That Galaxy With No Dark Matter? It's Probably Not Real | SciShow News

[@ralphhooker6019]

I am 66 years old. I have been reading science fiction my entire life. Nice to hear something new about our galaxy. Thanks Hank and crew!

[@FloozieOne]

When I was about 8 my father read (out loud) the entire Lord of the Rings series, one chapter or so each night. I never looked back and have been chasing the fantastic mental journeys through science fiction ever since. With computers now there are lots of movies with those basises, and although some of them are pretty awful a surprising number are quite good. Still, I grew up reading, (we never had a TV since my father thought they were bad for kids and kept them from thinking), and it is still my favorite way to experience new things. I'm 69 now and feel sorrow for todays kids that can't stretch their imaginations except for what movie makers and "smart phones" spoon-feed them.

[@bensmith7536]

This guy, whoever he is, is by far the best presenter for SciShow. Facts first, followed by excellent delivery and a perfect level of humour thrown in. Always keen to listen when he's on, and thats not to say the others are bad, just this guys the best.

[@gediminasII]

Ironic as he's the founder

[@Ace5665]

Hank Green. His name is Hank Green

[@fanOmry]

He's also the prettiest.

[@kickinrocks6055]

He's called muscle hank, cause he's a beast.

[@grantcirks362]

I'm listening to Hyperion right now on an audio book, nice coincidence!

[@aerospacenews]

These two stories both illustrate the value of science and the scientific method - keep checking the evidence - and the simple magic of it all. Great job as usual SciShow team!

[@GiantSlayerSVK]

And my idea of aliens' dark matter farming is out :(...

[@rugershooter5268]

Dark matter doesn't interact with actual matter dark matter makes stars act the way they do.........but doesn't interact....makes stars do......doesn't interact aaaaaaaaaaaaaaaaaaaaa does not compute

[@seifer666]

it interacts gravitationally but not through any other methods, we cant see it, its not magnetic, etc

[@SuperbusQuartus159]

I think of it like a bunch of mass floating about that doesn't interact with light. SO, the only way we can "see" it is by the effects it has on the other, visible mass around it----like the wind!!!

[@wmdkitty]

The Universe works in strange and mysterious Ways.

[@fanOmry]

In anyway other than gravity..

[@Erowens98]

After we get passed basic orbital mechanics, astronomy just loses me completely. None of it makes sense to me anymore, its all seems to both contradict and confirm itself. Especially when it comes to light, and the expansion of the universe.

[@pansepot1490]

That’s why I love science. They admit that they were wrong when they find a mistake or new data come up. Contrary to religion (and politicians) which stick to bs debunked over and over again.

[@patrickhalseth1632]

I think that is the difference between science and religion. Science is the study of observation and is therefore constantly evolving were as religion is the study of absolutes so it must remain constant. It's "this is what we see, so X must be true" vs "this is what's true, so what we see must mean X".

[@slumpkiid3570]

Science is not intertwined with religion. They are two totally different ways of thinking and should not be confused as a 'this or that' kind of thing. Leave those with religious views be, arguments are fruitless if either mind is not seeking to change.

[@nibblrrr7124]

The work that is described here was done by *different scientists,* though. _Van Dokkum et al._ did the original measurements of the galaxy and concluded its extraordinary properties in March 2018. The contradicting work described in this video was done by _Trujillo et. al,_ who published it as a draft in June 2018, to which _Van Dokkum et al._ replied in September (doubling down on their initial measurement with the exciting consequences). _Trujillo_ revised their draft in March 2019 to incorporate that reply (still disagreeing on the distance), and that got published just now in June 2019. I don't know if Van Dokkum,Trujillo, and all their collaborating authors have now reached consensus on the distance (and thus on how special that galaxy is), and I have even less of an idea how the opinion of their field has changed. But all their quibbling about methodology aside, they have publicly agreed on a lot of other properties of the galaxy, and Van Dokkum stated from the outset that if the distance turns out to be smaller, their estimates for the conclusions are moot. So sure, it would be nice to see politicians precommit to how they could be proven wrong. ;) (For that matter - to the best of my knowledge - everyone kept it civil, and no personal attacks were made...)

[@nibblrrr7124]

"Science" is not one monolithic hive mind, it's made up of countless individuals, who need publicity & funding, and have pride, envy, grievances, and essentially all the usual human failings & biases. Don't get me wrong, I trust the scientific method & the social institutions of science more than pretty much anything else. And there are genuine examples of scientists embodying the Enlightenment ideal by admitting they were wrong. (In fact, I don't know how Van Dokkum et al. stand on the issue now.) But my impression is that for the most part, *science works less by individual scientists changing their mind completely, but rather the community as a whole,* by giving less credence & time to hypotheses when they turn out to not fit the data. Or, as Max Planck put it: _"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."_

[@nibblrrr7124]

​@@slumpkiid3570 There are cases where religions include beliefs about phenomena in the universe that can be observed & potentially falsified experimentally, thus intertwining the domains of science & religion. Atheists may sometimes overstate the importance of believing a creation myth or miracles _actually, really happened_ (especially once you go outside fundamentalist Christianity & Islam, let alone consider non-Western religious traditions). But very few believers actually would say their religion is entirely restricted to morality & the afterlife, and quite a lot believe _evidently wrong things, sometimes with harmful conclusions._ The argument is that faith-based thinking may be emotionally helpful in some situations, but we should nevertheless apply reason to all domains that influence how we act - because it lets us make better decisions that lead to human flourishing, or maybe just for truth's sake. But yeah, I agree that arguing is pointless if neither side is open to actually changing their perspective, and just out to score points for their team.

[@NewMessage]

Now if only I could hide my middle's accretion disk so well.

[@1MarkKeller]

just fire up that interior black hole

[@NoName-fc3xe]

@@1MarkKeller don't you mean anterior? 😋

[@TheRogueWolf]

Maybe try releasing some cool gas?

[@KarlBunker]

Darrnit! I just learned about the no-dark-matter galaxy a little while ago, and I thought it was so cool. If scientists can't get things right the first time, I'm going to give up on science and become a Trump supporter. (Just kidding 🙂)

[@jdsevereide]

Yeah i love dan simmons. Fall of Hyperion is like comfort food for lunch.

[@eliasbarnard9397]

I couldn’t even get through the first page, but I also think it would be miserable to eat anything unhealthy for lunch, I hope we never ever meet.

[@jdsevereide]

same

[@eliasbarnard9397]

@@jdsevereide I am so happy you exist. Thanks for making my night, I have been played.

[@TheExoplanetsChannel]

_To be or not to be, that is the question_

[@ClockworkRBLX]

go away please

[@eaglecentury3409]

New Hubble data confirms the original team's results. Galaxies without dark matter do probably exist.

[@carlosmacedo1700]

So Dark matter doesn´t interact with normal matter, so how can it be that without it stars velocity in galaxies shoulnt move like that aound is center... and how does it only exist around gaaxies?.....maybe i´m dumb o understand.

[@corwyn2]

if you are, i am too. i would like to know how they know how much matter is in the universe when we cant get a decent look at most of it. and how do they know how much dark matter is or isn't there if it doesn't interact with anything. how do you measure something that doesn't interact?

[@Chris.Pippin]

Last year not one real picture of a black hole, 2019 we get 2.

[@MartialBorschel]

Wow, this is cool. You can tell a good scientist, and a great channel, and frankly a good person, by their willingness to report err. Thanks for the update!

[@General12th]

Strictly speaking, since SciShow profits from any news, they're just as incentivized to report retractions as they to report breakthroughs. A step in any direction is good for SciShow. But yes, this is a great video.

[@naotamf1588]

and the fact that he knows about the hyperion saga...

[@Just_A_Dude]

*errors.

[@MartialBorschel]

@@conwaymj88 Truth!

[@tr4l1975]

@@Just_A_Dude Definition of err intransitive verb 1a : to make a mistake erred in his calculations erred on the side of caution b : to violate an accepted standard of conduct

[@wezley123456789]

I actually really love the book Hyperion and the series

[@kebomueller732]

So what real effect has this discovery for dark matter? In which other ways the existance was proven and other theories have been ruled out? I can think of the bullet cluster where 2 galaxies passed through and most dust collided in between. Most gravity should come from the huge amount of dust which the galaxies left behind right between them. But through gravitational lensing it was clear that dark matter passed just right through and most of the gravity still comes from the 2 galaxies.

[@nibblrrr7124]

Not much, AFAIU? The new results are perfectly consistent with DM models, and there is plenty of other evidence; you mentioned the Bullet Cluster, the most direct example, and most devastating to competing explanations. In general, DM's raison d'être is to explain how stuff can orbit other stuff as fast as we see, without flying off. Fritz Zwicky coined the term "dark matter" when he inferred in the 1930's that the *Coma galaxy cluster* has to produce more gravity than what would be expected from what can be seen (and modern re-analysis of the cluster proved him basically right). The breakthrough evidence for DM being accepted was AFAIU that it solves the *galaxy rotation problem:* In the '70s, Vera Rubin observed stars on the edge of galactic disks to move just as quickly as those further in - which is e.g. not what you see in our Solar system, where Neptune orbits much slower than Earth. Besides for explaining motion of stars & galaxies, DM is also a *crucial ingredient in models for how galaxies & larger cosmological structures form & evolve.* Without it, it is hard to explain why visible matter clumps together in the ways we see. Alternative theories (MOND & other modifications to laws of gravity or motion) have been proposed with the goal to reproduce the observed flat galaxy rotation curves, but they struggle to fit all the data without adding some DM back in. They're also regarded as iffy from a theoretical perspective, because they require ad-hoc modification to the elegant laws of motion & general relativity. The debate & drama in the astronomical community is more about what dark matter consists of exactly. Large objects like MACHOs (black holes, brown dwarfs) are mostly ruled out b/c we would have seen their lensing effects. Fans of elegance were excited about the "WIMP miracle", where versions of supersymmetry predicted a particle that would neatly fit the properties you would predict from how the dark/regular-matter-ratio we observe could have arisen. However, the lack of observations of SUSY particles from the LHC put a damper on those hopes.

[@MichaelMiller-rg6or]

I think its amazing that something so small, the earth, can measure and store so much data about something so large and vast, the rest of the universe.

[@Thumbsupurbum]

All that data isn't even 1% of what's out there though. Not even close.

[@MichaelMiller-rg6or]

DirtyBlastard and thats why we love this stuff. Such wonder.

[@kickinrocks6055]

So we're a learning computer in a spinning hard drive. But do they call us artificial intelligence, or just intelligence?

[@ScufflesWaffles]

0:30 I'm kinda perplexed by that statement "that doesn't interact with regular matter". Doesn't dark matter interacts with regular matter GRAVITATIONALLY?

[@Vincenzo-wn1or]

I know, it's meant to keep galaxies together?

[@bobbobber4810]

Maybe he just mean that it can't interact with the normal matter directly... only indirectly by gravity. I could be wrong, not I scientist :p

[@dariusbozeman698]

@@bobbobber4810 Yeah we can measure gravity pretty accurately on our own planet but comically gravity is just a force. It's just invisible to our current understanding because all we can do is feel it.

[@kickinrocks6055]

I tried to listen to your ad at the end, but it was... inaudible.

[@Omnifarious0]

At 2:15 you used "double down' in a way that doesn't make sense for its general meaning.

[@wanderinghistorian]

Yeah, it sounds like he's saying they wouldn't let go of their incorrect distance measurement.

[@Sharpless2]

and thats a doomsday scenario? Comments sometimes...

[@Omnifarious0]

@@Sharpless2 - Where are you getting 'Doomsday scenario' from?

[@Sharpless2]

@@Omnifarious0 just forget it.

[@kickinrocks6055]

Im hoping to double down, this weekend.

[@anarchyantz1564]

Measure twice, report once.

[@SuperbusQuartus159]

So, the Accretion Disk of our galaxy's black hole got me thinking about a SmarterEveryDay video I saw the other day about Taylor-Couette Flow, ( kzbin.info/www/bejne/oGPClX2PlNJ8r9U ) which then made me question: If someone were to approach the event horizon of a black hole, instead of being "spaghettified" in a straight line down into the gravitational "pit" so to speak, assuming the matter around the event horizon acts as a hyper-viscous fluid, WHAT IF they were spun infinitely around (and into?) the event horizon in a manner not unlike Taylor-Couette Flow?

[@lawrencekimmel352]

Why is it that I can always guess the host by the title of the video?

[@danielpalmer8324]

God how stupid. NEWS FLASH!! there is not dark matter! Just like god, or big foot. So disappointed in this channel.

[@freedapeeple4049]

Thank you for stating the dark matter situation as it actually is; i.e. probable, but still hypothetical.

[@Welverin]

And yet, he said we know a lot about black holes.

[@freedapeeple4049]

@@Welverin Good point.

[@thelonecabbage7834]

@@Welverin We do know "quite a lot" about black holes though, and they certainly aren't hypothetical. We've predicted their existence for several decades, and now we have visual evidence as well. Do we know everything? No, but that doesn't mean we still don't know a lot about them.

[@Welverin]

@@thelonecabbage7834 Actually, no. Damn near everything we 'know' is theoretical and extends from the laws of physics we've developed and while we have accumulated some evidence that shows that the theories for them seem well founded and we have a lot of ideas about what they might be, we're a long way away from having a lot of actual knowledge and not just ideas. Furthermore, keep this in mind, there are theoretical physicist who don't believe they exist and that are alternative explanations for the phenomena we attribute to them.

[@LJMownage]

@@Welverin Well I've never known of a respected physicist who didn't think black holes existed. Please link me one who doesn't

[@sizanogreen9900]

Ah... hyperion... there were quite a few cool concepts in there if I remember correctly... good book.

[@Enceladus5280]

HBO, if you're listening, HYPERION is your next cash cow.

[@التسارعالكوني-ن3ب]

These are five questions about pseudo-stars (quasar) How was the quasar formed? What are the components of quasar? What is the fate of the Quasar? How will it end? Does the quasar revolve around the center of galaxies? Please send my five questions to space scientists We hope you make a film animated pictures of visual explanations In order to answer these questions نأمل أن تقوم بعمل فيلم رسوم متحركة للتفسيرات البصرية من أجل الإجابة على هذه الأسئلة

[@LeoStaley]

You can also get hank's book, an absolutely remarkable thing, on audible.

[@friedchickenUSA]

"Alma image of Cool Disk" youre right, it is kinda cool

[@lightdarkequivalent7143]

Homestuck lives on

[@plntycash]

They have dark matter at cern why do y’all keep calling it hypothetical

[@TheRogueWolf]

Science: "Could be...." Masses: "Is!" Science: "Isn't." Masses: "AHHHHHHH!"

[@paulkennedy8701]

You seem to be using "masses" in a different way from the way the video uses it. It is a little confusing.

[@astromanofficial]

Hyperion is good but Dune is better.

[@ludvigthebirb7131]

whos idea was it to call a black hole "a star"?

[@6ThreeSided9]

Based on my limited understanding: It wasn't anyone's idea. It's just a matter of fact. Well, sort of. You're technically right that a black hole isn't a star, but not for the reasons I think you're implying. Technically, a black hole is the spacetime phenomenon the star creates as a result of existing how it is, not the star itself. For example, you could take out the star-bits in a black hole and, if it continued to do what it was doing, it would still be a black hole - so the black hole isn't the matter itself, just the effect the matter has, and anything that could produce that phenomenon would be producing a black hole, star or not. However, the singularity in the center of every black hole we know to have existed is a star. So, when we talk about black holes, we also normally refer to them as the star that created them, since they're so tied conceptually.

[@zjpdarkblaze]

I have questions. Scientists didnt have a picture of a black hole before? Are'nt radio telescopes a few decades old technology?

[@chillsahoy2640]

Hyperion is better than An Absolutely Remarkable Thing? Interesting...

[@mxnjones]

Hank might be allowed to plug his own book here...

[@noahpage7459]

That book is CRAZY. Listened to it on Audible a few years ago. The whole series of books was mind bending.

[@KiddsockTV]

Have you guys ever thought of Sponsoring SETI @Home ? Let Nerdfighters help find Signals of ET by letting their computers do it. It would not really sponsoring since they are looking for donations, but sharing their work and how to get the screensaver.

[@JeremyWS]

Awwe I was really wanting a galaxy with no dark matter, guess we'll have to keep on looking. I like Sagittarius A*, why can't everything in astronomy have cool names?

[@ThainaYu]

One implication on this is, since there was no galaxy that could be voided from dark matter Then it might not be a matter. MOND and Verlinde and entropic gravity are back to business

[@earlofdoncaster5018]

Yeah I ceased to be a dark matter sceptic when I heard about this galaxy, now I'm sceptical again.

[@SuhailGanondorf1999Singh]

I am still skeptical about dark matter, but after taking an astronomy class I’ve started to lean towards dark matter

[@ThainaYu]

@@SuhailGanondorf1999Singh It was opposite for me. I start leaning toward believing in dark matter. But learning more physics pointed out that it should not be a matter, or at least a matter as we know it. It seem like it will never fit inside standard particle model. In physics words would call it as "not matter". But it might be a thing. Just other kind og thing

[@cgaccount3669]

He stated that dark matter doesn't have a gravitational effect on regular matter? Then said it holds galaxies together? Huh?

[@fernandoleanme5928]

Dark matter is a plug in, used to compensate for a flaw in general relativity

[@osmosisjones4912]

Could a moon Affects. Tge mejored distance of a planets pull on its star. If you major the light block and the planet's size to the stars wable if want is greater the what should be the mass of the planet should be . could indicate a moon as well

[@robohand]

...does he get an Xbox notification at 6:50? xD

[@SecondTremble]

But dark matter doesn’t exist...

[@bomma2694]

Well that's disappointing 😔

[@J-CBertrand-tp6bg]

Not watching 🙄‼️ I want to know when it’s ACTUALLY not real. Why would I want to know when it’s PROBABLY not real?

[@rastrisfrustreslosgomez544]

I do not understand... A high enough probability collapse the wave function into a single physical reality

[@yusefdanielhassounharmouch1520]

Why haven't there been any new gravitational wave findings or news since the neutron star collision?

[@NoName-fc3xe]

Have you been to ligo's website?

[@yusefdanielhassounharmouch1520]

@@NoName-fc3xe They've got a website?!!! Definitely on my way to checking that out!

[@thstroyur]

Not all science is sexy enough to make it to the headlines

[@deftist]

Hyperion series, plus the Endymion series by Dan Simmons.

[@Dantheman1219]

How is the light red or blue shifted if its coming from within our own galaxy? I thought that only happened with light that travels through a lot of empty space between galaxies.

[@robertt9342]

You are confusing redshirting from space expansion with shift from movement of an object relative to us.

[@artifactland69]

I can't wait to find out what all dark matter interacts with

[@phillipj1135]

i got a couple credits and I've been eyeing up Hyperion sense I got the account back in 13 so ill check it out

[@SKEC212]

All this talk about black holes is making me hungry.

[@3nimac]

Thumbs up for Hyperion, it's one of my favorites.

[@ShenGen69]

Love SciShow. Awesome video but I spent most of it checking out your jacket. Had to watch it a second time for the science. Your jacket is almost as cool as black holes. : )

[@josgibbons6777]

Even more recent research has suggested DF2, as well as another similar galaxy, is still somewhat deficient of dark matter. en.wikipedia.org/wiki/NGC_1052-DF2#Dark_matter

[@A3Kr0n]

Whew! Thank God that dark matter thing was cleared up.

[@freedapeeple4049]

Dang, Hank, you even make ads watchable. KZbin should have a Hank Green Award for best presenter.

[@nosuchthing8]

How depressing. Still no progress on dark matter.

[@iepineapple]

the entire galaxy is the accretion disk

[@jayw6034]

So I guess it's not guaranteed to actually be a kind of matter again.

[@1MarkKeller]

Why is it called Sagittarius A star, shouldn't it be called Sagittarius A hole?

[@thstroyur]

It should be called "the Sagittarius A* compact object" - but that wouldn't sell papers or get clicks, so it's a no-no...

[@wanderinghistorian]

Well technically it's still a star. In fact for a time people called black holes (then still theoretical) black stars. They are just a very compact neutron star so dense that the neutrons collapsed as well leaving only a singularity from which not even light can escape. Of course there are theories that some supermassive black holes might've been formed from different objects too.

[@thstroyur]

@@wanderinghistorian Well, technically, black holes _are_ still theoretical; the trouble is that astrophysicists use the expression to refer to generic compact objects with an event horizon (like M87's center - whose EH wasn't _directly_ imaged, but I nitpick, it _has_ one) and the specific theoretical singularity-containing solutions that you mentioned interchangibly - and I'd bet most probably believe they _are_ the same thing; but were they to use only rigorous GR theory to prove this identity to save their lives, they'd all be doomed...

[@Sharpless2]

this question has been asked 400 billion times atleast, and i bet Scientists have a valid reason to call it A*.

[@Ryukachoo]

This sort of complicates things after the many explanations that a galaxy devoid of dark matter would be an indicator for dark matter's expected properties. At this point, could there still be dark-matter-less galaxies out there?

[@bluesap7318]

I have no idea.

[@universe1225]

Go find out!

[@NicoAssaf]

We're on the verge of a paradgim shift.

[@thstroyur]

I think so; in another comment, I quoted observations in arxiv.org/abs/1006.1647 as a sort of a pointer for that

[@DrIBeast]

Maybe. It's not impossible for galaxy to form without it. But dark matter kinda acts like glue for galaxy. If galaxies did exist without it. They likely be very small and have fewer stars. Which also means they would be harder to detect.

[@AaronCano1]

Someone needs to tell Hank it's Summer now

[@ipissed]

They are in Montana, it's lower 50's at night, but high 80's, even 90's during the day during the seasonal change.

[@CorpusOrganic]

what would be good sites to read about the newest breakthroughs in science and technology? kind of similar to popular science magazines, beyond 2000, and such

[@DodgeThis]

So, hypothetically, they were wrong, and are probably still wrong.

[@Nightcoffee365]

Dodge This! That’s how science do. Many make the mistake of believing that science generates final answers as a habit; checking and checking and re-checking is how the best possible answers are found. It’s a process. There is always more to find and more to analyze, and sometimes we learn something new which gives new context to previous information. Science is done by humans, and humans screw up no doubt, but assuming they are still “wrong” because they caught a mistake is off base. Scientists don’t close books, and uncommon things get about a thousand times the scrutiny.

[@thstroyur]

Whether or not this DM-less galaxy was a fluke, there still seems to be some kind of friction between the CCM and satellite/DG halos ( arxiv.org/abs/1006.1647 ); the little bag of white lies (or dark lies, if you prefer) that we call DM profiles nonwithstanding, it's then at least reasonable to expect to eventually observe a DG with little to no DM

[@onemadscientist7305]

When the galaxy with no dark matter turns out not to be real _Reality is often disappointing_

[@xanider5098]

But Truth is exciting!

[@MatthewBishop64]

I'd like there to be a star in Galaxy DF2 to be named DF2BA!

[@timsmith6675]

This is how science works!

[@gravijta936]

Dark matter, light matter, it all comes from the same cosmic chicken!

[@annaliseoconner9266]

So you're saying we're all clucked?

[@gelgamath_9903]

Yes Hyperion is the best book series ever love it

[@PaulmichaelContreras]

Of course the previously mysterious galaxy is 42 million light-years away! 😏

[@peterxyz3541]

42!!!! 👍🏼❤️😂👽

[@psykkomancz]

Actually, in my opinion to get Hyperion Cantos as audiobook as first experience is very bad idea. This book requires concentration when reading, otherwise one can get easily lost in lots of characters, all the references and complicated story arcs . I just cannot imagine to just listen to it, that must be total chaos.

[@non-inertialobserver946]

This is a W for modified gravity theories

[@pitthepig]

They will need many more wins if they want to even be considered a serious competition.

[@nathansamuelson]

I don't get the whole dark matter/energy stuff. It's hypothetical yet we know it exists? How do we know macro physics aren't weird like quantum physics.

[@TNaizel]

They are hypothetical because there might be other explanations, but their effect are real and measurable

[@Meganopteryx]

DF2-BA

[@Turskaify]

"Perfectly ordinary galaxy with a normal amount of Dark Matter" Oh yeah totally nothing out of the ordinary we totally haven't been wrong for 5 years and are not sweeping this under the rug *cough*

[@ianrbuck]

Cool disk, bro.

[@DoctorX17]

Wonder if R34 will run with that accretion disk image like they did with the first black hole one... _There’s something wrong with the internet, guys_

[@OldKingSol]

When we view objects in deep space, the light we see is redshifted to some degree. Redshifted means the light is stretched out. Does that mean that we see events from heavily red-shifted regions more slowly than they actually occurred?

[@ElijsDima]

Not really, since the speed of light is constant*. It's only the wavelength that gets stretched, not the rate of arrival. *- at least, not considering space bending due to various gravity pools on the way

[@Bit-while_going]

@@ElijsDima don't forget that if the speed of light depends on its local gravity pool then it would be higher than expected out of the gravity pools, and that would mean that distant stars and galaxies would be closer than they appear and dark matter would be an illusion. The only way to know would be to measure the speed of light outside of the Galaxy where the gravity pool is very weak.

[@kickinrocks6055]

@@Bit-while_going gravity doesnt change the speed of light. It just changes it's path through curved spacetime. Like gravitational lensing. It takes a longer, curved path. It might take longer to reach you, when compared to a straight path. But it travels at the same speed. Correct?

[@Bit-while_going]

@@kickinrocks6055 how would you know if it was faster, since your local "spacetime" would be stretched causing you to measure the speed differently?

[@gregcampwriter]

Those data, not that data, and doubling down means to repeat one's commitment to a previous position, rather than giving the data are more detailed look.

[@ColeDedhand]

Bravo for science. Question everything. Another example of why there is no "settled science". Throughout history mankind has found that the facts were certain of were wrong. Just because many people believe something doesn't make it right. And the more people believe something the more important it is to question it. The greatest minds in history have been "deniers" of commonly held beliefs.

[@cloudpoint0]

The greatest minds in history had sensible alternative theories to replace commonly held beliefs. They weren't deniers since their alternative theories gave the same predictions as the commonly held beliefs, plus a few new predictions.

[@robinwang6399]

Does this mean Stephen Hawking’s black hole dark matter theory is back ?

[@audioguitarman]

It's always 42.

[@NoName-fc3xe]

Unless it's 33... *Cue spooky music. Woo woo woo*

[@cornlips7247]

I always love to see follow ups to old videos. Great work as always scishow space!

[@mattandmegandiercks8809]

Thank you

[@lachiem]

sixth

[@Rams495]

From Sci-Fi to Journalism aye? Should have said, "Sci-Fi to Fi" that would be more factual about today journalism.

[@thesingularitysociety7109]

It's ironic as if it had turned out to be true that there was no 'dark matter effect' in this galaxy, then it would have effectively disproven a few of the alternative theories to Dark Matter ... with this, those theories are still plausible.

[@nibblrrr7124]

It would have made it even less likely, but there was already a lot of data that massively favors dark matter over alternatives like MOND. Most famously, in the Bullet Cluster, gravitational lensing shows that the mass is not where the visible matter is. Dark matter is also a crucial ingredient in models of galaxy evolution/movement/collisions, and cosmology - so success of these theories is also evidence against the alternatives, unless they can also explain it (and they usually can't). Nothing is ever completely settled in science, and dark matter models still have a lot of open problems and can't explain everything perfectly, but all alternatives are even worse off.

[@brandodoinstuff]

Giving out a rare thumbs up because of the Hyperion mention!

[@overvieweffect9034]

I've read that astronomer had found a second galaxy without dark matter, so is that one also been wrongly measured?

[@poisontoad8007]

Anton Petrov

[@chessmoon]

MOND is back

[@sugarfrosted2005]

Probably not.

[@nibblrrr7124]

It's back to the distance it was before, which is still much farther away than dark matter. ^^ Gravitational lensing in the Bullet Cluster is another example where gravity dissociates from visible matter, and there are also many other empirical findings that support dark matter but are difficult to explain with MOND models. There are also theoretical issues with justifying the weird hacks to the rather elegant frameworks classical mechanics / general relativity, while dark matter circumvents that entirely. (OTOH, the favored WIMP candidates aren't looking as shiny after some failures to detect them, and the LHC & dark energy ruled out the neatest versions of supersymmetry, so maybe we have to deal with ugly hacks anyway. But most MOND models still require _some_ dark matter, so that's just as bad for them as well.)

[@bobbyharper8710]

"Why Most Studies Are Wrong" would be a great investigation.

[@alexv3357]

This is especially a problem with psychology, where so many studies have tiny, biased sample sizes, poorly designed experiments, and no other studies trying to replicate them. Of course, that's complicated by the fact that understanding human behaviour often requires causing people pain and stress to understand how they respond to it, and causing people pain for science is not ethical, which makes repeating many experiments is impossible

[@Cdubble]

Can you guys please do a video on the new theory that our universe is inside the singularity of a 4 dimensional black-hole that was created from the collapse of a 5 dimensional star

[@Erowens98]

I'll explain it, a physicist got high.

[@Barsabus]

No more comercials please

[@Azivegu]

10 views, zero likes, wtf?