Black Holes

Well, today I thought I'd talk about something else that is kind of mysterious... anything surrounded by a shroud of mystery is always exciting! Today's topic is Black Holes! There are so many black holes in our universe that it is impossible to count them all! Fortunately, there aren't any that are too close to the earth. Check out this snazzy video and website for a cool visual explanation as to what a black hole actually is and how it works: http://hubblesite.org/explore_astronomy/black_holes/

Basically... in a black hole, gravity is the strongest force, objects are pulled in by this gravity. Once something has entered a black hole, there is no chance of escaping... not even light itself can escape!
There are 2 types of black holes:

1. Stellar-mass: Form from the supernova explosions at the end of the life of a giant star. It is predicted that a new black hole is being born from a supernova every SECOND!
2. Supermassive: These are found in the centre of galaxies... and remember how huge our sun is? (110 earths across!) Well, these black holes are between a million and a billion times bigger! The closest one to us is in the centre of the Milky Way galaxy, 28,000 lightyears away.

Here are some neat facts about black holes:

• Black holes actually can be destroyed! (This was proved by Stephen Hawking in 1974 using quantum mechanics) What actually does happen is that they slowly evaporate, returning their energy to the universe. All of the black holes that have been discovered in our universe, however, are very small, and the time it would take to destroy them would be incomprehensible.
• Black holes can collide! What takes place when this happens is a merging of the two black holes into one big one. This would be an EXTREMELY violent event, and scientists do not even understand everything about it/ what the consequences would be. It would send a ripple through the space-time fabric of the universe... thats a crazy thought eh? the possibility of warping time! No one has actually witnessed this yet.

One of the main mysteries surrounding black holes is what is inside one? No one knows for sure, and it is impossible for us to find out, since nothing can escape, nor transmit information back to earth. Speculations range from a pile of objects and matter at the centre of gravity to a bridge to another universe! Einstein actually had a "wormhole" theory about this, but the solution to his equations had no event horizon...