Tag: zone (page 2 of 6)

Concorde Comeback? Two New Jets Plan to Take Air Passengers Supersonic Again

March 14, 2015 / / 0 Comments




Concorde Comeback? Two New Jets Plan to Take Air Passengers Supersonic Again
Lockheed Martin and NASA’s N+2 jet could cut cross-country flight times in half. (Photo: Lockheed Martin)



Excerpt from yahoo.com

Lockheed Martin and NASA’s N+2 jet could cut cross-country flight times in half. New York to Los Angeles in just over two hours? Passenger jets that fly faster than the speed of sound without that annoying sonic boom?  


That could become reality thanks to two projects that aim to bring supersonic planes back to commercial air travel.  Lockheed Martin is working with NASA on a design called the N+2, an 80-passenger jet capable of cruising at Mach 1.7 (1.7 times the speed of sound). 

But what about that loud sonic boom you get when an airplane exceeds the sound barrier? Lockheed Martin and NASA are working hard to lower the boom, so to speak. They say their proposed new jet will be 100 times quieter than the Concorde, the supersonic passenger jets that flew transatlantic routes from 1969 until they were grounded in 2003.

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The supersonic Concorde flew from 1969 to 2003. (Photo: AP)


A quieter jet would allow the N+2 to fly at supersonic speeds on cross-country routes as the FAA, concerned about sonic booms going off over sleepy U.S. suburbs, currently bans civilian planes from going all “Danger Zone” in American airspace. Lockheed Martin says their new jet would cut cross-country flight times in half.  Related: Race for the First Windowless Plane Heats Up  A rival supersonic jet development project is underway in Reno, Nevada, where European aircraft maker Airbus is working with American firm Aerion on a new, fuel-efficient plane for business clients. The 12-passenger Aerion AS2 will fly at 1,217 mph (which is almost as fast as the Concorde, which flew at 1,350 mph). That would take you from New York to London in three hours and from Los Angeles to Tokyo in six.  

Since the AS2 would do most of its flying over oceans, its designers aren’t as concerned with loud sonic booms. The AS2’s big innovation is fuel efficiency, with new wings that are said to reduce drag by 20 percent.  The makers of the AS2 plan to deliver their first plane in 2022 while Lockheed Martin hopes to have the N+2 flying in 2025.  

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A Complete Guide to the March 20th Total Solar Eclipse

March 12, 2015 / / 0 Comments


Credit
Totality! The 2012 total solar eclipse as seen from Australia. Credit and copyright: www.hughca.com.



Excerpt from universetoday.com



The first of two eclipse seasons for the year is upon us this month, and kicks off with the only total solar eclipse for 2015 on Friday, March 20th.

And what a bizarre eclipse it is. Not only does this eclipse begin just 15 hours prior to the March equinox marking the beginning of astronomical spring in the northern hemisphere, but the shadow of totality also beats path through the high Arctic and ends over the North Pole.


Credit:
An animation of the March 20th eclipse. Credit: NASA/GSFC/AT Sinclair.


Already, umbraphiles — those who chase eclipses — are converging on the two small tracts of terra firma where the umbra of the Moon makes landfall: the Faroe and Svalbard islands. All of Europe, the northern swath of the African continent, north-central Asia and the Middle East will see a partial solar eclipse, and the eclipse will be deeper percentage-wise the farther north you are .
2015 features four eclipses in all: two total lunars and two solars, with one total solar and one partial solar eclipse. Four is the minimum number of eclipses that can occur in a calendar year, and although North America misses out on the solar eclipse action this time ’round, most of the continent gets a front row seat to the two final total lunar eclipses of the ongoing tetrad on April 4th and September 28th.

How rare is a total solar eclipse on the vernal equinox? Well, the last total solar eclipse on the March equinox occurred back in 1662 on March 20th. There was also a hybrid eclipse — an eclipse which was annular along a portion of the track, and total along another — on March 20th, 1681. But you won’t have to wait that long for the next, as another eclipse falls on the northward equinox on March 20th, 2034.


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The path of the March 20th eclipse across Europe, including start times for the partial phases, and the path of totality, click to enlarge. For more maps showing the percentage of occlusion, elevation, and more, click here. Credit: Michael Zeiler/GreatAmercianEclipse.com.


Note that in the 21st century, the March equinox falls on March 20th, and will start occasionally falling on March 19th in 2044. We’re also in that wacky time of year where North America has shifted back to ye ‘ole Daylight Saving (or Summer) Time, while Europe makes the change after the eclipse on March 29th. It really can wreak havoc with those cross-time zone plans, we know…
The March 20th eclipse also occurs only a day after lunar perigee, which falls on March 19th at 19:39 UT. This is also one of the closer lunar perigees for 2015 at 357,583 kilometres distant, though the maximum duration of totality for this eclipse is only 2 minutes and 47 seconds just northeast of the Faroe Islands.


Credit:
Views from selected locales in Europe and Africa. Credit: Stellarium.



This eclipse is number 61 of 71 in solar saros series 120, which runs from 933 to 2754 AD. It’s also the second to last total in the series, with the final total solar eclipse for the saros cycle occurring one saros later on March 30th, 2033.



What would it look like to sit at the North Pole and watch a total solar eclipse on the first day of Spring? It would be a remarkable sight, as the disk of the Sun skims just above the horizon for the first time since the September 2014 equinox. Does this eclipse occur at sunrise or sunset as seen from the pole? It would be a rare spectacle indeed!


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An equinoctal eclipse as simulated from the North Pole. Credit: Stellarium.






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Practicing eclipse safety in Africa. Credit: Michael Zeiler/GreatAmericanEclipse.com


Safety is paramount when observing the Sun and a solar eclipse. Eye protection is mandatory during all partial phases across Europe, northern Asia, North Africa and the Middle East. A proper solar filter mask constructed of Baader safety film is easy to construct, and should fit snugly over the front aperture of a telescope. No. 14 welder’s goggles are also dense enough to look at the Sun, as are safety glasses specifically designed for eclipse viewing. Observing the Sun via projection or by using a pinhole projector is safe and easy to do.


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A solar filtered scope ready to go in Tucson, Arizona. Credit: photo by author.

Weather is always the big variable in the days leading up to any eclipse. Unfortunately, March in the North Atlantic typically hosts stormy skies, and the low elevation of the eclipse in the sky may hamper observations as well. From the Faroe Islands, the Sun sits 18 degrees above the horizon during totality, while from the Svalbard Islands it’s even lower at 12 degrees in elevation. Much of Svalbard is also mountainous, making for sunless pockets of terrain that will be masked in shadow on eclipse day. Mean cloud amounts for both locales run in the 70% range, and the Eclipser website hosts a great in-depth climatology discussion for this and every eclipse.


Credit
The view of totality and the planets as seen from the Faroe Islands. Credit: Starry Night.


But don’t despair: you only need a clear view of the Sun to witness an eclipse!

Solar activity is also another big variable. Witnesses to the October 23rd, 2014 partial solar eclipse over the U.S. southwest will recall that we had a massive and very photogenic sunspot turned Earthward at the time. The Sun has been remarkably calm as of late, though active sunspot region 2297 is developing nicely. It will have rotated to the solar limb come eclipse day, and we should have a good grasp on what solar activity during the eclipse will look like come early next week.

And speaking of which: could an auroral display be in the cards for those brief few minutes of totality? It’s not out of the question, assuming the Sun cooperates.  Of course, the pearly white corona of the Sun still gives off a considerable amount of light during totality, equal to about half the brightness of a Full Moon. Still, witnessing two of nature’s grandest spectacles — a total solar eclipse and the aurora borealis — simultaneously would be an unforgettable sight, and to our knowledge, has never been documented!

We also put together some simulations of the eclipse as seen from Earth and space:




Note that an area of southern Spain may witness a transit of the International Space Station during the partial phase of the eclipse. This projection is tentative, as the orbit of the ISS evolves over time. Be sure to check CALSky for accurate predictions in the days leading up to the eclipse.


Credit
The ISS transits the Sun during the eclipse around 9:05 UT as seen from southern Spain. Credit: Starry Night.


Can’t make it to the eclipse? Live in the wrong hemisphere? There are already a few planned webcasts for the March 20th eclipse:


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Chances of Exoplanet Life ‘Impossible’? Or ‘100 percent’?

March 9, 2015 / / 0 Comments


Kepler’s Exoplanets: A map of the locations of exoplanets, of various masses, in the Kepler field of view. 1,235 candidates are plotted (NASA/Wendy Stenzel)


 news.discovery.com 

Just in case you haven’t heard, our galaxy appears to be teeming with small worlds, many of which are Earth-sized candidate exoplanets and dozens appear to be orbiting their parent stars in their “habitable zones.”

Before Wednesday’s Kepler announcement, we knew of just over 500 exoplanets orbiting stars in the Milky Way. Now the space telescope has added another 1,235 candidates to the tally — what a difference 24 hours makes.

Although this is very exciting, the key thing to remember is that we are talking about exoplanet candidates, which means Kepler has detected 1,235 exoplanet signals, but more work needs to be done (i.e. more observing time) to refine their orbits, masses and, critically, to find out whether they actually exist.

But, statistically speaking, a pattern is forming. Kepler has opened our eyes to the fact our galaxy is brimming with small worlds — some candidates approaching Mars-sized dimensions!

Earth-Brand™ Life

Before Kepler, plenty of Jupiter-sized worlds could be seen, but with its precision eye for spotting the tiniest of fluctuations of star brightness (as a small exoplanet passes between Kepler and the star), the space telescope has found that smaller exoplanets outnumber the larger gas giants.

Needless to say, all this talk of “Earth-sized” worlds (and the much-hyped “Earth-like” misnomer) has added fuel to the extraterrestrial life question: If there’s a preponderance of small exoplanets — some of which orbit within the “sweet-spot” of the habitable zones of their parent stars — could life as we know it (or Earth-Brand™ Life as I like to call it) also be thriving there?
Before I answer that question, let’s turn back the clock to Sept. 29, 2010, when, in the wake of the discovery of the exoplanet Gliese 581 g, Steven Vogt, professor of astronomy and astrophysics at University of California Santa Cruz, told Discovery News: “Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on [Gliese 581 g] are 100 percent. I have almost no doubt about it.”

Impossible? Or 100 Percent?

As it turns out, Gliese 581 g may not actually exist — an excellent example of the progress of science scrutinizing a candidate exoplanet in complex data sets as my Discovery News colleague Nicole Gugliucci discusses in “Gliese 581g and the Nature of Science” — but why was Vogt so certain that there was life on Gliese 581 g? Was he “wrong” to air this opinion?

Going to the opposite end of the spectrum, Howard Smith, an astrophysicist at Harvard University, made the headlines earlier this year when he announced, rather pessimistically, that aliens will unlikely exist on the extrasolar planets we are currently detecting.
“We have found that most other planets and solar systems are wildly different from our own. They are very hostile to life as we know it,” Smith told the UK’s Telegraph.

Smith made comparisons between our own solar system with the interesting HD 10180 system, located 127 light-years away. HD 10180 was famous for a short time as being the biggest star system beyond our own, containing five exoplanets (it has since been trumped by Kepler-11, a star system containing six exoplanets as showcased in Wednesday’s Kepler announcement).

One of HD 10180′s worlds is thought to be around 1.4 Earth-masses, making it the smallest detected exoplanet before yesterday. Alas, as Smith notes, that is where the similarities end; the “Earth-sized” world orbiting HD 10180 is too close to its star, meaning it is a roasted exoplanet where any atmosphere is blasted into space by the star’s powerful radiation and stellar winds.
The Harvard scientist even dismissed the future Kepler announcement, pointing out that upcoming reports of habitable exoplanets would be few and far between. “Extrasolar systems are far more diverse than we expected, and that means very few are likely to support life,” he said.

Both Right and Wrong

So what can we learn about the disparity between Vogt and Smith’s opinions about the potential for life on exoplanets, regardless of how “Earth-like” they may seem?

Critically, both points of view concern Earth-Brand™ Life (i.e. us and the life we know and understand). As we have no experience of any other kind of life (although the recent eruption of interest over arsenic-based life is hotly debated), it is only Earth-like life we can realistically discuss.

We could do a Stephen Hawking and say that all kinds of life is possible anywhere in the cosmos, but this is pure speculation. Science only has life on Earth to work with, so (practically speaking) it’s pointless to say a strange kind of alien lifeform could live on an exoplanet where the surface is molten rock and constantly bathed in extreme stellar radiation.

If we take Hawking’s word for it, Vogt was completely justified for being so certain about life existing on Gliese 581 g. What’s more, there’s no way we could prove he’s wrong!

But if you set the very tight limits on where we could find Earth-like life, we are suddenly left with very few exoplanet candidates that fit the bill. Also, just because an Earth-sized planet might be found in the habitable zone of its star, doesn’t mean it’s actually habitable. There are many more factors to consider. So, in this case, Smith’s pessimism is well placed.

Regardless, exoplanet science is in its infancy and the uncertainty with the “is there life?” question is a symptom of being on the “raggedy edge of science,” as Nicole would say. We simply do not know what it takes to make a world habitable for any kind of life (apart from Earth), but it is all too tempting to speculate as to whether a race of extraterrestrials, living on one of Kepler’s worlds, is pondering these same questions.

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Habitable’ Super-Earth Might Exist After All

March 9, 2015 / / 0 Comments


Artist's impression of Gliese 581d, a controversial exoplanet that may exist only 20 light-years from Earth.



Excerpt from news.discovery.com

Despite having discovered nearly 2,000 alien worlds beyond our solar system, the profound search for exoplanets — a quest focused on finding a true Earth analog — is still in its infancy. It is therefore not surprising that some exoplanet discoveries aren’t discoveries at all; they are in fact just noise in astronomical data sets.

But when disproving the existence of extrasolar planets that have some characteristics similar to Earth, we need to take more care during the analyses of these data, argue astronomers from Queen Mary, University of London and the University of Hertfordshire.

In a paper published by the journal Science last week, the researchers focus on the first exoplanet discovered to orbit a nearby star within its habitable zone.

Revealed in 2009, Gliese 581d hit the headlines as a “super-Earth” that had the potential to support liquid water on its possibly rocky surface. With a mass of around 7 times that of Earth, Gliese 581d would be twice as big with a surface gravity around twice that of Earth. Though extreme, it’s not such a stretch of the imagination that such a world, if it is proven to possess an atmosphere and liquid ocean, that life could take hold.

And the hunt for life-giving alien worlds is, of course, the central motivation for exoplanetary studies.

But the exoplanet signal has been called into doubt.
Gliese 581d’s star, Gliese 581, is a small red dwarf around 20 light-years away. Red dwarfs are known to be tempestuous little stars, often generating violent flaring outbursts and peppered in dark features called starspots. To detect the exoplanet, astronomers measured the very slight frequency shift (Doppler shift) of light from the star — as the world orbits, it exerts a tiny gravitational “tug”, causing the star to wobble. When this periodic wobble is detected, through an astronomical technique known as the “radial velocity method,” a planet may be revealed.

Last year, however, in a publication headed by astronomers at The Pennsylvania State University, astronomers pointed to the star’s activity as an interfering factor that may have imitated the signal from an orbiting planet when in fact, it was just noisy data.

But this conclusion was premature, argues Guillem Anglada-Escudé, of Queen Mary, saying that “one needs to be more careful with these kind of claims.”

“The existence, or not, of GJ 581d is significant because it was the first Earth-like planet discovered in the ‘Goldilocks’-zone around another star and it is a benchmark case for the Doppler technique,” said Anglada-Escudé in a university press release. “There are always discussions among scientists about the ways we interpret data but I’m confident that GJ 581d has been in orbit around Gliese 581 all along. In any case, the strength of their statement was way too strong. If the way to treat the data had been right, then some planet search projects at several ground-based observatories would need to be significantly revised as they are all aiming to detect even smaller planets.”

The upshot is that this new paper challenges the statistical technique used in 2014 to account for the signal being stellar noise — focusing around the presence of starspots in Gliese 581′s photosphere.

Gliese 581d isn’t the only possible exoplanet that exists around that star — controversy has also been created by another, potentially habitable exoplanet called Gliese 581g. Also originally detected through the wobble of the star, this 3-4 Earth mass world was found to also be in orbit within the habitable zone. But its existence has been the focus of several studies supporting and discounting its presence. Gliese 581 is also home to 3 other confirmed exoplanets, Gliese 581e, b and c.

Currently, observational data suggests Gliese 581g was just noise, but as the continuing debate about Gliese 581d is proving, this is one controversy that will likely keep on rumbling in the scientific journals for some time.

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Do we really want to know if we’re not alone in the universe?

March 4, 2015 / / 0 Comments



Frank Drake, the founder of Search for Extraterrestrial Intelligence (SETI), at his home in Aptos, Calif. (Ramin Rahimian for The Washington Post)


Excerpt from washingtonpost.com

It was near Green Bank, W.Va., in 1960 that a young radio astronomer named Frank Drake conducted the first extensive search for alien civilizations in deep space. He aimed the 85-foot dish of a radio telescope at two nearby, sun-like stars, tuning to a frequency he thought an alien civilization might use for interstellar communication.

But the stars had nothing to say.

So began SETI, the Search for Extraterrestrial Intelligence, a form of astronomical inquiry that has captured the imaginations of people around the planet but has so far failed to detect a single “hello.” Pick your explanation: They’re not there; they’re too far away; they’re insular and aloof; they’re zoned out on computer games; they’re watching us in mild bemusement and wondering when we’ll grow up.

Now some SETI researchers are pushing a more aggressive agenda: Instead of just listening, we would transmit messages, targeting newly discovered planets orbiting distant stars. Through “active SETI,” we’d boldly announce our presence and try to get the conversation started.

Naturally, this is controversial, because of . . . well, the Klingons. The bad aliens.

 NASA discovers first Earth-size planet in habitable zone of another star

"NASA's Kepler Space Telescope has discovered the first validated Earth-size planet orbiting in the habitable zone of a distant star, an area where liquid water might exist on its surface. The planet, Kepler-186f, is ten percent larger in size than Earth and orbits its parent star, Kepler-186, every 130 days. The star, located about 500 light-years from Earth, is classified as an M1 dwarf and is half the size and mass of our sun." (NASA Ames Research Center)
“ETI’s reaction to a message from Earth cannot presently be known,” states a petition signed by 28 scientists, researchers and thought leaders, among them SpaceX founder Elon Musk. “We know nothing of ETI’s intentions and capabilities, and it is impossible to predict whether ETI will be benign or hostile.”

This objection is moot, however, according to the proponents of active SETI. They argue that even if there are unfriendlies out there, they already know about us. That’s because “I Love Lucy” and other TV and radio broadcasts are radiating from Earth at the speed of light. Aliens with advanced instruments could also detect our navigational radar beacons and would see that we’ve illuminated our cities.

“We have already sent signals into space that will alert the aliens to our presence with the transmissions and street lighting of the last 70 years,” Seth Shostak, an astronomer at the SETI Institute in California and a supporter of the more aggressive approach, has written. “These emissions cannot be recalled.”

That’s true only to a point, say the critics of active SETI. They argue that unintentional planetary leakage, such as “I Love Lucy,” is omnidirectional and faint, and much harder to detect than an intentional, narrowly focused signal transmitted at a known planet.

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Recent Disappearances & Strangeness in the Bermuda Triangle

March 1, 2015 / / 0 Comments

Excerpt from paranormal.lovetoknow.com By Michelle Radcliff The Bermuda Triangle is an area of mostly open ocean located between Bermuda, Miami, Florida and San Juan, Puerto Rico. The unexplained disappearances of hundreds of ships and air...

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Earth’s Moon May Not Be Critical to Life Afterall

February 19, 2015 / / 0 Comments




Excerpt from space.com

 The moon has long been viewed as a crucial component in creating an environment suitable for the evolution of complex life on Earth, but a number of scientific results in recent years have shown that perhaps our planet doesn't need the moon as much as we have thought.

In 1993, French astronomer Jacques Laskar ran a series of calculations indicating that the gravity of the moon is vital to stabilizing the tilt of our planet. Earth's obliquity, as this tilt is technically known as, has huge repercussions for climate. Laskar argued that should Earth's obliquity wander over hundreds of thousands of years, it would cause environmental chaos by creating a climate too variable for complex life to develop in relative peace.
So his argument goes, we should feel remarkably lucky to have such a large moon on our doorstep, as no other terrestrial planet in our solar system has such a moon. Mars' two satellites, Phobos and Deimos, are tiny, captured asteroids that have little known effect on the Red Planet. Consequently, Mars' tilt wobbles chaotically over timescales of millions of years, with evidence for swings in its rotational axis at least as large as 45 degrees. 


The stroke of good fortune that led to Earth possessing an unlikely moon, specifically the collision 4.5 billion years ago between Earth and a Mars-sized proto-planet that produced the debris from which our Moon formed, has become one of the central tenets of the 'Rare Earth' hypothesis. Famously promoted by Peter Ward and Don Brownlee, it argues that planets where everything is just right for complex life are exceedingly rare.

New findings, however, are tearing up the old rule book. In 2011, a trio of scientists — Jack Lissauer of NASA Ames Research Center, Jason Barnes of the University of Idaho and John Chambers of the Carnegie Institution for Science — published results from new simulations describing what Earth's obliquity would be like without the moon. What they found was surprising.

"We were looking into how obliquity might vary for all sorts of planetary systems," says Lissauer. "To test our code we began with integrations following the obliquity of Mars and found similar results to other people. But when we did the obliquity of Earth we found the variations were much smaller than expected — nowhere near as extreme as previous calculations suggested they would be."
Lissauer's team found that without the moon, Earth's rotational axis would only wobble by 10 degrees more than its present day angle of 23.5 degrees. The reason for such vastly different results to those attained by Jacques Laskar is pure computing power. Today's computers are much faster and capable of more accurate modeling with far more data than computers of the 1990s.

Lissauer and his colleagues also found that if Earth were spinning fast, with one day lasting less than 10 hours, or rotating retrograde (i.e. backwards so that the sun rose in the West and set in the East), then Earth stabilized itself thanks to the gravitational resonances with other planets, most notably giant Jupiter. There would be no need for a large moon. 

Earth's rotation has not always been as leisurely as the current 24 hour spin-rate. Following the impact that formed the moon, Earth was spinning once every four or five hours, but it has since gradually slowed by the moon's presence. As for the length of Earth's day prior to the moon-forming impact, nobody really knows, but some models of the impact developed by Robin Canup of the Southwest Research Institute, in Boulder, Colorado, suggest that Earth could have been rotating fast, or even retrograde, prior to the collision.

Tilted Orbits
Planets with inclined orbits could find that their increased obliquity is beneficial to their long-term climate – as long as they do not have a large moon.


"Collisions in the epoch during which Earth was formed determined its initial rotation," says Lissauer. "For rocky planets, some of the models say most of them will be prograde, but others say comparable numbers of planets will be prograde and retrograde. Certainly, retrograde worlds are not expected to be rare."

The upshot of Lissauer's findings is that the presence of a moon is not the be all and end all as once thought, and a terrestrial planet can exist without a large moon and still retain its habitability. Indeed, it is possible to imagine some circumstances where having a large moon would actually be pretty bad for life.

Rory Barnes, of the University of Washington, has also tackled the problem of obliquity, but from a different perspective. Planets on the edge of habitable zones exist in a precarious position, far enough away from their star that, without a thick, insulating atmosphere, they freeze over, just like Mars. Barnes and his colleagues including John Armstrong of Weber State University, realized that torques from other nearby worlds could cause a planet's inclination to the ecliptic plane to vary. This in turn would result in a change of obliquity; the greater the inclination, the greater the obliquity to the Sun. Barnes and Armstrong saw that this could be a good thing for planets on the edges of habitable zones, allowing heat to be distributed evenly over geological timescales and preventing "Snowball Earth" scenarios. They called these worlds "tilt-a-worlds," but the presence of a large moon would counteract this beneficial obliquity change.

"I think one of the most important points from our tilt-a-world paper is that at the outer edge of the habitable zone, having a large moon is bad, there's no other way to look at it," says Barnes. "If you have a large moon that stabilizes the obliquity then you have a tendency to completely freeze over."

Barnes is impressed with the work of Lissauer's team.
"I think it is a well done study," he says. "It suggests that Earth does not need the moon to have a relatively stable climate. I don't think there would be any dire consequences to not having a moon."

Mars' Changing Tilt
The effects of changing obliquity on Mars’ climate. Mars’ current 25-degree tilt is seen at top left. At top right is a Mars that has a high obliquity, leading to ice gather at its equator while the poles point sunwards. At bottom is Mars with low obliquity, which sees its polar caps grow in size.


Of course, the moon does have a hand in other factors important to life besides planetary obliquity. Tidal pools may have been the point of origin of life on Earth. Although the moon produces the largest tides, the sun also influences tides, so the lack of a large moon is not necessarily a stumbling block. Some animals have also evolved a life cycle based on the cycle of the moon, but that's more happenstance than an essential component for life.

"Those are just minor things," says Lissauer.

Without the absolute need for a moon, astrobiologists seeking life and habitable worlds elsewhere face new opportunities. Maybe Earth, with its giant moon, is actually the oddball amongst habitable planets. Rory Barnes certainly doesn't think we need it.
"It will be a step forward to see the myth that a habitable planet needs a large moon dispelled," he says, to which Lissauer agrees.
Earth without its moon might therefore remain habitable, but we should still cherish its friendly presence. After all, would Beethoven have written the Moonlight Sonata without it?

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Aliens Even More Likely Now To Be Out There ~ Average star has two potentially Earth-like worlds

February 7, 2015 / / 0 Comments



Concept art depicting the lights of an ET civilisation on an exoplanet. Credit: David A Aguilar (CfA)

Excerpt from theregister.co.uk



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.

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Eight New Goldilocks Planets that May Host Alien Life Found

February 4, 2015 / / 0 Comments



Eight New Goldilocks Planets that May Host Alien Life Found


Excerpt from utahpeoplespost.com
By Frank Smith

Scientists from the Harvard-Smithsonian Center for Astrophysics (CfA) recently reported that they identified eight new exoplanets orbiting their host stars in the so-called “Goldilocks” zone. Researchers also said that many of these objects have an increased chance to be Earth-like, rocky planets with a high potential of hosting alien life.
The “Goldilocks zone,” or the habitable zone, is a patch of space around a Sun-like star that allow planets orbiting within it hold liquid water on their surface if they also have the necessary atmospheric pressure for it. Most Goldilocks planets are Earth-sized so scientists hope that one of them may host life, even microbial forms of life.
The new discovery of the exoplanets doubles the number of known planets located in the habitable zone of their host stars. Scientists explain that the habitable zone implies that the planets within it receive as much solar as our planet does. Too much radiation and heat would boil the water on their surface and even blow away their atmosphere. Too little radiation would lead to a small icy world.
The authors of the discovery also reported that two of the newly found planets are the most akin to Earth than any other known exoplanets to this date. The two planets were named Kepler-438b and Kepler-442b after the space telescope that had discovered them.
Kepler-438b is located 470 light-years from our planet, while Kepler-442b stands in the constellation Lyra at a 1,120 light-year-long distance away from Earth. Kepler-442b is also the most remote exoplanet of the eight.
The two planets have also an extremely short orbit because they are very close to their host stars. On Kepler-438b, which has a diameter only 12 percent than the Earth’s, a year lasts only 35 days, while on Kepler-442b, which is nearly one third larger than our planet, a year passes every 112 days.
Scientists estimate that Kepler-438b has a 70 percent increased chance of having a rocky core, while Kepler-442b has only a 60 percent chance.
However, the two planets being in the habitable zone of their host stars is not a certain fact. For instance, astronomers estimate that Kepler-438b has only a 70 percent chance of being located in the Goldilocks zone, while Kepler-442b has a 97 percent chance of being a Goldilocks planet.
We don’t know for sure whether any of the planets in our sample are truly habitable. All we can say is that they’re promising candidates,”
David Kipping of the CfA and co-author of the discovery said.

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Neptune-Like Planets Could Transfom Into Habitable Worlds

January 30, 2015 / / 0 Comments

Strong irradiation from the host star can cause planets known as mini-Neptunes in the habitable zone to shed their gaseous envelopes and become potentially habitable worlds.Credit: Rodrigo Luger / NASA imagesExcerpt from sciencedaily.com Two ph...

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Three Earth-like planets sighted around nearby star

January 17, 2015 / / 0 Comments

This artistic impression shows NASA's planet-hunting Kepler spacecraft operating in a new mission profile called K2. By analyzing data captured by the Kepler spacecraft, a UA-led team of researchers has discovered three new Earth-size planets orbiti...

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The Best Bet for Alien Life May Be in Planetary Systems Very Different From Ours

January 16, 2015 / / 0 Comments




Excerpt from wired.com


In the hunt for extraterrestrial life, scientists started by searching for a world orbiting a star just like the sun. After all, the steady warmth of that glowing yellow ball in the sky makes life on Earth possible.

But as astronomers continue to discover thousands of planets, they’re realizing that if (or when) we find signs of extraterrestrial life, chances are good that those aliens will orbit a star quite different from the sun—one that’s redder, cooler, and at a fraction of the sun’s size and mass. So in the quest for otherworldly life, many astronomers have set their sights on these small stars, known as red dwarfs or M dwarfs.

At first, planet-hunting astronomers didn’t care so much about M dwarfs. After the first planet outside the solar system was discovered in 1995, scientists began hunting for a true Earth twin: a rocky planet like Earth with an orbit like ours around a sun-like star. Indeed, the search for that kind of system drove astronomers through most of the 2000s, says astronomer Phil Muirhead of Boston University.

But then astronomers realized that it might be technically easier to find planets around M dwarfs. Detecting another planet is really hard, and scientists rely on two main methods. In the first, they look for a drop in a star’s brightness when a planet passes in front of it. In the second, astronomers measure the slight wobble of a star, caused by the gentle gravitational tug of an orbiting planet. With both of these techniques, the signal is stronger and easier to detect for a planet orbiting an M dwarf. A planet around an M dwarf also orbits more frequently, increasing the chances that astronomers will spot it.

M dwarfs got a big boost from the Kepler space telescope, which launched in 2008. By staring at small patch of the sky, the telescope searches for suddenly dimming stars when a planet passes in front of them. In doing so, the spacecraft discovered a glut of planets—more than 1,000 at the latest count—it found a lot of planets around M dwarfs. “Kepler changed everything,” Muirhead said. Because M-dwarf systems are easier to find, the bounty of such planets is at least partly due to a selection effect. But, as Muirhead points out, Kepler is also designed to find Earth-sized planets around sun-like stars, and the numbers so far suggest that M-dwarfs may offer the best odds for finding life.

“By sheer luck you would be more likely to find a potentially habitable planet around an M dwarf than a star like the sun,” said astronomer Courtney Dressing of Harvard. She led an analysis to estimate how many Earth-sized planets—which she defined as those with radii ranging from one to one-and-a-half times Earth’s radius—orbit M dwarfs in the habitable zone, the region around the star where liquid water can exist on the planet’s surface. According to her latest calculations, one in four M dwarfs hosts such a planet.

That’s higher than the estimated number of Earth-sized planets around a sun-like star, she says. For example, an analysis by astronomer Erik Petigura of UC Berkeley suggests that fewer than 10 percent of sun-like stars have a planet with a radius between one and two times that of Earth’s.

This illustration shows Kepler-186f, the first rocky planet found in a star's habitable zone. Its star is an M dwarf.
This illustration shows Kepler-186f, the first rocky planet found in a star’s habitable zone. Its star is an M dwarf. NASA Ames/SETI Institute/JPL-Caltech


M dwarfs have another thing going for them. They’re the most common star in the galaxy, comprising an estimated 75 percent of the Milky Way’s hundreds of billions of stars. If Dressing’s estimates are right, then our galaxy could be teeming with 100 billion Earth-sized planets in their stars’ habitable zones.

To be sure, these estimates have lots of limitations. They depend on what you mean by the habitable zone, which isn’t well defined. Generally, the habitable zone is where it’s not too hot or too cold for liquid water to exist. But there are countless considerations, such as how well a planet’s atmosphere can retain water. With a more generous definition that widens the habitable zone, Petigura’s numbers for Earth-sized planets around a sun-like star go up to 22 percent or more. Likewise, Dressing’s numbers could also go up.
Astronomers were initially skeptical of M-dwarf systems because they thought a planet couldn’t be habitable near this kind of star. For one, M dwarfs are more active, especially during within the first billion years of its life. They may bombard a planet with life-killing ultraviolet radiation. They can spew powerful stellar flares that would strip a planet of its atmosphere.

And because a planet will tend to orbit close to an M dwarf, the star’s gravity can alter the planet’s rotation around its axis. When such a planet is tidally locked, as such a scenario is called, part of the planet may see eternal daylight while another part sees eternal night. The bright side would be fried while the dark side would freeze—hardly a hospitable situation for life.

But none of these are settled issues, and some studies suggest they may not be as big of a problem as previously thought, says astronomer Aomawa Shields of UCLA. For example, habitability may depend on specific types and frequency of flares, which aren’t well understood yet. Computer models have also shown that an atmosphere can help distribute heat, preventing the dark side of a planet from freezing over.

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Kepler Space Telescope Finds More Earth-like Planets ~ Learn how to join the search

January 8, 2015 / / 0 Comments


 


Excerpt from
waaytv.com

NASA's Kepler Space Telescope has been hunting the cosmos for exoplanets since March of 2009.  In its nearly five years of searching the stars, it has found thousands of possible candidates.  Scientists recently verified the thousandth planet Kepler had found, and even more exciting, they announced that Kepler had found three more Earth-like planets.
 Those three planets bring Kepler's Earth-like planet count to a total of eight.  In order to qualify as "Earth-like," these exoplanets must be less than twice the size of the Earth and orbit their own sun within the habitable zone.  This "Goldilocks zone" is a belt in solar systems where it's neither too hot nor too cold for liquid water to exist.

"Each result from the planet-hunting Kepler mission's treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe," said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “The Kepler team and its science community continue to produce impressive results with the data from this venerable explorer."

The Kepler team has also found super-Earths and gas giants like Jupiter around other stars.  NASA artists compiled retro-style travel posters from three discovered planets.
Kepler finds planets by watching distant stars for fluctuation in light.  If the light hitting the telescope drops dramatically and then returns to normal levels, chances are a planet came in between the star and Kepler.  Scientists can analyze the data and light filtered by the candidate planet's atmosphere to make guesses at the size, mass and composition.

"With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth," said co-author Doug Caldwell, SETI Institute Kepler scientist at NASA's Ames Research Center at Moffett Field, California. "The day is on the horizon when we’ll know how common temperate, rocky planets like Earth are.”

The space telescope actually has two crippled stabilizing gyros.  But instead of giving up on the mission, engineers are using pressure from photons emitted by the sun to stabilize the telescope.  The first space telescope looking for alien worlds is literally balancing on a sunbeam to continue its mission, and that's not science fiction, that's science fact.

Citizen scientists can also participate in the mission.  The website PlanetHunters.org contains catalogs of data from K1, the original Kepler mission, and K2, the extended mission making use of the sun to balance the telescope.  The K2 data has been sorted through, but Planet Hunters still needs help sifting through the K1 data.
The website's instructions read:

"As the planet passes in front of (or transits) a star, it blocks out a small amount of the star’s light, making the star appear a little bit dimmer. You’re looking for points on the light curve that appear lower than the rest. When you spot a potential transit, mark each one on the light curve."

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