* The Sun came first. The Sun formed from a massive cloud of gas and dust about 4.6 billion years ago. It was the first major object to form in our solar system.
* Earth formed next. Earth formed around the Sun about 4.5 billion years ago, from the same cloud of gas and dust that formed the Sun.
* The Moon came last. The prevailing theory is that the Moon formed after Earth collided with a Mars-sized object about 4.5 billion years ago. The debris from this collision coalesced to form our Moon.
So, while the Sun is the oldest, the Earth actually formed before the Moon.
