Excerpt from latimes.comCheck out the best images yet of the dwarf planet Pluto.The moving images of Pluto and its Texas-sized moon Charon you see below were taken by NASA's New Horizons spacecraft, which has spent nine years on a high-speed j...
Tag: distant (page 2 of 7)
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The Hooker 100-inch reflecting telescope at the Mount Wilson Observatory, just outside Los Angeles. Edwin Hubble's chair, on an elevating platform, is visible at left. A view from this scope first told Hubble our galaxy isn't the only one. Courtesy of The Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, Calif. |
Excerpt from hnpr.org
The Hubble Space Telescope this week celebrates 25 years in Earth's orbit. In that time the telescope has studied distant galaxies, star nurseries, planets in our solar system and planets orbiting other stars.
But, even with all that, you could argue that the astronomer for whom the telescope is named made even more important discoveries — with far less sophisticated equipment.
A young Edwin Hubble at Mount Wilson's 100-inch telescope circa 1922, ready to make history.
Edwin Hubble Papers/Courtesy of Huntington Library, San Marino, Calif.
In the 1920s, Edwin Hubble was working with the 100-inch Hooker telescope on Mount Wilson, just outside Los Angeles. At the time, it was the largest telescope in the world.
On a chilly evening, I climb up to the dome of that telescope with operator Nik Arkimovich and ask him to show me where Hubble would sit when he was using the telescope. Arkimovich points to a platform near the top of the telescope frame.
"He's got an eyepiece with crosshairs on it," Arkimovich explains. The telescope has gears and motors that let it track a star as it moves across the sky. "He's got a paddle that allows him to make minor adjustments. And his job is to keep the star in the crosshairs for maybe eight hours."
"It's certainly much, much easier today," says John Mulchaey, acting director of the observatories at Carnegie Institution of Science. "Now we sit in control rooms. The telescopes operate brilliantly on their own, so we don't have to worry about tracking and things like this."
The headquarters of the Carnegie observatories is at the foot of Mount Wilson, in the city of Pasadena. It's where Hubble worked during the day.
A century's worth of plates are stored here in the basement. Mulchaey opens a large steel door and ushers me into a room filled with dozens of file cabinets.
"Why don't we go take a look at Hubble's famous Andromeda plates," Mulchaey suggests.
The plates are famous for a reason: They completely changed our view of the universe. Mulchaey points to a plate mounted on a light stand.
"This is a rare treat for you," he says. "This plate doesn't see the light of day very often."
This glass side of a photographic plate shows where Hubble marked novas. The red VAR! in the upper right corner marks his discovery of the first Cepheid variable star — a star that told him the Andromeda galaxy isn't part of our Milky Way.
Courtesy of the Carnegie Observatories
The plate shows the spiral shape of the Andromeda galaxy. Hubble was looking for exploding stars called novas in Andromeda. Hubble marked these on the plate with the letter "N."
"The really interesting thing here," Mulchaey says, "is there's one with the N crossed out in red — and he's changed the N to VAR with an exclamation point."
Hubble had realized that what he was seeing wasn't a nova. VAR stands for a type of star known as a Cepheid variable. It's a kind of star that allows you to make an accurate determination of how far away something is. This Cepheid variable showed that the Andromeda galaxy isn't a part of our galaxy.
At the time, most people thought the Milky Way was it — the only galaxy in existence.
"And what this really shows is that the universe is much, much bigger than anybody realizes," Mulchaey says.
It was another blow to our human conceit that we are the center of the universe.
Hubble went on to use the Mount Wilson telescope to show the universe was expanding, a discovery so astonishing that Hubble had a hard time believing it himself.
If Hubble could make such important discoveries with century-old equipment, it makes you wonder what he might have turned up if he'd had a chance to use the space telescope that bears his name.
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Excerpt from computerworld.com
By Sharon Gaudin
IBM scientists say they have made two critical advances in an industrywide effort to build a practical quantum computer, shaving years off the time expected to have a working system.
"This is critical," said Jay Gambetta, IBM's manager of theory of quantum computing. "The field has got a lot more competitive. You could say the [quantum computing] race is just starting to begin… This is a small step on the journey but it's an important one."
Gambetta told Computerworld that IBM's scientists have created a square quantum bit circuit design, which could be scaled to much larger dimensions. This new two-dimensional design also helped the researchers figure out a way to detect and measure errors.
Quantum computing is a fragile process and can be easily thrown off by vibrations, light and temperature variations. Computer scientists doubt they'll ever get the error rate down to that in a classical computer.
Because of the complexity and sensitivity of quantum computing, scientists need to be able to detect errors, figure out where and why they're happening and prevent them from recurring.
IBM says its advancement takes the first step in that process.
"It tells us what errors are happening," Gambetta said. "As you make the square [circuit design] bigger, you'll get more information so you can see where the error was and you can correct for it. We're showing now that we have the ability to detect, and we're working toward the next step, which would allow you to see where and why the problem is happening so you can stop it from happening."
Quantum computing is widely thought to be the next great step in the field of computing, potentially surpassing classical supercomputers in large-scale, complex calculations.
Quantum computing would be used to cull big data, searching for patterns. It's hoped that these computers will take on questions that would lead to finding cures for cancer or discovering distant planets – jobs that might take today's supercomputers hundreds of years to calculate.
IBM's announcement is significant in the worlds of both computing and physics, where quantum theory first found a foothold.
Quantum computing, still a rather mysterious technology, combines both computing and quantum mechanics, which is one of the most complex, and baffling, areas of physics. This branch of physics evolved out of an effort to explain things that traditional physics is unable to.
For instance, each bit, also known as a qubit, in a quantum machine can be a one and a zero at the same time. When a qubit is built, it can't be predicted whether it will be a one or a zero. A qubit has the possibility of being positive in one calculation and negative in another. Each qubit changes based on its interaction with other qubits.
Because of all of these possibilities, quantum computers don't work like classical computers, which are linear in their calculations. A classical computer performs one step and then another. A quantum machine can calculate all of the possibilities at one time, dramatically speeding up the calculation.
However, that speed will be irrelevant if users can't be sure that the calculations are accurate.
That's where IBM's advances come into play.
"This is absolutely key," said Jim Tully, an analyst with Gartner. "You do the computation but then you need to read the results and know they're accurate. If you can't do that, it's kind of meaningless. Without being able to detect errors, they have no way of knowing if the calculations have any validity."
If scientists can first detect and then correct these errors, it's a major step in the right direction to building a working quantum computing system capable of doing enormous calculations.
"Quantum computing is a hard concept for most to understand, but it holds great promise," said Dan Olds, an analyst with The Gabriel Consulting Group. "If we can tame it, it can compute certain problems orders of magnitude more quickly than existing computers. The more organizations that are working on unlocking the potential of quantum computing, the better. It means that we'll see something real that much sooner."
A year ago, D-Wave Systems Inc. announced that it had built a quantum system, and that NASA, Google and Lockheed Martin had been testing them.
Many in the computer and physics communities doubt that D-Wave has built a real quantum computer. Vern Brownell, CEO of the company, avows that they have.
"I think that quantum computing shows promise, but it's going to be quite a while before we see systems for sale," said Olds.
IBM's Gambetta declined to speculate on whether D-Wave has built a quantum computing but said the industry is still years away from building a viable quantum system.
"Quantum computing could be potentially transformative, enabling us to solve problems that are impossible or impractical to solve today," said Arvind Krishna, senior vice president and director of IBM Research, in a statement.
IBM's research was published in Wednesday's issue of the journal Nature Communications.
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| A telescope at Lick Observatory on Mount Hamilton. (CBS) |
SAN JOSE (CBS SF) – Astronomers at the Lick Observatory atop Mount Hamilton have confirmed the existence of three planets described as “supersized Earths” orbiting a star 54 light years away.
Researchers from the University of California, University of Hawaii, the University of California Observatories and Tennessee State University have been working for years to confirm the planets were there.
The planets orbit a star called HD
7924. They orbit at a distance closer than Mercury orbits our sun (35.9 million miles), and complete their orbits in five, 15 and 24 days, respectively.“The three planets are unlike anything in our solar system, with masses seven to eight times the mass of Earth and orbits very close to their host star,” UC Berkeley graduate student Lauren Weiss said in a written statement.
The researchers used a robotic telescope called the “Automated Planet Finder,” which searches for planets around nearby stars that could be suitable for life. Most distant planets discovered by astronomers so far are gas giants like Jupiter.
Astronomers first found evidence of planets surrounding HD 7924 six years ago. The planets are not visible to the naked eye.
Excerpt from thespacereporter.com
According to a NASA statement, the agency’s Spitzer Space Telescope has taken part in the discovery of one of the most distant exoplanets yet found. Spitzer observations were combined with data from the Polish Optical Gravitational Lensing Experiment’s Warsaw Telescope, part of the Las Campanas Observatory in Chile. The newly found exoplanet is approximately 13,000 light-years from Earth, and could yield new clues as to the distribution of planets throughout the Milky Way.
The Warsaw Telescope gathers data through the phenomenon known as microlensing, which occurs when a star passes in front of another, more distant star as seen from Earth’s vantage point. The gravity of the nearer star magnifies and intensifies the distant star’s light; any planets orbiting the distant star appear as small disruptions in the magnification. So far, the microlensing methods has identified around 30 exoplanets, the most distant of which is around 25,000 light-years away.
However, the microlensing method cannot always show how far away are the more distant stars and their planets; the distances to about half of the exoplanets found with microlensing cannot be ascertained. Fortunately, Spitzer is able to help. Located 128 million miles from Earth, Spitzer is able to observe a microlensing event at a different time from the Warsaw Telescope, a method called parallax. In the case of the newly discovered exoplanet, the microlensing event was longer than norman, lasting 150 days.
Spitzer observed the event 20 days earlier than Warsaw. This time delay allowed the distance to the newly found planet to be calculated. With the distance, the planet’s mass, approximately half that of Jupiter, also was determined.
“We’ve mainly explored our own solar neighborhood so far,” said Sebastiano Calchi Novati of NASA’s Exoplanet Science Institute at the California Institute of Technology. “Now we can use these single lenses to do statistics on planets as a whole and learn about their distribution in the galaxy.”
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| The James Webb Telescope |
Excerpt from space.com
A telescope will soon allow astronomers to probe the atmosphere of Earthlike exoplanets for signs of life. To prepare, astronomer Lisa Kaltenegger and her team are modeling the atmospheric fingerprints for hundreds of potential alien worlds. Here's how:
The James Webb Space Telescope, set to launch in 2018, will usher a new era in our search for life beyond Earth. With its 6.5-meter mirror, the long-awaited successor to Hubble will be large enough to detect potential biosignatures in the atmosphere of Earthlike planets orbiting nearby stars.
And we may soon find a treasure-trove of such worlds. The forthcoming exoplanet hunter TESS (Transiting Exoplanet Survey Satellite), set to launch in 2017, will scout the entire sky for planetary systems close to ours. (The current Kepler mission focuses on more distant stars, between 600 and 3,000 light-years from Earth.)
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| Astronomer Lisa Kaltenegger |
While TESS will allow for the brief detection of new planets, the larger James Webb will follow up on select candidates and provide clues about their atmospheric composition. But the work will be difficult and require a lot of telescope time.
"We're expecting to find thousands of new planets with TESS, so we'll need to select our best targets for follow-up study with the Webb telescope," says Lisa Kaltenegger, an astronomer at Cornell University and co-investigator on the TESS team.
To prepare, Kaltenegger and her team at Cornell's Institute for Pale Blue Dots are building a database of atmospheric fingerprints for hundreds of potential alien worlds. The models will then be used as "ID cards" to guide the study of exoplanet atmospheres with the Webb and other future large telescopes.
Kaltenegger described her approach in a talk for the NASA Astrobiology Institute's Director Seminar Series last December.
"For the first time in human history, we have the technology to find and characterize other worlds," she says. "And there's a lot to learn."
Detecting life from space
In its 1990 flyby of Earth, the Galileo spacecraft took a spectrum of sunlight filtered through our planet's atmosphere. In a 1993 paper in the journal Nature, astronomer Carl Sagan analyzed that data and found a large amount of oxygen together with methane — a telltale sign of life on Earth. These observations established a control experiment for the search of extraterrestrial life by modern spacecraft."The spectrum of a planet is like a chemical fingerprint," Kaltenegger says. "This gives us the key to explore alien worlds light years away."
Current telescopes have picked up the spectra of giant, Jupiter-like exoplanets. But the telescopes are not large enough to do so for smaller, Earth-like worlds. The James Webb telescope will be our first shot at studying the atmospheres of these potentially habitable worlds.
Some forthcoming ground-based telescopes — including the Giant Magellan Telescope (GMT), planned for completion in 2020, and the European Extremely Large Telescope (E-ELT), scheduled for first light in 2024 — may also be able to contribute to that task. [The Largest Telescopes on Earth: How They Compare]
And with the expected discovery by TESS of thousands of nearby exoplanets, the James Webb and other large telescopes will have plenty of potential targets to study. Another forthcoming planet hunter, the Planetary Transits and Oscillations of stars (PLATO), a planned European Space Agency mission scheduled for launch around 2022-2024, will contribute even more candidates.
However, observation time for follow-up studies will be costly and limited.
"It will take hundreds of hours of observation to see atmospheric signatures with the Webb telescope," Kaltenegger says. "So we'll have to pick our targets carefully."
Set to see its first light in 2021, The Giant Magellan Telescope will be the world’s largest telescope.
Getting a head start
To guide that process, Kaltenegger and her team are putting together a database of atmospheric fingerprints of potential alien worlds. "The models are tools that can teach us how to observe and help us prioritize targets," she says.To start, they have modeled the chemical fingerprint of Earth over geological time. Our planet's atmosphere has evolved over time, with different life forms producing and consuming various gases. These models may give astronomers some insight into a planet's evolutionary stage.
Other models take into consideration the effects of a host of factors on the chemical signatures — including water, clouds, atmospheric thickness, geological cycles, brightness of the parent star, and even the presence of different extremophiles.
"It's important to do this wide range of modeling right now," Kaltenegger said, "so we're not too startled if we detect something unexpected. A wide parameter space can allow us to figure out if we might have a combination of these environments."
She added: "It can also help us refine our modeling as fast as possible, and decide if more measurements are needed while the telescope is still in space. It's basically a stepping-stone, so we don't have to wait until we get our first measurements to understand what we are seeing. Still, we'll likely find things we never thought about in the first place."
A new research center
The spectral database is one of the main projects undertaken at the Institute for Pale Blue Dots, a new interdisciplinary research center founded in 2014 by Kaltenegger. The official inauguration will be held on May 9, 2015."The crux of the institute is the characterization of rocky, Earth-like planets in the habitable zone of nearby stars," Kaltenergger said. "It's a very interdisciplinary effort with people from astronomy, geology, atmospheric modeling, and hopefully biology."
She added: "One of the goal is to better understand what makes a planet a life-friendly habitat, and how we can detect that from light years away. We're on the verge of discovering other pale blue dots. And with Sagan's legacy, Cornell University is a really great home for an institute like that."
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| WHAT’S FOR DINNER? Signals detected by the Parkes radio telescope (pictured) suggest that intelligent life in the universe has a penchant for leftovers. |
Excerpt from sciencenews.org
Mysterious radio signals detected by the Parkes telescope appear to come from an advanced civilization in the Milky Way.
Unfortunately, it’s the one civilization we already know about.
Microwave ovens opened before they’re done cooking have been muddling the hunt for far more distant radio signals, researchers report online April 9 at arXiv.org. Astronomers have had to contend with enigmatic flares dubbed “perytons” ever since discovering equally puzzling fast radio bursts, or FRBs (SN: 8/9/14, p. 22), in 2007. Perytons and FRBs are quite similar, except that astronomers realized that perytons originate on Earth, possibly from some meteorological phenomenon, while FRBs come from other galaxies.
Three perytons in January coincided with independently detected blasts of 2.4 gigahertz radio waves — the same frequency that microwave ovens use to heat food. So researchers at the Parkes telescope in Australia spent weeks heating mugs of water while moving the massive radio dish around the sky, trying to re-create the phenomenon. Finally, researchers tried opening the oven door mid-cooking instead of letting the timer run out. Suddenly, perytons started showing up in the data.
The source of the galactic FRBs remain an intriguing mystery. Astronomers suspect they have something to do with imploding neutron stars or eruptions on magnetars. At this point, however, they might want to consider extraterrestrials nuking frozen pizzas.
Excerpt from stgist.com
The sun, or the nearest star from Earth, was formed around 5 billion years after the Milky Way galaxy’s peak production of stars, a new research published in the Astrophysical Journal.
It’s like traveling back in time. Researchers from Texas A&M University in College Station, headed by astronomer Casey Papovich, were able to see the undepicted past of our own galaxy by observing similar regions located billions of light years away from us.
The “baby boom” happened around 10 billion years ago, the new study published in Astrophysical Journal revealed. At that time, the Milky Way galaxy was producing 30 times more stars than today. If so, then our solar system’s 4.6 billion years old Sun was formed more than 5 billion years after the production peak.
Sun’s late formation allowed the solar system we know today to produce planets with heavier elements. Scientists say elements heavier than hydrogen and helium became more abundant in “late to the game systems”, and the death of massive stars that were formed before the Sun had provided materials needed to form planets, including Earth and its complex life forms.
Scientists scanned through a collection of more than 24,000 galaxies, and took at least 2,000 snapshots of galaxies that closely resemble our own. The census has provided the most complete picture yet of how spiral galaxies similar to Milky Way form in the universe.
According to Mr. Papovich, the lead author of the study who also serves as an associate professor in the Department of Physics and Astronomy at A&M University in Texas, they know where to find traces by analyzing how galaxies like our own were formed.
Papovich said his team has provided a data that clearly show the rapid phase of growth around 9 to 10 billion years ago, or at least more than 5 billion years after our Sun formed. They also found the connection between the size of the galaxy, and the formation of stars.
Surprisingly, the robust collection of distant galaxies confirmed that stars formed inside the Milky Way, instead of forming in other smaller baby galaxies that later merged to join the system.
In separate studies, scientists were able to confirm that our own solar system is wetter than thought. Beyond Earth, celestial objects like Jupiter’s Galilean moons Europa and Ganymede, Saturn’s Enceladus, and even the dwarf planet Ceres in the asteroid belt, are hosting fluid slightly similar to Earth’s — and it is highly possible that the Sun’s late formation allowed this setup to exist.
Papovich who worked alongside Texas A&M postdoctoral researchers Vithal Tilvi and Ryan Quadri, were joined by at least two dozen astronomers from other countries. The research is published April 9th entitled “ZFOURGE/CANDELS: ON THE EVOLUTION OF M* GALAXY PROGENITORS FROM z = 3 TO 0.5*.” The research was funded by NASA
By Calia Cofield
Don't forget to look skyward in the early hours of Saturday morning (April 4), to catch a glimpse of the shortest total lunar eclipse of the century.
The moon will be completely swallowed by Earth's shadow for just 4 minutes and 43 seconds on Saturday morning, according to NASA officials. During that time, the moon may change from its normal grayish hue to a deep, blood red. The total eclipse begins at 6:16 a.m. EDT (1016 GMT). You can watch a live webcast of the eclipse on the Slooh Observatory website, Slooh.com, or here at Space.com courtesy of Slooh, starting at 6 a.m. EDT (1000 GMT).
That color change can make for a dramatic display, especially for humans in the distant past, NASA officials said.
"For early humans, [a lunar eclipse] was a time when they were concerned that life might end, because the moon became blood red and the light that the moon provided at night might have been taken away permanently," Mitzi Adams, an astronomer at NASA's Marshall Space Flight Center in Huntsville, Alabama, said during a news conference today (April 3). "But fortunately, [the light] always returned."
The April 4 eclipse is the third in a series of four total lunar eclipses — known as a lunar tetrad — visible in the United States. Each of the eclipses is separated by about 6 months. The final installment of this four-eclipse series will occur on Sept. 28. Saturday's lunar eclipse follows closely behind the total solar eclipse that took place on March 20.
Earth's shadow has an outer ring, called the penumbra, and an inner core, called the umbra. Where the moon passes into the penumbra, it appears dark, as if a bite had been taken out of it. When the moon passes though the umbra, it turns a deep, red color.
A total lunar eclipse occurs when the moon is totally submerged in the umbra. On Saturday, the moon will begin to enter the umbra at about 6:16 a.m. EDT (1016 GMT) but will not be completely covered by the shadow until about 7:57 EDT (1157 GMT), after the moon has set in most locations east of the Mississippi River.
While the total eclipse will last less than five minutes, the moon will be partially submerged in the umbra for about one hour and 40 minutes. The dark shadow of the penumbra will first be visible on the moon's surface starting at about 5:35 a.m. EDT (0935 GMT), according to Sky and Telescope magazine.
Viewers west of the Mississippi River will be able to see the total lunar eclipse, starting at about 4:57 a.m. PDT (1157 GMT). Skywatchers in Hawaii and western Alaska will be able to watch the entire eclipse, from the moon's entrance to its exit from the penumbra.
This world maps shows the regions where the April 4 total lunar eclipse will be visible. The best viewing locations are in the Pacific Ocean.
This weekend's eclipse is extremely short because the moon is only passing through the outskirts of the umbra. (The shortest total lunar eclipse in recorded history, according to Adams, was in 1529 and lasted only 1 minute and 41 seconds).
The eclipse will not be visible in Europe or most of Africa. The partial eclipse will be visible in all except the easternmost parts of South America. The best viewing locations for the total eclipse will be in the Pacific region, including eastern Australia, New Zealand and other parts of Oceania.
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| The full visible sky as seen by the Planck space observatory. The band running through the middle corresponds to dust in our Milky Way galaxy. The black dots indicate the location of the proto-cluster candidates identified by Planck and subsequently observed by the Herschel space telescope. (Photo : ESA and the Planck Collaboration) |
Excerpt from natureworldnews.com
Treasure seekers have found the haul of a lifetime, but it wasn't in some ancient temple or mysterious island. Instead, it was in the sky. Researcher using two of the European Space Agency's (ESA) impressive space telescopes have successfully identified what they are calling a "treasure chest" of ancient galaxy clusters, which could help explain how the Universe came to be the way it is today.
That's at least according to a study recently published (PDF) in the journal Astronomy and Astrophysics, which details how cosmologists used the ESA's Planck space observatory to identify the distant precursor galaxy clusters, and then poured over data from the Herschel telescope for a closer look.
"Finding so many intensely star-forming, dust galaxies in such concentrated groups was a huge surprise," Hervé Dole, lead author of the report from the Institut d'Astrophysique Spatiale in France, said in a statement. "We think this is a missing piece of cosmological structure formation."
So what does he mean by that? Let's turn back to the treasure chest metaphor for this one. While Planck was the space observatory to dig up the chest, it was the Herschel data that allowed experts to look closely at each and every gold coin (galaxy cluster) inside. Now they are able to learn more about each coin's make, mint, and ultimately, its origins.
And that's a big step in better understanding the early Universe. Expects believe that it took a great deal of time after star and galaxies first sprung to life for them to assemble into large clusters.
(Photo : ESA – C. Carreau) A summary of the 14 billion years out Universe has been in existence, as seen by the Plank space telescope. Light coming from some of the oldest parts of the Universe are just reaching the observatory now, allowing for experts to see the incredible uniformity of the early matter, compared to the chaotic beautify of star, galaxy, and cluster formation that crowds space today.
That's why looking at some of the oldest 'coins' ever made - estimated to date back to up-to 11 billion light-years ago - could be exceptionally helpful.
"We still have a lot to learn about this new population," Dole said in an ESA release. "Hints of these kinds of objects had been found earlier in data from Herschel and other telescopes, but the all-sky capability of Planck revealed many more candidates for us to study."
"Even when we combined the powerful capabilities of Planck and Herschel, we were only scratching the surface of the phenomena taking place at this critical era in the history of our universe, when stars, galaxies and clusters seem to be forming simultaneously,"
added George Helou, director of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. "That's one of the reasons this finding is exciting. It shows us that there is so much more to be learned.
Excerpt from csmonitor.com
Researchers have found Jupiter-scale gas giants orbiting binary stars and estimate that Earth-like planets orbiting binary stars could be as numerous as rocky planets orbiting single-star systems.
For all the sci-fi charm of watching a pair of suns sink below a distant horizon on a planet in a galaxy far, far away, conventional wisdom has held that binary-star systems can't host Earth-scale rocky planets.
As the two stars orbit each other like square-dance partners swinging arm in arm, regular variations in their gravitational tug would disrupt planet formation at the relatively close distances where rocky planets tend to appear.
Not so fast, say two astrophysicists. They argue that only are Tatooine-like planets likely to be out there. They could be as numerous as rocky planets orbiting single-star systems – which is to say, there could be large number of them.
Building rocky planets in a binary system not only is possible, it's "not even that hard," says Scott Kenyon, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who along with University of Utah astrophysicist Benjamin Bromley performed the calculations.
Researchers have found Jupiter-scale gas giants orbiting binary stars and have estimated that such gas giants are likely to be as common in binary systems as they are in systems with a single star.
"If that's true, then Earth-like planets around binaries are just as common as Earth-like planets around single stars," Dr. Kenyon says. "If they're not common, that tells you something about how they form or how they interact with the star over billions of years."
The modeling study grew out of work the two researchers were undertaking to figure out how the dwarf planet Pluto and its largest moon Charon manage to share space with four smaller moons that orbit the two larger objects.
Pluto and Charon form a binary system that early in its history saw the two objects graze each other to generate a ring of dust that would become the additional moons.
The gravity the surrounding dust felt as Pluto and Charon swung about their shared center of mass would vary with clock-like precision.
Conventional wisdom held that this variable tug would trigger collisions at speeds too fast to allow the dust and larger chunks to merge into ever larger objects.
Kenyon and Dr. Bromley found that, in fact, the velocities would be smaller than people thought – no greater than the speeds would be around a single central object, where velocities are slow enough to allow the debris to bump gently and merge to build ever-larger objects.
They recognized that binary stars hosting planets are essentially scaled-up versions of the Pluto-Charon system. So they applied their calculations to a hypothetical binary star system with a circumstellar disk of dust and debris.
"The modest jostling in these orbits is the same modest jostling you'd get around a single star," Kenyon says, allowing rocky inner planets to form.
As for the Jupiter- or Neptune-scale planets found around binary stars, they would have formed farther out and migrated in over time, the researchers say, since there is too little material within the inner reaches of a circumstellar disk to build giant planets.
The duo's calculations imply that as more planets are discovered orbiting binary stars, a rising number of Tatooines will be among them.
Tatooine "was science fiction," Kenyon says. But "it's not so far from science reality."
Excerpt from huffingtonpost.comI am a huge science enthusiast and an unabashed science fiction fan. There are tons of really cool stories out there that fire the imagination and even inspire young people to go into science. (I know they did me.) ...
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| (Photo : NASA/ESA) In early days of solar system, Jupiter destroyed everything that came in its way, researchers have found. |
Excerpt from latimes.com
Before Mercury, Venus, Earth and Mars occupied the inner solar system, there may have been a previous generation of planets that were bigger and more numerous – but were ultimately doomed by Jupiter, according to a new study.
If indeed the early solar system was crowded with so-called super-Earths, it would have looked a lot more like the planetary systems found elsewhere in the galaxy, scientists wrote Monday in the Proceedings of the National Academy of Sciences.
As NASA’s Kepler space telescope has found more than 1,000 planets in orbit around other stars, along with more than 4,000 other objects that are believed to be planets but haven’t yet been confirmed. Kepler finds these planets by watching their host stars and registering tiny drops in their brightness – a sign that they are being ever-so-slightly darkened by a planet crossing in front of them.
In addition, ground-based telescopes have detected hundreds of exoplanets by measuring the wiggles of distant stars. Those stars wiggle thanks to the gravitational pull of orbiting planets, and the Doppler effect makes it possible to estimate the size of these planets.
The more planetary systems astronomers discovered, the more our own solar system looked like an oddball. Exoplanets – at least the ones big enough for us to see – tended to be bigger than Earth, with tight orbits that took them much closer to their host stars. In multi-planet systems, these orbits tended to be much closer together than they are in our solar system. For instance, the star known as Kepler-11 has six planets closer to it than Venus is to the sun.
Why does our solar system look so different? Astrophysicists Konstantin Batygin of Caltech and Greg Laughlin of UC Santa Cruz summed it up in one word: Jupiter.
Here’s what could have happened, according to their models:
In Solar System 1.0, the region closest to the sun was occupied by numerous planets with masses several times bigger than that of Earth. There were also planetesimals, “planetary building blocks” that formed within the first million years after the birth of the sun, Batygin and Laughlin wrote.
This is how things might have stayed if the young Jupiter had stayed put at its initial orbit, between 3 and 10 astronomical units away from the sun. (An astronomical unit, or AU, is the distance between the Earth and the sun. Today, Jupiter’s orbit ranges between 5 and 5.5 AUs from the sun.)
But Jupiter was restless, according to a scenario known as the “Grand Tack.” In this version of events, Jupiter was swept up by the currents of gas that surrounded the young sun and drifted toward the center of the solar system.
Jupiter, however, was too big to travel solo. All manner of smaller objects would have been dragged along too. With so many bodies in motion, there would have been a lot of crashes.
The result was “a collisional cascade that grinds down the planetesimal population to smaller sizes,” the astrophysicists wrote. For the most part, these planetary crumbs were swept toward the sun and ultimately destroyed, like disintegrating satellites falling back to Earth.
The planetesimals wouldn’t have been Jupiter’s only victims. Assuming the early solar system resembled the planetary systems spied by Kepler and other telescopes, there would have been “a similar population of first-generation planets,” the pair wrote. “If such planets formed, however, they were destroyed.”
Jupiter probably got about as close to the sun as Mars is today before reversing course, pulled away by the gravity of the newly formed Saturn. That would have ended the chaos in the inner solar system, allowing Earth and the other rocky planets to form from the debris that remained.
“This scenario provides a natural explanation for why the inner Solar System bears scant resemblance to the ubiquitous multi-planet systems” discovered by Kepler and other survey efforts, Batygin and Laughlin wrote.
Although their models show that this is what might have happened, they don’t prove that it actually did. But there may be a way to get closer to the truth.
The scientists’ equations suggest that if a star is orbited by a cluster of close-in planets, there won’t be a larger, farther-out planet in the same system. As astronomers find more exoplanetary systems, they can see whether this prediction holds up.
Also, if far-away solar systems are experiencing a similar series of events, telescopes ought to be able to detect the extra heat thrown off by all of the planetesimal collisions, they added.
Sadly for those hoping to find life on other planets, the pair’s calculations also imply that most Earth-sized planets are lacking in water and other essential compounds that can exist in liquid or solid form. As a result, they would be “uninhabitable,” they wrote.
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