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Posts Tagged ‘astrophysics’

Realistic Simulation of the Formation of a Milky Way-Like Galaxy

August 31, 2011 1 comment

The first realistic simulation of a spiral galaxy similar to our own Milky Way has been generated by researchers at the University of California, Santa Cruz, and the Institute for Theoretical Physics in Zurich.

The simulation, called ERIS, took 1.4 million processor hours to complete. And that was on the 7th most powerful supercomputer in the world, NASA’s Pleiades supercomputer, which runs at 1.09 petaflops per second.

The simulation follows the formation of a galaxy equivalent to 7.9 × 1011 solar masses (1 solar mass is equal to the mass of our Sun) and has a total of 18.6 million particles.

The resulting galaxy has a radius of 2.5 kilo-parsecs (about 7.7 × 1016 kilometers). Previous attempts at simulating a realistic galaxy have failed, resulting in simulated galaxies which have too large of a central bulge. The finding of this study, which has been accepted for publication in Astrophysical Journal, found that,

A high star formation threshold appears therefore key in obtaining realistic late-type galaxies, as it enables the development of an inhomogeneous interstellar medium where star formation and heating by supernovae occur in a clustered fashion. The resulting outflows at high redshifts reduce the baryonic content of galaxies and preferentially remove low angular momentum gas, decreasing the mass of the bulge component.

Another important result of this work is that it supports the idea that cold dark matter constitutes a large portion of the mass in the universe.

Planck Sees the Universe as Never Before

January 12, 2011 Leave a comment

The first results from the European Space Agency’s Planck survery have been released today, and what a pretty picture these results make.

The Planck space telescope was launched in 2009 and currently resides in a Lagrangian point between the Earth and the Sun, roughly 1.5 million km away.

(A Lagrangian point is a point in space where the gravity from two bodies cancel each other out).

Planck’s mission is to study the Cosmic Microwave Background, the “echoes” from the Big Bang that appear everywhere in the sky.Plank was designed to be successor to the recently retired WMAP satellite, which measured the CMB with more accuracy than any instrument before it.

Artist's Conception of the Planck Telescope. Photo: ESA

The image above the top of the page was released back in July 2010, but the first scientific results have just been made public. They include 25 papers submitted to the journal Astronomy & Astrophysics. The results include some pretty cool stuff.

Planck has found evidence for an otherwise invisible population of galaxies shrouded in dust billions of years in the past, which formed stars at rates some 10–1000 times higher than we see in our own Galaxy today. Measurements of this population had never been made at these wavelengths before. “This is a first step, we are just learning how to work with these data and extract the most information,” says Jean-Loup Puget, CNRS-Université Paris Sud, Orsay, France.

These studies allow us to gain a better picture of how the Universe formed in its very early stages, about 380 000 years after the Big Bang.When the CMB was first discovered, it was thought to be completely isotropic over the entire sky. This made no sense, however, since the Universe is made up of clumps of matter like stars and galaxies. There had to be some structure in the CMB, and that is why these tools like WMAP and Planck have been developed; to see that structure in the CMB.While these results are exciting, the best is yet to come,

Today’s results are the tip of the scientific iceberg. Planck is exceeding expectations thanks to the dedication of everyone involved in the project,” says David Southwood, ESA Director of Science and Robotic Exploration.

What Does a Black Hole Look Like?

December 9, 2010 Leave a comment

Credit & Copyright: Alain Riazuelo - Click Image for Large Version

Not to sound like a smart ass…but it would look like a big black hole.

This is a computer generated image by Alain Riazuelo and I saw it the other day as the Astronomy Picture of the Day.

Aside from eating all the light hitting the black hole straight on, notice the “rings” around it as well. This is called gravitational lensing, and is something astronomers look for in order to identify a black hole, since the lensing is easily visible at a larger distance.

Deep Space Probe IKAROS: Update

June 17, 2010 Leave a comment

I recently wrote about the new Japanese space probe IKAROS. It is the first probe designed to test the idea of using solar sails to travel the universe.

A couple new photos were just released showing IKAROS with its sail unfurling, confirming the first stage of its mission.

IKAROS with sails in the process of unfolding. Photo: JAXA

IKAROS with solar sail completely unfurled. Photo: JAXA

Now its just a matter of getting it up to speed. I’m really interested in this one folks, and I’ll keep you up to date.