Earth Ate A Planet And The Milky Way Secretly Worked Out

Did Earth's Twin Cores Spark Plate Tectonics?

"It's a classic image from every youngster's science textbook: a cutaway image of Earth's interior. The brown crust is paper-thin; the warm mantle orange, the seething liquid of the outer core yellow, and at the center the core, a ball of solid, red-hot iron.
Now a new theory aims to rewrite it all by proposing the seemingly impossible: Earth has not one but two inner cores.
The idea stems from an ancient, cataclysmic collision that scientists believe occurred when a Mars-sized object hit Earth about 4.45 billion years ago. The young Earth was still so hot that it was mostly molten, and debris flung from the impact is thought to have formed the moon.
Haluk Cetin and Fugen Ozkirim of Murray State University think the core of the Mars-sized object may have been left behind inside Earth, and that it sank down near the original inner core. There the two may still remain, either separate or as conjoined twins, locked in a tight orbit. "

Milky Way 'bigger than thought'

"Our galaxy is much bigger than once thought, according to research presented at a major astronomy meeting this week.
The results suggest the Milky Way is roughly the same size as Andromeda, the largest galaxy in our local group.
What is more, it is moving 15% faster than earlier predictions."