What is at the center of a galaxy? How does it have such a gargantuam gravitational power that it keeps billions of stars and other celestial bodies trillions of kilometers away in it's orbit?

File: 206 KB, 1900x1425, 1086.ngsversion.1491440409220.adapt.1900.1.jpg [View same] [iqdb] [saucenao] [google]

Anonymous Sat Feb 3 02:28:05 2018 No.9481657 [Reply] [Original]

What is at the center of a galaxy?

How does it have such a gargantuam gravitational power that it keeps billions of stars and other celestial bodies trillions of kilometers away in it's orbit?

Anonymous Sat Feb 3 02:29:55 2018 No.9481660

>What is at the center of a galaxy?

A supermassive blackhole

>How does it have such a gargantuam gravitational power that it keeps billions of stars and other celestial bodies trillions of kilometers away in it's orbit?

It doesn't. That's why physicists have theorized the existence of dark matter.

>>	Anonymous Sat Feb 3 02:30:39 2018 No.9481662 >>9481657 https://en.m.wikipedia.org/wiki/Quasar Use Google you fuck.

>>	Anonymous Sat Feb 3 02:31:49 2018 No.9481663 >>9481660 >That's why physicists have theorized the existence of dark matter. Can you explain that to a brainlet, please?

Anonymous Sat Feb 3 02:36:27 2018 No.9481665

>>9481663
Basically the thing at the center of the galaxy doesn't have enough of a gravitational pull to keep the entire galaxy in orbit, in the first place.

So, all galaxies SHOULD be breaking apart, with all the stuff in between should be flying off into space. But that clearly doesn't happen. Meaning there has to be some "matter" with enough gravitational influence that holds the galaxy together.

TL;DR: It's the "gravity rope" that keeps galaxies together.

Anonymous Sat Feb 3 02:37:28 2018 No.9481667

>>9481663
Galaxies tend to have a particular shape and move in a particular way.
Current theories predict that they'll only move that way if they have a particular threshold of mass.
However, if we look at them, most of them seem to be much lighter than this threshold.
It's theorised therefore that there's a lot of heavy matter in galaxies that we aren't capable of seeing.
We call this hypothetical source of mass 'dark matter'.

Anonymous Sat Feb 3 02:37:29 2018 No.9481668

Basically the thing at the center of the galaxy doesn't have enough of a gravitational pull to keep the entire galaxy in orbit, in the first place.

So, all galaxies SHOULD be breaking apart, with all the stuff in between should be flying off into deep space. But that clearly doesn't happen. Meaning there has to be some "matter" in between with enough gravitational influence that holds the galaxy together.

TL;DR: It's the "gravity rope" that keeps galaxies together.

Anonymous Sat Feb 3 02:38:30 2018 No.9481670

>>9481663
Basically the thing at the center of the galaxy doesn't have enough of a gravitational pull to keep the entire galaxy in orbit, in the first place.

So, all galaxies SHOULD be breaking apart, with all the stuff in between should be flying off into deep space. But that clearly doesn't happen. Meaning there has to be some "matter" in between with enough gravitational influence that holds the galaxy together.

TL;DR: It's the "gravity rope" that keeps galaxies together.

>>	Anonymous Sat Feb 3 03:18:05 2018 No.9481707 >>9481663 only 9% of milky way's mass is normal matter

>>	Anonymous Sat Feb 3 03:47:32 2018 No.9481759 >>9481657 Gravity isn't real. Supermassive black holes and dark matter are sci-fi memes that have been taken literally.

Anonymous Sat Feb 3 04:25:18 2018 No.9481790

Basically the thing at the center of the galaxy doesn't have enough of a gravitational pull to keep the entire galaxy in orbit, in the first place.

So, all galaxies SHOULD be breaking apart, with all the stuff in between should be flying off into deep space. But that clearly doesn't happen. Meaning there has to be some "matter" in between with enough gravitational influence that holds the galaxy together.

TL;DR: It's the "gravity rope" that keeps galaxies together.

>>	Anonymous Sat Feb 3 06:01:31 2018 No.9481860 Spin power

Anonymous Sat Feb 3 06:42:41 2018 No.9481885

>>9481657
>What is at the center of a galaxy?
Black holes and the like.
>How does it have such a gargantuam gravitational power that it keeps billions of stars and other celestial bodies trillions of kilometers away in it's orbit?
It doesn't. They mostly keep each other in orbit.

>>	Anonymous Sat Feb 3 08:19:32 2018 No.9482001 >>9481667 >we don't know therefore an invisible force is there that will make our theory true yep, we're back at square one

>>	Anonymous Sat Feb 3 08:39:08 2018 No.9482025 >>9481668 But shouldn't the dark matter be all at the center of the galaxy for this to work?

Anonymous Sat Feb 3 08:48:15 2018 No.9482038

>>9481657
>What is at the center of a galaxy?

Sagittarius A*, a supermassive Black Hole 25,640 light years away from us and 4.1 million times the mass of Sol

>How does it have such a gargantuam gravitational power that it keeps billions of stars and other celestial bodies trillions of kilometers away in it's orbit?

Dark Matter

>>	None !niqjediPCA Sat Feb 3 09:50:16 2018 No.9482134 >>9481657 >What is at the center of a galaxy? Well, the center of our galaxy is Sagittarius A*

>>	Anonymous Sat Feb 3 12:59:01 2018 No.9482527 >>9481657 Ur mom's butthole lol xDD

>>	Anonymous Sat Feb 3 13:03:39 2018 No.9482540 >>9482038 >Sagittarius A*, a supermassive Black Hole 25,640 light years away from us and 4.1 million times the mass of Sol do you have actual proofs or it's just someone s fantasy?

>>	Anonymous Sat Feb 3 13:13:04 2018 No.9482574 >>9482540 It's scientific fact. There's no real evidence for it, but it is scientific fact.

>>	Anonymous Sat Feb 3 13:16:11 2018 No.9482586 File: 31 KB, 250x251, 1385777144980.jpg [View same] [iqdb] [saucenao] [google] >>9482574

One opinion Sat Feb 3 20:37:32 2018 No.9483540

>>9482025
If that were the case, we'd simply have an EMSMBH (Even More SuperMassive Black Hole) (N.B. Not actual scientific name)
I may be wrong here, but I am pretty certain that the idea comes from the edges of the galaxy spinning so quickly that it would tear itself apart. Thus, if we had DM spread out over an even larger volume than the galaxy itself, providing a larger pull towards the centre without affecting gravitational interaction at short ranges (much).

TL;DR it's much bigger than the galaxy

DM is theorized to be a massive substance that only interacts through the gravitational force (i.e. Not electromagnetic, not strong nuclear, not weak nuclear) and thus is "invisible" to other attempts to detect it. In theory it would bend light with gravitational lensing, but as we see no evidence of this it adds validity to the disperse theory of DM. Theorists of DM boil into 2 categories WIMPs (Weakly interacting Massive Particles) and MACHOs (MAssive Compact Halo Objects).

TL;DR DM is stuff that we either can't or can barely see.

>>	One opinion Sat Feb 3 20:39:47 2018 No.9483545 >>9483540 I very nearly posted Weakly Interacting Massive Panties.

Anonymous Sat Feb 3 21:03:21 2018 No.9483600

>>9481665
Your comment got me thinking about the masses of Sagittarius a* and the Milky way:
Sagittarius a* - 4 million solar masses
Milky Way - 5.8*10^11 solar masses

That is many times greater than the black hole, why aren't they in a unstable binary orbit?

>>	Anonymous Sat Feb 3 21:04:32 2018 No.9483605 >>9482574 Are we being raided by /pol/?

Anonymous Sat Feb 3 21:08:37 2018 No.9483616
File: 151 KB, 1274x1649, N019 rotation, actual.jpg [View same] [iqdb] [saucenao] [google]

>>9481657
Supermassive black hole.
Actually, fairly small as SBHs go (compared to some seen in other galaxies) and it doesn't hold our galaxy together.
But we can see stars close to the centerpoint whirling about something massive at goodly fractions of lightspeed. They move visibly in photos taken months or years apart. Given that they're 33,000 light-years distant, that means they're really hustling!

>>9482025
You wouldn't want all the dark matter to be at the center of the galaxy. You may know that a hollow sphere exerts no net gravitational force on objects within it.
The orbits of stars are only affected by matter closer to the center-of-rotation than they are. I stellar velocities at various distances from the core (as measured by Doppler effect) were only due to the visible suns and dust, the rotation curve would have a particular shape; i.e. velocities would fall off steadily towards the outskirts. Stars near the rim should just crawl if most of the mass was in the central core. That's not what we see. Velocities become almost constant. It indicates that a large amount of unseen mass is distributed throughout the entire disc.

Anonymous Sat Feb 3 21:14:38 2018 No.9483628

>>9483600
As stated in >>9483616 and elsewhere, the SBH isn't holding the galaxy together. It's only effects are the rapid circling of nearby stars (a few light-years) and the X- and gamma- radiation given off by the accretion disk of infalling matter. And it's not being "fed" regularly or our galaxy would have immense jets blowing out along the axis of rotation.

>>	Anonymous Sat Feb 3 21:32:13 2018 No.9483679 If Dark Matter is somehow proven to exist one day, how would that change physics as we know it today? How would that change space exploration?

Anonymous Sat Feb 3 21:53:51 2018 No.9483715
File: 301 KB, 1200x1200, Sagittarius_A_.jpg [View same] [iqdb] [saucenao] [google]

>>9482540
>>9482574

We know Sagittarius A* exists because we can detect emissions coming from the center of the Milky Way. And we know it is a black hole because we can observe nearby stars orbiting around it.

>>	Luke Gladely Sat Feb 3 21:58:58 2018 No.9483718 At the center of the galaxy there is not a black hole. It is said that ice giants protect a land of Fortnite and Ugandan armies. Stop listening to whatever crap your teacher tells you

>>	Anonymous Sat Feb 3 22:36:59 2018 No.9483793 >>9483679 Can we run into Dark Matter? How does it interact with things without being seen? How can we not detect it with all the stuff we've made to detect insignificant things (like gravity waves and whatnot)?

Anonymous Sat Feb 3 23:03:21 2018 No.9483831

Is it stupid to think that maybe instead of a force pulling them inward there is a force pushing them in to where the innermost stars and planets and other forces of mass have no way of escape but to indefinitely push away from another force so it wouldn't collapse?
So the outermost masses are preventing escape outward but not in a line which they orbit, while all outer masses are very slowly pushing away into space as there is nothing holding them in.
The creation of the universe in the cosmos started small, in relation to its current infinite size, and expanded, and now we're waiting as it continues to expand.

Anonymous Sat Feb 3 23:12:58 2018 No.9483848

>>9483793
When you run into things -- you bang your fist on the desk, for example, the electron clouds of the desk atoms are repelling the electron clouds of your hand atoms. Except for gravitation, electromagnetism is the only force we experience in everyday life.
Dark matter (assuming it's not baryonic matter, not made of protons and neutrons) isn't supposed to interact with electromagnetism. So you can't touch it. And because it doesn't interact with electromagnetism, you can't see it. That's why it's dark. (Bad name, but we're stuck with it now.) If it doesn't emit light, reflect light, or hinder light passing through it, it's invisible.
The only force which Our stuff and Dark stuff share is gravitation.
Think about neutrinos. They feel neither electromagnetism nor the strong nuclear force. They go through you, through the Earth, through several lightyears of solid lead as if they weren't there. Occasionally, they interact with the weak nuclear force, so we can spot one out of every zillion which pass through our detectors. Dark matter will be as hard, or harder, to find.
Gravity waves were detected because certain rare events (colliding neutron stars or black holes) briefly create staggering amounts of them. Judging by the way dark matter influences the orbits of stars, it's not especially concentrated in any one spot. Even if it outmasses all the stars in a galaxy, a galaxy is still pretty big, and if we COULD touch the dark matter, it'd likely still be a pretty good vacuum insofar as density goes.

Anonymous Sat Feb 3 23:18:17 2018 No.9483857

>>9483831
If there was a repulsive force "constraining" the stars in a galaxy, the particles exerting that force would feel a reaction and be shoved outwards. They wouldn't "clump". They'd diffuse away into the space between galaxies.
But dark matter acts as if it's concentrated within galaxies.

>>	Anonymous Sun Feb 4 00:51:12 2018 No.9483964 File: 254 KB, 486x386, i guess we'll never know.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Sun Feb 4 01:50:28 2018 No.9484023 >>9481663 This might help if the former answers weren't sufficient: https://www.youtube.com/watch?v=32qqEzBG9OI

Anonymous Sun Feb 4 03:52:36 2018 No.9484144

The dark matter thing reminds of a book I read years ago called the capacitance theory of gravity. Written by some crazy old physicist.

Basically the guy says with regards to dark matter is that the more space, the more capacitance, so the more gravity. Vacuum having a pretty good k value in itself.

Anonymous Sun Feb 4 05:43:19 2018 No.9484253

>>9483715

there is a fascinating documentary on the astronomer whose name i forget who spent a lifetime charting the orbit of stars around the center of the galaxy to show that there must be a supermassive black hole

I dont think it was a Nova show but something like that, either PBS or BBC I think

It might be on TPB

it was really good, gave one a feel for doing real science and the joy of real discovery

Anonymous Sun Feb 4 05:51:42 2018 No.9484261

>>9484253

maybe this one?:

http://www.pbs.org/wgbh/nova/space/monster-milky-way.html

Participants

Eric Becklin
UCLA personnel.physics.ucla.edu/directory/faculty/index.php?f_name=becklin
Gregory Benford
University of California, Irvine
Neil deGrasse Tyson
Astrophysicist, American Museum of Natural History www.haydenplanetarium.org/tyson/profile/bio
Tiziana Di Matteo
Carnegie Mellon University web.phys.cmu.edu/~tiziana/
Reinhard Genzel
Max-Planck Institute, Garching
Andrea Ghez
UCLA www.astro.ucla.edu/~ghez/
Andrew Hamilton
University of Colorado casa.colorado.edu/~ajsh/
Brian McNamara
University of Waterloo
Steve Ritz
NASA Goddard Space Flight Center lheawww.gsfc.nasa.gov/~ritz/
Antony A. Stark
Harvard-Smithsonian Center for Astrophysics cfa-www.harvard.edu/
Kip Thorne
California Institute of Technology

>>	Anonymous Sun Feb 4 06:00:26 2018 No.9484269 >>9481657 No, what holds them on orbit are themselves, not center of the galaxy!

>>	Anonymous Sun Feb 4 06:01:20 2018 No.9484270 >>9483715 >because we can detect emissions coming from the center of the Milky Way how do you know where is the center of milky way? how do you know this is "emission" from the imaginary "black hole"? this is all nothing but fantasies.

>>	Anonymous Sun Feb 4 06:01:28 2018 No.9484271 >>9484269 It's that "thing" propagates troughs those celestial bodies from one to another.

>>	Anonymous Sun Feb 4 06:32:54 2018 No.9484302 >>9484261 Eric Becklin: https://www.sofia.usra.edu/sites/default/files/Menten_Eric_Becklin-pioneer_of_infrared_astronomy.pdf

>>	Anonymous Sun Feb 4 07:27:50 2018 No.9484366 >>9481660 >A supermassive blackhole Nice phantasmagory.

>>	Anonymous Sun Feb 4 08:24:37 2018 No.9484430 >>9481657 A monkey named Steve

Advanced search
Text to find
Subject [?]Search by post subject. Leave empty for any.
Username [?]Search for user name. Leave empty for any user name.
Tripcode [?]Search for tripcode. Leave empty for any.
Email [?]Search by email. Leave empty for any.
Filename [?]Search by image filename. Leave empty for any.
From Date [?]Enter what date to start searching from. Format is YYYY-MM-DD
To Date [?]Enter what date to start searching until. Format is YYYY-MM-DD
Image hash
Search in	All Posts OPs Only
Deleted posts	Show all posts Show only deleted posts Only show non-deleted posts
Internal posts	Show all posts Show only internal posts Show only archived posts
Order	New posts first Old posts first
Capcode	All Posts Only by Users Only by Mods Only by Admins Only by Developers
Results	Posts Threads
Action	[ Simple ]

/sci/ - Science & Math