Chapter 1 A SECOND HOME IN SPACE Earth is our home planet It formed from the dust in the solar nebula around 4 5 billion years ago Although life on Earth began as microbes very quickly after the birth of our planet human beings did not appear until three million years ago Like all other organisms on Earth humans have evolved to suit Earth’s environment Our eyes are adapted to see in full sunlight Our lungs work perfectly with Earth’s atmosphere at sea level and our skeletons are designed to cope with Earth’s gravity Our Dangerous World Although Earth is the only place we know of that has life it is also a dangerous place Just think of the extinction of the dinosaurs 65 million years ago We know an asteroid around 6 2 miles 10 km wide hit Earth at this time and massive volcanic eruptions also affected Earth’s climate The asteroid punched a hole in Earth’s surface 112 miles 180 km wide but this crater was discovered only in the 1990s It was not just the dinosaurs that suffered around three-quarters of all plant and animal species became extinct 4
Going back even further around 252 million years ago another mass extinction took place It is known as The Great Dying Nobody is sure whether volcanic activity an asteroid or something else caused it but an incredible 96 of all species on Earth were wiped out A Home on Mars Earth is still not safe today Volcanoes and asteroids threaten us We also face new disasters that are more likely to be caused by humans than nature Climate change overpopulation pollution and nuclear disasters are just some of the problems humans have created Earth is our home but it is under threat One day people may need a new place to live If we are to make sure that the human race survives we need a second home in space That home may be on Mars The explosion that made the world’s dinosaurs extinct was more than a billion times greater than the atomic bombs dropped on Hiroshima and Nagasaki during World War II 5
THE HISTORY OF MARS Ancient civilizations were fascinated by special stars that moved slowly across the sky over days weeks and months The ancient Greeks named them planetes meaning wanderer The five planets that you can see with the naked eye without a telescope were named for their gods The Greeks named them Hermes Aphrodite Ares Zeus and Cronus However we are more familiar with their Roman names Mercury Venus Mars Jupiter and Saturn Looking for Life Although Mars is not the brightest of the planets in the night sky it stands out because of its color On a clear night Mars appears as a bright star but its orangey-red color led the ancient Greeks and Romans to name it after their god of war because it was the color of blood It is also called the red planet due to its color Italian astronomer Galileo Galilei 1564 1642 was the first person to look at Mars through a telescope although the telescope’s low power meant that he could not see any detail As telescopes became bigger and more powerful bright and dark patches on Mars’s surface were seen including bright white polar caps It was then that astronomers noticed that Mars was similar to Earth in many ways The telescope was invented in 1608 but Galileo first used it for astronomy in 1609 He studied the moon and discovered Jupiter’s moons 6
Mars canyon In the late 1800s another Italian astronomer Giovanni Schiaparelli 1835 1910 claimed to see long dark lines on Mars through his telescope People started to believe these lines were canals dug by aliens living on Mars They believed the aliens used the canals to bring water from the polar caps We now know that the lines were an optical illusion Learning More About Mars It was not until the Space Age that people were able to see Mars close up from space probes and landers While much of the planet is covered with craters other parts contain some of the greatest wonders of the solar system The first probe to orbit Mars was Mariner 9 It journeyed to Mars in 1971 and discovered giant volcanoes such as Olympus Mons that are much bigger than any on Earth Olympus Mons rises to a height of nearly 13 6 miles 22 km which is around 2 5 times the height of Mount Everest Mariner 9 also discovered a canyon more than 2,500 miles 4,023 km long and up to 23,000 feet 7,000 m deep 7
