Tag archive for space

It’s about time to…

It’s about time to throw some credibility to fans of the 2012 apocalypse theory. There is a lot of talk of ancient Mayan calendars, interstellar collisions, and terrestrial polar shifts and while there is minimal scientific relevance to these claims, one cataclysmic event is likely to occur in the next several years. A supernova. Betelgeuse, a star in the Orion constellation is a first magnitude super giant. The size of a star is one of the most important intrinsic features. Bigger stars form faster, live shorter, and die more explosively. Super giants are the last step in a star’s evolution.

All stars start out using hydrogen as nuclear fuel. This hydrogen is fused together to form helium in a very explosive nuclear reaction that “powers” the star. As the hydrogen runs out, the star begins to collapse from a lack of radiative pressure from the core. The collapse of this much mass increases the temperature until the core is hot enough for Helium fusion. This process is repeated as the fuel continues to be consumed, from hydrogen to helium, helium to carbon, carbon to silicon, and silicon to iron. It is at this point that the already explosive reactions become even more cataclysmic. All of the previous fusion reactions release energy, but an iron fusion reaction actually requires energy. This process reverses the radiation pressure which causes a irreversible pull towards the center of mass. At its most compressed state, all electrons in the star are compressed into contact with the nucleus against the strong force. The resulting rebound causes one of the most powerful explosions in the universe a supernova.

Since Betelgeuse is near the end of its life as a super giant it is due to supernova in the next several years. When this happens, the resulting explosion will be approximately 10,000 times brighter than our sun, though it will be very distant. The supernova will last for several months, up to even a year. The brightness will block out every star in the night sky and will even be brighter than the moon. It will even be visible in the daytime. The extreme distance will limit any detrimental effects here on Earth (whether it be radiation or charged particles), preventing any poorly done future Hollywood movies. It won’t end the world, but having two suns in the sky will sure look cool.

See Also: http://stars.astro.illinois.edu/sow/betelgeuse.html

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Just an incredible picture

s01_PIA11667_01.jpg

[nasa via gizmodo]

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The second law isn’t just slowly killing you in PChem, but slowly killing the universe…

Black-holeThe second law of thermodynamics states that the entropy of the universe is increasing. Black holes contribute to the entropy of the universe by breaking down matter into more disordered states. Previous studies on a black hole’s effect on the entropy of the galaxy have only been done on smaller black holes. Recently, Australian scientists have looked into the effects of supermassive black holes on entropy. They discovered that the previously predicted value for the effects of the supermassive black holes to be much less then what they really are. When entropy in the universe is maximized heat flow would no longer exist.

“in the case of the universe, Egan says, ‘we’d like to know [when and] if the entropy will eventuallyreach a maximum value, marking the end of all dissipative processes, including life.’ Physicists have dubbed that maximum entropy ‘heat death.’”

While the universe is closer to ‘heat death’ than previously estimated it still far from reaching its maximum entropy. Others note that if entropy is concentrated in these supermassive black holes, then the remainder of the universe should be at a lower entropy and further away from ‘heat death.’

[via usnews & world report]

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