Even though Mars is considered too dry and cold for water to exist on its surface, scientists recently found large amounts of water trapped under the southern polar icecaps. But wait—if the water is so deep underground, how did scientists even find it? Low-frequency radio pulses, of course! While not exactly an everyday activity for us, it is one of the methods used to explore deep beneath a planet’s surface. The Mars Express spacecraft, part of a space exploration mission being conducted by the European Space Agency, has been orbiting Mars for fifteen years. Using its Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS, for short) instrument, low-frequency radio pulses are transmitted to the planet’s surface. These pulses penetrate the surface and transmit data whenever there is a change in density.
What does this discovery mean? For one, it can help us understand if and how life on Mars exists. You see, life on Mars is not evident to the human eye; it could live in the form of bacteria or microorganisms too! One way to think of this is, there are resources on other planets that people on Earth could actually use to explore other planets!