大象传媒

On Science in Action this week Nasa scientists have observed that the Earth鈥檚 Energy Imbalance has doubled in just 15 years. As greenhouse gas atmospheric concentrations have risen, so too has the difference between the total amount of energy being absorbed from the sun, and the total amount being re-radiated back into space. Meanwhile, as we all heat up, scientists at the LIGO Gravitational Wave Observatory have managed to do something very cool with their mirrors. Such is the precision with which the detectors have been engineered, they have managed to effectively reduce the temperature of one of the big 10kg reflectors to such an extent that it betrays its quantum state as if it were simply one big subatomic particle. So what? Roland Pease finds out.

Also, Scales don鈥檛 come planet-sized, so answering a question from David in Ghana may require some ingenuity, after all, calculating the weight of the Earth is a huge task.

Using a set of weighing scales and a 400 year-old equation, Marnie Chesterton attempts to find out just how much the Earth weighs and is it getting heavier or lighter over time?

But how would a planet gain or lose mass? Which tips the scales: meteorites falling from space or gases constantly escaping from our atmosphere?
And does the answer have any implications for the future of Earth? Could the atmosphere eventually run out?

(Image: Getty Images)