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.
The book is currently available as a free download on the website of the illustrator, Andrew Kolb.
I love the song, and as an adult I think the illustrations are kinda cool. But the whole story might be a little traumatic as a kid.
Then again, so is “The Land Before Time“. (seriously, who DIDN’T cry when Littlefoot’s mom got killed by the T-Rex?)
The song, of course, is awesome. So give it a listen if you’ve never heard it. And if you have heard it…well, still give it a listen!
It happens pretty often, but seeing it on video is quite cool.
On August 24, 2011 there was a large electrical storm over Toronto, Ontario. The CN Tower itself was struck by lightning about 15 times in a half hour.
Gotta love Saturday Morning Breakfast Cereal!
The Institute of Medicine has released a comprehensive report on the safety of vaccines. They looked at a wide range of vaccine types and various adverse affects known to be associated, and thought to be associated, with vaccines.
The report looked at claims which were submitted to the National Vaccine Injury Compensation Program (VICP), which was setup in 1986 to compensate those who were injured by vaccines.
They then looked for a causal relationship between the administration of the vaccine and the adverse effect reported in the claim.
In short, the committee found that most issues with vaccines were rare and mild.
Additionally, evidence favors rejection of five vaccine-adverse event relationships, including MMR vaccine and autism and inactivated influenza vaccine and asthma episodes.
A summary of the report very aptly states:
Despite much media attention and strong opinions from many quarters, vaccines remain one of the greatest tools in the public health arsenal. Certainly, some vaccines result in adverse effects that must be acknowledged. But the latest evidence shows that few adverse effects are caused by the vaccines reviewed in this report.
Of course, this doesn’t sway the staunch anti-vax supporters. Age of Autism, a group which is hell-bent on rejecting any scientific evidence showing that vaccines do not cause autism, had this to say about the study:
The IOM report took two years to produce, mostly behind closed doors, and was paid for by the Department of Health and Human Services, the government agency which is also a defendant against the vaccine-injured in the government’s vaccine court
Their arguments are as predictable as the sun rising in the east. It is a government agency, therefore they don’t accept the research.
If people want to keep their heads buried in the sand that is one thing, but the problem is that it is children who end up suffering when people don’t accept the science behind one of the greatest medical advances in history.
But I guess I shouldn’t be surprised. Though that doesn’t mean I can’t be disappointed.
Thanks to all my dedicated readers who have stuck with me through this dry-spell of posts.
I’m going to start ramping back up to roughly a post per day. Where better to start than a Star Wars-related YouTube video?
I know its a comedy, but it’s an important issue. Jar Jar Binks is NOT cool!