Dark matter: smooth or clumpy?! | The Dark Energy Survey Results!

A week ago the Dark Energy Survey released its long-awaited 3 years worth of data - the positions of 226 million galaxies! Along with that came a whole load of new science in 30 papers (!) - I dived into them and picked out all the highlights, plus I spoke to Dr. Alexandra Amon on the DES team about her results showing dark matter might be distributed more smoothly than. we thought.

Here's the video with my full chat with Dr. Alexandra Amon: https://youtu.be/la8yanvdb2c

You can follow Dr. Alexandra Amon on Twitter: https://twitter.com/astroalexamon
Or on Instagram: https://www.instagram.com/astroalexamon/

My video on different theories of gravity: https://www.youtube.com/watch?v=dtfEzDAlL5k
My video on the history of dark matter and all the evidence we have for it: https://www.youtube.com/watch?v=nbE8B7zggUg

You can access the Dark Energy Survey data for free here: https://des.ncsa.illinois.edu/releases/dr2
And read all the 30 papers (again, for free!) describing it here: https://www.darkenergysurvey.org/des-year-3-cosmology-results-papers/

Riess et al. (1998; first evidence for accelerating expansion) - https://arxiv.org/pdf/astro-ph/9805201.pdf
Caldwell et al. (2002; "phantom menace" dark energy) - https://arxiv.org/pdf/astro-ph/9908168.pdf
Riess et al. (2004; w=-1.02) - https://arxiv.org/pdf/astro-ph/0402512.pdf
WMAP collaboration (2013; w=-1.084) - https://arxiv.org/pdf/1212.5226.pdf
Planck collaboration (2015; w = -1.006) - https://arxiv.org/pdf/1502.01589.pdf
DES collaboration; Abbott et al. (2021; w = -0.98) - https://www.darkenergysurvey.org/wp-content/uploads/2021/05/desy3_3x2_results.pdf
Amon et al. (2021; dark matter is smoother with S8 = 0.772) - https://www.darkenergysurvey.org/wp-content/uploads/2021/05/desy3_cosmic_shear_cosmology1.pdf

[Note these papers are all free to access!]

00:00 - Introduction
00:48 - What is the Dark Energy Survey?
01:36 - Why is it making a big galaxy map?
04:15 - What is dark energy?
05:20 - What can it tell us about dark matter?
07:28 - Fixing the crisis in cosmology?
08:43 - What happened this week?
10:16 - Result 1: constraining dark energy
14:46 - Result 2: smoother dark matter?
18:44 - Chat with Dr. Alex Amon
26:35 - Outro
27:21 - Bloopers
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👩🏽‍💻 I'm Dr Becky Smethurst, an astrophysicist at University of Oxford (Christ Church). 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.

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