It is a nightmare that has stalked us for centuries: hordes of human beings transformed into mindless, cannibalistic monsters. Could this civilization-ending nightmare become reality? Scientists have discovered pathogens that turn insects into the walking dead. New strains of viruses are attacking humans every day. Mathematicians have calculated the likelihood of surviving a zombie virus outbreak: they’re not hopeful. Now neuroscientists are discovering how easy it is for us to lose conscious control of our bodies. Are we at risk of becoming puppets? If we were in the middle of a zombie apocalypse, would we even know it?

Humanity is under threat - from storms that seem to get ever fiercer, earthquakes that seem ever more deadly, and killer viruses that are engulfing the globe. Some scientists think it's time for us to fight back. Can we - should we -hack the planet?

Every 17 minutes in America, someone is killed with a gun. Politicians can't seem to stop the violence. But epidemiologists, psychologists and big data crunchers are discovering that gun crime spreads like a virus -and science may be able to stop its spread.

With a little imagination, could a few terrorists sabotage a mighty nation? Perhaps even tear down modern civilization? The stability of the US, Europe, China, or any global power depends on high-speed digital communication. Our increasing dependence on digital devices and global interactivity may be placing us in grave danger. Scientists around the world are dealing with new threats such as body hacking, Trojan horse viruses, and brain-damaging Internet addiction. But what if the ultimate threat isn’t an attack on technology, but the technology? Could the final superpower be the disembodied mind of the Internet itself?

Dr Chris van Tulleken, Dr Hannah Fry and Michael Mosley examine the latest research and explore some of the big questions about Covid-19 and the pandemic it has created. Michael visits the UK government's high-security laboratory Porton Down, where vaccines are being tested. He also uncovers what the experience of the 2002 SARs epidemic reveals about this one. Both were caused by coronaviruses, but certain key changes to today's virus have allowed it to infect the world, where SARs was contained.

Right now cosmic forces prowl the universe and threaten man's very existence. They're asteroids and comets; they've left their imprint on planet Earth, literally. Initially helping to build planets through violent collisions, during this fiery bombardment period they may have even seeded Earth with water and the building blocks for life. Since the turbulent formation of the solar system, these space rocks have continued to impact Earth. Some have been so violent that they've led to mass extinctions, including one that wiped out the dinosaur. New theories suggest that asteroid and comet dust harbour deadly viruses that may have triggered some of our worst pandemics. The possibility of future collisions remains a legitimate threat yet despite their dangers, asteroids and comets may hold vital natural resources, which could actually preserve