Is the strength of gravity really CONSTANT? | Solving the crisis in cosmology
260.2 هزار بار بازدید -
2 سال پیش
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Is the gravitational constant, G,
Is the gravitational constant, G, really a constant? Or does it change with time, or with space, or with scale in the Universe?! And if it did, could this help solve the crisis in cosmology?! Or even be an explanation for dark energy and the accelerated expansion of the universe?
A big thanks to Dr Harry Desmond, my colleague at Oxford who is an expert on modified gravity theories, for very helpful discussion while I prepared this video. https://www.physics.ox.ac.uk/our-peop...
Anderson et al. (2015; claim of periodic variation in G) -
Schlamminger et al. (2015; debunking periodic variation in G) -
Mould & Uddin (2014; measuring change in G with supernovae) -
REVIEW PAPER on measuring change in G astrophysically, see Section 4, Uzan (2010) - https://arxiv.org/abs/1009.5514
Hanımeli et al. (2022; G changing with time explaining dark energy) -https://arxiv.org/pdf/2201.04629.pdf
Desmond et al. (2022; first measurement of G outside solar system in LMC) - https://arxiv.org/pdf/2012.05028.pdf
Simpson et al. (2015; G_matter and G_light measurement) - https://arxiv.org/pdf/1212.3339.pdf
Joudaki et al. (2021; Jordan-Brans-Dicke test to find G_matter) - https://arxiv.org/abs/2010.15278
More information on the Euclid mission: https://sci.esa.int/web/euclid
00:00 - Introduction to G
01:15 - Measuring G on Earth, a brief history
02:39 - The 3 questions you can ask
04:02 - Does G vary with time?
07:04 - Can G changing with time explain dark energy effects?
08:56 - Does G vary with position in space? Measuring G in the LMC
11:11 - Does G vary with scale?
13:30 - A recap on the crisis in cosmology
14:17 - Jordan-Brans-Dicke theory, scalar fields and no-slip gravity
16:10 - Does a variable G solve the crisis in cosmology?
17:35 - The Euclid mission could help
19:01 - Bloopers
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👕 Check out my merch here: https://teespring.com/stores/dr-becky
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📚 "Space: 10 Things You Should Know": http://bit.ly/SpaceDrBecky (NOTE THIS HAS DIFFERENT TITLE IN USA & CANADA)
📚 US & Canada version: "Space at the speed of light" (*same book, different title*, with some beautiful illustrations): https://www.penguinrandomhouse.com/bo...
📚 German translation "Das kleine Buch vom großen Knall" : https://www.dtv.de/buch/becky-smethur...
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🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
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🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
---
👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
http://drbecky.uk.com
https://rebeccasmethurst.co.uk
A big thanks to Dr Harry Desmond, my colleague at Oxford who is an expert on modified gravity theories, for very helpful discussion while I prepared this video. https://www.physics.ox.ac.uk/our-peop...
Anderson et al. (2015; claim of periodic variation in G) -
Schlamminger et al. (2015; debunking periodic variation in G) -
Mould & Uddin (2014; measuring change in G with supernovae) -
REVIEW PAPER on measuring change in G astrophysically, see Section 4, Uzan (2010) - https://arxiv.org/abs/1009.5514
Hanımeli et al. (2022; G changing with time explaining dark energy) -https://arxiv.org/pdf/2201.04629.pdf
Desmond et al. (2022; first measurement of G outside solar system in LMC) - https://arxiv.org/pdf/2012.05028.pdf
Simpson et al. (2015; G_matter and G_light measurement) - https://arxiv.org/pdf/1212.3339.pdf
Joudaki et al. (2021; Jordan-Brans-Dicke test to find G_matter) - https://arxiv.org/abs/2010.15278
More information on the Euclid mission: https://sci.esa.int/web/euclid
00:00 - Introduction to G
01:15 - Measuring G on Earth, a brief history
02:39 - The 3 questions you can ask
04:02 - Does G vary with time?
07:04 - Can G changing with time explain dark energy effects?
08:56 - Does G vary with position in space? Measuring G in the LMC
11:11 - Does G vary with scale?
13:30 - A recap on the crisis in cosmology
14:17 - Jordan-Brans-Dicke theory, scalar fields and no-slip gravity
16:10 - Does a variable G solve the crisis in cosmology?
17:35 - The Euclid mission could help
19:01 - Bloopers
---
👕 Check out my merch here: https://teespring.com/stores/dr-becky
---
📚 "Space: 10 Things You Should Know": http://bit.ly/SpaceDrBecky (NOTE THIS HAS DIFFERENT TITLE IN USA & CANADA)
📚 US & Canada version: "Space at the speed of light" (*same book, different title*, with some beautiful illustrations): https://www.penguinrandomhouse.com/bo...
📚 German translation "Das kleine Buch vom großen Knall" : https://www.dtv.de/buch/becky-smethur...
---
🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
---
🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
---
👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford. I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
http://drbecky.uk.com
https://rebeccasmethurst.co.uk
2 سال پیش
در تاریخ 1401/01/25 منتشر شده
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