I am a Physics teacher from Pakistan. I am genuinely inspired by you, owing to your extremely practical explanations. Unfortunately, I teach online. Had this not been the case, I would've taught my students the same way as you do.
Can someone explain clearly how the parallax angle (p) is derived purely from the distance of displacement of the star against the faraway stars? If all I know if the distance of the earth to the sun, and the distance the star has seemingly moved against the background, how is that distance translated to the parallax angle? All that is said in the video is that after we measure the amount the star has moved against the background after 6 months, we know the angle. How do we determine the angle if all we see is a distance of displacement? We can’t see angles as such.
For the past 1 year I was trying to figure out the parallax method. Only after watching your video I am satisfied that I really understood. Thanks a lot. Very simple and detailed explanation. Could you please share the link of your video for other method? ( luminasity)
Great explanation of parallax I’m 13 and I’m studying astronomy a lot and this is one of the last things I need to know and you simplified to make it less complex
What about the Sun’s Motion around the Galactic centre? While the Earth revolves half a circle around the Sun, the Sun itself has moved with respect to the galactic centre. If our target of observation is not moving at the same speed as our Sun so that any motion relative to the background stars are due to the Earth’s motion around the Sun, then the parallax measured will not correspond to a baseline of 2 AU, but 2 AU + the distance moved by the Sun instead. This problem has puzzled me for quite some time and I have no idea how to get it solved... Does this means that the method of parallax is applicable only to those stars moving in the same spiral arm as our Sun?
I assume the distance the Sun and other stars move compared to each other during half a year is negligible. Note that it takes around 250 million years for the Sun to make a full circle around the galaxy.
We use parallax to determine that stars are extremely far away. To measure the parallax and determine the distance, we have to use as large of a baseline as possible because the stars are extremely far away..
How is it done to make the perdincular of the baseline to exactly go toward the star you want to measure the distance to? Do you measure the angle everyday for 365 days and then choose the pair of angles that are 6 months apart and have the same value?
OOPS! My bad ! Diameter of earth's orbit, not of the earth. Of course earth's orbit is elliptical and the earth's position is not at the center of the ellipse, but in common parlance the radius is 93 million miles give or take ... because for a 1/2 of a base line, considering the change of position of the solar system in 6 months, is 2,2 trillion miles .. that makes the earth orbit diameter only 4 % of what the base line should be should actually be.. i guess making the star 96% farther from our solar system.
If we use this baseline measurement to check the distance of stars, how do we know our baseline measurement is good? Isn't measuring the distance to the sun difficult to do accurately, and if that baseline is off, would it result in...rough measurements? My brain is having a hard time with this one.
The diameter measurement is more than accurate enough for measurement. It’s approximately 300 million km. The uncertainty you talk of is minuscule at theses scales.
So we get a triangle with a base of 0,000316 Lightyear and a length of about 4,4 Lightyear, and that is for the nearest star. The shifting should be really really small right? And we have to assume stars are not moving. I cannot get my head around it.
BUT! You are going by earth's diameter. Have you forgotten that our solar system has travelled @ 500,000 mile per hour for 4380 hours(6 months)!!! ... So, earth's position in relation to that star has changed by 2 200 000 000 miles (forget the earth's diameter!) Whoa! Put that in your parallax and smoke it ... that star is not so very far away!!!
you mean the parallax angle? I guess they just have to measure how much the star has moved compared to it's background stars. A full circle on the sky would be equal with 360°.
I'm still trying to figure that out. I've made quite some research and the way the parallax method works is quite clear, but I still don't really grasp HOW we actually get the ANGLE. (Also the star is should not be making a right triangle as there's no reason to think it's exactly at the middle...)
This all wrong. How can you use a simply way to measure. The formula doesn't take into account how light travel through space it only takes into account how light travels through air. Also, it doesn't take into account how gravity bends light. It doesn't take into account the space time that is bending around the sun and earth. It doesn't take into account the temperature of space and how light travels through it. It doesn't take into account that after a certain point parallel lines are no longer parallel. It doesn't take into account the movement of any heavenly body or the rotation of the earth. This formula uses currency math (math used inside earths closed system, used for counting money, used to find area for square, doesn't take into account any force being imposed, all parallel lines are always parallel), it doesn't use language math (math which includes all forces being imposed, parallel are only parallel for a certain distance as long as no force is being imposed). In other words, you can't measure something like that using this equation because it doesn't take into effect any forces being imposed on the light that is traveling.
Where is the speed of light traveling from the sun to the earth and the earth rotation in this formula D = (d/l)*L? Where is any of the forces being apply to the light of the stars we are looking at in this formula D = (d/l)*L? WHERE? WHERE? WHERE? WHERE?
All your calculations are based on a stated distance from the sun to the earth but you don't tell us how we can know that this stated distance is correct. What if I had no knowledge of any distances to any of the celestial bodies? Tell me how I can calculate distances to the sun, moon, and stars beginning without any claims of known distances to them.
The distance to sun has been do a for a few centuries curious.astro.cornell.edu/about-us/41-our-solar-system/the-earth/orbit/87-how-do-you-measure-the-distance-between-earth-and-the-sun-intermediate
All I am asking is that you show us how to begin from a point of having no measurements at all, and then taking our own measurements of what we see in the sky, before we get to the point of doing mathematical calculations. Can you do that?
@@vincentmcardell8183 I wouldn't expect any meaningful answer to that question, seeing how the distance has never actually been measured, only assumed based on a mathematical model.
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Clearest explanation of parallax and parsecs that I've found to date!
I am a Physics teacher from Pakistan. I am genuinely inspired by you, owing to your extremely practical explanations. Unfortunately, I teach online. Had this not been the case, I would've taught my students the same way as you do.
Can someone explain clearly how the parallax angle (p) is derived purely from the distance of displacement of the star against the faraway stars? If all I know if the distance of the earth to the sun, and the distance the star has seemingly moved against the background, how is that distance translated to the parallax angle? All that is said in the video is that after we measure the amount the star has moved against the background after 6 months, we know the angle. How do we determine the angle if all we see is a distance of displacement? We can’t see angles as such.
Awesome, outstanding, Marvelous, STUPENDOUS Explanation!!!
Thanks
Amazing video. Helped me make sense of my college lecture. Thanks Paul!
8:53 how do you measure that angle though
Very minor, you ref to approximate and used the symbol for exact. very well done appreciate your work Thanks.
Well done lecture. You made it interesting.
Best video on this topic on RUclips
This detailed explanation is what I needed
Thanks
For the past 1 year I was trying to figure out the parallax method. Only after watching your video I am satisfied that I really understood. Thanks a lot. Very simple and detailed explanation.
Could you please share the link of your video for other method? ( luminasity)
In studying the subject I think it’s so much fun...Thank you for this video!
Great explanation of parallax I’m 13 and I’m studying astronomy a lot and this is one of the last things I need to know and you simplified to make it less complex
Great stuff.
Such an awesome explanation!
What about the Sun’s Motion around the Galactic centre? While the Earth revolves half a circle around the Sun, the Sun itself has moved with respect to the galactic centre. If our target of observation is not moving at the same speed as our Sun so that any motion relative to the background stars are due to the Earth’s motion around the Sun, then the parallax measured will not correspond to a baseline of 2 AU, but 2 AU + the distance moved by the Sun instead. This problem has puzzled me for quite some time and I have no idea how to get it solved... Does this means that the method of parallax is applicable only to those stars moving in the same spiral arm as our Sun?
I assume the distance the Sun and other stars move compared to each other during half a year is negligible. Note that it takes around 250 million years for the Sun to make a full circle around the galaxy.
how do u measure the angle?!!?!?
if I got this correct 50000 parsec would be 160 thousand light years that to me seems incredible. Thanks so much for the information.
We use parallax to determine that stars are extremely far away. To measure the parallax and determine the distance, we have to use as large of a baseline as possible because the stars are extremely far away..
Amazing explanation!
How is it done to make the perdincular of the baseline to exactly go toward the star you want to measure the distance to? Do you measure the angle everyday for 365 days and then choose the pair of angles that are 6 months apart and have the same value?
OOPS! My bad ! Diameter of earth's orbit, not of the earth. Of course earth's orbit is elliptical and the earth's position is not at the center of the ellipse, but in common parlance the radius is 93 million miles give or take ... because for a 1/2 of a base line, considering the change of position of the solar system in 6 months, is 2,2 trillion miles .. that makes the earth orbit diameter only 4 % of what the base line should be should actually be.. i guess making the star 96% farther from our solar system.
How did you get 41.4 for the one side?
how do you know how much angle shifted by just viewing the star shifting...
We measure apparent distances on the sky with grades. A full circle on the sky is 360°.
Same doubt
Conclusion of the video: Great knowledge= Great Math
Great video and explanations
Thanks
If we use this baseline measurement to check the distance of stars, how do we know our baseline measurement is good? Isn't measuring the distance to the sun difficult to do accurately, and if that baseline is off, would it result in...rough measurements? My brain is having a hard time with this one.
The diameter measurement is more than accurate enough for measurement. It’s approximately 300 million km. The uncertainty you talk of is minuscule at theses scales.
So we get a triangle with a base of 0,000316 Lightyear and a length of about 4,4 Lightyear, and that is for the nearest star. The shifting should be really really small right? And we have to assume stars are not moving. I cannot get my head around it.
BUT! You are going by earth's diameter. Have you forgotten that our solar system has travelled @ 500,000 mile per hour for 4380 hours(6 months)!!! ... So, earth's position in relation to that star has changed by 2 200 000 000 miles (forget the earth's diameter!)
Whoa! Put that in your parallax and smoke it ... that star is not so very far away!!!
How to find the angle as 1 parsec
Distance is 1 parsec when the angle variation (parallax) is 1 second (which is 1/3600 of a degree )
The important point to be explained is HOW the small angle is measured
you mean the parallax angle? I guess they just have to measure how much the star has moved compared to it's background stars. A full circle on the sky would be equal with 360°.
I'm still trying to figure that out. I've made quite some research and the way the parallax method works is quite clear, but I still don't really grasp HOW we actually get the ANGLE.
(Also the star is should not be making a right triangle as there's no reason to think it's exactly at the middle...)
did any of you figure it out yet?
Try decaf
0:06 If you you knew what I know about them, 😒 you wouldn't want to even look at them.
Parallax you say? ....in brightest day ....
Without knowing trigonometry, you are wasting time here
No. Without trigonometry, YOU are wasting time here.
@@Elo-hv3fw how did you guessed that i have not studied trigonometry? 😂
So how far is the sun from the moon? And....how big is the sun and the moon?
This all wrong. How can you use a simply way to measure. The formula doesn't take into account how light travel through space it only takes into account how light travels through air. Also, it doesn't take into account how gravity bends light. It doesn't take into account the space time that is bending around the sun and earth. It doesn't take into account the temperature of space and how light travels through it. It doesn't take into account that after a certain point parallel lines are no longer parallel. It doesn't take into account the movement of any heavenly body or the rotation of the earth. This formula uses currency math (math used inside earths closed system, used for counting money, used to find area for square, doesn't take into account any force being imposed, all parallel lines are always parallel), it doesn't use language math (math which includes all forces being imposed, parallel are only parallel for a certain distance as long as no force is being imposed). In other words, you can't measure something like that using this equation because it doesn't take into effect any forces being imposed on the light that is traveling.
I just cant believe how you can past this as right.
Where is the speed of light traveling from the sun to the earth and the earth rotation in this formula D = (d/l)*L? Where is any of the forces being apply to the light of the stars we are looking at in this formula D = (d/l)*L? WHERE? WHERE? WHERE? WHERE?
All your calculations are based on a stated distance from the sun to the earth but you don't tell us how we can know that this stated distance is correct.
What if I had no knowledge of any distances to any of the celestial bodies? Tell me how I can calculate distances to the sun, moon, and stars beginning without any claims of known distances to them.
The distance to sun has been do a for a few centuries
curious.astro.cornell.edu/about-us/41-our-solar-system/the-earth/orbit/87-how-do-you-measure-the-distance-between-earth-and-the-sun-intermediate
@@PhysicsHigh I am asking you tell us how we can measure the distance to the sun, not how we can take it on faith that others have it right.
@@PhysicsHigh You have measured that distance yourself, correct? You are not just taking it on faith that what you have been told is true, right?
All I am asking is that you show us how to begin from a point of having no measurements at all, and then taking our own measurements of what we see in the sky, before we get to the point of doing mathematical calculations. Can you do that?
@@vincentmcardell8183 I wouldn't expect any meaningful answer to that question, seeing how the distance has never actually been measured, only assumed based on a mathematical model.
I bet you have a very nice telescope
Ha. Actually I don’t but wish for one. The opening shot was just done with dSLR and wide angle lens as time lapse.
Could always go with a quality set of binocs, just sayin
Pay attention in math class kids