Tag: change (page 28 of 102)

Surface of Venus revealed by new radio telescope data


Excerpt from smnweekly.com
By David M. DeMar

New radio telescope data from the National Radio Astronomy Observatory has revealed for the first time ever just what Venus has under its thick veil of clouds that otherwise occlude its surface from view.
25 million miles distant from us, Venus looks to the naked eye – or through a light telescope – much like a cloudy marble, thanks to the thick cloudbanks of carbon dioxide ringing the planet. However, the surface underneath, long a mystery to planetary scientists, has been laid bare thanks to the work of Puerto Rico’s Arecibo Observatory radio transmitter and the Green Bank Telescope, a radio telescope located in West Virginia and operated by the National Science Foundation.
The two facilities worked together with the NRAO in order to uncover the hidden surface of Mars. Arecibo sent radar signals to Venus, where they penetrated the thick atmosphere and bounced off the ground. The returning radio signals were picked up by the GBT in West Virginia in a process known as bistatic radar; the result is a radar image that shows craters and mountains strewn across the surface of Venus at a surprisingly high resolution.
The image is bisected by a dark line, representing areas where it’s particularly difficult to receive useful image data through the use of bistatic radar. However, scientists are intending to compare multiple images as time goes by in order to identify any active geologic processes on the surface of Venus such as volcanic activity.
It’s no particularly easy task to compare radar images in search of evidence of any change in this manner says Smithsonian senior scientist Bruce Campbell, but the work will continue. Campbell, who works at the National Air and Space Museum in the nation’s capital and is associated with the center for Earth and Planetary Studies, added that combining images from the latest NRAO endeavor and others will yield large amounts of data on how the surface of Venus might be altered by other processes.
The radar data, and a scientific paper based on it, will be published in April in Icarus, the scientific journal dedicated to studies of the solar system.

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Let There Be Light! Photo Shows Light As Wave And Particle For First Time

Light as a particle and a wave

Excerpt from escapistmagazine.com

According to quantum mechanics light acts as both a particle and a wave, but now we can finally see what that looks like.

Quantum mechanics is an incredibly complex field for a simple reason: So much of what it studies can be two different things at the exact same time. Light is a great example since it behaves like both a particle and a wave, but only appears in one state during experiments. Mathematically speaking, we have to treat light as both ways for the universe to make sense but actually confirming it visually has been impossible. Or at least that was the case until scientists from Switzerland's École polytechnique fédérale de Lausanne developed their own unique photography method.
The image was created by shooting a pulse of laser light at a metallic nanowire to make its charged particles vibrate. Next the scientists fired a stream of electrons past the wire holding the trapped light. When the two collided, it created an energy exchange that could be photographed from the electron microscope.

So what does this mean when looking at the photograph? When the photons and electrons collide, they either slow down or speed up, which creates a visualization of a light wave. At the same time the speed change appears as a quanta - packets of energy - transferred between the electrons and photons as particles. In other words, it's the first case of observing light particles and waves simultaneously.

"This experiment demonstrates that, for the first time ever, we can film quantum mechanics - and its paradoxical nature - directly," research leader Fabrizio Carbone explained. This has enormous implications not only for quantum research, but also quantum-based technologies still in development. "Being able to image and control quantum phenomena at the nanometer scale like this opens up a new route towards quantum computing," he continued.

The experiment results were posted in today's Nature Communications, which will help other scientists build on this research with further studies. After all, it's not like we've unlocked all of light's secrets yet - we can barely even tell what color a dress is sometimes.

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Skywatch: Venus and Jupiter continue to accentuate the night heavens

Venus (right) & Jupiter

Excerpt from washingtonpost.com
By Blaine Friedlander Jr. 
In winter’s waning weeks, Venus and Jupiter continue to accentuate the night heavens, we change our clocks forward and we grab spring with no intention of letting go.

Check the west-southwestern heavens at dusk to spy the vivacious Venus and the dim Mars. In late February, the two planets met for a sweet cosmic waltz, but in March, they appear to separate. Venus approaches negative fourth magnitude (very bright) while Mars makes do at magnitude 1.3 (dim, hard to find in urban light pollution). With a clear sky, Mars looks like a red pinpoint. 

A young, waxing crescent moon visits Mars on the evening of March 21, and on the next evening the crescent flirts with Venus.
Robust Jupiter ascends the evening’s eastern sky. Find this gas giant at a -2.5 magnitude, very bright, in the constellation Cancer. The lion in the constellation Leo appears to stare at the planet. By the Ides of March, find it south around 10:30 p.m. 

The waxing gibbous moon drops by the dazzling Jupiter on March 2, days before the moon itself becomes full on March 5. 

Catch the ringed Saturn rising after midnight in the east-southeast now, hanging out near a gang of constellations, Scorpius, Ophiuchus and Libra. It’s a zero magnitude object, bright enough that it can be seen under urban skies. The waning moon loiters near Saturn before dawn on March 12. On that morning, the reddish star below them is Antares.
We adjust our clocks to Daylight Saving Time at 2 a.m. March 8. Spring forward, moving the clock ahead one hour. 

Winter is almost over. Spring is weeks away. The vernal equinox brings spring’s official arrival on March 20 at 6:45 p.m. 

Also on March 20 — the day a new moon — the North Atlantic and the Arctic waters get a short total eclipse. We won’t see it here, but Slooh.com will carry it live. Totality will start seconds after 5:44 a.m. and end at 5:47 a.m., according to Geoff Chester of the U.S. Naval Observatory. 

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Bees Do It, Humans Do It ~ Bees can experience false memories, scientists say

Excerpt from csmonitor.com

Researchers at Queen Mary University of London have found the first evidence of false memories in non-human animals.

It has long been known that humans – even those of us who aren't famous news anchors – tend to recall events that did not actually occur. The same is likely true for mice: In 2013, scientists at MIT induced false memories of trauma in mice, and the following year, they used light to manipulate mice brains to turn painful memories into pleasant ones.

Now, researchers at Queen Mary University of London have shown for the first time that insects, too, can create false memories. Using a classic Pavlovian experiment, co-authors Kathryn Hunt and Lars Chittka determined that bumblebees sometimes combine the details of past memories to form new ones. Their findings were published today in Current Biology.
“I suspect the phenomenon may be widespread in the animal kingdom," Dr. Chittka said in a written statement to the Monitor.
First, Chittka and Dr. Hunt trained their buzzing subjects to expect a reward if they visited two artificial flowers – one solid yellow, the other with black-and-white rings. The order didn’t matter, so long as the bee visited both flowers. In later tests, they would present a choice of the original two flower types, plus one new one. The third type was a combination of the first two, featuring yellow-and-white rings. At first, the bees consistently selected the original two flowers, the ones that offered a reward.

But a good night’s sleep seemed to change all that. One to three days after training, the bees became confused and started incorrectly choosing the yellow-and-white flower (up to fifty percent of the time). They seemed to associate that pattern with a reward, despite having never actually seen it before. In other words, the bumblebees combined the memories of two previous stimuli to generate a new, false memory.

“Bees might, on occasion, form merged memories of flower patterns visited in the past,” Chittka said. “Should a bee unexpectedly encounter real flowers that match these false memories, they might experience a kind of deja-vu and visit these flowers expecting a rich reward.”

Bees have a rather limited brain capacity, Chittka says, so it’s probably useful for them to “economize” by storing generalized memories instead of minute details.

“In bees, for example, the ability to learn more than one flower type is certainly useful,” Chittka said, “as is the ability to extract commonalities of multiple flower patterns. But this very ability might come at the cost of bees merging memories from multiple sequential experiences.”

Chittka has studied memory in bumblebees for two decades. Bees can be raised and kept in a lab setting, so they make excellent long-term test subjects.

“They are [also] exceptionally clever animals that can memorize the colors, patterns, and scents of multiple flower species – as well as navigate efficiently over long distances,” Chittka said.

In past studies, it was assumed that animals that failed to perform learned tasks had either forgotten them or hadn’t really learned them in the first place. Chittka’s research seems to show that animal memory mechanisms are much more elaborate – at least when it comes to bumblebees.

“I think we need to move beyond understanding animal memory as either storing or not storing stimuli or episodes,” Chittka said. “The contents of memory are dynamic. It is clear from studies on human memory that they do not just fade over time, but can also change and integrate with other memories to form new information. The same is likely to be the case in many animals.”

Chittka hopes this study will lead to a greater biological understanding of false memories – in animals and humans alike. He says that false memories aren’t really a “bug in the system,” but a side effect of complex brains that strive to learn the big picture and to prepare for new experiences.

“Errors in human memory range from misremembering minor details of events to generating illusory memories of entire episodes,” Chittka said. “These inaccuracies have wide-ranging implications in crime witness accounts and in the courtroom, but I believe that – like the quirks of information processing that occur in well known optical illusions – they really are the byproduct of otherwise adaptive processes.”

“The ability to memorize the overarching principles of a number of different events might help us respond in previously un-encountered situations,” Chittka added. “But these abilities might come at the expense of remembering every detail correctly.”
So, if generating false memories goes hand in hand with having a nervous system, does all this leave Brian Williams off the hook?

“It is possible that he conflated the memories,” Chittka said, “depending on his individual vulnerability to witnessing a traumatic event, plus a possible susceptibility to false memories – there is substantial inter-person variation with respect to this. It is equally possible that he was just ‘showing off’ when reporting the incident, and is now resorting to a simple lie to try to escape embarrassment. That is impossible for me to diagnose.”

But if Mr. Williams genuinely did misremember his would-be brush with death, Chittka says he shouldn’t be vilified.

“You cannot morally condemn someone for reporting something they think really did happen to them,” Chittka said. “You cannot blame an Alzheimer patient for forgetting to blow out the candle, even if they burn down the house as a result. In the same way, you can't blame someone who misremembers a crime as a result of false memory processes."

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Rare doomed planet with extreme seasons discovered

Illustration provided by the University of Heidelberg of the orbit of Kepler-432b (inner, red) in comparison to the orbit of Mercury around the Sun (outer, orange). The red dot in the middle indicates the position of the star around which the planet is orbiting. The size of the star is shown to scale, while the size of the planet has been magnified ten times for illustration purposes. (Graphic: Dr. Sabine Reffert)

Excerpt from foxnews.com/science

A rare planet has been discovered, and it doesn’t seem like a stop anyone would want to make on an intergalactic cruise. Found by two research teams independently of each other, Kepler-432b is extreme in its mass, density, and weather. Roughly the same size of Jupiter, the planet is also doomed- in 200 million years it will be consumed by its sun. “Kepler-432b is definitively a rarity among exoplanets around giant stars: it is a close-in gas-giant planet orbiting a star whose radius is 'quickly' increasing,” Davide Gandolfi, from the Landessternwarte Koenigstuhl (part of the Centre for Astronomy of the University of Heidelberg), told FoxNews.com. “The orbit of the planet has a radius of about 45 million kilometers [28 million miles] (as a reference point, the Earth-Sun distance is about 150 million kilometers [93.2 Million miles]), while most of the planets known to orbit giant stars have wider orbits. The stellar radius is already 3 million kilometers [almost 2 million miles] (i.e., about 4 times the Sun radius) and in less than 200 million years it will be large enough for the star to swallow up its planet.”

Gandolfi, a member of one of the research groups who discovered the rare planet, explains that much like Jupiter, Kepler-432b is a gas-giant celestial body composed mostly of hydrogen and helium, and is most likely to have a dense core that accounts for 6 percent or less of the planet’s mass. “The planet has a mass six times that of Jupiter, but is about the same size!” he says. “This means that it is not one of the largest planets yet discovered: it is one of the most massive!” The planet’s orbit brings it extremely close to its host star on some occasions, and very far away at others, which creates extreme seasonal changes. In its year - which lasts 52 Earth days - winters can get a little chilly and summers a bit balmy, to say the least. According to Gandolfi, “The highly eccentric orbit brings Kepler-432b at ‘only’ 24 million kilometers [15 million miles] from its host star, before taking it to about three times as far away. This creates large temperature excursions over the course of the planet year, which is of only 52 Earth days. During the winter season, the temperature on Kepler-432b drops down to 500 degrees Celsius [932 degrees Fahrenheit], whereas in summer it can goes up to nearly 1000 degrees Celsius [1832 degrees Fahrenheit].”

Then again, if you are crazy enough to visit Kepler-432b, you’d better do it fast. As stated before, its host star is set to swallow the planet whole in 200 million years, making the celestial body a rare find. “The paucity of close-in planets around giant stars is likely to be due to the fact that these planets have been already swallowed up by their host stars,” Gandolfi says. “Kepler-432b has been discovered ‘just in time before dinner!” The host star, which is red and possesses 1.35 times the mass of our sun, has partly exhausted the nuclear fuel in its core, and is slowly expanding, eventually growing large enough to swallow Kepler-432b. According to Gandolfi, this is a natural progression for all stars. “Stars first generate nuclear energy in their core via the fusion of Hydrogen into Helium,” he explained. “At this stage, their radii basically do not change much. This is because the outward thermal pressure produced by the nuclear fusion in the core is balanced by the inward pressure of gravitational collapse from the overlying layers. In other words, the nuclear power is the star pillar! Our Sun is currently ‘burning’ hydrogen in its core (please note that I used quotes: ‘burning’ does not mean a chemical reaction- we are talking about nuclear fusion reaction). However, this equilibrium between the two pressures does not last forever. Helium is heavier than hydrogen and tends to sink. The stellar core of the Kepler-432b's host star is currently depleted of hydrogen and it is mainly made of inert helium. The star generates thermal energy in a shell around the core through the nuclear fusion of hydrogen into helium. As a result of this, the star expands and cools down. This is why we call it ‘red giant’- the reddish color comes from the fact that the external layers of the atmosphere of the star are cooling down because they expand.”

Both research teams (the other was from the Max Planck Institute for Astronomy in Heidelberg) used Calar Alto Observatory’s 7.2- foot telescope in Andalucia, Spain. The planet was also studied by Landessternwarte Koenigstuhl researchers using the 8.5-foot Nordic Optical Telescope on La Palma, which is located in Spain’s Canary Islands.

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Monster Black Hole’s Mighty Belch Could Transform Our Entire Galaxy

This artist's illustration depicts the furious cosmic winds streaming out from a monster supermassive black hole as detected by NASA's NuSTAR space telescope and the European Space Agency's XMM-Newton X-ray observatory.
This artist's illustration depicts the furious cosmic winds streaming out from a monster supermassive black hole as detected by NASA's NuSTAR space telescope and the European Space Agency's XMM-Newton X-ray observatory.

Except from space.com

A ravenous, giant black hole has belched up a bubble of cosmic wind so powerful that it could change the fate of an entire galaxy, according to new observations.
Researchers using two X-ray telescopes have identified a cosmic wind blowing outward from the supermassive black hole at the center of galaxy PDS 456. Astronomers have seen these winds before, but the authors of the new research say this is the first observation of a wind moving away from the center in every direction, creating a spherical shape.
The wind could have big implications for the future of the galaxy: It will cut down on the black hole's food supply, and slow star formation in the rest of the galaxy, the researchers said. And it's possible that strong cosmic winds are a common part of galaxy evolution — they could be responsible for turning galaxies from bright, active youngsters to quiet middle-agers. 

Big eater

The supermassive black hole at the center of PDS 456 is currently gobbling up a substantial amount of food: A smorgasbord of gas and dust surrounds the black hole and is falling into the gravitational sinkhole.
As matter falls, it radiates light. The black hole at the center of PDS 456 is devouring so much matter, that the resulting radiation outshines every star in the galaxy. These kinds of bright young galaxies are known as quasars: a galaxy with an incredibly bright center, powered by a supermassive black hole with a big appetite.
New observations of PDS 456 have revealed a bubble of gas moving outward, away from the black hole. Using NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and ESA’s (European Space Agency) XMM-Newton, the authors of the new research imaged the galaxy on five separate occassions in 2013 and 2014. The researchers say they can show that the photons of light emitted by the in-falling matter are pushing on nearby gas, creating the wind.
Scientists have studied these cosmic winds before, but the authors of the new research say their work goes a step further.
"It tells us that the shape of the wind is not just a narrow beam pointed in our direction. It is really a wind that is flowing in every direction away from the black hole," said Emanuele Nardini, a postdoctoral researcher at Keele University in Staffordshire, England. "With a spherical wind, the amount of mass it carries out is much larger than just a narrow beam."
According to a statement from NASA, galaxy PDS 456 "sustains winds that carry more energy every second than is emitted by more than a trillion suns." Such powerful winds could change the entire landscape of PDS 456, the researchers say. First, the wind will blow through the disk of matter surrounding the black hole — this disk currently serves as the black hole's food supply. The cosmic wind created by the black hole's appetite could significantly reduce or destroy the disk. In other words, the black hole cannot have its cake and eat it, too. 

Bright young things

With no matter left to fall into the black hole, the radiation would cease as well. The brilliant center of the quasar will dim. By diminishing the black hole's food supply, they may turn quasars and other "active galaxies" like PDS 456 into quiescent galaxies like the Milky Way. Theorists have proposed that cosmic winds could explain why there are more young active galaxies than old active galaxies.
"We know that in almost every galaxy, a supermassive black hole resides in the center," said Nardini. "But, most of the galaxies we see today are quiescent, they are not active in any way. The fact that galaxies today are quiescent — we have to find an explanation for that in something that happened a long time ago."
In addition to quenching the radiation from an active black hole, these cosmic winds may slow down star formation in galaxies. The cosmic wind could blow through regions thick with gas and dust, where young stars form, and thin out the fertile stellar soil.
"If you have a black hole with this kind of wind, in millions of years [the winds] will be able to quench star formation and create a galaxy like our own," Nardini said. Stars will still form in the Milky Way, but not at the high rate of many young galaxies.
It's possible that these cosmic winds are a central reason why most galaxies go from being brightly burning active youngsters to quiet middle-agers.

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Earth’s Moon May Not Be Critical to Life Afterall

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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Birth of the Nibiru Legend? Astronomers Say Alien Star System Buzzed Our Sun

Scholz's star - shown in this artist's impression - is currently 20 light-years away. But it once came much closerExcerpt from bbc.comAn alien star passed through our Solar System just 70,000 years ago, astronomers have discovered.  No othe...

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