x-ray

The first picture an expecting mother is likely to see of her developing fetus is not, technically, a picture at all. Most likely, it's an ultrasound image, produced by technology that has more to do with hearing than with seeing.

In 1967 a team of astronomers in Great Britain thought they had found extraterrestrial intelligence. They discovered radio sources in deep space that produced pulses of energy at very precise intervals ranging from milliseconds to seconds.

King Tutankhamen of Egypt has fascinated people ever since archeologist Howard Carter discovered his splendid tomb in 1922. He ruled ancient Egypt as Pharaoh around 1330 BC, and died when he was only eighteen years old.

A planet has to have a magnetic field to make aurora lights. The sun is always sending out particles called the solar wind. That wind frequently increases in intensity to become a solar storm when large numbers of particles are released.