Passage
Out of This World: Deep Space Observation
by Kathiann M. Kowalski
1) Some of America's greatest man-made marvels are literally out of this world. Space-based telescopes and ground-based observatories don't just provide awesome views of the stars, planets, and distant galaxies. They're expanding our knowledge and understanding of the universe.
2) "NASA's space telescopes are really tools for answering some of the most exciting questions that people have ever asked," says Paul Hertz, astrophysics division director for the National Aeronautics and Space Administration (NASA). Those questions include: How did the universe begin? How did the stars and planets come to be? Are there planets around other stars? And might those planets hold life?
3) The Hubble Space Telescope "might be the most well-known and well-loved scientific experiment ever built," Hertz notes. Launched in 1990, the telescope celebrated its 25th anniversary in 2015.
4) Costs up through its 1990 launch were around $2.5 billion, and five subsequent repair missions brought the figure up to around $10 billion by 2010. Although it is expensive, Hubble's legacy is a wealth of scientific information.
5) For example, scientists using Hubble have shown that expansion of the universe is accelerating, because of a force scientists now call dark energy. Hubble helped scientists show that 95 percent of the universe is composed of dark energy or dark matter—something other than the atoms we understand. Hubble has also measured atmospheres of planets around other stars.
6) And then there are the photos. "Hubble has given us some of the most vivid pictures of our very beautiful universe and helped those of us who spend our lives here on the ground feel that we can soar through space like the astronauts and see the universe in all its grandeur," Hertz says.
7) But no one telescope can show everything, just as no one tool can do every job. Thus, there are multiple space-based telescopes. Another space telescope, the Chandra X-ray Observatory, detects X-rays in hot and other regions of space. It was launched in 1999 and flies in an elliptical orbit that reaches much higher than Hubble's orbit. Its pictures are helping scientists locate and study high-energy phenomena, such as areas around black holes, remnants of supernovas, and million-degree gas found in clusters of galaxies.
8) "One question everybody has been asking for thousands of years is, Are we alone?" Hertz says. Launched in 2009, the Kepler Space Telescope's four-year mission was to find planets beyond our solar system. Hubble and other telescopes can't detect such planets because stars near them are too bright. The Kepler telescope used a different strategy. It basically "stared at 150,000 stars for four straight years without 'blinking," Hertz says. "It was looking to see if a planet around any of those stars would pass between us and the star and block out a very tiny fraction of that star's light—as small as one-millionth of the light."
9) Using that strategy, Kepler found thousands of stars with planets. "Because of Kepler, we now know that probably almost every star in the night sky has planets around it," Hertz notes. Kepler could not hold its position much beyond the planned four years. But it earned a bonus mission, known as K2. As it changes position, Kepler has been able to capture things such as flares on stars, black holes swallowing asteroids, and even pulsing on the surface of the planet Neptune.
10) NASA's next big telescope launch in 2018 will be beyond cool—it will be frigid! Working at 40 degrees above absolute zero, it will detect infrared light from far away. "The James Webb Space Telescope will be able to detect the very first galaxies and the very first stars that arose after the Big Bang and that are at the edges of the visible universe," explains Hertz.
11) Ground-based telescopes are marvels as well. "It's always cheaper to build a telescope on the ground than to put one into space," notes Hertz. For instance, the Pan-STARRS-1 telescope atop Haleakala on Maui, Hawaii, is the first of four such telescopes. It was designed primarily to detect hazardous objects in space, and it began operating in late 2008 with the world's largest digital camera. Its images have 1.4 billion pixels each. Most cellphone cameras, in contrast, have fewer than 10 million pixels. A second telescope, Pan-STARRS-2, should soon operate nearby.
12) "Pan-STARRS, among other things, is looking at large pieces of the sky, looking for new asteroids and other things that are changing," explains Hertz. "The more of the sky you can see at a time, the more things you can discover." The Large Synoptic Survey Telescope in the next decade will be even more sensitive.
13) Plans also call for NASA's space-based Wide-Field Infrared Survey Telescope, or WFIRST, to have a large camera. It will be "100 times larger than the Hubble camera," notes Hertz. "Every time we take a picture with the WFIRST, it will be like putting 100 pictures with Hubble together." WFIRST images should help scientists understand more about dark energy and planets outside our solar system.
14) Telescopes in space and on the ground represent amazing feats of engineering. Mankind's curiosity about space has sparked an effort to build things that allow us to see and experience that vast frontier. Together, these tools give us amazing views and help us understand how our universe works.
Read the following passage and answer the questions that follow.
Choose three sentences from the passage that should be included in a summary.