Humans could be Martians says Brian Cox

Could life pre-date Earth? A famous scientist thinks that life may have begun on Mars and come to Earth on a space rock. Is there any truth in his idea? What's happening? For thousands of years, humans have guessed about where we came from.  Now, some scientists say life might have come from space. Find out more Brian Cox is a physicist. He thinks about how the universe works. He says life on Earth might have started on MarsThe fourth planet from the Sun and the second-smallest planet in the Solar System. . Billions of years ago, Earth was not a very good place to live. It was mostly covered in water. It was cold. Meanwhile, Mars was warmer. It had a mix of land and water. Then, something happened. Mars became dry and cold. Brian Cox and other scientists think life began on Mars but moved to Earth. Small living things called microbes left Mars on a space rock called an asteroidA small body in space, made of metal and rock material. Asteroids usually orbit the sun, but if knocked off course they can be drawn into Earth’s gravity and fall towards it. .  When they landed, they found a perfect planet to live on.  Could life pre-date Earth? Some say Yes! It is unlikely that life existed on both planets without being connected. To prove the theory, we now need to find proof that there was once life on Mars. Others think No. We do not even know if the cells could survive on an asteroid. This is a crazy suggestion. It is more likely that life grew on Earth. KeywordsMars - The fourth planet from the Sun and the second-smallest planet in the Solar System.