Hi there Keith, I know you haven't finished the astronomy series yet, but I can't believe I've just received a grade 9 self studying the subject and your videos were such a huge help! Just wanted to say a big thank you for the support; I'm so grateful for it (especially over lockdown). Wishing you good luck with the future of your channel and I hope more GCSE students are inspired to find a love for astronomy! 😊
@@PhysicswithKeith Thank you, and yes I am. With discord, I just wondered what time the AQA A level physics sessions would be and will you be going back over yr12 content starting from September?
@@katiesmith9023 that's great news. The A-level sessions start at 7pm on Thursdays (there's a calendar on my website www.physicswithkeith.com) and we will be starting from the very start. It's good for Year 13s to revise from the start of Year 12 anyway, and I want it to be accessible to new Year 12s too
The objection within the astronomical community regarding declassifying Pluto as a planet, is due to the IAU definition of a planet being applied inconsistently. A planet is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. Pluto was demoted to a dwarf planet because it doesn't meet point 3. However, applied strictly there is only one planet in the Solar System and that is Jupiter. Additionally more recent measurements demonstrate that Mercury does not meet point 2 (it's almost round but not in hydrostatic equilibrium) and yet hasn't been demoted to a small solar system body. It wouldn't be a dwarf planet as a dwarf planet is defined as meeting points 1 and 2, all other bodies in orbit around the sun are SSSB So if they're are no scientifically definitive rules around what constitutes a planet then they are definitely by consensus only and therefore there was no good reason to demote Pluto.
@@PhysicswithKeithIndeed. Although, Ceres was upgraded from asteroid to dwarf planet in the IAUs ruling and people tend to be less grumpy about things getting upgraded. Perhaps in the 1800s when Ceres was down graded from a planet to an asteroid it was also as controversial but I'm not that old and useless at history so don't know. There are some who argue that all the dwarf planets should count as planets, but I wouldn't like have to learn all their names in school, 9 was enough, could have stretched to 10!
Hi there Keith, I know you haven't finished the astronomy series yet, but I can't believe I've just received a grade 9 self studying the subject and your videos were such a huge help! Just wanted to say a big thank you for the support; I'm so grateful for it (especially over lockdown). Wishing you good luck with the future of your channel and I hope more GCSE students are inspired to find a love for astronomy! 😊
Such a lovely thing to say, thank you! Will you be taking A Level Physics this year?
Congratulations! A Grade 9 after self study is an amazing achievement!! 🏆
@@PhysicswithKeith Thank you, and yes I am. With discord, I just wondered what time the AQA A level physics sessions would be and will you be going back over yr12 content starting from September?
@@katiesmith9023 that's great news. The A-level sessions start at 7pm on Thursdays (there's a calendar on my website www.physicswithkeith.com) and we will be starting from the very start. It's good for Year 13s to revise from the start of Year 12 anyway, and I want it to be accessible to new Year 12s too
Did you study is completely on your own? I recently discovered this but it wasn’t offered at my school but really want to teach myself it!
appreciate the time you put into this, you helping me through my Astronomy GCSE, Love
How did u find the first test?
Many thanks for putting another lesson online. Daughter is studying for GCSE next summer and these are a great help.
TY FOR UPLOADING, ive been waiting for this one 😭!
The objection within the astronomical community regarding declassifying Pluto as a planet, is due to the IAU definition of a planet being applied inconsistently.
A planet is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
Pluto was demoted to a dwarf planet because it doesn't meet point 3. However, applied strictly there is only one planet in the Solar System and that is Jupiter.
Additionally more recent measurements demonstrate that Mercury does not meet point 2 (it's almost round but not in hydrostatic equilibrium) and yet hasn't been demoted to a small solar system body. It wouldn't be a dwarf planet as a dwarf planet is defined as meeting points 1 and 2, all other bodies in orbit around the sun are SSSB
So if they're are no scientifically definitive rules around what constitutes a planet then they are definitely by consensus only and therefore there was no good reason to demote Pluto.
Or Ceres 😁
@@PhysicswithKeithIndeed. Although, Ceres was upgraded from asteroid to dwarf planet in the IAUs ruling and people tend to be less grumpy about things getting upgraded. Perhaps in the 1800s when Ceres was down graded from a planet to an asteroid it was also as controversial but I'm not that old and useless at history so don't know. There are some who argue that all the dwarf planets should count as planets, but I wouldn't like have to learn all their names in school, 9 was enough, could have stretched to 10!
Got my paper 2 exam tomorrow, thank you so much for the help!!
Could you please, possibly record up to topic 16?
That's the plan
I love how you pronounce Cassegrain 😂😂😂