MY MONEY IS ON THE EXPERT ON BLACK HOLES STEVEN HAWKINGS

To say that the idea of black holes is complicated is an understatment. Even the great Steven Hawking changed his mind on the subject. Here are some nice pictures on what a Black Hole might look like- (Sandi has the best Picture on here blog, check it out.)




In an artical in news @ nature. com back in 2004, The eminent physicist Stephen Hawking has conceded that information can escape from black holes after all. The idea has been gaining popularity with physicists for some time, but the fact that Hawking, a pioneer of black-hole theory in the 1970s, has finally accepted it is something of a watershed.

Hawking had believed that anything swallowed by a black hole was forever hidden from the outside universe. A freind of Hawking- John Preskill bet that the information carried by an object was not destroyed when it plummeted into a collapsed star, and could actually be recovered.

Hawking's original view follows Einstein's general theory of relativity, which predicts that, at certain locations in space, matter collapses into an infinitely small and dense point, called a singularity. The theory says that the force of gravity at this point is so great that nothing, not even light itself, can escape, hence the term 'black hole'.



Because the singularity is infinitely small, it cannot possibly have any structure and so there is no way that it can hold information. Any data about particles entering the black hole must be lost forever.

The problem is that quantum theory, which describes space and matter on very tiny scales, contradicts this. Quantum theory says any process can be run in reverse, so starting conditions can theoretically be inferred from the end products alone. This implies that a black hole must somehow store information about the items that fell into it.

So an object falling into a black hole is not completely obliterated. Instead, the black hole is altered as it absorbs the object. Although it would certainly be very difficult to retrieve any information about that object, the data are still there, somewhere inside the black hole.
How could that information ever escape? The answer lies in one of Hawking's greatest discoveries: that black holes slowly evaporate into space by losing particles from the very edge of the gravitational precipice at their rim, called Hawking radiation. The black hole eventually shrinks to a tiny kernel, at which point a growing torrent of radiation begins to leak out, potentially carrying the lost information with it.

SUNDIAL ACTIVITIES

HERE ARE SOME GREAT SITES FOR SOME FUN ACTIVIES ON SUNDIALS - http://www.fi.edu/time/Journey/Sundials/interactsd.htm http://www.bbc.co.uk/norfolk/kids/summer_activities/make_sundial.shtml
THESE SITES HAVE CROSSWORD PUZZLES & GAMES THAT KIDS MIGHT ENJOY.

I found some interesting information on sundials that helps me have a better appreciation for this instrument - here are some nice pictures & some details on how a sundail works.



This is a Sundial for Mars - very cool!!!


As the earth turns on its axis, the sun appears to move across the sky. The shadows the sun casts move in a clockwise direction for objects in the northern hemisphere. If the sun rose and set at the same time and spot on the horizon each day shadow sticks would have been accurate clocks. However, the earth is always spinning like a top. It spins around an imaginary line called its axis. The axis runs through the center of the earth from the North Pole to the South Pole. The earth's axis is always tilted at the same angle.
Every 24 hours the earth makes one complete turn, or rotation. The earth rotates on its axis from west to east. The earth's rotation causes day and night. As the earth rotates, the night side will move into the sunlight, and the day side will move into the dark.
On the earth's yearly trip around the sun the North Pole is tilted toward the sun for six months and away from the sun for six months. This means the shadows cast by the sun change from day to day.
Because the earth is round, or curved, the ground at the base of a shadow stick will not be at the same angle to the sun's rays as at the equator. Because of this the shadow of the shadow stick will not move at a uniform rate during the day.
Eventually man discovered that angling the gnomon and aiming it north made a more accurate sundial. Because its angle makes up for the tilt of the Earth, the hour marks remained the same all year long. This type of gnomon is called a style. After this discovery, people were able to construct sundials that were much better at keeping accurate time.

BUMBLE BALL MANIA!

One of the more interesting experiments we did in class is when we used a bumble ball to model the random walk of photons in the Sun. I can see how the bumble ball experiment can give my students a hands look at how electrons scatter. Also, In the experiment we wanted to know how the photons get from the Sun's core and "escape" as light.

Once we got some good data went into the lab and did the computer simulation. The simulation was excellent because I see how the data came to life. An interesting note in class was the fact that a Sun’s photon only travels one centimeter before it gets remittedd in a process called "random walk".
After this experiment I was interested in knowing more about the photosphere - I found some great photos that I think may give my students a better understand of this concept.

The photosphere is lowest layer of the atmosphere. This zone emits the light that we see. The photosphere is about 300 miles (500 kilometers) thick. But most of the light that we see comes from its lowest part, which is only about 100 miles (150 kilometers) thick. Astronomers often refer to this part as the sun's surface. At the bottom of the photosphere, the temperature is 6400 K, while it is 4400 K at the top.

The photosphere consists of numerous granules, which are the tops of granulation cells. A typical granule exists for 15 to 20 minutes. The average density of the photosphere is less than one-millionth of a gram per cubic centimeter. This may seem to be an extremely low density, but there are tens of trillions to hundreds of trillions of individual particles in each cubic centimeter.




A Moreton wave, a type of surface wave caused by a sudden release of energy by the sun, spreads across the solar surface in a series of four images. This wave front traveled at about 186 miles (300 kilometers) per second.


The surface of the sun is marked by many small patches of gas called granules, which are believed to be produced by the violent churning of gases in the sun's interior.


A rapidly expanding solar quake, which resembles an Earthquake, is shown in a series of images of the sun's surface. This quake spread out across the surface more than 62,150 miles (100,000 kilometers).