A star explodes in a blinding supernova, spraying X-rays across the galaxy to
tell its tale. X-rays also tells a dentist which tooth to drill, and a surgeon
which bones to mend.
In 1895 Wilhelm Roentgen discovered that firing streams of x-rays through arms
and hands created eerie, but detailed images of the bones inside.
X-rays are high energy light rays with wavelengths between 3 and 0.03
nanometers. So small that some x-rays are no bigger than many individual atoms.
In laboratories, scientists fire beams of x-rays at unknown substances to learn
what elements they contain and to decode their atomic structure. This scientists
unraveled complex molecules like penicillin and DNA.
Scientists can also detect the x-rays emitted from extremely hot and energetic
objects in the Universe. NASA's robotic rovers recorded x-rays to identify the
spectral signatures of elements, such as zinc and nickel, in Martian rocks.
X-rays can also reveal an object's temperature since temperature determines the
wavelength of its radiation. The hotter the object, the shorter that wavelength
is. X-rays come from objects that seethe at millions of degrees — such as
pulsars, black holes, supernovas, or the plasma in our Sun's corona. Our Sun has
a surface temperature of around 6,000 degrees Celsius and radiates most of its
energy in visible wavelengths. But it is easier to study the massive energy
flows in the corona's energetic plasma by observing x-rays like this image from
the Hinode satellite, a joint Japanese — NASA mission.
NASA's SOHO satellite produced these x-rays images of the Sun that allow
scientists to see and record these energy flows within the corona. NASA's
orbiting Chandra x-ray observatory detects x-rays created by objects spread far
across space such as this supernova explosion that occurred 10,000 light years
from earth. The colors in the gas and dust cloud correspond to different energy
levels of the x-rays created by the blast. X-rays at different wavelengths
provide information about an object's composition, temperature, density, or its
Human eyes may not be able to see x-rays but, from seething cosmic bodies to
individual atomic elements, x-rays provide a wealth of information to exploring