A Sultry World Is Found Orbiting a Distant Star
L. Calçada/European Southern Observatory
An artist’s rendering of a second super-Earth exoplanet for which astronomers have determined the mass and radius.
Published: December 16, 2009
Call it Steam World.
Astronomers said Wednesday that they had discovered a planet composed mostly of water.
You would not want to live there. Besides the heat — 400 degrees Fahrenheit on the ocean surface — the planet is probably cloaked in a dark fog of superheated steam and other gases. But its discovery has encouraged a growing feeling among astronomers that they are on the verge of a breakthrough and getting closer to finding a planet that something could live on.
“This probably is not habitable, but it didn’t miss the habitable zone by that much,” said David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, who led the team that discovered the new planet and will reports its findings on Thursday in the journal Nature.
Geoffrey W. Marcy, a planet hunter from the University of California, Berkeley, wrote in an accompanying article in Nature that the new work provided “the most watertight evidence so far for a planet that is something like our own Earth, outside our solar system.”
Only 2.7 times the size of Earth and 6.6 times as massive, the new planet takes 38 hours to circle a dim red star, GJ 1214, in the constellation Ophiuchus — about 40 light-years from here. It is one of the lightest and smallest so-called extrasolar planets yet found, part of a growing class of planets that are less than 10 times the mass of Earth.
Dr. Charbonneau’s announcement capped a week in which the list of known planets, including these “super-Earths,” grew significantly.
An international team of astronomers using telescopes in Australia and Hawaii reported in one paper that they had found three planets, including a super-Earth, orbiting 61 Virginis, a star in the constellation Virgo that is almost a clone of the Sun. It was the first time, they said, that a super-Earth had been found belonging to a star like the Sun; the other home stars have been dwarfs. And in a separate paper, they reported finding a planet somewhat larger than Jupiter at the star 23 Librae.
And in yet another paper, a subset of the same group reported finding a super-Earth and probably two bigger planets circling HD 1461, a star in Cetus.
Paul Butler of the Carnegie Institution of Washington, who was involved in all three papers, said astronomers thought that one-third to one-half of all Sun-like stars harbored such super-Earths orbiting at scorching distances much closer than Mercury is to the Sun.
In the 15 years since the first extrasolar planet was found, more than 400 have been detected. The field is getting more intense as dedicated planet-hunting instruments like the Kepler satellite from the National Aeronautics and Space Administration, due to report a new batch of such planets next month, get into the game.
Alan P. Boss, a planetary theorist at the Carnegie Institution of Washington, said of the planet hunters, “Give them a couple more years and they’re going to knock your socks off.”
Dr. Charbonneau’s planet, only 1.3 million miles from its home star, is distinguished by its relative coolness — a consequence of the dimness of GJ 1214, which puts out one three-hundredth of the Sun’s energy. He and his colleagues had set out to search for planets around such stars, noting that they are more numerous and that it is easier to discern planets around them.
His planet-hunting equipment is a bank of eight telescopes called MEarth, pronounced “mirth,” on Mount Hopkins in Arizona. Each telescope is only 16 inches in diameter, no bigger than those that grace the backyard of many amateur astronomers. They monitor the light of 2,000 nearby stars, looking for the regular blips caused when a planet passes by, or transits.
In May, Zachory Berta, a first-year graduate student of Dr. Charbonneau, called the group’s attention to blips in the Ophiuchus star that seemed to be happening every 1.6 days. If he was right, Mr. Berta said, the next transit would occur at 6 a.m. on May 13.
Dr. Charbonneau was in Washington later that day preparing for a State Department dinner when he got a group e-mail message that began: “We have a winner. Congrats Zach!”
From the drop in starlight, the astronomers could calculate the diameter of the Ophiuchus planet, known now as GJ 1214b. Then they used a sensitive spectrograph on a 3.6-meter telescope in Chile to measure its gravitational tug on the star, thus deriving the planet’s mass. Using those two numbers, Dr. Charbonneau and his colleagues could calculate the density of the planet, about one-third that of Earth.
“What we probably have here is a water world,” Dr. Charbonneau said.
Dr. Charbonneau said the weight of the new planet’s presumptive atmosphere kept the water liquid rather than just boiling into space. He acknowledged that a different recipe, with more rock and a very puffy atmosphere, would also fit the data. That is unlikely, he and other planet experts say, but the steam-world theory may be soon tested.
The new planet is close enough to be studied directly by telescopes on or near Earth. Indeed, Dr. Charbonneau said his team had already applied for observing time on the Hubble Space Telescope.
“Our own TV signals,” he said, “have already passed this star.”
Earth's Moon
During its mission, the Galileo spacecraft returned a number of images of Earth's only natural satellite. Galileo surveyed the moon on Dec. 7, 1992, on its way to explore the Jupiter system in 1995-1997.
This color mosaic was assembled from 18 images taken by Galileo's imaging system through a green filter. On the upperleft is the dark, lava-filled Mare Imbrium, Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 400-mile impact structure partly filled with dark volcanic deposits, is seen at the center of the image.
Image Credit: NASA/JPL/USGS
This color mosaic was assembled from 18 images taken by Galileo's imaging system through a green filter. On the upperleft is the dark, lava-filled Mare Imbrium, Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 400-mile impact structure partly filled with dark volcanic deposits, is seen at the center of the image.
Image Credit: NASA/JPL/USGS
2012- ? answered by NASA
2012: Beginning of the End or Why the World Won't End?
Remember the Y2K scare? It came and went without much of a whimper because of adequate planning and analysis of the situation. Impressive movie special effects aside, Dec. 21, 2012, won't be the end of the world as we know. It will, however, be another winter solstice.
Much like Y2K, 2012 has been analyzed and the science of the end of the Earth thoroughly studied. Contrary to some of the common beliefs out there, the science behind the end of the world quickly unravels when pinned down to the 2012 timeline. Below, NASA Scientists answer several questions that we're frequently asked regarding 2012.
Question (Q): Are there any threats to the Earth in 2012? Many Internet websites say the world will end in December 2012.
Answer (A): Nothing bad will happen to the Earth in 2012. Our planet has been getting along just fine for more than 4 billion years, and credible scientists worldwide know of no threat associated with 2012.
Q: What is the origin of the prediction that the world will end in 2012?
A: The story started with claims that Nibiru, a supposed planet discovered by the Sumerians, is headed toward Earth. This catastrophe was initially predicted for May 2003, but when nothing happened the doomsday date was moved forward to December 2012. Then these two fables were linked to the end of one of the cycles in the ancient Mayan calendar at the winter solstice in 2012 -- hence the predicted doomsday date of December 21, 2012.
Q: Does the Mayan calendar end in December 2012?
A: Just as the calendar you have on your kitchen wall does not cease to exist after December 31, the Mayan calendar does not cease to exist on December 21, 2012. This date is the end of the Mayan long-count period but then -- just as your calendar begins again on January 1 -- another long-count period begins for the Mayan calendar.
Q: Could a phenomena occur where planets align in a way that impacts Earth?
A: There are no planetary alignments in the next few decades, Earth will not cross the galactic plane in 2012, and even if these alignments were to occur, their effects on the Earth would be negligible. Each December the Earth and sun align with the approximate center of the Milky Way Galaxy but that is an annual event of no consequence.
Much like Y2K, 2012 has been analyzed and the science of the end of the Earth thoroughly studied. Contrary to some of the common beliefs out there, the science behind the end of the world quickly unravels when pinned down to the 2012 timeline. Below, NASA Scientists answer several questions that we're frequently asked regarding 2012.
Question (Q): Are there any threats to the Earth in 2012? Many Internet websites say the world will end in December 2012.
Answer (A): Nothing bad will happen to the Earth in 2012. Our planet has been getting along just fine for more than 4 billion years, and credible scientists worldwide know of no threat associated with 2012.
Q: What is the origin of the prediction that the world will end in 2012?
A: The story started with claims that Nibiru, a supposed planet discovered by the Sumerians, is headed toward Earth. This catastrophe was initially predicted for May 2003, but when nothing happened the doomsday date was moved forward to December 2012. Then these two fables were linked to the end of one of the cycles in the ancient Mayan calendar at the winter solstice in 2012 -- hence the predicted doomsday date of December 21, 2012.
Q: Does the Mayan calendar end in December 2012?
A: Just as the calendar you have on your kitchen wall does not cease to exist after December 31, the Mayan calendar does not cease to exist on December 21, 2012. This date is the end of the Mayan long-count period but then -- just as your calendar begins again on January 1 -- another long-count period begins for the Mayan calendar.
Q: Could a phenomena occur where planets align in a way that impacts Earth?
A: There are no planetary alignments in the next few decades, Earth will not cross the galactic plane in 2012, and even if these alignments were to occur, their effects on the Earth would be negligible. Each December the Earth and sun align with the approximate center of the Milky Way Galaxy but that is an annual event of no consequence.
Q: Is there a planet or brown dwarf called Nibiru or Planet X or Eris that is approaching the Earth and threatening our planet with widespread destruction?
A: Nibiru and other stories about wayward planets are an Internet hoax. There is no factual basis for these claims. If Nibiru or Planet X were real and headed for an encounter with the Earth in 2012, astronomers would have been tracking it for at least the past decade, and it would be visible by now to the naked eye. Obviously, it does not exist. Eris is real, but it is a dwarf planet similar to Pluto that will remain in the outer solar system; the closest it can come to Earth is about 4 billion miles.
Q: What is the polar shift theory? Is it true that the earth’s crust does a 180-degree rotation around the core in a matter of days if not hours?
A: A reversal in the rotation of Earth is impossible. There are slow movements of the continents (for example Antarctica was near the equator hundreds of millions of years ago), but that is irrelevant to claims of reversal of the rotational poles. However, many of the disaster websites pull a bait-and-shift to fool people. They claim a relationship between the rotation and the magnetic polarity of Earth, which does change irregularly, with a magnetic reversal taking place every 400,000 years on average. As far as we know, such a magnetic reversal doesn’t cause any harm to life on Earth. A magnetic reversal is very unlikely to happen in the next few millennia, anyway.
A: Nibiru and other stories about wayward planets are an Internet hoax. There is no factual basis for these claims. If Nibiru or Planet X were real and headed for an encounter with the Earth in 2012, astronomers would have been tracking it for at least the past decade, and it would be visible by now to the naked eye. Obviously, it does not exist. Eris is real, but it is a dwarf planet similar to Pluto that will remain in the outer solar system; the closest it can come to Earth is about 4 billion miles.
Q: What is the polar shift theory? Is it true that the earth’s crust does a 180-degree rotation around the core in a matter of days if not hours?
A: A reversal in the rotation of Earth is impossible. There are slow movements of the continents (for example Antarctica was near the equator hundreds of millions of years ago), but that is irrelevant to claims of reversal of the rotational poles. However, many of the disaster websites pull a bait-and-shift to fool people. They claim a relationship between the rotation and the magnetic polarity of Earth, which does change irregularly, with a magnetic reversal taking place every 400,000 years on average. As far as we know, such a magnetic reversal doesn’t cause any harm to life on Earth. A magnetic reversal is very unlikely to happen in the next few millennia, anyway.
Q: Is the Earth in danger of being hit by a meteor in 2012?
A: The Earth has always been subject to impacts by comets and asteroids, although big hits are very rare. The last big impact was 65 million years ago, and that led to the extinction of the dinosaurs. Today NASA astronomers are carrying out a survey called the Spaceguard Survey to find any large near-Earth asteroids long before they hit. We have already determined that there are no threatening asteroids as large as the one that killed the dinosaurs. All this work is done openly with the discoveries posted every day on the NASA NEO Program Office website, so you can see for yourself that nothing is predicted to hit in 2012.
Q: How do NASA scientists feel about claims of pending doomsday?
A: For any claims of disaster or dramatic changes in 2012, where is the science? Where is the evidence? There is none, and for all the fictional assertions, whether they are made in books, movies, documentaries or over the Internet, we cannot change that simple fact. There is no credible evidence for any of the assertions made in support of unusual events taking place in December 2012.
Q: Is there a danger from giant solar storms predicted for 2012?
A: Solar activity has a regular cycle, with peaks approximately every 11 years. Near these activity peaks, solar flares can cause some interruption of satellite communications, although engineers are learning how to build electronics that are protected against most solar storms. But there is no special risk associated with 2012. The next solar maximum will occur in the 2012-2014 time frame and is predicted to be an average solar cycle, no different than previous cycles throughout history.
A: The Earth has always been subject to impacts by comets and asteroids, although big hits are very rare. The last big impact was 65 million years ago, and that led to the extinction of the dinosaurs. Today NASA astronomers are carrying out a survey called the Spaceguard Survey to find any large near-Earth asteroids long before they hit. We have already determined that there are no threatening asteroids as large as the one that killed the dinosaurs. All this work is done openly with the discoveries posted every day on the NASA NEO Program Office website, so you can see for yourself that nothing is predicted to hit in 2012.
Q: How do NASA scientists feel about claims of pending doomsday?
A: For any claims of disaster or dramatic changes in 2012, where is the science? Where is the evidence? There is none, and for all the fictional assertions, whether they are made in books, movies, documentaries or over the Internet, we cannot change that simple fact. There is no credible evidence for any of the assertions made in support of unusual events taking place in December 2012.
Q: Is there a danger from giant solar storms predicted for 2012?
A: Solar activity has a regular cycle, with peaks approximately every 11 years. Near these activity peaks, solar flares can cause some interruption of satellite communications, although engineers are learning how to build electronics that are protected against most solar storms. But there is no special risk associated with 2012. The next solar maximum will occur in the 2012-2014 time frame and is predicted to be an average solar cycle, no different than previous cycles throughout history.
"There apparently is a great deal of interest in celestial bodies, and their locations and trajectories at the end of the calendar year 2012. Now, I for one love a good book or movie as much as the next guy. But the stuff flying around through cyberspace, TV and the movies is not based on science. There is even a fake NASA news release out there..."
- Don Yeomans, NASA senior research scientist
- Don Yeomans, NASA senior research scientist
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