When so many use the internet for disinformation or misinformation, it's so cathartic to see a person who reminds us that it has incredibly noble utility. I'm 68 yo and have been looking for clarity on this subject for decades. I picked a winning lottery ticket with your video. Thank you so much!
Am I stupid or what? I have been searching and watched countless of videos about Cepheid Variables but still don't have a clue what Cepheid Variable are... until I watch your video. I am dumbfounded by your excellent presentation and explanations. Now I am totally understood what Cepheid Variables are. Thank you so much!
It's not every day you get an aha-moment, but your explanation of Cepheid variables did it for me. I was going to watch a last video to get to sleep, but now I'm wide awake. Your students are lucky!
Thank you soooo much. All other explanations just say she plotted luminousity vs period, but I always wondered how actual luminosity was determined in 1912 before h-r diagram. This clears it up. Thank you!
Lots of thanks for making our personal universe a bit larger by showing this important turning point in history, explaining it, and allowing us to make our own calculations. Wow!
I find your pace and clarity to be excellent and exemplary! Your usage of diagrams and equations is similarly well paced and precise! Thanks and God Bless you and yours.
Wow I can't believe that some people don't even know that this Turning point happened in our history, I guess there's lot more that I don't know so I guess I have to subscribe Tanks for the video
This was so good! It turned a land of obscure confusion into something genuinely really interesting. The comparison between the 100ly, 50,000 ly, and 20 million ly actually blew my mind.
I had a question. at 12:56 you mentioned that de brightness witnessed on earth is b = 4,57*10^-17 w/m2. Because of the change in the brightness of the star, is this the maximum intensity we measured? Also the luminosity that is measured because of the period/days, is that there max luminosity? *great video by the way, its probably me that i don't know but i couldn't find it.
Sir,what about the spectroscopic parallax or main sequence fitting which can be used to measure distance using the relations of brightness and luminosity upto 10^5 light years ?
-Wait then how have we been measuring the distance of stars? -Weren't actual hypothesis of star make up verified with calculations including refraction of light. ---Am I wrong here? -Wait how does this even work because stars different in brightness. How can you tell if these stars are breaking the rules? -How come we can't see years in the future from our earth view point, to a set star if we are using a telescope that not on earth? But light years closer to star x? Wouldn't we see a whole new topography hundreds f years past what we see on earth?
Efficient lecture. These techniques makes the ground under the feet of the astronomers more stable. But I think they should be careful using the word "exact".
When so many use the internet for disinformation or misinformation, it's so cathartic to see a person who reminds us that it has incredibly noble utility. I'm 68 yo and have been looking for clarity on this subject for decades. I picked a winning lottery ticket with your video. Thank you so much!
Aw thanks so much! So happy this was helpful!
Am I stupid or what? I have been searching and watched countless of videos about Cepheid Variables but still don't have a clue what Cepheid Variable are... until I watch your video. I am dumbfounded by your excellent presentation and explanations. Now I am totally understood what
Cepheid Variables are. Thank you so much!
I tried several times to understand this method without sucess until I found this video. EXCELLENT! So I subscribed the channel.
This was EXCELLENT! The best explanation I've heard so far - great job! I subscribed.
Thanks so much!
It's not every day you get an aha-moment, but your explanation of Cepheid variables did it for me. I was going to watch a last video to get to sleep, but now I'm wide awake. Your students are lucky!
Thank you soooo much. All other explanations just say she plotted luminousity vs period, but I always wondered how actual luminosity was determined in 1912 before h-r diagram. This clears it up. Thank you!
Lots of thanks for making our personal universe a bit larger by showing this important turning point in history, explaining it, and allowing us to make our own calculations. Wow!
This is by far the best explanation on Cepheid variable I have come across. Thank you. Keep it up.
Wow this explains it so easily. Also, Levitt was a genius for figuring this out.
I find your pace and clarity to be excellent and exemplary! Your usage of diagrams and equations is similarly well paced and precise! Thanks and God Bless you and yours.
So happy it's been helpful!!
Wow I can't believe that some people don't even know that this Turning point happened in our history, I guess there's lot more that I don't know so I guess I have to subscribe
Tanks for the video
tysm!! this video was super helpful and I can't imagine how long it took to film these. I appreciate your work immensely :)) keep going !
This was so good! It turned a land of obscure confusion into something genuinely really interesting. The comparison between the 100ly, 50,000 ly, and 20 million ly actually blew my mind.
Aw so nice to get this feedback, thank you!
You explained it so nicely and with so much detail. Keep up the great work
+1 for best explanation and another subscriber for you
such a nice explanation and head off for lady astronomer she did a good job indeed
Wow! this is extremely helpful and clear. Thanks!
Super Helpful!!!
Our doctor preferred your medicine for Astrophysics
man you are a life saver
Very well done! Thanks very much for your help with this:)
Brilliant!
Very Good
My Salute
I had a question. at 12:56 you mentioned that de brightness witnessed on earth is b = 4,57*10^-17 w/m2. Because of the change in the brightness of the star, is this the maximum intensity we measured? Also the luminosity that is measured because of the period/days, is that there max luminosity? *great video by the way, its probably me that i don't know but i couldn't find it.
Outstanding
Are all cepheids the same size and comprised of the same elements? Could not the luminosity variance be caused by an obstruction orbiting the star?
Are all these variable stars roughly the same mass? That is; are there Sol sized up to Betelgeuse sized Cepheid variable stars?
Sir,what about the spectroscopic parallax or main sequence fitting which can be used to measure distance using the relations of brightness and luminosity upto 10^5 light years ?
The closest known cepheid is is polaris which is around 500 light years aways, how come we have cepehids stars under 100 light years?
-Wait then how have we been measuring the distance of stars?
-Weren't actual hypothesis of star make up verified with calculations including refraction of light. ---Am I wrong here?
-Wait how does this even work because stars different in brightness. How can you tell if these stars are breaking the rules?
-How come we can't see years in the future from our earth view point, to a set star if we are using a telescope that not on earth? But light years closer to star x? Wouldn't we see a whole new topography hundreds f years past what we see on earth?
Efficient lecture. These techniques makes the ground under the feet of the astronomers more stable. But I think they should be careful using the word "exact".