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Cosmology Discussion Thread

Posted: 25 Jan 2019 08:13
by A-L-E-X
Wat I remember we discussed this awhile back!

Cosmology Discussion Thread

Posted: 30 Jan 2019 12:15
by Gnargenox
A Black Hole in 3D is a sphere, but in 4D Spacetime, is it a cylinder or a black torus ring with a black hole in the middle? Or maybe multiple rings, each with separate Horizons or infinite surface planes with their own timelines? I'm thinking basically an expanding 3D space within the shell or outer "black ring" of a 4D black hole. Maybe a unique multiverse spawned from a black hole singularity. I guess then a 5D black hole would be a naked singularly surrounded by a ring of Spheres, each a separate black hole really.

Just thinking while driving around lol
Any plans to include black rings in Space Engine?
What would happen if I wrote a script with a black hole inside another black hole?

Cosmology Discussion Thread

Posted: 30 Jan 2019 14:16
by DoctorOfSpace
Gnargenox wrote:
Source of the post Any plans to include black rings in Space Engine?


No

Gnargenox wrote:
Source of the post What would happen if I wrote a script with a black hole inside another black hole?


You get a z conflict where different distances and different angles cause one to render on top of the other. Have experimented with stacked objects plenty.

Cosmology Discussion Thread

Posted: 30 Jan 2019 20:28
by Watsisname
Gnargenox wrote:
Source of the post A Black Hole in 3D is a sphere, but in 4D Spacetime, is it a cylinder or a black torus ring with a black hole in the middle?

How far down the rabbit hole do you want to go? :)

► Take the blue pill


► Take the red pill

Cosmology Discussion Thread

Posted: 30 Jan 2019 21:02
by Gnargenox
Lol OMG I went ahead and took the red pill but my head exploded halfway to the event horizon! I'll keep trying though.

Cosmology Discussion Thread

Posted: 31 Jan 2019 00:55
by Stellarator
Watsisname wrote:
How far down the rabbit hole do you want to go? :)


► Take the red pill


This made my day :).

Cosmology Discussion Thread

Posted: 31 Jan 2019 01:22
by Watsisname
:P  Wanted to try to make it fun.  Black holes are weird.

Cosmology Discussion Thread

Posted: 31 Jan 2019 05:10
by A-L-E-X
You know I love the red pill method and thats how I had always envisioned it- I had even created a universe made of negative dimensions (complementary to ours) with the time arrow flowing opposite to ours (but always forward relative to itself) and the complementary dimensions being like the subtractive primaries of CMY compared to our additive primaries RGB, and the white hole concept worked well too because while our background is black, there's would be white (compared to ours.) It's all mathematically consistent and I've seen papers on such a possibility, but everything needs to be "perfect" to be able to create and make such a portal traversable doesn't it?  One little wrinkle and it collapses?

My model (thought experiment really) also envisions an asymptote that needs to be jumped over rather than crossed directly, the "light barrier."  I started on this line of thinking back in 7th grade but the seeds of it were planted back in 4th grade when I read a book about quasars and extended later in 8th grade when I incorporated string theory and the different types of black holes.  Thats how long ago I started thinking about all this lol.

Cosmology Discussion Thread

Posted: 07 Feb 2019 15:48
by Watsisname
PBS Space Time did an episode on "Primordial Sound Waves", or the Baryon Acoustic Oscillations, which are a powerful tool for testing cosmology.  Earlier and elsewhere on the forum I also described a bit about how these oscillations reveal the amount of dark matter and dark energy in the universe.  So for anyone wanting to learn more about them, this episode is a great introduction to what those oscillations are, and their physics. :)


Cosmology Discussion Thread

Posted: 21 Feb 2019 14:35
by Watsisname
Next in the series: a deep look at the Cosmic Microwave Background, and the information that we glean from its "angular power spectrum".  This builds off of ideas presented in the above episode about Baryon Acoustic Oscillations, which I would consider prerequisite.  That being said, I think the payoff is well worth it.


Cosmology Discussion Thread

Posted: 23 Feb 2019 00:56
by Stellarator
Has anyone here heard of the Illustris Project? It's an astrophysical simulation program, aiming to fully generate the formation of galaxies and their clusters based on the cosmological laws thought to underpin what is present in current observations and predictions of our universe. By seeing how they compare to reality, we can further refine the models. Personally, I find the quality and informative nature of the project's aims and results unsurpassed. More info can be found on the webpage.

Image


Cosmology Discussion Thread

Posted: 23 Feb 2019 18:57
by Watsisname
Stellarator wrote:
Source of the post Personally, I find the quality and informative nature of the project's aims and results unsurpassed.

Absolutely. :)  Thanks for linking this!  The results are breathtaking, and I love how the different visualizations of the data (by gas density, temperature, velocity, visible light, dark matter, etc) capture different aspects of the dynamics.  Outflows from supernovae are literally like cosmic fireworks, and seeing the gas flows rendered by velocity is mesmerizing.  It's also amazing simply comparing the results to what we actually see on the sky.

Also check out their latest project, IllustrisTNG, which simulates volumes of up to 300Mpc on a side with even richer treatment of the physics.
Formation of a galaxy cluster rendered by gas velocity, then switching to visible light.
Formation of a single spiral galaxy similar to M31.

Cosmology Discussion Thread

Posted: 24 Feb 2019 02:33
by Stellarator
Watsisname wrote:
Source of the post Formation of a galaxy cluster rendered by gas velocity, then switching to visible light.
Formation of a single spiral galaxy similar to M31.

It is amazing how organic it looks. These were probably the most beautiful and evocative images and videos I've seen for a long time.

Cosmology Discussion Thread

Posted: 16 Mar 2019 02:42
by Stellarator
I thought I'd post this video here, because it is dedicated to the cosmological discoveries of the Hubble space telescope. While the images herein are not exclusively from that instrument, they remain a fitting choice for the piece. 

Welcome to the beauty and grandeur that is the universe...


Cosmology Discussion Thread

Posted: 20 Mar 2019 17:10
by Watsisname


A new method of measuring the universe's early expansion history by the UV and X-ray emission of quasars has led to the startling result that the strength of dark energy appears to have increased over time.  Does this mean the Lambda-CDM model with dark energy as an unchanging cosmological constant is incorrect?  Will the universe eventually tear itself apart in a Big Rip?!  Details in the video.

(Spoiler: probably not, since this method is brand new and not well proofed, but it is another observational discrepancy and something cosmologists will need to investigate closely).