How do invisible x-rays help us see?

A member of clinical staff views an x-ray of a patient's hand on a computer screen in the Accident and Emergency department of the 'Royal Albert Edward Infirmary' in Wigan, north west England on April 2, 2015. AFP PHOTO / OLI SCARFF        (Photo credit should read OLI SCARFF/AFP/Getty Images)

Looking at an x-ray. (OLI SCARFF/AFP/Getty Images)

X-rays, part of the electromagnetic spectrum, help doctors see our bones — but they also help scientists understand the very smallest particles and the most massive black holes. We’ll follow the electrons, wind up at a synchrotron, get frozen in crystal and travel to the edges of the universe.

• Find out more about Chandra X-Ray Observatory at Harvard
• Check out the SLAC National Accelerator Laboratory

Hear “The Electromagnetic Spectrum Song” by The Dino Birds:

Scientists have made high-resolution X-ray laser images of an intact cellular structure much faster and more efficiently than ever possible before. The results are an important step toward atomic-scale imaging of intact biological particles, including viruses and bacteria. Here a 20-sided structure from a bacterial cell, called a carboxysome, is struck by an X-ray pulse (purple) at SLAC’s Linac Coherent Light Source. (Courtesy of Slac National Accelerator Laboratory)

Here a 20-sided structure from a bacterial cell, called a carboxysome, is struck by an X-ray pulse (purple) at SLAC’s Linac Coherent Light Source. (Courtesy of SLAC National Accelerator Laboratory)

The Coherent X-ray Imaging experimental station at SLAC's Linac Coherent Light Source is specialized for X-ray crystallography experiments. (Courtesy of SLAC National Accelerator Laboratory)

The Coherent X-ray Imaging experimental station at SLAC’s Linac Coherent Light Source is specialized for X-ray crystallography experiments. (Courtesy of SLAC National Accelerator Laboratory)

Jets in the early Universe give astronomers a way to probe the growth of black holes at a very early epoch in the cosmos. Using Chandra, astronomers recently discovered a jet in X-rays being illuminated by the cosmic microwave background. The light from this jet was emitted when the Universe was only one fifth of its present age. The main panel of this graphic shows Chandra's X-ray data combined with an optical image, while the inset focuses on the details of the X-ray emission. (X-ray: NASA/CXC/ISAS/A.Simionescu et al, Optical: DSS)

Jets in the early Universe give astronomers a way to probe the growth of black holes at a very early epoch in the cosmos. Using Chandra, astronomers recently discovered a jet in X-rays being illuminated by the cosmic microwave background. The light from this jet was emitted when the Universe was only one fifth of its present age. The main panel of this graphic shows Chandra’s X-ray data combined with an optical image, while the inset focuses on the details of the X-ray emission. (X-ray: NASA/CXC/ISAS/A.Simionescu et al, Optical: DSS)

Using Chandra observations, astronomers have discovered the nearest supermassive black hole to Earth that is currently undergoing powerful outbursts. This main panel shows the galaxy M51 in visible light from Hubble (red, green, and blue). The box at the top outlines the Chandra image in this study, which focuses on the smaller component of M51, NGC 5195. In the inset, a pair of arcs can be seen in the Chandra data (blue) and is evidence for outbursts from the supermassive black hole at the center of NGC 5195. Such outbursts are important in the evolution of the black hole and the galaxy it inhabits. (X-ray: NASA/CXC/Univ of Texas/E.Schlegel et al; Optical: NASA/STScI)

Using Chandra observations, astronomers have discovered the nearest supermassive black hole to Earth that is currently undergoing powerful outbursts. This main panel shows the galaxy M51 in visible light from Hubble (red, green, and blue). The box at the top outlines the Chandra image in this study, which focuses on the smaller component of M51, NGC 5195. In the inset, a pair of arcs can be seen in the Chandra data (blue) and is evidence for outbursts from the supermassive black hole at the center of NGC 5195. Such outbursts are important in the evolution of the black hole and the galaxy it inhabits. (X-ray: NASA/CXC/Univ of Texas/E.Schlegel et al; Optical: NASA/STScI)