Archive | February 2015

Cat’s Eye Nebula

Cats eyeIn 1786, high in the Northern Sky in the constellation Draco, William Herschel discovered a planetary nebula now known as the Cat’s Eye Nebula. It has become particulary well known today through the magnificent detailed images made by the Hubble Space Telescope. The nebula is quite young-around 1,000 years old-and, at about 3,300 light years from Earth, is only a small object in the night sky.

What makes the Cat’s Eye Nebula so fascinating is that it is surrounded by a series of faint concentric shells of gas, which may be material blown into space by the central star in an earlier phase of its life, at intervals of a few hundred to a couple of thousand years, but astronomers are still in the dark about the precise
causes. They do know, however, that the star sill has an enormously strong stellar wind, losing twenty billion tons of per second!

The central star is not a white dwarf, as with many other planetary nebulae, but a massive, hot Wolf-Rayet star, 10,000 times as luminous as the Sun and with a surface temperature of 80,000 Celsius. The Cat’s Eye Nebula proved to have more surprises in store. The American space telescope Chandra discovered that there is a source of
extremely high-energy X-rays at the center of the nebula. The radiation may be emitted by gas from the central star that is being captured by a companion and heated to high temperatures in the process. An invisible companion could also explain the complex structure of the nebula.

(Source: Deep Space by Govert Schilling

Does the 5 second rule work?

Does the 5 second rule work? Lets say your going to eat a banana and you drop it, I’m pretty sure most of us will pick it up and eat it. Some of us will use the 5 second rule others even the 10 second rule but does the 5 second rule work? In 2003 Jillian Clarke famously did a study on this subject and she found out that 50 percent of men use this rule to eat food off the ground and 70 percent of women use this the rule but more importantly she also found out that if any food has brief contact with the floor it gets contaminated wet or dry. A paper published by a Journal Applied microbiology got more in-depth, the researchers contaminated different floor surfaces with salmonella and they found out that 5 seconds contaminates it almost instantly but time can help. At 5 seconds they found out the food had collected wherever from 150 to 8000 bacteria but if it is left for a minute the number is 10 times greater. Knowing it only takes 10 bacteria of certain salmonella to effect you, you should reconsider eating food off the ground.
(source – http://news.aces.illinois.edu/news/if-you-drop-it-should-you-eat-it-scientists-weigh-5-second-rule )

(source- http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2006.03171.x/full )

Schrodinger’s Cat

Schrödingers-Cat-3Some of us may have heard of Schrodinger’s cat but do you know what it is, if you do great! And if you don’t I’ll explain it for you. In 1935, Austrian physicist Erwin Schrodinger published an article on this extraordinary paradox with consequences that are so striking that it continues to mystify and concern scientist to this day.

Schrodinger had been upset about the recently proposed Copenhagen interpretation of quantum mechanics that stated, in essence, that quantum system exist as a cloud of probability until an observation is made. At a higher level, it seemed to suggest that it is meaningless to ask precisely what atoms and particles were doing when unobserved; in some sense, reality is created by the observer but before being observed, the system takes on all possibilities. What could this mean for our everyday lives? Imagine that a live cat is placed in a box with a Radioactive source, a Geiger Counter, and sealed glass flask containing deadly poison. When a radioactive decay event occurs, the Geiger counter measures the event, triggering a mechanism that releases the hammer that shatters the flask and releases the hammer that shatters the flask and releases the poison that kills the cat. Imagine that quantum theory predicts predicts a 50 percent probability that one decay particle is emitted each hour. After an hour, there is an equal probability that the cat is alive or dead. According to some flavors of the Copenhagen interpretation, the cat seemed to be both alive and dead – a mixture of two states that is called a superposition of states. Some theorists suggested that if you open the box, the very act of observation “collapses the superposition” making the cat either alive or dead.

Schrodinger said that his experiment demonstrated the invalidity of the Copenhagen interpretation, and Albert Einstein agreed. Many questions spun from this thought experiment: What is considered to be a valid observer? The Geiger counter? A fly? Could the cat observe itself and so collapse its own state? What does the experiment really say about the nature of reality?

Some references were taken from ‘The Physics Book’ by Clifford Pickover