollution!
I am having a good time with my new Nikon FX lens at a surprising 75mm. The problem is those stars move so fast. 1 arc minute every 4 seconds.
This might be cured by stacking many short exposures on a computer, which is what that Seestar S50 does, along with automatic guidance.
This is what Andrew McCarthy does with something quite sophisticated:
https://cosmicbackground.io/
He adds thousands of small highly magnified images together and works fast:
We all know that this familiar star has a fusion core at many millions of degrees about the size of the Earth, but see the bigger cooler surface gases at 5,500C.
I like this colour shot of The Moon:
This is a goodie too. I have rotated his occultation image to get Mars the right way up.
The detail is fantastic. Aristotle in ancient Greece worked out that Mars is further away than the Moon from an occultation, which I have seen too. I can imagine the headlines in the Athens Gazette!
Mars currently has an elliptical orbit, but every 2 million years, it becomes nearly circular. Its axis also wobbles hugely, creating huge polar caps at times and a mini Ice Age.
I am having a good time with my new Nikon FX lens at a surprising 75mm. The problem is those stars move so fast. 1 arc minute every 4 seconds.
This might be cured by stacking many short exposures on a computer, which is what that Seestar S50 does, along with automatic guidance.
This is what Andrew McCarthy does with something quite sophisticated:
https://cosmicbackground.io/
He adds thousands of small highly magnified images together and works fast:
We all know that this familiar star has a fusion core at many millions of degrees about the size of the Earth, but see the bigger cooler surface gases at 5,500C.
I like this colour shot of The Moon:
This is a goodie too. I have rotated his occultation image to get Mars the right way up.
The detail is fantastic. Aristotle in ancient Greece worked out that Mars is further away than the Moon from an occultation, which I have seen too. I can imagine the headlines in the Athens Gazette!
Mars currently has an elliptical orbit, but every 2 million years, it becomes nearly circular. Its axis also wobbles hugely, creating huge polar caps at times and a mini Ice Age.
Headline news at diyaudio:
SCIENTIST DISCOVERS FUSION POWER IS A WASTE OF TIME!!!!! 😱
I was completely wrong about the size of fusion core of the Sun. As any budding Einstein knows, there is no gravity at the centre of the Sun, only immense pressure and temperature:
The result of all this is that the Fusion Core is about 25% of the radius. I know the overall density of the Sun is about 3X that of water, but at the core it rises a lot to 150g/cc or thereabouts.
https://en.wikipedia.org/wiki/Sun#Structure_and_fusion
I must have mixed it up with White Dwarfs, which are older, smaller and more dense.
This is the lowdown:
This is worrisome for the future of terrestrial fusion power. A cubic metre of Sun core makes a puny 275W of heat per cubic metre. It only works because the Sun is so big.
If the boffins recreate such a very hot and pressurised volume in a magnetic toroid or something, the size of a medium fridge, it will make as much power as your average compost bin!
My back of a beermat calculations suggest practical fusion plants are just not going to do anything useful. We might as well bring the compost bin indoors and huddle round it.
You heard it here first! I amaze myself, againl! Why aren't I in charge? 😀
SCIENTIST DISCOVERS FUSION POWER IS A WASTE OF TIME!!!!! 😱
I was completely wrong about the size of fusion core of the Sun. As any budding Einstein knows, there is no gravity at the centre of the Sun, only immense pressure and temperature:
The result of all this is that the Fusion Core is about 25% of the radius. I know the overall density of the Sun is about 3X that of water, but at the core it rises a lot to 150g/cc or thereabouts.
https://en.wikipedia.org/wiki/Sun#Structure_and_fusion
I must have mixed it up with White Dwarfs, which are older, smaller and more dense.
This is the lowdown:
This is worrisome for the future of terrestrial fusion power. A cubic metre of Sun core makes a puny 275W of heat per cubic metre. It only works because the Sun is so big.
If the boffins recreate such a very hot and pressurised volume in a magnetic toroid or something, the size of a medium fridge, it will make as much power as your average compost bin!
My back of a beermat calculations suggest practical fusion plants are just not going to do anything useful. We might as well bring the compost bin indoors and huddle round it.
You heard it here first! I amaze myself, againl! Why aren't I in charge? 😀
Here's what @Bonsai had to say some time back about the Sun's power output:
"Interesting fact if I got my math right, 1 square meter on the suns surface outputs 62 million watts. 15 m^2 gives 1 GW. Been doing it for billions of yrs, and will do it for a few more. Energy density in the Sun’s core, paradoxically only about 275 W/m^3 or about 1/3 that of a human."
I can add that only one billionth of the Sun's total radiated energy actually falls on planet Earth, representing a power delivery of 173,000 trillion watts. However, the Earth's surface and atmosphere radiate much of the energy back into space.
"Interesting fact if I got my math right, 1 square meter on the suns surface outputs 62 million watts. 15 m^2 gives 1 GW. Been doing it for billions of yrs, and will do it for a few more. Energy density in the Sun’s core, paradoxically only about 275 W/m^3 or about 1/3 that of a human."
I can add that only one billionth of the Sun's total radiated energy actually falls on planet Earth, representing a power delivery of 173,000 trillion watts. However, the Earth's surface and atmosphere radiate much of the energy back into space.
Elsewhere in our 'Universe', Bonsai remarked on the power density at the centre of the sun being remarkably low and likened it to the centre of an average compost heap.
Which led him to question the Earth bound fusion processes that scientists are working on for energy production because the one in the Sun doesn't look all that promising.
Which led him to question the Earth bound fusion processes that scientists are working on for energy production because the one in the Sun doesn't look all that promising.
The fact is that terrestrial fusion experiments employ a different process than that which occurs in the core of the Sun.
Proton-proton fusion is the process that powers stars like our sun. This gravity-powered reaction requires enormous densities and takes about a billion years to complete. Thus, it’s not something that would be practical for energy production on Earth.
Instead, terrestrial magnetic fusion experiments employ lower densities but far higher temperatures, around 100 million degrees Celsius. When confined at these temperatures, the nuclei can collide with sufficient speed to overcome Coulomb repulsion and fuse together.
https://www.powermag.com/fusion-energy-is-coming-and-maybe-sooner-than-you-think/
I thought physicists of earth were trying to fuse deuterium with tritium, which is easier than proton-proton fusion.
Requires some pre-screening of the feedstock, water, but apparently deuterium separation from water is much cheaper than U235-U238 separation. However Tokyo Electric Power Co is finding tritium separation from the waste water at Fukushima site too expensive to be accomplished at the volume & rate required.
The Norwegians were accomplishing the separation of heavy water at a dam site at a rural fiord in 1941. UK sent some commandoes to sabotage the factory.
Requires some pre-screening of the feedstock, water, but apparently deuterium separation from water is much cheaper than U235-U238 separation. However Tokyo Electric Power Co is finding tritium separation from the waste water at Fukushima site too expensive to be accomplished at the volume & rate required.
The Norwegians were accomplishing the separation of heavy water at a dam site at a rural fiord in 1941. UK sent some commandoes to sabotage the factory.
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The Sun’s overall density is 1.4x that of water, the core temperature 15.7 million K and the core density 150g/cm^3
As celebrated in the 1965 British war film, The Heroes of Telemark!
https://en.wikipedia.org/wiki/The_Heroes_of_Telemark
Slight change of tack. Tonight's occultation of the Pleiades in North America is looking plausible in a few hours time:
Took this an hour ago. Horrible picture. I have no idea of the size of the nearly full Moon, except it is much smaller. All is glare.
Should be above Jupiter (bottom left) tomorrow. Weather permitting.
Took this an hour ago. Horrible picture. I have no idea of the size of the nearly full Moon, except it is much smaller. All is glare.
Should be above Jupiter (bottom left) tomorrow. Weather permitting.
I was testing my Camera at 75mm tonight. The Moon is indeed only a third of the size of the Pleides, but it is impossible to photograph both simultaneously with it.
My very magnified picture of The Moon taken at 1/100 s, F8 and ISO 100 is somewhat wanting:
Compared to more Professional efforts by Andrew McCarthy:
Oh well. I have an exciting new book I found in the sale at the library for a mere 25p. Amazing what people throw away!
My lucky bookie, Will, has a tattoo of Einstein sticking his tongue out on his arm, so was very interested in what I was reading.
It is rather good, and describes Albert Einstein's wilderness years around 1914 when he was trying to flesh out General Relativity.
http://www.stuartclark.com/books/723-the-day-without-yesterday-by-stuart-clark
A unlikely Priest, Georges Lemaitre came to his aid with some ideas of an expanding Universe. I'll tell you how it goes when I have finished it.
Seems all the great men had to contend with Religion or Plague or War interrupting their pure contemplations. It still all goes on, of course.
In some parts of the World, The Big Bang Theory, along with Darwinism, is being banned from school curriculums! The World is mad. Everybody knows. 😀
My very magnified picture of The Moon taken at 1/100 s, F8 and ISO 100 is somewhat wanting:
Compared to more Professional efforts by Andrew McCarthy:
Oh well. I have an exciting new book I found in the sale at the library for a mere 25p. Amazing what people throw away!
My lucky bookie, Will, has a tattoo of Einstein sticking his tongue out on his arm, so was very interested in what I was reading.
It is rather good, and describes Albert Einstein's wilderness years around 1914 when he was trying to flesh out General Relativity.
http://www.stuartclark.com/books/723-the-day-without-yesterday-by-stuart-clark
A unlikely Priest, Georges Lemaitre came to his aid with some ideas of an expanding Universe. I'll tell you how it goes when I have finished it.
Seems all the great men had to contend with Religion or Plague or War interrupting their pure contemplations. It still all goes on, of course.
In some parts of the World, The Big Bang Theory, along with Darwinism, is being banned from school curriculums! The World is mad. Everybody knows. 😀
The novel sounds interesting.
It was Georges Lemaitre who, in 1927, came up with the idea of a Universe which had originated from a single point.
He called this the hypothesis of the primeval atom - with the primeval atom referring to what we now call the singularity.
The story started in 1922 when Alexander Friedmann discovered a solution to Einstein's equations in which the universe expanded.
Lemaitre realised if you traced the expansion of the universe backwards into the past it would get tinier and tinier until you came to a creation event - what is now called the Big Bang.
Portsmouth's premier Citizen Scientist has been out observing the Moon and Jupiter and Pleiades again tonight!
Recall what we saw last night:
As predicted, the very overexposed Moon has moved above Jupiter in the Ecliptic, and you can just see the Hyades to the right:
Jupiter is a well behaved Planet and stays within a degree of the Ecliptic, which is the path of the Sun. You can see that the Moon is well above the Ecliptic here so no chance of eclipses.
The Moon has all sorts of wobbles in Orbit, angle to the Ecliptic at a maximum of about 5 degrees, and distance. I think there is an approx. 18 year cycle in Eclipses, which this year happen in March and September when the Moon crosses the Ecliptic, but really it gets complicated.
The news always bangs on about Supermoons, and the effect of is quite noticeable over the year:
There is also an effect called libration of about 5 degrees where you can see more or less at the equatorial edges due to the Moon's elliptical orbit.
Recall what we saw last night:
As predicted, the very overexposed Moon has moved above Jupiter in the Ecliptic, and you can just see the Hyades to the right:
Jupiter is a well behaved Planet and stays within a degree of the Ecliptic, which is the path of the Sun. You can see that the Moon is well above the Ecliptic here so no chance of eclipses.
The Moon has all sorts of wobbles in Orbit, angle to the Ecliptic at a maximum of about 5 degrees, and distance. I think there is an approx. 18 year cycle in Eclipses, which this year happen in March and September when the Moon crosses the Ecliptic, but really it gets complicated.
The news always bangs on about Supermoons, and the effect of is quite noticeable over the year:
There is also an effect called libration of about 5 degrees where you can see more or less at the equatorial edges due to the Moon's elliptical orbit.
