Category Archives: Physical Sciences

The New Heavyweight Champion of the Universe

Posted on February 16, 2011 by | 2 comments

EDIT: added in another image of star cluster R136

Ladies and gentlemen, let me introduce you, to Hypergiant “blue” R136a1, “The New” Solar Mass Heavyweight Champ! Weighing in at an estimated 265 solar masses, he may very well be the most massive star in our universe! He’s  so big, that scientists are baffled by how he came to be.

Size Comparison for R136a1

You heard it folks, there’s a newly discovered star, that’s so heavy that it disputes current models of how stars may be formed. R136a1 was discovered last year with the findings published in July 2010. It’s found in a star cluster known as R136 that’s 165,000 light-years away.

In 2005 NASA had released an article which suggested that in our current era of the universe, stars cannot exceed 150 solar masses (i.e. 150 times the mass of the sun) otherwise they would violate the Eddington Limit. This limit is where the radiation force outwards of a star is equal to the gradational force pulling inwards. Stars bigger than this would have too much out flowing radiation that they would eject all their gaseous matter into space.

This may be the case for R136a1: scientists speculate it was actually much heavier at its formation and may have lost as much as 50 solar masses through continuous emission of stellar winds in the last million years due to its instability. So, how did R136a1 come to be? Scientists speculate that its ridiculous size may be attributed to several young stars colliding together to form a single object.

Size Comparison for VY Canis Majoris

One thing to keep in mind is that while R136a1 is the heaviest known star, at only 35 solar radii (i.e. 35 times the radius of the sun), it is certainly not the largest. The title of “biggest star” belongs to VY Canis Majoris that is 1800-2,100 solar radii in size! At the same time, it is only 30 times the mass of our sun.

As for its fate, R136a1 is too big to form a black hole and may instead explode as hypernova (an explosion equivalent to over  100 supernovae). Of course, that’s only if it doesn’t blow all of its matter into space before then..

The original article can be found here (#83, “The Biggest Star of All”):  http://discover.coverleaf.com/discovermagazine/201101?pg=76#pg76

NASA’s 2005 article can be found here:  http://www.nasa.gov/home/hqnews/2005/mar/HQ_05071_HST_galaxy.html

For more general information on hypergiant stars, see:  http://en.wikipedia.org/wiki/Hypergiant

Hubble - R136 - Stellar Nursery

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Posted in Physical Sciences, Science in the News

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The Brain: Seeing the Person Behind the Face

Posted on January 30, 2011 by | Comments Off on The Brain: Seeing the Person Behind the Face

People have the capacity to recognize twenty faces better than recognizing twenty pictures of roses. The Brain: Seeing the Person Behind the Face provides a hypothesis to how we are able to recognize faces altogether.

One condition called Prosopagnosia is responsible for the inability to identify faces.  It is a common disorder, but is not clearly understood.  One of my favorite neuroscientists , Oliver Sacks who is 78 this year was only recently diagnosed with Prosopagnosia. In his book, he says “I have had difficulty remembering faces for as long as I can remember.”

The reason why Prosopagnosia is not clearly understood is because doctors have not understood how normal face recognition works. Cognitive Neuroscientist Marlene Behrmann, found that human brains know how to identify faces by carrying out a “mathematical transformation of each face, encoding it as a point in a multidimensional face space” rather than being able to identify faces through photographic images.

The face space model has become much more accepted by neuroscientist today. They suggest the way we store faces in our brains is by decreasing the face to a point, by creating a dense code for representing many numbers of faces. It suggests that our brains only need to store the distance and direction of a point from the center of face space. Average looking faces are located in the center of face space, however, people with more distinctive features deviate from the center of the face space.

It goes on to describe how caricatures of famous people allow us to sometimes recognize them more quickly than a photographic image.

Several experiments were conducted to further understand this hypothesis, but the seven participants in the experiment were not adequate enough to make a statement that claims people who are face-blind can still retain face space.  They did, however admit that further research is needed to interpret how we recognize faces.

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The Origin of Our Solar System

Posted on January 28, 2011 by | 1 comment

Has anyone ever wondered about how the world, and our solar system started? I have countless times, but I am still questioning our current theory of origin, the Nebular Hypothesis. http://en.wikipedia.org/wiki/Nebular_hypothesis

A. solar nebula B. contraction into rotating disk C. Cooling causing condensing into tiny (dust sized) solid particles D. Collisions between these form larger bodies E. These accrete to form planets

First proposed by Emanuel Swedenborg, the Nebular Hypothesis is the most widely accepted theory for the origin of our solar system. It is based upon the assumption that the universe already exists under the Big Bang theory. Under this model, the  molecular hydrogen and “dust particles” had clumped together to form a giant cloud, called a nebula. Due to their own gravity, they collapsed, spiralling down to the centre of the cloud to form a central mass and a rotating flattened disk. High concentration in the center of the cloud lead to temperature and pressure increases, and resulted in nuclear fusion.

Nuclear fusion was the process of which hydrogen molecules fused together, released energy and formed the Sun. The “leftover” dust clumps became the planets, and this is the current theory of how the Solar System came to be. It explains why the planets revolve around the Sun on the ecliptic plane, and the proximity of terrestrial planets and gaseous planets.

However, I question how the hydrogen molecules came together to make a giant ball in the first place. I thought that gaseous molecules have a tendency to go from areas of high concentration to low concentration. Did the gravity of one hydrogen molecule attract another hydrogen molecule, and eventually became a huge giant cloud of hydrogen, and suddenly collapse? The force of gravity of one hydrogen atom to another would not be such a significant force, as Fg = km1m2/ r2, and the constant, k is a very small number of 9.0*10-9.

I am sceptical. What about the second law of thermodynamics, entropy? Molecules want to increase their entropy, and disperse when they can. Would there be any other forces that attracted the hydrogen molecules and dust particles together besides the force of gravity? Perhaps one day, we will be able to understand the mechanisms of our world better.

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Science + Music = An Interesting Take on Learning

Posted on January 27, 2011 by | 4 comments

So midterms are coming up, and continuing along the same vein of this course here are a couple interesting examples of scientists and professors communicating their profession through song.

First up is a collection of songs entitled “Metabolic Melodies” written by Dr. Kevin Ahern, a biochemistry professor just across the border at Oregon State University. What really separates his examples apart from others floating around the web are the excellent production values. Rather than writing new melodies for his songs, he takes existing popular music tunes from artists like Bob Dylan, Simon and Garfunkel and the Beatles and uses them to create quick, catchy study aids. By using familiar music the songs are more likely to get stuck in your head and thus are better able to retain the information. Also, although the listener at home will use it to supplement their studying, Dr. Ahern uses the songs in class and performs them live. As the videos on his website show, the performances are an excellent way to add energy to a lecture. Plus, instructing the students to sing along karaoke style to words displayed on an overhead seems to be a highly effective teaching technique. Unfortunately viewing them requires a YouTube account, so it is best to follow the links rather than embedding them here.

Here is a link to his full list of songs, as well as aforementioned videos. It’s worth it just to check out the names given to the various songs and which melodies he uses. My personal favourites are En-er-gy (to the tune of “Let It Be”) and The Tao of Hormones (to the tune of “The Sound of Silence”).

http://www.davincipress.com/metabmelodies.html

Finally here is a mainstay of science music, the venerable “The Elements” by Tom Lehrer. Written all the way back in 1959 it is popular enough that there is even an app for that. The Elements for iPad provides a nice animation along with the tune.

Here are both the song + animation and it’s Wikipedia entry for reference:

www.privatehand.com/flash/elements.html

http://en.wikipedia.org/wiki/The_Elements_%28song%29

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Posted in Biological Sciences, Fun!, Physical Sciences, Science Communication

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