Your article neglects the most difficult problem associated with sending a probe to the vicinity of Earth’s core: sending the information back. Even a few feet of earth will stop conventional radio waves. Extra-low-frequency transmissions would do the job, but a transmission could take years.
Augusto Soux
San Diego, Calif.
David J. Stevenson of the California Institute of Technology in Pasadena envisions a probe that sends data via encoded vibrations at low frequencies. Sensitive detectors at Earth’s surface can pick up small seismic waves that would be produced by a 10-watt vibrating source, he notes. Over the course of a mission, the probe would send out about 100 million vibrations–enough to encode sufficient information about the deep-Earth environment
Science News headlines, in your inbox
Headlines and summaries of the latest Science News articles, delivered to your email inbox every Thursday.
.–S. Perkins
The liquid iron channels already exist–in the form of active volcanoes.
Allan Morrison
Manitoba, Canada
There is a far more interesting way to get to the core than setting off hydrogen bombs and filling the crack immediately afterwards. A better method would be to drop a 100,000-ton hardened-iron mass shaped like a spear from a great height, like an orbit. This would go through the crust pronto. To get the spear in orbit, you simply go to the moon with a few robots and mine the needed iron. With a little acceleration, the iron is in orbit, and presto, you’re ready for action. Cheers.
Thor Olson
Redmond, Wash.
