"Hacking the Universe" --Astrophysicists Recreating the Cosmos from Scratch

 

       

Scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) and their colleagues at the Heidelberg Institute for Theoretical Studies (HITS) have invented a new computational approach that can accurately follow the birth and evolution of thousands of galaxies over billions of years. For the first time it is now possible to build a universe from scratch with galaxies like we observe beyond the Milky Way.

"We've created the full variety of galaxies we see in the local universe," said Mark Vogelsberger (CfA). Our cosmic neighborhood is littered with majestic spiral galaxies like Andromeda, the Pinwheel, and the Whirlpool. Spirals are common, but previous simulations had trouble creating them. Instead, they produced lots of blobby galaxies clumped into balls, without the broad disks and outstretched arms of a typical spiral.

The new software, called Arepo, solves this problem. Created by Volker Springel (HITS), Arepo generates a full-fledged simulation of the universe, taking as input only the observed afterglow of the Big Bang and evolving forward in time for 14 billion years. This computer animation, created using new software called Arepo, simulates 9 billion years of cosmic history.

"We took all the advantages of previous codes and removed the disadvantages," explained Springel. "Our simulations improve over previous ones as much as the Giant Magellan Telescope will improve upon any telescope that exists now," said Debora Sijacki (CfA). When completed later this decade, the Giant Magellan Telescope's 24.5-meter aperture will make it the largest telescope in the world.

 

          

 

One of Arepo's key advantages is the geometry it uses. Previous simulations divided space into a bunch of cubes of fixed size and shape. Arepo uses a grid that flexes and moves in space to match the motions of the underlying gas, stars, dark matter, and dark energy.

The simulations ran on Harvard's Odyssey high-performance supercomputer, using in total 1024 processor cores. This fast machine allowed the scientists to compress 14 billion years into only a few months - an endeavor that would have kept a desktop computer busy for hundreds of years!

The team's future goals include simulating much larger volumes of the universe at unprecedented resolution, thus creating the largest and most realistic model of the universe ever. Their work is described in three papers accepted for publication in the Monthly Notices of the Royal Astronomical Society. Those papers can be found online at arxiv.org/abs/1109.1281 , arxiv.org/abs/1109.3468 , and arxiv.org/abs/1109.4638 .

Journal reference: The Monthly Notices of the Royal Astronomical Society

The Daily Galaxy via Harvard-Smithsonian Center for Astrophysics

Comments

[dr burke]

So, if they can track everything over billions of year; where in the universe, did the BIG BANG
take place? Surely, they can pin point the location? Surely; everything, must be spreading
away from one location? Where is that damn big bang, scientist keep talking about?

[Paradox]

It's like an explosion, there was no specific point of occurrence.

[Bob Greenwade]

The universe no longer includes the point in which the Big Bang occurred. It's an expanding supersphere: it gets larger in all directions, including the fourth spatial dimension.

In a way, think of it as a beach ball that starts as a single point and just keeps getting bigger. (In the case of the beach ball, one assumes that the air is getting in from somewhere; ignore that flaw in the analogy for now.) When the beach ball is full size, there's no single point on the beach ball where that single point exists. The point is in the center of the ball, which could not be found on the surface no matter how hard you try.

[smartypants]

Paradox
Have you ever seen an explosion? The specific point of occurrence is where the chemical reaction or pressure overload occurs. There may be more ways but those 2 come to mind the easiest.

Bob
An explosion/expansion so strong that all the cosmos was created and it vanishes. Sounds funny to me. Sure, theres no single point on the surface of a beach ball where it would exist. The surface of a beach ball is 2D. We are not 2D, nor are we on the "surface" of the expansion. We are deep into the 3D part of it. After thinking about it the one way that might make sense would be to say that everything we see is the point of the Big Bang. We are inside the remnant with everything else created by it. Not that I believe in the Big Bang but since I cant disprove it (yet) I might as well play along with small parts.

[Bob Greenwade]

smartypants -

Yes, we are indeed on the "surface" of the expansion. Our 3D universe is on the surface of the 4D supersphere that (according to the theory) has expanded since the Big Bang.

It's a common mistake to limit thinking to three dimensions of space and one of time, when most theories of the cosmos tell us that there are many more than that.

[smartypants]

Ahhhh, I see. Im sorry Bob. If you dont know, just say so. Making up all storys just to not be wrong is below you. You are better than that my friend!