Dreams of Other Worlds

In the sprint to identify planets beyond our Solar System, scientists scan the skies for habitable worlds similar to Earth with the goal of finding life beyond ours.  With each new confirmation of smaller and more Earth-sized planets, and a possible 400 billion exoplanets in the Milky Way alone, the odds are high that habitable worlds abound. Several of the missions discussed in Dreams of Other Worlds by Chris Impey and Holly Henry have been instrumental in this research, including the beloved Hubble Space Telescope.

Impey_Dreams_F13The book details the methods scientists use to detecting extrasolar planets, the wild variety of planets found so far, and the teams and researchers making the discoveries, including Planethunters.org, the online survey of Kepler data that citizen scientists are currently scouring for evidence of these worlds. The chapter on the Viking mission comments on how, in searching for life on Mars, James Lovelock and Lynn Margulis determined that volatile gases such as oxygen or ozone are replenished by living organisms in Earth’s biosphere and will be important biomarkers of life on exoplanets.  The chapter on the Spitzer mission details the ways complex organisms on Earth developed eyes designed to best use the light of our own star, the Sun, as well as how life forms elsewhere might be adjusted to existence on a planet orbiting a red dwarf star, the most common star type in the Milky Way. While the Hipparcos mission inadvertently identified exoplanets orbiting other stars, its successor mission, Gaia, is poised to detect thousands more.

Beyond artist depictions of exoplanets in orbit of distant stars, the book considers the artwork of Chesley Bonestell whose imaginative paintings of planetary landscapes inspired his and future generations to consider the variable landscapes within our Solar System and beyond.  And, of course, the gold-plated phonograph records attached to the ongoing Voyager spacecraft were intended for civilizations potentially inhabiting an exoplanet in our galactic neighborhood.

The book’s conclusion looks to the upcoming James Webb Space Telescope that will turn its infrared seeking lenses to the search of far-flung worlds.  What we find, the authors remind us, is bound to completely rewrite our understanding of life and where it can exist, as well as our place in the unimaginably vast universe that surrounds us.

 

Read a sample chapter from Dreams of Other Worlds: http://press.princeton.edu/chapters/i10067.pdf

“Dreams of Other Worlds”: Chandra and HST #WSW2013

Houston, we have lift off!

All week long for World Space Week, we will be posting exclusive excerpts from Chris Impey and Holly Henry’s new book, Dreams of Other Worlds: The Amazing Story of Unmanned Space Exploration. Each day will include an excerpt from a different chapter(s) about a different unmanned spacecraft, along with a picture of the craft that doubles as an iPhone background!

Today we have two excerpts. The first is from Chapter 10, and it describes some of the leaps and bounds we have been able to make in black hole exploration thanks to Chandra. The second excerpt is from Chapter 11, which talks about what is probably the most famous spacecraft, the Hubble Space Telescope.

Tomorrow will bring another chapter and another adventure, so stay tuned!

chandra99-13Chandra has the sensitivity to detect stellar black holes hundreds of light-years away. Only about twenty binary systems have well-enough measured masses to be sure the dark companion is a black hole, but X-ray observations can be used to identify black holes with fairly high reliability. The examples studied with X-ray telescopes are the brightest representatives of a population of about 100 million black holes in the Milky Way.
X-ray observations have also pushed the limit of our understanding of black holes. In 2007, a research team used Chandra to discover a black hole in M33, a nearby spiral galaxy. The black hole was sixteen times the mass of the Sun, making it the most massive stellar black hole known.32 Moreover, it was in a binary orbit with a huge star seventy times the Sun’s mass. The formation mechanism of the black hole that placed it in such a tight embrace with its companion is unknown. This is the first black hole in a binary system that shows eclipses, which provides unusually accurate measurements of mass and other properties. The massive companion will also die as a black hole, so future astronomers will be able to gaze on a binary black hole where energy is lost as gravitational radiation and the two black holes dance a death spiral as they coalesce into a single beast.
hubble89-13Above all scientific projects, the Hubble Space Telescope encapsulates and recapitulates the human yearning to explore distant worlds, and understand our origins and place in the universe. Its light grasp is 10 billion times better than Galileo’s best spyglass, and many innovations were needed for it to be realized: complex yet reliable instruments, the ability for astronauts to service the telescope, and the infrastructure to support the projects of thousands of scientists from around the world. The facility and its supporters experienced failure and heartache as well as eventual success and vindication.
Hubble’s legacy has touched every area of astronomy, from the Solar System to the most distant galaxies. In the public eye, it’s so well known that many people think it’s the only world-class astronomy facility. In fact, it operates in a highly competitive landscape with other space facilities and much larger telescopes on the ground. Although it doesn’t own any field of astronomy, it has made major contributions to all of them. It has contributed to Solar System astronomy and the characterization of exoplanets, it has viewed star birth and death in unprecedented detail, it has paid homage to its namesake with spectacular images of galaxies near and far, and it has cemented important quantities in cosmology, including the size, age, and expansion rate of the universe.

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