"A young astronaut is trying to find life on Mars, but he's made a very big oversight"--

"Does life exist on Mars? The question has captivated humans for centuries, but today it has taken on new urgency. NASA plans to send astronauts to Mars orbit by the 2030s. SpaceX wants to go by 2024, while Mars One wants to land a permanent settlement there in 2032. As we gear up for missions like these, we have a responsibility to think deeply about what kinds of life may already inhabit the planet-and whether we have the right to invite ourselves in. David Weintraub tells why, of all the celestial bodies in our solar system, Mars has beckoned to us the most. He traces how our ideas about life on Mars have been refined by landers and rovers, terrestrial and Mars-orbiting telescopes, spectroscopy, and even a Martian meteorite. He explores how finding DNA-based life on the Red Planet could offer clues about our distant evolutionary past, and grapples with the profound moral and ethical questions confronting us as we prepare to introduce an unpredictable new life form -- ourselves -- into the Martian biosphere."--

The six-member crew of the International Space Station is on the cutting edge of one of the most important discoveries in human history: the first evidence of extraterrestrial life on Mars. As the crew begins to conduct research, their methods end up having unintended consequences and the life form proves more intelligent than anyone ever expected.

Follow the re-election of President Bartlet to his second term and some crises both during and after the election in this 22-episode fourth season.

Who built the first houses? What's the difference between an arch and an architrave? How does a dome stay up? Who invented concrete? Can you build a house from paper? If you want to know more about the buildings around you, this entertaining illustrated guide is a perfect introduction to architecture around the world. From the mud huts of ancient history to today's towering edifices, you can explore iconic buildings and find out more about the people who created them. You'll also discover the development of different building materials, from mud and straw to paper, steel and reinforced concrete.