Astronomy - Measuring Distance, Size, and Luminosity (30 of 30) Expansion of the Universe!
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- Опубликовано: 25 авг 2024
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In this video I will explain how we know the expansion of the universe is speeding up!
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Thank you again for the best lectures on measuring luminosity, distance, size and everything of stars! You have proved the charm of lectures!
You are welcome. Thanks for the comment.
Thats how teaching of a subject should begin..... great series.
Outstanding series!!! Thank you so much for putting the time into this. Bravo!
Our pleasure! Thank you.
Jajakallahu khairan.
This playlist is amazing. Sir
Only 176 times watched??? Man, that should be 176.000!!! Great series of videos. Thanks a lot! By the way, your name looks dutch. Greetings from the Netherlands.
Sjaak,
Bedankt voor jouw respons. Ik woonde in Belgie, vier kilometer van de grens. (But that was a long time ago)
Hello Sir, I don't get why the type 1A Supernovas being further away from Earth than calculations say they are means that the Hubble constant used to be smaller. If they are further away, it means that in the same time as we thought (so from the Big Bang until the time in which they were observed) they travelled more than we previously thought they had travelled. And since they travelled more in the same time, shouldn't it mean that they used to be faster?
There are indeed other possible explanations for the observations, which include the speed of light not being constant and the Hubble constant not being constant, as well as the expansion of the universe not being constant. It is always a good idea to question the prevailing theories as they may not be correct.
Hmm...I don't get it. Why would the discrepancy in distance confuse us ? The calculated distance to a Cepheid star needn't be the same as the distance to another star in the same galaxy, because the objects in the observed galaxy are not all at the same distance from us, obviously. I'm missing something here.
The distance from here to the galaxy is so much greater than the size of the galaxy, that the small differences between distances inside the galaxy are not important and make very little difference in our estimates.
I really enjoyed watching this series. Can you recommend me a book that cover this topic like that in this video series.
The are a lot of excellent astronomy books. It comes to personal preference because they are all very good.
Hi Professor. Thank you for this great work. after I finished the astronomy series what field would you recommend for my next studies?
There are many topics. it is really up to you to find the topic you are interested in.
Hello, I guess this makes sense as a Type 1a Supernova has M of -19 can see further than Cephid variables where M is max -8. This may have been why the Ho calculated using Type 1a Supernovas was lower 40-65 than the current accepted value of 73 km/s/Mpc. Another assumption is that the hubble constant is uniform in all directions. Is it possible that Ho maybe different in different directions or in different pockets (so varying in direction as well as time)?
Ho is "constant" in all directions. However that said, we know there are places in the Universe where local gravitational influences cause the galaxies to move differently, making it harder to determine and use the Hubble constant. (As near the Virgo cluster of galaxies).
@@MichelvanBiezen Thank you.