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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.)
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."
|Astronomer Lisa Kaltenegger |
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."
Excerpt from news.discovery.com
The geode (above), described in the latest issue of Comptes Rendus Palevol, was found in the Cioarei-Boroşteni Cave, Romania. A Neanderthal had painted it with ochre.
"The Neanderthal man must have certainly attached an aesthetic importance to it, while its having been painted with ochre was an addition meant to confer symbolic value," said Marin Cârciumaru of Valahia University and colleagues.
The researchers also noted that "the geode was undoubtedly introduced into the cave by the Neanderthal," since they ruled out that it could have originated in the cave itself.Was the geode used in rituals, or was it just a treasured object of beauty? Its precise meaning to the Neanderthal remains a mystery for now.
Based on archaeological finds, necklaces made out of Spondylus (a spiky, colorful mollusk) were all the rage. (Above)
This specimen has more of a reddish hue, but Michel Louis Séfériadès of CNRS notes that most are "a highly colored, very attractive purplish crimson." Séfériadès added that the shells were valued, early trade items and that they are now "found in the archaeological remains of settlements and cemeteries, in graves, and as isolated finds."
Some of the shells were made into jewelry, including necklaces and bracelets.
We sing about "five gold rings," but the rings would more likely have been ivory back in the day -- as in around 50,000 years ago, before ivory-producing animals were mostly hunted to extinction. Early humans in northern regions, for example, made rings out of mammoth ivory. A Neanderthal site at Grotte du Renne, France yielded a carefully crafted ivory ring (above), as well as grooved and perforated "personal ornaments," according to archaeologist Paul Mellars of Cambridge University.
Charcoal (shown avove), ochre and other materials were applied to the face by early Homo sapiens as well as by other human subspecies.
The ochre, used to paint the geode, mentioned earlier, was also used as makeup, hair dye, paint (to create rock and cave art), as well as to color garments.
Early humans used combs made out of shells and fish bones to both comb their hair and as personal decoration. (Above)
The shell from the Venus comb murex, a large predatory sea snail, is just one species that seems perfect for this purpose. Gibraltar Museum researchers Clive Finlayson and Kimberley Brown also found evidence that Neanderthals valued large, elaborate feathers, which the scientists suspect were worn by the individuals.
|Nearly all early cultures had coveted figurines holding probable symbolic value. Some of the earliest carved objects are known as "Venus" figurines. They present women with exaggerated sexual features. Their exact meaning remains unclear. (Above)|
Pendants made of animal teeth were common and probably served many different functions, such as showing the hunter's success, offering symbolic protection, and just as fashion.
Some of the funkiest-looking teeth were made into worn objects.
Animal teeth could be on a gift list dated to 540,000 years ago, and possibly earlier, as a recent study in the journal Nature found that a population of Homo erectus at Java, Indonesia, was collecting shark teeth and using them as tools and possibly as ornamentation.
The world's oldest known musical instrument is a bone flute (Above). While the earliest excavated flute dates to about 42,000 years ago, comparable flutes were probably made much earlier.
Flutes, like most of the items on this list, were not essential to survival, but yet they somehow contributed to the prehistoric peoples' quality of life.
Boffins in Australia have applied a hundreds-of-years-old astronomical rule to data from the Kepler planet-hunting space telescope. They've come to the conclusion that the average star in our galaxy has not one but two Earth-size planets in its "goldilocks" zone where liquid water - and thus, life along Earthly lines - could exist.“The ingredients for life are plentiful, and we now know that habitable environments are plentiful,” says Professor Charley Lineweaver, a down-under astrophysicist.Lineweaver and PhD student Tim Bovaird worked this out by reviewing the data on exoplanets discovered by the famed Kepler planet-hunter space scope. Kepler naturally tends to find exoplanets which orbit close to their parent suns, as it detects them by the changes in light they make by passing in front of the star. As a result, most Kepler exoplanets are too hot for liquid water to be present on their surfaces, which makes them comparatively boring.Good planets in the "goldilocks" zone which is neither too hot nor too cold are much harder to detect with Kepler, which is a shame as these are the planets which might be home to alien life - or alternatively, home one day to transplanted Earth life including human colonists, once we've cracked that pesky interstellar travel problem.However there exists a thing called the Titius-Bode relation - aka Bode's Law - which can be used, once you know where some inner planets are, to predict where ones further out will be found.Assuming Bode's Law works for other suns as it does here, and inputting the positions of known inner exoplanets found by Kepler, Lineweaver and Bovaird found that on average a star in our galaxy has two planets in its potentially-habitable zone.That doesn't mean there are habitable or inhabited planets at every star, of course. Even here in our solar system, apparently lifeless (and not very habitable) Mars is in the habitable zone.Even so, there are an awful lot of planets in the galaxy, so some at least ought to have life on them, and in some cases this life ought to have achieved a detectable civilisation. Prof Lineweaver admits that the total lack of any sign of this is a bit of a puzzler."The universe is not teeming with aliens with human-like intelligence that can build radio telescopes and space ships," admits the prof. "Otherwise we would have seen or heard from them.“It could be that there is some other bottleneck for the emergence of life that we haven’t worked out yet. Or intelligent civilisations evolve, but then self-destruct.”Of course, humans - some approximations of which have been around for some hundreds of thousands of years, perhaps - have only had civilisation of any kind in any location for a few thousand of those years. Our civilisation has only risen to levels where it could be detectable across interstellar distances very recently.There may be many planets out there inhabited by intelligent aliens who either have no civilisation at all, or only primitive civilisation. There may be quite a few who have reached or passed the stage of emitting noticeable amounts of radio or other telltale signs, but those emissions either will not reach us for hundreds of thousands of years - or went past long ago.It would seem reasonable to suspect that there are multitudes of worlds out there where life exists in plenty but has never become intelligent, as Earth life was for millions of years before early humans began using tools really quite recently.But the numbers are still such that the apparent absence of star-travelling aliens could make you worry about the viability of technological civilisation if, like Professor Lineweaver, you learn your astrophysics out of textbooks and lectures (and publish your research, as we see here, in hefty boffinry journals like the Monthly Notices of the Royal Astronomical Society).But if movies, speculofictive novels and TV have taught us anything here on the Reg alien life desk, it is that in fact the galaxy is swarming with star-travelling aliens (and/or humans taken secretly from planet Earth for mysterious purposes in the past, or perhaps humans from somewhere else etc). The reason we don't know about them is that they don't want us to.
Excerpt from earthsky.org
Admit it. You’ve probably got a pair of binoculars lying around your house somewhere. They may be perfect – that’s right, perfect – for beginning stargazing. Follow the links below to learn more about the best deal around for people who want to get acquainted with the night sky: a pair of ordinary binoculars.1. Binoculars are a better place to start than telescopes2. Start with a small, easy-to-use size3. First, view the moon with binoculars.4. Move on to viewing planets with binoculars.5. Use your binoculars to explore inside our Milky Way.6. Use your binoculars to peer beyond the Milky Way.1. Binoculars are a better place to start than telescopes. The fact is that most people who think they want to buy a telescope would be better off using binoculars for a year or so instead. That’s because first-time telescope users often find themselves completely confused – and ultimately put off – by the dual tasks of learning the use a complicated piece of equipment (the ‘scope) while at the same time learning to navigate an unknown realm (the night sky).Beginning stargazers often find that an ordinary pair of binoculars – available from any discount store – can give them the experience they’re looking for. After all, in astronomy, magnification and light-gathering power let you see more of what’s up there. Even a moderate form of power, like those provided by a pair of 7×50 binoculars, reveals 7 times as much information as the unaided eye can see.You also need to know where to look. Many people start with a planisphere as they begin their journey making friends with the stars. You can purchase a planisphere at the EarthSky store. Also consider our Astronomy Kit, which has a booklet on what you can see with your binoculars.2. Start with a small, easy-to-use size. Don’t buy a huge pair of binoculars to start with! Unless you mount them on a tripod, they’ll shake and make your view of the heavens shakey, too. The video above – from ExpertVillage – does a good job summing up what you want. And in case you don’t want to watch the video, the answer is that 7X50 binoculars are optimum for budding astronomers. You can see a lot, and you can hold them steadily enough that jitters don’t spoil your view of the sky. Plus they’re very useful for daylight pursuits, like birdwatching. If 7X50s are too big for you – or if you want binoculars for a child – try 7X35s.
3. First, view the moon with binoculars. When you start to stargaze, you’ll want to watch the phase of the moon carefully. If you want to see deep-sky objects inside our Milky Way galaxy – or outside the galaxy – you’ll want to avoid the moon. But the moon itself is a perfect target for beginning astronomers, armed with binoculars. Hint: the best time to observe the moon is in twilight. Then the glare of the moon is not so great, and you’ll see more detail.
February 24, 2014 moon with earthshine by Greg Diesel Landscape Photography.
You’ll want to start your moon-gazing when the moon is just past new – and visible as a waxing crescent in the western sky after sunset. At such times, you’ll have a beautiful view of earthshine on the moon. This eerie glow on the moon’s darkened portion is really light reflected from Earth onto the moon’s surface. Be sure to turn your binoculars on the moon at these times to enhance the view. Each month, as the moon goes through its regular phases, you can see the line of sunrise and sunset on the moon progress across the moon’s face. That’s just the line between light and dark on the moon. This line between the day and night sides of the moon is called the terminator line. The best place to look at the moon from Earth – using your binoculars – is along the terminator line. The sun angle is very low in this twilight zone, just as the sun is low in our sky around earthly twilight. So, along the terminator on the moon, lunar features cast long shadows in sharp relief.You can also look in on the gray blotches on the moon called maria, named when early astronomers thought these lunar features were seas. The maria are not seas, of course, and instead they’re now thought to have formed 3.5 billion years ago when asteroid-sized rocks hit the moon so hard that lava percolated up through cracks in the lunar crust and flooded the impact basins. These lava plains cooled and eventually formed the gray seas we see today.The white highlands, nestled between the maria, are older terrain pockmarked by thousands of craters that formed over the eons. Some of the larger craters are visible in binoculars. One of them, Tycho, at the six o’clock position on the moon, emanates long swatches of white rays for hundreds of miles over the adjacent highlands. This is material kicked out during the Tycho impact 2.5 million years ago.
4. Move on to viewing planets with binoculars. Here’s the deal about planets. They move around, apart from the fixed stars. They are wanderers, right?You can use our EarthSky Tonight page to locate planets visible around now. Notice if any planets are mentioned in the calendar on the Tonight page, and if so click on that day’s link. On our Tonight page, we feature planets on days when they’re easily identifiable for some reason – for example, when a planet is near the moon. So our Tonight page calendar can help you come to know the planets, and, as you’re learning to identify them, keep your binoculars very handy. Binoculars will enhance your view of a planet near the moon, for example, or two planets near each other in the twilight sky. They add a lot to the fun!Below, you’ll find some more simple ideas on how to view planets with your binoculars.Mercury and Venus. These are both inner planets. They orbit the sun closer than Earth’s orbit. And for that reason, both Mercury and Venus show phases as seen from Earth at certain times in their orbit – a few days before or after the planet passes between the sun and Earth. At such times, turn your binoculars on Mercury or Venus. Good optical quality helps here, but you should be able to see them in a crescent phase. Tip: Venus is so bright that its glare will overwhelm the view. Try looking in twilight instead of true darkness.Mars. Mars – the Red Planet – really does look red, and using binoculars will intensify the color of this object (or of any colored star). Mars also moves rapidly in front of the stars, and it’s fun to aim your binoculars in its direction when it’s passing near another bright star or planet.Jupiter. Now on to the real action! Jupiter is a great binocular target, even for beginners. If you are sure to hold your binoculars steadily as you peer at this bright planet, you should see four bright points of light near it. These are the Galilean Satellites – four moons gleaned through one of the first telescopes ever made, by the Italian astronomer Galileo. Note how their relative positions change from night to night as each moon moves around Jupiter in its own orbit.Saturn.Although a small telescope is needed to see Saturn’s rings, you can use your binoculars to see Saturn’s beautiful golden color. Experienced observers sometimes glimpse Saturn’s largest moon Titan with binoculars. Also, good-quality high-powered binoculars – mounted on a tripod – will show you that Saturn is not round. The rings give it an elliptical shape.Uranus and Neptune. Some planets are squarely binocular and telescope targets. If you’re armed with a finder chart, two of them, Uranus and Neptune, are easy to spot in binoculars. Uranus might even look greenish, thanks to methane in the planet’s atmosphere. Once a year, Uranus is barely bright enough to glimpse with the unaided eye . . . use binoculars to find it first. Distant Neptune will always look like a star, even though it has an atmosphere practically identical to Uranus.There are still other denizens of the solar system you can capture through binocs. Look for the occasional comet, which appears as a fuzzy blob of light. Then there are the asteroids – fully 12 of them can be followed with binoculars when they are at their brightest. Because an asteroid looks star-like, the secret to confirming its presence is to sketch a star field through which it’s passing. Do this over subsequent nights; the star that changes position relative to the others is our solar system interloper.
Photo of Jupiter’s moons by Earthsky Facebook friend Carl Galloway. Thank you Carl! The four major moons of Jupiter are called Io, Europa, Ganymede and Callisto. This is a telescopic view, but you can glimpse one, two or more moons through your binoculars, too.
5. Use your binoculars to explore inside our Milky Way. Binoculars can introduce you to many members of our home galaxy. A good place to start is with star clusters that are close to Earth. They cover a larger area of the sky than other, more distant clusters usually glimpsed through a telescope.Beginning each autumn and into the spring, look for a tiny dipper-like cluster of stars called the Pleiades. The cluster – sometimes also called the Seven Sisters – is noticeable for being small yet distinctively dipper-like. While most people say they see only six stars here with the unaided eye, binoculars reveal many more stars, plus a dainty chain of stars extending off to one side. The Pleiades star cluster is looks big and distinctive because it’s relatively close – about 400 light years from Earth. This dipper-shaped cluster is a true cluster of stars in space. Its members were born around the same time and are still bound by gravity. These stars are very young, on the order of 20 million years old, in contrast to the roughly five billion years for our sun.Stars in a cluster all formed from the same gas cloud. You can also see what the Pleiades might have like in a primordial state, by shifting your gaze to the prominent constellation Orion the Hunter. Look for Orion’s sword stars, just below his prominent belt stars. If the night is crisp and clear, and you’re away from urban streetlight glare, unaided eyes will show that the sword isn’t entirely composed of stars. Binoculars show a steady patch of glowing gas where, right at this moment, a star cluster is being born. It’s called the Orion Nebula. A summertime counterpart is the Lagoon Nebula, in Sagittarius the Archer.With star factories like the Orion Nebula, we aren’t really seeing the young stars themselves. They are buried deep within the nebula, bathing the gas cloud with ultraviolet radiation and making it glow. In a few tens of thousands of years, stellar winds from these young, energetic stars will blow away their gaseous cocoons to reveal a newly minted star cluster.Scan along the Milky Way to see still more sights that hint at our home galaxy’s complexity. First, there’s the Milky Way glow itself; just a casual glance through binoculars will reveal that it is still more stars we can’t resolve with our eyes . . . hundreds of thousands of them. Periodically, while scanning, you might sweep past what appears to be blob-like, black voids in the stellar sheen. These are dark, non-glowing pockets of gas and dust that we see silhouetted against the stellar backdrop. This is the stuff of future star and solar systems, just waiting around to coalesce into new suns.
Pleiades star cluster, also known as the Seven Sisters
Andromeda Galaxy from Chris Levitan Photography.
6. Use your binoculars to view beyond the Milky Way. Let’s leap out of our galaxy for the final stop in our binocular tour. Throughout fall and winter, she reigns high in the sky during northern hemisphere autumns and winters: Andromeda the Maiden. Centered in the star pattern is an oval patch of light, readily visible to the unaided eye away from urban lights. Binoculars will show it even better.It’s a whole other galaxy like our own, shining across the vastness of intergalactic space. Light from the Andromeda Galaxy has traveled so far that it’s taken more than 2 million years to reach us.Two smaller companions visible through binoculars on a dark, transparent night are the Andromeda Galaxy’s version of our Milky Way’s Magellanic Clouds. These small, orbiting, irregularly-shaped galaxies that will eventually be torn apart by their parent galaxy’s gravity.Such sights, from lunar wastelands to the glow of a nearby island universe, are all within reach of a pair of handheld optics, really small telescopes in their own right: your binoculars.John Shibley wrote the original draft of this article, years ago, and we’ve been expanding it and updating it ever since. Thanks, John!Bottom line: For beginning stargazers, there’s no better tool than an ordinary pair of binoculars. This post tells you why, explains what size to get, and gives you a rundown on some of the coolest binoculars sights out there: the moon, the planets, inside the Milky Way, and beyond. Have fun!
Many people use the M- or W-shaped constellation Cassiopeia to find the Andromeda Galaxy. See how the star Schedar points to the galaxy?