What are the threats to Earth from Space?

We know that the Big Bang of 13 billion years ago saw the birth of the sun and many other planets. It just took an instant for the birth of the universe and the universe has been growing or expanding at the speed of light ever since. There are 100 billion galaxies within the universe and our galaxy is just one of them with over 100 billion stars. The sun which is 90 million miles away from the earth is our own star. The activity on the sun, with its almost constant eruptions of super heated plasma and vast waves of radiation can at times be directed towards the earth. On 15th February 2013, people on their way to work in Chelyabinsk, Russia were to witness an event that happens every fifty to one hundred years. A meteorite, which looked like a fireball, brighter than any of the planets and brighter than the sun, was recorded on the cameras many have in their cars.