Among 1,200 Possible Planets, Some Seem Like Our Own
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SHIRLEY GRIFFITH: And I’m Shirley Griffith with EXPLORATIONS in VOA Special English. Today we tell about an American spacecraft that has a date with a comet. We hear the latest about a space shuttle commander whose wife continues to recover from a deadly gun attack. And we remember a sad anniversary. But first, the discovery of possible planets like our own.
STEVE EMBER: Last week, American space agency scientists announced the discovery of possible Earth-like planets. The announcement came from newly released information from the Kepler space-based telescope.
The researchers say six new planets have been confirmed. But the Kepler mission’s chief scientist, William Borucki, says eighty percent of the possible planets will probably be confirmed in the coming months and years.
Before last week’s announcement, the total number of so-called exoplanets outside our solar system was just over five hundred. Mr. Borucki says that number increased, based on new information from the small part of the sky examined by the Kepler telescope.
WILLIAM BORUCKI: “Kepler looks at one-four-hundredth of the sky. If we had four hundred of these fields of view, we would see four hundred times that number of candidates.”
SHIRLEY GRIFFITH: Mr. Borucki notes that they have found many possible planets in a small part of the sky. This suggests that there are countless planets orbiting stars like our sun in our galaxy. He says there must be millions of planets orbiting the stars that surround our sun.
Mr. Borucki says he was surprised to find sixty-eight suspected planets about the size of Earth or smaller. Fifty-four of the possible exopla on the planet’s surface. He says some of the possible planets could even have moons with liquid wable area of their parent stars.
STEVE EMBER: NASA scientists using the Kepler space telescope also announced the discovery of six planets orbiting a star called Kepler-11. Investigator Jack Lissauer described the discovery.
JACK LISSAUER: “Kepler 11 is a surprising flat and compact system of six transiting planets. The five inner planets are especially close together, something that we didn’t think would happen for worlds of this size.”
NASA says Kepler-11 has the fullest, most compact planetary system yet discovered beyond our own. Mr. Lissauer says the five inner planets areases, possibly including water ice.
The Kepler space telescope looks for planets by measuring tiny decreases in the brightness of stars when planets cross in front of them. Scientists
non-professional astronomers around the world are helping study the new information about the possible planets. They are doing this on an Internet website called PlanetHunters.org.
SHIRLEY GRIFFITH: A spacecraft from the United States space agency has a date with comet Temple 1 on February fourteenth. The Stardust-NExT spacecraft is to meet the comet on Valentine’s Day. This is the day when many people will be going out on a date with someone special in their lives.
This meeting is all the more meaningful because comet Temple 1 has been visited before. And scientists are very interested in seeing how this solar system
of ice and rock that leave behind a trail of gas and dust in space as they approach the sun’s warming light.
Sometimes, observers see this as a comet’s tail, which can be visible to the unaided eye stretching across the night sky.
On February fourteenth, Stardust will approach to within two hundred kilometers of comet Temple 1. The spacecraft will take seventy-two high quality pictures of the comet’s nucleus, which is about six kilometers across. But this is not the first time that Temple 1 has been observed closely.
STEVE EMBER: In two thousand five, another NASA spacecraft called Deep Impact paid a visit to Temple 1. It released a small device, or probe, that crash
The main Deep Impact spacecraft was able to send back information to scientists on Earth. They found evidence of carbon-based chemicals, sand and, most importantly, water ice. Scientists will have a second look at comet Temple 1 with Stardust. This doule take is something new for comet experts.
SHIRLEY GRIFFITH: Joe Veverka is principal investigator of Stardust-NExT. He says it will give scientists their first chance to see how comets change with each close approach to the sun.
JOE VEVERKA: “We know that comets lose material, ut the question is, ‘How much does the surface change and where does the surface change?’ So we’ll be able to answer that question by comparing our images with those taken by Deep Impact in 2005.”
STEVE EMBER: Astronomers have known about Comet Temple 1 for a long time. They discovered it in eighteen sixty-seven. They have observed it ost of its returns the inner solar system since then.It is a short-period comet. This means it orbits the sun in a relatively short time. For Temple 1, that is about five and a half years.
Where does the comet go when it is not close to the sun? Short-period comets like Temple 1 have orbits that take them only as far as the outer planets like Jupiter. In fact, Temple 1 is a member of the Jupiter family of comets. These are all influenced by vity of the solar system’s largest planet. Long-period comets, however, may take several hundred years to orbit the sun.
SHIRLEY GRIFFITH: Scientists t water and carbon compounds to Earth. That means they may have supplied the Earth with the basic building blocks of life nearly four billion years ago. That is a big reason why scientists are so interested in them.
STEVE EMBER: Late last week, NASA said astronaut Mark Kelly would return to train with crewmembers on the last flight of the space shuttle Endeavor in April. Mark Kelley is the husband of United States Representative Gabrielle Giffords of Arizona. A shot her in the head on January eighth at a political gathering in Tuscon, Arizona. Six people were killed in the attack, including a young girl and a federal judge.
Gabrielle Giffords has since beea hospital in Houston, Texas. Astronaut Mark Kelly trains at the Johnson Space Center in that city.
Recently Mr. Kelly said he plans to command the final flight of the Endeavor. He said he hopes his wife Gabrielle Giffords will be at the launch. Mr. Kelly’s brother, Scott Kelly, is the current commander of the International Space Station. NASA plans to retire the space shuttle program this year.
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SHIRLEY GRIFFITH: On January twenty-eighth, nineteen eighty-six, tragedy struck NASA’s Space Shuttle program.
It was only seventy-three seconds into the twenty-fifth flight for the program. A problem with one of its booster rockets caused space shuttle Challenger to explode. Seven astronauts were killed. Many Americans clearly remember the event as terday. Students were watching the launch from their classrooms. One of the astronauts was Christa McAuliffe, a school teacher.
two thousand three, another accident on the space shuttle Columbia claimed the lives of seven more astronauts.STEVE EMBER: Valerie Neal supervises the human spaceflight collection at the Smithsonian National Air and Space Museum in Washington, D.Cbecause spaceflight is experimental, it continues to be risky. But Ms. Neal says the United States space program always seems to recover from hardship.
VALERIE NEAL: “The fact, though, that the space shuttle program didn’t close down, that we didn’t close up shop and say, ‘This is too
SHIRLEY GRIFFITH: This program was written and produced by Mario Ritter. I’m Shirley Griffith.
STEVE EMBER: And I’m Steve Ember. Join us again next week for EXPLORATIONS in VOA Special English.
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