March 6, 2010

Ideas in astronomy have changed a lot since the mid-80s as have music and everything else. In the old days it was thought that the dinosaurs were wiped out due to gradual changes in conditions on earth. I accepted that. It was also believed that the earth and moon formed at the same time as a kind of double planet. Now it is accepted that an asteroid collided with earth 65 million years ago wiping out not only the dinosaurs but 90% of all species. This house-cleaning allowed for the rise of mammals and ultimately homo sapiens. Us! It is also nearly accepted that a Mars-like object hit the earth in the early period of the solar system to cause the moon. The heavy part of the object sunk into the earth as the earth literally reformed itself. The lighter stuff drifted out to become the moon. That explains why the moon does not have a metallic core. I am not an astronomer. But it has been a hobby with me since I was 15. I read and write about it and attend star parties when I can. The universe is vast beyond anyone's ability to comprehend it. It is said to have originated 13.7 billion years ago with a surge of energy called the "Big Bang." If you believe in God, you can say God called this surge. Space and time are connected. As we probe the depths of space, we are looking back in time. The universe can be very violent even though there are great distances between galaxies and groups of galaxies. More and more phenomena are being explained in terms of collisions.