Black Holes

Black holes are the cold remnants of former stars, so dense that no matter—not even light—is able to escape their powerful gravitational pull.
While most stars end up as white dwarfs or neutron stars, black holes are the last evolutionary stage in the lifetimes of enormous stars that had been at least 10 or 15 times as massive as our own sun.
When giant stars reach the final stages of their lives they often detonate in cataclysms known as supernovae. Such an explosion scatters most of a star into the void of space but leaves behind a large "cold" remnant on which fusion no longer takes place.
In younger stars, nuclear fusion creates energy and a constant outward pressure that exists in balance with the inward pull of gravity caused by the star's own mass. But in the dead remnants of a massive supernova, no force opposes gravity—so the star begins to collapse in upon itself.
With no force to check gravity, a budding black hole shrinks to zero volume—at which point it is infinitely dense. Even the light from such a star is unaBlack holes are small in size. A million-solar-mass hole, like that believed to be at the center of some galaxies, would have a radius of just about two million miles (three million kilometers)—only about four times the size of the sun. A black hole with a mass equal to that of the sun would have a two-mile (three-kilometer) radius.
Because they are so small, distant, and dark, black holes cannot be directly observed. Yet scientists have confirmed their long-held suspicions that they exist. This is typically done by measuring mass in a region of the sky and looking for areas of large, dark mass.
Many black holes exist in binary star systems. These holes may continually pull mass from their neighboring star, growing the black hole and shrinking the other star, until the black hole is large and the companion star has completely vanished.
Extremely large black holes may exist at the center of some galaxies—including our own Milky Way. These massive features may have the mass of 10 to 100 billion suns. They are similar to smaller black holes but grow to enormous size because there is so much matter in the center of the galaxy for them to add. Black holes can accrue limitless amounts of matter; they simply become even denser as their mass increases.
Black holes capture the public's imagination and feature prominently in extremely theoretical concepts like wormholes. These "tunnels" could allow rapid travel through space and time—but there is no evidence that ble to escape its immense gravitational pull. The star's own light becomes trapped in orbit, and the dark star becomes known as a black hole.
Black holes pull matter and even energy into themselves—but no more so than other stars or cosmic objects of similar mass. That means that a black hole with the mass of our own sun would not "suck" objects into it any more than our own sun does with its own gravitational pull.
Planets, light, and other matter must pass close to a black hole in order to be pulled into its grasp. When they reach a point of no return they are said to have entered the event horizon—the point from which any escape is impossible because it requires moving faster than the speed of light

The asteriod which completely wiped out the dinosaur

The cataclysmic extinction of that time was not caused by massive volcanic activity, as another theory has suggested, according to the new analysis, published today in the journal Science.
A panel of 41 experts from Europe, the U.S., Mexico, Canada and Japan analyzed new data from ocean drilling and continental sites and reviewed the research of palaeontologists, geochemists, climate modelers, geophysicists and sedimentologists who have been collecting evidence over the last 20 years to determine the cause of the Cretaceous-Tertiary (KT) extinction, which happened around 65 mi"They find that alternative hypotheses are inadequate to explain the abrupt mass extinction and that the impact hypothesis has grown stronger than ever," the University of Texas at Austin said in a news statement.
"Today's review of the evidence shows that the extinction was caused by a massive asteroid slamming into Earth at Chicxulub in MexicSome scientists have suggested that the Chicxulub impact happened 300,000 years before the KT boundary, and therefore came too early to have been the major cause of extinctions, the University of Texas said.
The KT boundary, also known as the Cretaceous-Paleogene (K-Pg) boundary, is how geologists refer to the time of the great extinction. Life on Earth after the event that caused the extinction was dramatically different to what was on the planet before.o," said Imperial College London, in a separate statement.
Scientists from both institutions participated in the study.
The KT extinction wiped out more than half of all species on the planet, including thThe asteroid, which was around 15 kilometers [9 miles] wide, is believed to have hit Earth with a force one billion times more powerful than the atomic bomb at Hiroshima. It would have blasted material at high velocity into the atmosphere, triggering a chain of events that caused a global winter, wiping out much of life on Earth in a matter of days," Imperial College said.e dinosaurs, birdlike pterosaurs and large marine reptiles, clearing the way for mammals to become the dominant species on Earth, Imperial College added in its releasellion years ago.

10/3-10 (Wednesday)

Mrs. Ibrahim will be not here on that day because of that she have to take a course. So, a relieve teacher will take over.

Items to bring:-

-Necessaries

-H.E. Book ( Health Education)

-Social Studies WB&TB

Regards,

Alan

Subject Reps:

Try to find articles and stuff to decorate and fill up our "Noticeboard Of Knowledge".

5I pupils can also contribute, the notice-board i/c will put them up.

I will contribute three articles tomorrow.

Sony Creative (Duties)

Hello,

5I pupils, please take note that you have to create a sketch and a toy during your March Holidays.

(Miss Tan's words)

A toy is COMPULSORY for all students. If possible, try to make more of them.

If lucky, toys will be elected to participate in Sony Creative Awards Competition.

Your Classmate,

Alan :D

Science Toys' links

Hi kids!

You can check out the links below for ideas on making your toys!

All the best!

Rgds,
Mrs Ibrahim

External Links
Dr Toy
http://www.drtoy.com
Information on the best toys and educational products as well as articles, resources and toy-related links.
Mathematical Games, Toys and Puzzles
http://compgeom.cs.uiuc.edu/~jeffe/mathgames.html
Web directory of mathematical games, toys and puzzles.
Science Toys
http://www.scitoys.com
Instructions in making toys for kids with common household materials to demonstrate scientific principles.
Sony ExploraScience
http://www.sonyexplorascience.jp/english/
A place to meet science and to venture into the unknown.
Wild Planet Toys
http://www.wildplanet.com
Where all the things wild and wonderful, award winning toys that parents and kids both love.
A*Star
http://www.a-star.edu.sg/astar/index.jsp
Ministry of Education
http://www.moe.edu.sg
Sony
http://www.sony.com.sg

Exam fever

Hi Kids!!
The exams are almost over.. 2 papers down, 2 more to go.. Hope you guys are coping fine with the workload. Just hang in there, 2 more days to go!! Persevere!!

Regards,
Mrs Ibrahim