Author and nuclear physicist Professor Jim Al-Khalili looks at what led to the discovery that everything is made of atoms. The programme looks at how the discovery affected the scientific world including the atomic energy theories of Albert Einstein and Werner Heisenberg and quantum mechanics

Global CO2 emissions coming from aviation will go from about 2% to, by 2050, something closer to 20%. Technology is the only key to open up a brighter future that can be sustainable at the same time. The way we fly is about to change, driven by a new breed of aviators not afraid to think differently. From clean, green electric aircraft to autonomous sky taxis, could the days of the jet age be numbered?

Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved. Today, they think there must be five times as much dark matter as regular matter out there. But they have no idea what it is - onl that it's not made of atoms, or any other matter we are familiar with. And Dark Matter is not the only strange substance in the Universe - a newly discovered force, called Dark Energy, seems to be pushing the very fabric of the cosmos apart.

On July 4, 2012, scientists at the giant atom smashing facility at CERN announced the discovery of a subatomic particle that seems like a tantalizingly close match to the elusive Higgs Boson, thought to be responsible for giving all the stuff in the universe its mass. Since it was first proposed nearly fifty years ago, the Higgs has been the holy grail of particle physicists: finding it completes the 'standard model" that underlies all of modern particle physics. Now CERN's scientists are preparing for the Large Hadron Collider's second act, when they restart the history-making collider, running at higher energy--hoping to find the next great discovery that will change what we know about the particles and forces that make up our universe.

Scientists investigate the way the Sun builds its power -- through fusion -- hoping to find a way to use fusion as a less dangerous and less radioactive waste-producing path to energy than fission. But there are some major difficulties along the way. Fusion really is the perfect way to make energy. We have millions of years worth of fuel. It produces no long-lived radioactive waste. If we can solve the engineering challenges, energy will become cheaper, more available for everybody.

Are rising temperatures driving Earth's ecosystems past a point of no return? We have promising technologies that put solutions within our grasp. Scientists are exploring solutions: from geoengineering to sucking carbon out of the air to cloud brightening, as means to cool the planet. Cutting-edge solutions and high-risk measures. But would they work? And what are the risks of engineering Earth's climate?