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Download "Gravity Without Mass Could Explain Dark Matter"

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dark matter
gravity
mass-less gravity
gravity without mass
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hollow spheres with no gravity
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00:00:00
I got several questions this week about
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a few headlines that said something
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about a new study that challenges dark
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matter and that it's possible to create
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gravity without mass that sounds very
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interesting so I had a look at the paper
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the idea in the paper is based on a
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peculiar property of gravity that you
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might have heard of but forgotten so
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maybe let me start with recalling it
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it's that inside a hollow sphere there's
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no gravitational raction this is already
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the case in Newtonian gravity but it's
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also true in Einstein's theory of
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general relativity even though in this
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case one strictly speaking has no
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force that there's no gravitational pull
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inside a holosphere is a matter of
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geometry suppose you're near this side
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of the sphere the gravitational pull of
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the mass closest to you has the
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strongest pull but there's more mass
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further away from you so which one wins
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out well if you add it all up you find
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that the total gravitational pool is
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exactly zero it's like when people
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complain about me on Twitter it averages
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out to zero to explain dark matter with
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this the author of the new paper
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proceeds roughly as follows suppose you
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not only have positive Mass but also
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negative Mass yes there's no negative
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Mass so this is kind of like saying
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suppose you have a laser unicorn but
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let's leave this aside for now I'll come
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back to this later so let's just assume
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some matter with negative Mass exists
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somewhere out there now for the
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gravitational force Mass plays the role
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of a charge like the electric charge for
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the electric force you can see this if
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you compare Newton's law of gravity with
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kum's law for the electric force the
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masses act like charges the difference
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is that for the electric interaction
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like charges repel and unlike charges
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attract for gravity like charges attract
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and unlike charges repel to come back to
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the paper we now put a shell of negative
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Mass inside a shell of positive Mass but
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so that the total mass is zero since the
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total mass is zero the gravitational
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pull outside the two spheres is zero we
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also know that the gravitational pole
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inside is zero because it's a sphere but
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between the two spheres the
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gravitational pole isn't zero now
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suppose you have a normal positive Mass
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moving to towards the shells from the
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inside it feels no gravitational pull
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until it reaches the innermost shell
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then it gets repelled by that negative
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Mass behind it and attracted by the one
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ahead then it passes through and there's
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no gravity anymore the result is that it
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was accelerated now you have to imagine
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that you move these spheres towards each
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other until they sit right on top of
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each other you then have a solution that
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has no Mass because the negative and
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positive masses cancel each other out
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but that generates a sudden acceleration
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perfect for those days when you have
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trouble getting out of bed if you were
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to do the math of the example that I
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just gave it wouldn't work what he does
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in the paper is somewhat more
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complicated but the gist of it is the
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same no total mass but a sudden
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acceleration so this is where the idea
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comes from that you can have gravity
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without Mass it's because you have both
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positive and negative Mass together on
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the shell how does this help with
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explaining Dark Matter well remember
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that one of the observations that we
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usually attribute to dark matter is that
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the outer parts of spiral galaxies
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rotate to fast yes this is also the case
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for the Mickey way you see the velocity
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of a star in its orbit around the center
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of a galaxy is determined by the
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gravitational pull that comes from the
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matter inside the or the higher the
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gravitational pull the faster the star
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needs to go to stay in that orbit it's
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kind of like you need to paddle faster
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on your bike the more snacks you've
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eaten the author of the new paper now
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says there are like a billion or so of
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these no Mass shells inside of galaxies
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and they gradually increase the
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acceleration as you go further to the
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outer reaches of a galaxy so it looks
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like dark matter even though there's no
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Mass
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you might think that the obvious problem
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with this idea is that we've never seen
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any particles with negative mass and yes
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that's that but I think it's not any
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worse than dark matter which we have
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also never seen have we maybe negative
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mass is out there we just haven't
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measured it yet and let's be honest dark
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matter is so mainstream now it makes
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poor headlines no the major problem is
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the stability of these shells remember
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that for Gravity like charg attract and
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unlike charges repel if you push
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together like and unlike they'll not
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stay on the shell they'll want to
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separate and they'll also not stay in a
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shell of course they'll try to Clump
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it's a long story but I tried something
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very similar about 10 years ago it
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didn't work now it's quite possible that
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I'm missing something and I think this
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is a nice idea but I'm rather skeptical
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that it'll work though I must admit I'm
00:05:28
very tempted by getting a pair of
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anti-gravity shoes I've tried a lot of
00:05:34
science magazines but most of them I
00:05:36
found either to flaky or to politicize
00:05:40
or just not up to dat if you know what I
00:05:42
mean I recommend you check out Nautilus
00:05:45
which has become my favorite Science
00:05:47
magazine Nautilus has both a digital and
00:05:50
a print version and it's just a pleasure
00:05:52
to read they really put a lot of effort
00:05:54
into writing and the graphic design is
00:05:57
top you notice immediately if you open
00:05:59
the print version that it's a high
00:06:01
quality production I've written several
00:06:03
contributions for Nautilus myself the
00:06:06
most recent one about John oppenheim's
00:06:08
theory of postquantum gravity but I
00:06:10
enjoy this magazine because it tells me
00:06:13
what's going on in other scientific
00:06:14
Fields what I particularly like about
00:06:17
Nautilus is that they cover all areas of
00:06:19
science from astronomy to economics
00:06:21
history Neuroscience to philosophy and
00:06:24
physics they tell me what I need to know
00:06:27
you can join Nautilus as a digital only
00:06:29
number or get a print subscription in
00:06:31
addition to full access to all the
00:06:33
stories and Nautilus members receive
00:06:35
benefits like Priority Access to events
00:06:38
exclusive products and product discounts
00:06:41
and of course we have a special offer
00:06:43
for our viewers if you use our custom
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link join nautilus.com
00:06:48
szabina you'll get 15% off your
00:06:51
membership subscription so go and check
00:06:53
this out thanks for watching see you
00:06:55
tomorrow

Description:

Special Offer! Use our link https://nautil.us/join/sabine/ to get 15% off your membership! I recently read that you can have gravity without mass. Ha, no way, I thought and had a look at the paper. It's wild, people. The author says that there are hollow spheres scattered across the universe that have no gravitational attraction and that these spheres explain dark matter. I will try to sort it out for you. Paper: https://academic.oup.com/mnras/article/531/1/1630/7673084 🤓 Check out my new quiz app ➜ https://quizwithit.com/ 💌 Support me on Donorbox ➜ https://donorbox.org/swtg 📝 Transcripts and written news on Substack ➜ https://sciencewtg.substack.com/ 👉 Transcript with links to references on Patreon ➜ https://www.patreon.com/Sabine 📩 Free weekly science newsletter ➜ https://sabinehossenfelder.com/newsletter/ 👂 Audio only podcast ➜ https://open.spotify.com/show/0MkNfXlKnMPEUMEeKQYmYC 🔗 Join this channel to get access to perks ➜ https://www.youtube.com/channel/UC1yNl2E66ZzKApQdRuTQ4tw/join 🖼️ On instagram ➜ https://www.facebook.com/unsupportedbrowser

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