A Geophysicist and a seismologist recently found new evidence that deep beneath the surface of our planet lies what could very well be the largest reservoir of water on Earth.  We'll talk with one of the researchers to learn more about their studies and the evidence for their finding. And… The solar energy market is growing rapidly so scientists are looking for more inexpensive and environmentally friendly ways of harnessing the sun's power. NASA's Mars rover Curiosity recently sent a selfie it had taken of itself back to Earth to celebrate its first Mars Year on the Red Planet.  A Martian year is equal to 687 Earth Days. Security experts say those who defend computer systems first need to be able to hack them to understand their weaknesses.  So, tech-savvy kids in San Diego are learning to hack computers. We've talked about the growing problem of the growing amount of space debris a number of times on our program. Now, the European Space Agency is planning to do its part to solve this potentially dangerous problem. A new study says that people, who are low in Vitamin D, appear to be at higher risk for developing high blood pressure/hypertension, which is a risk factor for heart disease and diabetes.   This past week, the UN’s World Meteorological Organization released its El Niño prediction and says that the world can expect hotter, dryer and wetter weather toward the end of the year. These stories and more are coming up for you on VOA's science, health and technology magazine, "Science World."