Tag: smaller (page 3 of 9)

An Alien Radio Beacon? Possibly Not This Time

April 5, 2015 / / 0 Comments



An Alien Radio Beacon? Possibly Not This Time.

Excerpt from postpioneer.com


For practically a decade, astronomers have puzzled over strong bursts of radio energy that appear to be hailing from billions of light years away. Recently, we received reports of a new wrinkle to this mystery: The bursts seem to comply with a mathematical...

For practically a decade, astronomers have puzzled over strong bursts of radio energy that appear to be hailing from billions of light years away. Recently, we received reports of a new wrinkle to this mystery: The bursts seem to comply with a mathematical pattern, one that does not line up with something we know about cosmic physics.

And, of course, when we hear “mathematical pattern,” “radio transmission,” and “outer space,” all strung collectively, we straight away jump to our preferred explanation—aliens! (Or, you know, a decaying pulsar star, an unmapped spy satellite, or a cell telephone tower.)

It’s also probable that the pattern doesn’t basically exist.

Because 2007, telescopes have picked up almost a dozen so-known as “fast radio bursts,” pulses that last for mere milliseconds, but erupt with as a great deal power as the sun releases in a month. Where could they be coming from? To come across out, a group of researchers took advantage of a basic principle: That higher frequency radio waves encounter less interference as they traverse space, and are detected by our telescopes earlier than reduce frequency waves. The time delay, or “dispersion measure”, in between larger and reduce frequency radio waves from the very same pulse event can be applied to figure out the distance those waves traveled.

Here’s where things got weird. When researchers calculated the dispersion distance for each and every of eleven rapid radio bursts, they identified that every distance is an integer many of a single number: 187.5. When plotted on a graph, as the researchers show us in Figure 1 of their paper, the points type a striking pattern.

A single explanation is that the bursts are coming from distinctive sources, all at on a regular basis spaced intervals from the Earth, billions of light years away. They could also be brought on by a smaller cosmic object a lot closer to residence, such as a pulsar star, behaving according to some sort of physics we don’t yet understand. And then there’s the possibility that aliens are trying to communicate, by blasting simple numeric patterns into space.

But no matter how you slice it, eleven data points is a tiny sample set to draw any meaningful conclusions from. A handful of deviant observations could bring about the complete pattern to unravel.

And that is precisely what seems to be happening. As Nadia Drake reports for National Geographic, newer observations, not integrated in the most up-to-date scientific report or other well known media articles, don’t fit:

“There are 5 quickly radio bursts to be reported,” says Michael Kramer of Germany’s Max Planck Institute for Radioastronomy. “They do not fit the pattern.”
Rather of aliens, unexpected astrophysics, or even Earthly interference, the mysterious mathematical pattern is probably an artifact produced by a little sample size, Ransom says. When working with a limited quantity of data – say, a population of 11 quickly radio bursts – it’s straightforward to draw lines that connect the dots. Usually, on the other hand, these lines disappear when much more dots are added.
“My prediction is that this pattern will be washed out quite immediately after a lot more fast radio bursts are located,” says West Virginia University’s Duncan Lorimer, who reported the very first burst in 2007. “It’s a great instance of how apparently considerable final results can be identified in sparse information sets.”

That is a bit of a bummer, but nevertheless, these radio bursts are fascinating, and what could be causing them remains as a lot of a mystery as ever. It could even nonetheless be aliens, if not an alien beacon. As SETI Institute Director Seth Shostak told me in an e mail:

“If it is a signal, nicely, it is surely NOT a message — except perhaps to say ‘here we are’. There’s not actual bandwidth to it, which suggests these speedy radio bursts can not encode several bits. But there are so many other possibilities, I feel that automatically attributing one thing in the sky that we don’t (at very first) understand to the operate of aliens is … premature!”

If there’s 1 point that is clear in this whole organization, it is that we’ve nonetheless got plenty to discover about the patterns woven into the universe around us.

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Citizen Scientists Find Green Blobs in Hubble Galaxy Shots

April 3, 2015 / / 0 Comments





Excerpt from wired.com

In 2007, A Dutch schoolteacher named Hanny var Arkel discovered a weird green glob of gas in space. Sifting through pictures of galaxies online, as part of the citizen science project Galaxy Zoo, she saw a cloud, seemingly glowing, sitting next to a galaxy. Intrigued, astronomers set out to find more of these objects, dubbed Hanny’s Voorwerp (“Hanny’s object” in Dutch). Now, again with the help of citizen scientists, they’ve found 19 more of them, using the Hubble space telescope to snap the eight haunting pictures in the gallery above.



Since var Arkel found the first of these objects, hundreds more volunteers have swarmed to help identify parts of the universe in the Galaxy Zoo gallery. To find this new set, a couple hundred volunteers went through nearly 16,000 pictures online (seven people went through all of them), clicking yes/no/maybe as to whether they saw a weird green blob. Astronomers followed up on the galaxies they identified using ground-based telescopes, and confirmed 19 new galaxies surrounded by green gas.



What causes these wispy tendrils of gas to glow? Lurking at the center of each of these galaxies is a supermassive black hole, millions to billions times as massive as the sun, with gravity so strong that even light can’t escape them. As nearby gas and dust swirls into the black hole, like water circling a drain, that material heats up, producing lots of radiation—including powerful ultraviolet. Beaming out from the galaxy, that ultraviolet radiation strikes nearby clouds of gas, left over from past collisions between galaxies. And it makes the clouds glow an eerie green. “A lot of these bizarre forms we’re seeing in the images arise because these galaxies either interacted with a companion or show evidence they merged with a smaller galaxy,” says William Keel, an astronomer at the University of Alabama, Tuscaloosa.



The eight in this gallery, captured with Hubble, are especially weird. That’s because the quasar, the black-hole engine that’s supposed to be churning out the ultraviolet radiation, is dim—too dim, in fact, to be illuminating the green gas. Apparently, the once-bright quasar has faded. But because that UV light takes hundreds of thousands of years to travel, it can continue to illuminate the gas long after its light source has died away.  


Hubble finds phantom objects close to dead quasars

That glowing gas can tell astronomers a lot about the quasar that brought it to light. “What I’m so excited about is the fact that we can use them to do archaeology,” says Gabriela Canalizo, an astronomer at the University of California, Riverside, who wasn’t part of the new research. Because the streaks of gas are so vast, stretching up to tens of thousands of light years, the way they glow reveals the history of the radiation coming from the quasar. As the quasar fades, so will the gas’s glow, with the regions of gas closer to the quasar dimming first. By analyzing how the glow dwindles with distance from the quasar, astronomers can determine how fast the quasar is fading. “This was something we’ve never been able to do,” Canalizo says.

Measuring how fast the quasar fades allows astronomers to figure out exactly what’s causing it to turn off in the first place. “What makes them dim is running out of material to eat,” Canalizo says. That could happen if the quasar is generating enough radiation to blow away all the gas and dust surrounding the black hole—the same gas and dust that feeds it. Without a steady diet, the quasar is powerless to produce radiation. Only if more gas happens to make its way toward the black hole can the quasar turn on again. The glowing gas can provide details of this process, and if other mechanisms are at play.

With more powerful telescopes, astronomers will likely find many more. Hanny’s Verwoort, it turns out, may not be that weird after all.

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Why Luke Skywalker’s binary sunset may be real after all

March 30, 2015 / / 0 Comments






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."

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Jupiter May Be Behind The Mysterious ‘Gaping Hole’ In Our Solar System

March 30, 2015 / / 0 Comments

Excerpt from huffingtonpost.comWhen astronomers began studying other solar systems in the Milky Way galaxy back in the 1990s, they noticed something peculiar: most of these systems have big planets that circle their host stars in tight orbits, a fin...

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The Story of Human Evolution Now Challenged

March 29, 2015 / / 0 Comments



Story of Human Evolution Challenged


Excerpt from newhistorian.com

The history of the evolution of early humans has been challenged.
Until now, one of the most dominant theories about our evolution claimed that our genus, Homo, had evolved from smaller early humans becoming taller, heavier and longer-legged. This process eventually resulted in Homo erectus, which was able to migrate out of Africa and colonise Eurasia.

Whilst we know that small-bodied H. erectus, averaging less than five feet tall and weighing under 50 kilograms, were living in southern Europe by 1.77 million years ago, the origin of the larger body size associated with modern humans has been elusive.

The paucity of knowledge about the origins of larger members of the Homo genus is primarily a result of a lack of evidence. Previous estimates of body size had been based on well-preserved specimens which were easy to assign a species to. Since these samples are rare and disparate in terms of both space and time, little is known about geographical and chronological variation in the body sizes of the early Homo.

A joint study between the Universities of Cambridge and Tübingen has shown that increases in body size occurred thousands of years after H. erectus left Africa; this growth in Homo body sizes primarily took place in the Koobi Fora region in modern Kenya.

“The evolution of larger bodies and longer legs can thus no longer be assumed to be the main driving factor behind the earliest excursions of our genus to Eurasia,” said Manuel Will, co-author of the study which has been published in the Journal of Human Evolution.

By using tiny fragments of fossil, the team were able to estimate our earliest ancestors’ height and body mass. Their findings, rather surprisingly, indicate a huge diversity in body size; this is particularly surprising as the wide variation we see in humans today was thought to be a relatively recent development.

“If someone asked you ‘are modern humans 6 foot tall and 70kg?’ you’d say ‘well some are, but many people aren’t,’ and what we’re starting to show is that this diversification happened really early in human evolution,” said Dr Jay Stock, co-author of the study.

Stock and Will are the first scientists in 20 years to compare the body size of humans from between 2.5 and 1.5 million years ago. They are also the first to use fragmentary fossils – many as small as toes, none longer than 5cm – to estimate body sizes.

By comparing measurements of fossils from sites in Kenya, Tanzania, South Africa and Georgia, the researchers have revealed substantial regional variation in the size of early humans. Groups who lived in South African caves, for example, were 4.8 feet tall on average. Some of the skeletons found in Kenya’s Koobi Fora region would have stood nearly 6 feet tall, a height comparable to the average height of modern British males.
“Basically every textbook on human evolution gives the perspective that one lineage of humans evolved larger bodies before spreading beyond Africa. But the evidence for this story about our origins and the dispersal out of Africa just no longer really fits,” said Stock.

It appears that Stock and Will have rewritten the history of the development of early humans; diversity has deep roots amongst the Homo genus.

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Black Holes, the Large Hadron Collider, & Finding Parallel Universes

March 27, 2015 / / 0 Comments

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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Young Jupiter wiped out solar system’s early inner planets, study says

March 24, 2015 / / 0 Comments


Ganymede
(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.


Inner planets
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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Exoplanet Bonanza Boosts Count by 1,200

March 9, 2015 / / 0 Comments

Excerpt from news.discovery.comDozens of candidate worlds reside within the "habitable zones" of their parent stars. THE GIST - NASA's Kepler telescope has found more than 1,200 extrasolar planet candidates. - Smaller worlds, like Earth,...

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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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Ancient ‘Blue’ Mars Lost an Entire Ocean to Space

March 7, 2015 / / 0 Comments


Artist impression of Mars ocean

Excerpt from news.discovery.com

Mars was once a small, wet and blue world, but over the past 4 billion years, Mars dried up and became the red dust bowl we know today.

But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.

“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”

Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.

It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.

This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 meters deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere. 
The water in Earth’s oceans contains molecules of H2O, the familiar oxygen atom bound with 2 hydrogen atoms, and, in smaller quantities, the not-so-familiar HDO molecule. HDO is a type of water molecule that contains 1 hydrogen atom, 1 oxygen atom and 1 deuterium atom. The deuterium atom is an isotope of hydrogen; whereas hydrogen consists of 1 proton and an electron, deuterium consists of 1 proton, 1 neutron and 1 electron. Therefore, due to the extra neutron the deuterium contains, HDO molecules are slightly heavier than the regular H2O molecules.

Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.

By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.

Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.

Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.

Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.

“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.

This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.

Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO

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“Seedling” For Supermassive Black Holes Found

February 27, 2015 / / 0 Comments




Excerpt from clapway.com

By William Large 

A recently discovered black hole may help astronomers to piece together the family tree of these enigmatic cosmic objects. While most black holes are classified as either stellar-mass or the supermassive black holes that can be found at the center of some galaxies, this new find fits into neither category.

The discovery, called the intermediate-mass black hole (IMBH), has proved to be a tricky proposition. With a mass somewhere between a few hundred to a few hundred thousand times that of our own Sun, the size of these intermediates can vary widely.

This particular black hole was found in an arm of the spiral galaxy NGC-2276, and has been sensibly named NGC-2276-3c. Lying about 100 million light-years from earth, astronomers were able to tease images through the use of NASA’s Chandra X-Ray Observatory and the European Very Long Baseline Interferometry Network.

Although researchers have theorized about the existence of these IMBHs, locating one has proven elusive until now. A recent to-be-published paper by an international team of researchers delves into the specifics of NGC-2276-3c.

“Astronomers have been looking very hard for these medium-sized black holes,” study co-author Tim Roberts, of the University of Durham in the United Kingdom, said in a statement. “There have been hints that they exist, but the IMBHs have been acting like a long-lost relative that isn’t interested in being found.”

So what was found? It appears that the recently discovery has characteristics of both the smaller stellar-mass and the much larger supermassive black holes. It serves as an intermediary between the two, and some think that these intermediaries are the beginnings of what could very well become a supermassive.

The team of researchers also noted that the black holes is firing off super powerful blasts of radio jets. Think of these as material, traveling at nearly the speed of light and emitting radio waves, which are thrown out of dense objects. Our newly found black hole is shooting them out almost 2000 light-years into space. Within a radius of approximately 1000 light-years around NGC-2276-3c there are no new star formations, suggesting that the radio jets are pushing out all the gas necessary for star creation.

The full report on NGC-2276-3c should be appearing shortly in the journal Monthly Notices of the Royal Astronomical Society.

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Windwheel concept combines tourist attraction with "silent turbine"

February 26, 2015 / / 0 Comments


 The Dutch Windwheel concept is designed to be part energy icon, part tourist attraction an...


Excerpt from gizmag.com
By Stu Robarts


The Dutch have long used windmills to harness wind energy. A new concept proposed for city of Rotterdam, however, is surely one of the most elaborate windmills ever conceived. The Dutch Windwheel is a huge circular wind energy converter that houses apartments, a hotel and a giant coaster ride.

The concept is designed to be part energy icon, part tourist attraction and part residential building. It is a 174-m (571-ft) structure comprising two huge rings that appear to lean against each other. "We wanted to combine a big attraction for Rotterdam with a state-of-the-art sustainable concept," explains Lennart Graaff of the Dutch Windwheel Corporation, to Gizmag.

The larger outer ring houses 40 pods on rails that move around the ring and provide those who visit with views of Rotterdam and its port. The smaller inner ring, meanwhile, houses 72 apartments, a 160-room hotel across seven floors and a panoramic restaurant and viewing gallery. Perhaps most remarkable feature of of all, however, is a huge "bladeless turbine" that spans the center smaller ring.

Although this may look and sound like some of the more out-there architectural concepts that Gizmag has featured, it is actually based on existing (albeit prototypical) technology. The electrostatic wind energy convertor (EWICON) was developed at Delft Technical University and generates electricity by harnessing the movement of charged water droplets in the wind. Its lack of moving parts makes it noiseless and easier to maintain than traditional turbines.

Dhiradj Djairam, of the TU Delft team that developed the EWICON, tells Gizmag that the Dutch Windwheel Corporation has expressed "a serious interest" in the technology. Djairam says he has provided an explanation of the technology to the organization and provided a rough outline for a realistic research and development program. To date, only small-scale research projects have been carried out, with additional funding opportunities being explored.

The Dutch Windwheel concept is 174 m (571 ft) tall and has underwater foundations

The Dutch Windwheel concept has other sustainable aspects, too. Photovoltaic thermal hybrid panels would be used to contribute to the generation of electricity, and rainwater would be collected for use in the building. The Dutch Windwheel Corporation says the building itself is designed to be built with locally-sourced materials, and in such a way as it could ultimately be disassembled and re-used elsewhere.

Among the other features of the design are space for commercial functions in the structure's plinth, and foundations that are underwater, making it it look as though the structure is floating. 

We're told that the amount of power the Dutch Windwheel will require to run – and be able to generate – is not yet clear. Likewise, the final technologies and additional sustainability features that would be present in the building have yet to be finalized...

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