NASA releases free e-book on Hubble space mysteries

Since 1990, the Hubble Space Telescope has offered scientists an incredible view of the universe. It has provided well over 1 million observations.

Now, NASA has released “Hubble Focus: The Dark Universe,” a free e-book that explores what the Hubble mission has taught scientists about dark matter and dark energy — and how those lessons are shaking up long-standing theories.

We can’t see it, but dark matter is thought to make up most of the mass of the universe. Unlike normal matter, which has mass, takes up space and is visible either by the human eye or through a telescope that shows other wavelengths, dark matter is invisible and mostly undetectable.

For years, researchers have been teasing out its role in the universe, and astronomers now believe dark matter makes up 27 percent of the universe. Dark energy, which is thought to be responsible for the expansion of our universe, is thought to make up 68 percent.

The massive instruments aboard the Hubble Space Telescope, which has orbited Earth for decades, detect objects the human eye can’t see. The data has enabled scientists to better understand the invisible universe, although it sometimes poses a challenge to the cosmological model that scientists use to explain how the universe works.

The free book goes over some of the discoveries enabled by the Hubble mission and breaks down the mysteries it has uncovered in plain English. It is also packed with photos from the mission and quotes from experts, and contains links to videos that dive further into such topics as the Hubble constant, the rate at which the universe is expanding.

“Much remains to be done, but this book will give you a front row seat to what’s been happening in this quest,” Hubble operations project scientist Ken Carpenter said in a news release. The book is the fifth in a series of similar volumes about the Hubble mission and its discoveries.

Ready to learn more about the mysterious forces around you? You can download the book in PDF or EPUB format at bit.ly/hubblebook