Review: Light from the Void

Light from the Void: Twenty Years of Discovery with NASA’s Chandra X-ray Observatory
by Kimberly K. Arcand, Grant Tremblay, Megan Watzke, Martin C. Weisskopf, and Belinda J. Wilkes
Smithsonian Books, 2019
hardcover, 204 pp., illus.
ISBN 978-1-58834-669-8

The celebrations in July for the 50th anniversary of Apollo 11 overshadowed another major space anniversary. July 23 marked the 20th anniversary of the launch of the shuttle Columbia on mission STS-93, commanded by Eileen Collins, the first female commander of a shuttle mission. (The launch had been scheduled for July 20th, the anniversary of the Apollo 11 landing, but scrubbed by a technical issue.) For astronomers, though, the mission is historic because is placed into orbit the Chandra X-Ray Observatory, a giant x-ray telescope that was one of NASA’s original “Great Observatories” alongside Hubble and others.

Two decades later, Chandra is still in operation, continuing to provide insights from within our own solar system to distant galaxy clusters. Chandra is overshadowed by its more famous fellow space telescope, Hubble, particularly among the general public (most people have heard of Hubble, but far fewer know about Chandra) in part because x-ray imagery often isn’t as picturesque as the visible and near-infrared imagery that Hubble churns out.

That’s rectified in Light from the Void, a new book by several astronomers involved with Chandra. This large-format book includes dozens of color images created with Chandra, often combined with visible and other images. The result is a set of images that are both beautiful and insightful.

After some brief introductory information about the development and launch of Chandra, including a recollection by Collins about the launch of the telescope, the book dives into the images, and the science they reveal. Chapters examine the use of Chandra to study the birth of new stars, and the death of old stars, with later chapters explore our galaxy and others as seen by the telescope, or simply show off what it can do. Each page is dominated by color images, with single-paragraph captions discussing the object and its scientific significance.

Most of the images are not from Chandra alone: the x-ray observations are combined with visible, infrared, and sometimes even radio observations for a more complete view of objects like a cluster of newborn stars or a distant galactic center. The images are created by assigning different colors to different classes of observations, although those colors are not consistent from one image to the next: x-rays might be blue in one image, red in the next, and purple in yet another. In some images, the authors include insets showing how the same object appears in x-ray, visible, and other wavelengths; more of those would be helpful to illustrate how x-rays can resolve newborn stars cloaked in nebulae or streams of gas from active galactic nuclei.

Twenty years after its launch, Chandra is still working well, and the authors, who include the key scientists involved with the mission, write they hope the spacecraft will operate for at least another decade. One of the flagship missions under consideration in the ongoing 2020 decadal survey of astrophysics is a next-generation x-ray telescope, called Lynx, although even if selected it’s unlikely to be launched before the mid-2030s. Astronomers will hope that Chandra remains healthy for many more years to come, using it to see the otherwise unseen in our universe as illustrated in this book.

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