Monday 26 November 2012

Black Hole


Black Hole

A black hole is a region of spacetime where gravity prevents anything, including light, from escaping. The theory of general relativitypredicts that a sufficiently compact mass will deform spacetime to form a black hole.


Sunday 25 November 2012

Aurora

An aurora is a natural light display in the sky particularly in the high latitude (Arctic and Antarctic) regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere.


Tuesday 20 November 2012

Eclipses


One consequence of the Moon's orbit about the Earth is that the Moon can shadow the Sun's light as viewed from the Earth, or the Moon can pass through the shadow cast by the Earth. The former is called a solar eclipse and the later is called a lunar eclipse. The small tilt of the Moon's orbit with respect to the plane of the ecliptic and the small eccentricity of the lunar orbit make such eclipses much less common than they would be otherwise, but partial or total eclipses are actually rather frequent.



 

Tuesday 13 November 2012

Force To Do!

A stationary object begins to move when it is pushed. Pushing is a force that acts on the ball and makes it move. Force can be applied from the opposite direction to stop a moving ball. Force can also make a moving object go faster, slower or change direction.


The trolley is going down too fast. Applying force from the opposite direction will slow down a moving object. Pushing the trolley in the same direction will make it move faster. Applying a force to the side of the trolley changes its direction.