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Rad
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« on: Jun 29, 2015, 06:13 AM »

Hi All,

Thought we could start a new thread on space and solar system news as it occurs. Feel free to post any stories you find interesting.

God Bless, Rad
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Rad
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« Reply #1 on: Jun 29, 2015, 06:14 AM »

NASA scientists begin search for Mars landing sites

June 28, 2015
Shayne Jacopian for redOrbit.com – @ShayneJacopian

In roughly two decades, NASA astronauts will be setting foot on Mars—and the space agency is already mapping out a good location for them to do so, according to a report from Space.com.

NASA will be holding a four-day workshop at the Lunar and Planetary Institute in Houston, TX this October in an effort to stir up some real discussion about where the astronauts should do the whole small step/giant leap thing.

Researchers will be given the opportunity to propose 100-kilometer-wide “exploration zones” that they believe will not only actually be interesting enough to warrant exploration (we argue that it’s freakin’ Mars and anywhere would be pretty darn interesting, but we’ll leave that to NASA), but will also have resources to support humans, like water ice under the surface.

Data collection begins now

Using the Mars Odyssey and the Mars Reconnaissance Orbiter, both of which began orbiting Mars in the previous decade, NASA will survey the Red Planet, gathering high-resolution images of the terrain as well as mineral samples.

“Humans are going to need high-resolution [imagery] over their whole exploration zone,” Green told Space.com. “Therefore, we need to know where they’re going. It’s really that simple.”

Sounds like a solid plan. Anyone who’s ever gone out to eat with a group of friends should be on board with the whole “figuring out where you’re going before you actually leave” thing.

“This, I think, is an enormous step in defining how we’re going to operate on Mars, and what do we need to take with us, because we will have a much better idea of what’s there,” he added.

To [very, very loosely] paraphrase George Orwell: All red dirt is created equal, but some red dirt is more equal than the other red dirt. You want to send astronauts to the best red dirt you can find. Preferably, the kind with water under it.


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Rad
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« Reply #2 on: Jun 29, 2015, 06:15 AM »

How do planets form?

June 27, 2015
Chuck Bednar for redOrbit.com – @BednarChuck

During the early stages of their formation, stars are surrounded by rotating disks of dust and gas, but how do these particles manage to avoid getting sucked into the star’s gravitational field for long enough to accumulate into celestial bodies?

Dr. Alan P. Boss from the Carnegie Institution for Science’s Department of Terrestrial Magnetism and his colleagues wanted to know, and they tackle the question in new research published earlier this week in The Astrophysical Journal. The current prevailing theory of rocky planet formation states that grains of dust collide and aggregate, growing increasingly larger until they form new worlds.

However, one of the problems with this theory is that the pressure gradient of the gas in the disk would create a headwind, pushing the still-forming pebble- and boulder-sized planetoids inwards to the forming protostar, thus destroying these young planets. Objects between one- and ten-meters in radius would be most susceptible to the gas drag, and if too many such objects wound up being lost, there would not be enough material left to form a planet.

Spiral arms play a key role

According to Dr. Boss and his team, observations of protostars that are still surrounded by their dust disks have revealed that those about the same size of the Sun often experience periodic bursts of explosive activity that last about 100 years. During these events, the star becomes more luminous and the disk experiences a period of gravitational instability.The study reveals that this phenomenon can cause smaller bodies to be scattered away from the developing star instead of towards it.

Furthermore, recent studies have shown that young stars have spiral arms that are believed to play a key role in the short-term disruptions of the disk, Boss and his co-authors said.

The gravitational forces of these spiral arms could scatter boulder-sized objects, making it possible for them to accumulate and form objects large enough to overcome gas drag. Modeling techniques used in the Carnegie team’s study could further demonstrate how these spiral arms help contain smaller planetoids on their way to becoming planets.

“This work shows that boulder-sized particles could, indeed, be scattered around the disk by the formation of spiral arms and then avoid getting dragged into the protostar at the center of the developing system,” Boss said in a statement. “Once these bodies are in the disk’s outer regions, they are safe and able to grow into planetesimals.”


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Rad
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« Reply #3 on: Jun 29, 2015, 06:16 AM »

Monster black hole wakes up after 26 years

June 26, 2015
Shayne Jacopian for redOrbit.com – @ShayneJacopian

Wait, black holes can hibernate?! And then just… come back? Oh no…

Over the last week, the ESA Integral satellite has observed some powerful bursts of light created by a black hole “consuming a stellar companion.”

According to an ESA press release, this black hole, observed on June 15, 2015, is part of V404 Cygni, a system in the Milky Way galaxy in which a black hole and a star orbit one another.

The high-energy light is a result of material drifting from the star and into the black hole, with the material forming a disc of intensely hot material that gives off a bright light before quickly descending into the black hole.

“The behavior of this source is extraordinary at the moment, with repeated bright flashes of light on time scales shorter than an hour, something rarely seen in other black hole systems,” comments Erik Kuulkers, Integral project scientist at ESA. “In these moments, it becomes the brightest object in the X-ray sky – up to fifty times brighter than the Crab Nebula, normally one of the brightest sources in the high-energy sky.”

This behavior was previously observed in 1989 with the Japanese satellite X-ray Ginga, but V404 Cygni hasn’t been nearly as bright or active since, until now.

“The community couldn’t be more thrilled: many of us weren’t yet professional astronomers back then, and the instruments and facilities available at the time can’t compare with the fleet of space telescopes and the vast network of ground-based observatories we can use today. It is definitely a ‘once in a professional lifetime’ opportunity,” Kuulkers goes on.

Looks like Taylor Swift isn’t the only one partying like it’s 1989.

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« Reply #4 on: Jun 29, 2015, 06:17 AM »

Three crescent moons imaged around Saturn

June 26, 2015
Chuck Bednar for redOrbit.com – @BednarChuck

A new image captured by NASA’s Cassini orbiter and released by the US space agency earlier this week shows not just one or two, but three of Saturn’s moons as crescents.

According to the Washington Post, the picture was taken on March 25. While it captures the moons Mimas, Rhea, and Titan “striking the same interstellar pose” (so to speak), the image also emphasizes just how different each of these three moons are from one another.

Experts at the Cassini Imaging Team and the Cassini Imaging Central Laboratory for Operations (CICLOPS) explained that the view shown in the image is looking toward the Titan’s anti-Saturn hemisphere, and was captured using the spacecraft’s narrow-angle camera instrument.

The image was obtained at a distance of approximately 1.2 million miles from Titan. The scale of the image at Titan is 75 miles per pixel, CICLOPS noted. Mimas was 1.9 million miles away with an image scale of 11.4 miles per pixel, and Rhea was 2.2 million miles away with an image scale of 13.1 miles per pixel, officials at the imaging team added.

About the moons

Mimas, at just 246 miles across, is the smallest of the three and is made primarily of ice. It has a rough, cratered surface, and has a large one that making it resemble the Death Star of Star Wars fame, the newspaper said. That crater, known as the Herschel Crater, is 88 miles wide, has walls about three miles high, and is up to six miles deep in spots, according to NASA.

Rhea, the second largest moon of Saturn, has a diameter of 949 miles and is described by the US space agency as “a small, cold, airless body” with temperatures reaching as low as -364 degrees Fahrenheit in the shaded areas. It also has high reflectivity, suggesting it’s largely made out of water ice, and its surface contains subsidence fractures that make canyons.

The third object in the image, Titan, is Saturn’s largest moon with a diameter of roughly 3,200 miles across. It is also one of the most Earth-like worlds found to date, according to NASA, and has a thick atmosphere and organic-rich chemistry reminiscent of a frozen version of our planet. It appears to be fuzzy in the picture due to its dense atmosphere scattering the light.


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Rad
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« Reply #5 on: Jun 29, 2015, 06:18 AM »

Are there active volcanoes on Venus?

June 25, 2015
Chuck Bednar for redOrbit.com – @BednarChuck

Despite its demise last December, the ESA’s Venus Express spacecraft is still providing data, and research based on evidence collected by the fallen orbiter has found that volcanoes on the Earth’s sister planet may still be actively spewing lava.

According to Discovery News, lava flows were reported on Venus as recently as 2010. However, the new findings appear to indicate that the planet’s volcanoes remain active. Reported this week by National Geographic, the volcanoes are producing eruptions responsible for spiking temperatures to more than 1500 degrees Fahrenheit in some parts of the planet.

Led by researchers from the Max Planck Institute for Solar System Research and published in the May edition of the journal Geophysical Research Letters, the study reported that the ESA orbiter’s Venus Monitoring Camera revealed transient bright spots that are “consistent with the extrusion of lava flows” and cause surface temperature spikes.

The correlation of these transient bright spots with the extremely young Ganiki Chasma (a group of rift zones on the surface of Venus) and their similarity to regions of rift-associated volcanism on Earth combine to provide strong evidence that they are volcanic in origin and that Venus “is currently geodynamically active” – a discovery which co-author and Brown University planetary scientist James Head told Nat Geo was “really exciting.”

The past, present, and future of Venus volcano research

Venus’s history of volcanic activity is well known. In the early 1990s, the Magellan orbiter’s cloud-penetrating radar revealed that the surface of the planet was filled with mountains resembling volcanoes on Earth. Five years ago, Magellan’s data was compared to that from the Venus Express probe, and found minerals abundant in lava on Earth in some areas.

Also in 2010, Venus Express detected excess heat coming from three spots on the surface, suggesting that lava had flowed on the planet as recently as 2.5 million years ago. Then, in 2012, the orbiter recorded a sudden rise in atmospheric sulfur dioxide followed by a gradual decrease in the gas, commonly spewed from volcanoes.

That detection “provided even more evidence that the volcanoes are awake,” Discovery News said, and National Geographic added that these newly identified hotspots “are about as close as you could get to a smoking gun” in terms of evidence of ongoing volcanic activity. Furthermore, Suzanne Smrekar of NASA’s Jet Propulsion Laboratory in California called the findings “very significant.”

Learning more about volcanoes on Venus “will likely require another long-term mission, but unfortunately there is nothing firmed up yet,” Discovery News said. One proposed US mission, the Venus In Situ Explorer, would be able to examine the planet’s atmospheric composition in search of more details about its interior, and the website added that there may still be yet more data in the Venus Express archive that could help scientists glean new insights.


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Rad
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« Reply #6 on: Jun 29, 2015, 06:19 AM »

Blue auroras may greet first people on Mars

June 25, 2015
Chuck Bednar for redOrbit.com – @BednarChuck

When astronauts first arrive on Mars, they may be greeted by a stunning blue-colored aurora in the southern hemisphere of the Red Planet, researchers from Aalto University in Finland and an international team of colleagues report in a recently-published study.

According to Space.com, while previous research confirmed there were southern auroras on Mars, the new Planetary and Space Science paper marks the first time a team of scientists has predicted that the phenomenon will actually be visible to the human eye.

“The study indicates that the strongest color in the Martian aurorae is deep blue,” author Cyril Simon Wedlund Aalto University’s Department of Radio Science and Engineering explained in a statement. “An astronaut looking up while walking on the red Martian soil would be able, after intense solar eruptions, to see the phenomena with the naked eye.”

The findings indicate that the upper atmosphere of the Red Planet may be closer in nature to that of Earth’s than previously believed. Even though Mars no longer has a global magnetic field, the planet still sporadically has smaller fields appear, particularly in the southern hemisphere, which can excite atmospheric atoms and molecules and cause them to produce light emission.

Creating simulated auroral displays

The presence of aurorae on Mars were originally confirmed by the European Space Agency’s Mars Express spacecraft and NASA’s MAVEN mission, according to Space.com. However, neither of those missions could tell for sure whether or not the phenomenon would be visible to humans.

In their new study, Wedlund’s team used a sphere known as a Planeterella, in which magnetic fields and charged particles produced simulated auroral displays. In their experiment, they filled the Planeterella with carbon dioxide (the dominant component of the atmosphere on Mars) and watched as an electrical discharge was created in the simulated upper atmosphere.

This discharge created a blue glow following the magnetic field structure, Space.com said, and the study shows that aurorae on Mars occur in the visible range. Furthermore, the findings may help scientists better understand the physics, mass, and evolution of the Martian atmosphere.


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Rad
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« Reply #7 on: Jun 29, 2015, 06:20 AM »

Why does this Neptune-like exoplanet have a tail?

June 24, 2015
Chuck Bednar for redOrbit.com – @BednarChuck

A red dwarf star is causing a giant cloud of hydrogen gas to escape from a warm, Neptune-mass world, causing the exoplanet to have a massive comet-like tail, astronomers at the University of Warwick in the UK report in the latest edition of the journal Nature.

According to the university, the phenomenon was depicted in an image by Dr. Mark Garlick, and the discovery seems to indicate that low mass exoplanets orbiting close to their host stars may have had a percentage of their atmospheres burned off due to extreme irradiation from the star.

The planet in question is Gliese 436b (also known as GJ 436b), which was discovered in August 2004 by R. Paul Butler from the Carnegie Institute of Washington and Geoffrey Marcy from the University of California, Berkeley using the radial velocity method. At the time, it was one of the smallest known transiting planets in terms of mass and radius.

First confident detection of atmosphere loss in Neptune-sizes exoplanets

According to co-author Dr. Peter Wheatley of the Warwick Astronomy and Astrophysics Group, a large cloud of hydrogen gas was seen absorbing light from its parent red dwarf star. The cloud is created as a result of x-ray emissions from the star burning off the planet’s upper atmosphere.

“We knew that some Jupiter-mass planets are gradually evaporating due to irradiation by their parent stars, and we set out to use the Hubble Space Telescope to try to detect absorption by hydrogen gas escaping from the Neptune-sized planet GJ 436b,” Dr. Wheatley told redOrbit via email. “We were amazed by the strength of the absorption we found.”

“Usually signals of planetary atmospheres are very subtle, but here we see a very extended comet-like tail from the planet that covers more than half of the star!” he added. “This is the first time anyone has made a confident detection of the atmosphere escaping from a Neptune-sized exoplanet. With such a strong signal, future measurements can probe the composition of the planetary atmosphere – and for other small planets as well.”

In fact, Dr. Wheatley and his colleagues believe that not only are such processes occurring on other exoplanets, but that they could be strong enough to result in the evaporation of the planet’s entire atmosphere.


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Kristin
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« Reply #8 on: Jun 29, 2015, 09:43 AM »

Hi Rad,

I love this new thread ~ thank you!!!

Peace,
Kristin
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Rad
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« Reply #9 on: Today at 06:01 AM »

Should we colonize Venus instead of Mars?

June 29, 2015
Emily Bills for redOrbit.com – @emilygbills

A recent YouTube video put out by PBS has caused a stir in the space community, as it points out all of the benefits of colonizing Venus over Mars. We’ve all been fixated on going to Mars, but have we set our sights on the wrong planet?

So what’s the big deal with Venus?

Venus is actually an easier and less costly target. It’s way closer to Earth, and we sent probes there long before we sent anything to Mars. Because of the distance, the roundtrip could be up to 50% shorter than a trip to Mars. (And a shorter trip is a big advantage. Think less supplies and fuel.)

The planet itself also has some significant advantages. Because it’s closer to the sun, you could get about 4 times more solar power than that on Mars, and with it’s extremely thick atmosphere, we’d be better protected from space radiation and debris. According to the video, the real kicker is the planet’s gravity: Venus has .9 Earth g’s, while Mars pales in comparison, coming in with less than .4 g’s. Prolonged exposure to low gravity could cause a super-speedy loss of bone mass, something that’s not great.

The video explains that the problem with Venus is that we can’t actually land on it. There’s so much CO2 on Venus that the surface is hotter than the Evangelical portrayal of hell. Along with the heat, the surface pressure is an even bigger problem at more than 90 Earth atmospheres and would crush us immediately.

So NASA proposed an alternative: cloud cities. The upper atmosphere of Venus is pretty close to an Earthlike environment (sans the sulfuric acid floating around), and NASA digs this. They mapped out a conceptual blueprint for this and call it the High Altitude Venus Operational Concept (or HAVOC).

The video spits out many reasons why Venus would be a better choice, and by the end, has everyone questioning why the heck anyone hasn’t thought of this before. We thought this was too good to be true, so we reached out to Dr. David Weintraub, a professor of astronomy at Vanderbilt University, and asked him what he thought about all this Venus business.

RedOrbit: Do you think Venus would be a better choice than Mars for colonization?

Dr. David Weintraub: No. I think this HAVOC idea is imaginative for exploration, but a little crazy for the idea of colonization. The folks at NASA are very imaginative. The idea of cloud colonies on Venus seems pretty far-fetched. (Star Wars, anyone?) Even if we can imagine these cloud vehicles in Venus’ atmosphere, there’s no water there. There’s sulfuric acid and carbon dioxide and interesting, nasty stuff there, but there is no water of any sort on Venus. Venus is bone dry, and it’s lost all of its water. We would either have to take water there or somehow manufacture water, so unless they figure out how to take the hydrogen out of the sulfuric acid and the oxygen out of the carbon dioxide to make water, it’s farfetched.

Whereas, one of the appealing things about Mars is that it has water. Yes it’s gravity is weaker and it’s further away; it’s colder; it’s atmosphere is thinner: All of that stuff is true. But Mars has water. We don’t know how much water it has, but Mars has some water, and we obviously can’t survive without water. That gives Mars such an enormous advantage, that it’s hard to even get beyond that for me.

RO: Couldn’t we take water there?

DW: We could take a little bit of water for something like seven astronauts living in an experimental chamber, so I could easily see in some imaginative future NASA scenario in which we launch some floating balloon with a half-dozen astronauts to float in the atmosphere of Venus for a year and do all sorts of experiments, and that could be REALLY neat. We could learn a lot, but that’s not colonizing Venus.

Now water’s simple: It’s hydrogen and oxygen, so someone needs to develop some widget that can take carbon dioxide and sulfuric acid and mix it together with ultraviolet light and presto! Out comes water. If somebody can make that widget, well, we’re in great shape.

But Mars has water, and that’s the magic of Mars.


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Rad
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« Reply #10 on: Today at 06:02 AM »

First smaller-than-Earth exoplanet discovered

June 29, 2015
Chuck Bednar for redOrbit.com – @BednarChuck

A planet located approximately 200 light-years from our solar system has been identified as the first alien world to be smaller than Earth in terms of both measured mass and size, according to a study published in a recent edition of the journal Nature.

The discovery was made by researchers from the Pennsylvania State University Department of Astronomy, the NASA Ames Research Center, the SETI Institute, and the University of Chicago Department of Astronomy and Astrophysics. They measured the size and mass of the Mars-sized planet Kepler-138b, an extrasolar planet in orbit around a red dwarf star.

According to Space.com, since Kepler 138b is about the same size as Mars, and Mars is just 53 percent as big as Earth, the new planet must be smaller than our home world. Furthermore, they found it to have a mass of about 6.7 percent that of Earth and two-thirds that of Mars, and is also the smallest exoplanet ever to have its density measured.

More about Kepler-138b and its sister planets

The new study, led by Penn State University astronomer Daniel Jontof-Hutter, looked at a total of three planets in orbit around a cold red dwarf, Kepler-138. It’s a cold, dim star located in the constellation Lyra, and is located roughly 10 million times further away from Earth than our sun, Jontof-Hutter said.

Two of the planets orbiting Kepler-138, Kepler-138c and Kepler-138d, are about 1.2 times the width of Earth, while Kepler-138b is slightly more than half the width of Earth. All three exoplanets orbit their star closely. Kepler-138b takes a little more than 10 days to complete one orbit, while Kepler-138c needs nearly 14 days and Kepler-138d requires approximately 23 days.

Using the NASA Kepler spacecraft, they were able to examine the relationship between gravity and the length of their orbits, and since they knew the strength of a planet’s gravitational pull is directly related to its mass, they were able to determine each planet’s size, the website explained. In addition, after Kepler-138b’s mass and width, they were able to determine its density, which is approximately two-thirds that of Mars and indicates that it is a rocky planet.

Because of its proximity to its host star, Kepler-138b is believed to be too hot to retain liquid water, as are its sister planets. In fact, Jontof-Hutter said the outermost of the three worlds could experience surface temperatures of 250 degrees Fahrenheit (120 degrees Celsius), while the innermost planet likely sees temperatures of up to 610 degrees F (320 degrees C).


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Rad
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« Reply #11 on: Today at 06:08 AM »

Mars pyramid: Alien structure or everyday pareidolia?

NASA says it has spotted a pyramid on Mars. Did an advanced civilization once exist on Mars, or is the brain seeing patterns where there are none?

By Beatrice Gitau, Staff writer June 25, 2015   
Christian Science Monitor

Are there pyramids on Mars? Or is it just one pyramid-shaped rock?

On May 7, NASA's Mars Curiosity rover took a snapshot of an atypical stone on the Red Planet.

A raw image from the mission shows a rock that appears to be pyramid-shaped, leading some to speculate that it may be the result of intelligent sculptors. NASA, for its part, says it's just an ordinary rock.

Jim Bell, a member of NASA's Mars Rover Explanation Team told Indianapolis's WISH TV that the object was unlikely to be man- or alien-made, adding that rock formations which look like recognizable objects are very common.

But that hasn't stopped people from speculating about its origin or design. "I would theorize that the [artifact] is either the capstone of a much larger pyramid, possibly buried deep beneath the surface, or perhaps a marker stone," says a robotic narrator in a YouTube video uploaded by a user called Paranormal Crucible.

Writing for the website Exopolitics.org, Dr. Michael Salla speculates that NASA deliberately took pains to prevent showing other views of the object to the public in subsequent photos.

Or is it just a rock, as NASA says?

Perhaps interpretations of the object as a man-made structure are driven by our own expectations. A well-known psychological phenomenon known as pareidolia can cause people to interpret random images as significant or meaningful.

A series of reports published by Japanese palaeontologist Chonosuke Okamura in the 1970s and '80s demonstrate the dangers of interpretations resulting from pareidolia. Mr. Okamura described finding ancient fossils of dogs, fish, birds and men, all at tiny sizes, leading him to conclude that modern body shapes existed in ancient times, but at 1/350th scale. Okamura was awarded the 1996 Ig Nobel Prize for his research.

American astronomer and author Carl Sagan argues that pareidolia evolved as a survival tool that allowed humans to recognize faces from a distance or in the dark. The instinct was vital to identifying friend or foe, but Dr. Sagan noted that it could cause people to misinterpret patterns.

And don't underestimate the power of expectations, says Sophie Scott, professor of neuroscience at the University College London. "Being able to see Jesus's face in toast is telling you more about what's happening with your expectations, and how you're interpreting the world based on your expectations, rather than anything that's necessarily in the toast," Dr. Scott told the BBC.

In other words, seeing a pyramid on Mars, instead of just a funny-shaped rock, could tell us more about our expectations of life in Mars than anything about actual Martian history.


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« Reply #12 on: Today at 06:11 AM »


The Christian Science Monitor

Star of Bethlehem? Jupiter and Venus converge in night sky

On June 30, Jupiter and Venus will converge and create a dramatic 'star' in the Western sky after sunset.
By Beatrice Gitau June 27, 2015   

Jupiter and Venus are set to converge in an epic sky event. (NASA)   

Jupiter and Venus will merge into a dazzling "super-star" in the Western horizon by the end of June, NASA says.

The conjunction of the two planets has been building during the month of June and will culminate in a spectacular display on June 30. “Every night in June, the separation between Venus and Jupiter will visibly shrink,” says NASA.

A conjunction is when two or more objects appear very close together on the sky.

On the evening of June 30, Venus and Jupiter will appear in the sky just a third of a degree apart. “That's less than the diameter of a full Moon. You'll be able to hide the pair not just behind the palm of your outstretched hand, but behind your little pinky finger,” NASA enthuses.

Sky & Telescope suggests that a similar rare conjunction of Venus and Jupiter may have been what's been called the "Star of Bethlehem" in 3-2 BC.

While the conjunction is certainly visible with the naked eye, Sky and Telescope says viewing it with a telescope or binoculars will offer a different perspective: “Both planets will crowd into same telescopic field of view, Venus appearing as a fat crescent and round Jupiter accompanied by its four large moons. The two planets will appear nearly as the same size, but Jupiter, though much larger in reality, is much farther away.... Their globes will contrast dramatically in brightness, with Venus’s crescent appearing dazzling white compared to Jupiter’s duller, striped cloud deck.”

Pat Hartigan, an astronomer at Rice University, says the conjunction on June 30 is the best one we will have for over a decade, rivaled only by one on March 1, 2023, which will not be not quite as close.

So where and when should we look for it? Look to the west-northwest as soon as it gets dark, says Dr. Hartigan. "After about two hours for most latitudes the objects will become difficult to observe as they begin to set. They are bright. You might mistake them for airplanes."

Is this a significant astronomical event? Not really. "These planetary groupings in the sky have no effect on Earth or human affairs – except for one," says Alan MacRobert at Sky & Telescope. "They can lift our attention away from our own little world into the enormous things beyond. That's what amateur astronomers do all the time."

[Editor's note: The original story incorrectly indicated when the last, close convergence of Jupiter and Venus occurred.]


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« Reply #13 on: Today at 07:15 AM »

Christian Science Monitor

Young crater on Mars hints at Earth-like climate

For the first time, scientists calculate water volumes in a young crater on Mars, revealing Earth-like conditions in the recent past.

By Shontee Pant, Staff writer June 23, 2015   

An image by the High Resolution Imaging Science Experiment (HiRISE) camera on the NASA's Mars Reconnaissance Orbiter shows Gullies at the Edge of Hale Crater on Mars recorded during the month of April through early August 2009. (Reuters/NASA/JPL/University of Arizona/Handout)   

Mars is a planet of paradoxes, red in color but icy cold. Did its climate ever resemble that of our warm, blue planet? Maybe so, suggests a new study of Istok crater – and not billions of years ago, but in the recent geologic past.

A study led by Tjalling de Haas of Utrecht University has found that the gullies in Istok crater are similar to those on Earth, and could have formed during recent periods of high orbital obliquity.

Istok crater, located in the Aonia Terra region of Mars, has remarkably well-preserved debris-flow tracks, or gullies. These are the first tracks imaged clearly enough to allow scientists to calculate the amount and frequency of water that flowed through them. As he told the Monitor, this is "really something new!"

Debris flows, such as mudslides and avalanches, differ from pure-water flows in that they contain about only 20-60 percent water, located in the tiny gaps between the rocks and dirt.

Once the scientists had calculated the amount of water necessary to create the gullies they observed, they could estimate the amount of snowfall necessary to generate that much water.

Previous research concluded that these tracks could have been carved with just millimeters of water, but Dr. de Haas disagrees. His team calculated that inches or even feet of snow had to pile up at the heads of these valleys in order to explain the debris flow patterns visible in the images taken from orbit.

The Martian climate is currently quite dissimilar from Earth's climate, with very cold temperatures and an almost nonexistent atmosphere. Most of the known water on the planet is frozen at the poles or hidden in deep underground springs. But finding debris flow tracks in a crater that is less than a million years old – their best estimate dates the crater impact to about 190,000 years ago – demonstrates that temperatures were warm enough in the recent past to allow ice to melt, at least in that region.

How could that happen? De Haas theorizes that these Earth-like debris flows occurred at times of high orbital obliquity, because when Mars's axis is tilted more dramatically, it can have much hotter summers (and colder winters) than the present.

While Earth’s axis has remained relatively constant over its history, only shifting between 22.1 to 24.5 degrees (thanks to stabilization from our large moon), Mars has bobbled like a top over tens of millions of years, moving between an almost vertical axis down to an axial tilt of more than 60 degrees. Its axis is currently tilted 25 degrees, but during high obliquity intervals, Mars is lying down almost sideways with respect to its orbit, like Uranus does.

It's still uncertain exactly how much these dramatic changes in axial tilt affect Martian climate, but for comparison, a one degree change in Earth's axis may have ended the ice age, melting glaciers from New York City to Greenland. It's not unreasonable to conclude that massive axial swings on Mars could lead to greater climate variation, creating conditions where snow and ice can first accumulate and then melt, causing debris flows.   

This study, published in the current issue of Nature Communications, contributes to the emerging understanding of the dynamic climatic history of the red planet; if these results are replicated in other areas around the planet, it may turn out that Mars was once much more habitable than it currently is.

However, de Haas cautions that his team identified only “a local occurrence, and only during very short periods at high orbital obliquity.” More research is necessary, he adds, to determine whether these conditions were present elsewhere or whether they only speak to an isolated, transient incidence of climate conditions like those on Earth.

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The Christian Science Monitor

Mars was not only habitable, it was downright Earth-like, Curiosity finds

Mars' Gale Crater had a long, thin lake that could have supported microbial life in a setting 'really similar to an Earth environment,' according to data collected by NASA's Curiosity rover.
By Pete Spotts, Staff writer December 9, 2013   

This file image shows a self-portrait of the Mars rover, Curiosity. Curiosity has uncovered signs of an ancient freshwater lake on Mars that may have teemed with microbes for tens of millions of years, far longer than scientists had imagined, new research suggests. (JPL-Caltech/MSSS/NASA/Reuters/FIle)   

NASA's Mars rover Curiosity has uncovered mineral and chemical leftovers in the rocks of Gale Crater that paint a remarkable picture of a modest lake whose mucky bed could have supported microbial life as early as 3.6 billion years ago.

In the process, the rover has laid bare the challenges and opportunities the rover's science team faces as it moves into the second phase of the mission: hunting for organic compounds that would enhance the crater's cosmic credibility as a once-habitable spot beyond Earth.

The lessons learned exploring a formation known as Yellowknife Bay suggest that well-preserved organics – easily destroyed by prolonged long exposure to radiation – may exist within reach of Curiosity's drill if the rover's handlers can find the right spot.

That is encouraging news for a mission that, seven months after it landed, answered "yes" to the question of whether its landing site could once have been habitable. The results released on Monday at the fall meeting of the American Geophysical Union in San Francisco add richness to the story.

The lakes, streams, and groundwater systems the team says were once in Gale Crater “are really similar to an Earth environment,” said John Grotzinger, a geologist at the California Institute of Technology in Pasadena and the project scientist for the mission, at the briefing.

The lake, nestled against the base of Mt. Sharp, the crater's central peak, would have been similar in size to those in the Finger Lakes region of upstate New York – perhaps 30 miles long by 3 miles wide. The climate likely would have been cold and arid, with water supplied by snow in the mountains that form Gale crater's rim.

The rocks the team explored span “millions to even tens of millions of years of time, which is quite a long window of habitability,” Dr. Grotzinger said. He and four colleagues summarized the results in six research papers appearing Friday in the journal Science.

Last March, after drilling into a rock named John Klein, the team announced that the site had been habitable. The site yielded evidence of flowing water. Chemical analysis of the rock sample revealed several of the basic chemical elements important for organic life.

Indeed, the team's interpretation of the data led the scientists to conclude that they had a system of environments that involved not just a lake, but the rivers that fed it and the groundwater deposits that would have developed there.

But there was still some uncertainty about whether the minerals analyzed formed locally, and so pointed to past habitats in the crater, or formed elsewhere and were transported and deposited, suggesting that perhaps the crater might not have had a complete package of traits for habitability.

Team members cleared that up in the new reports, which include analysis of a sample from a mudstone rock dubbed Cumberland. Unlike samples of Martian soil analyzed elsewhere, the clay Cumberland contained was heavy on magnetite and light on olivine, suggesting the clay formed from a local mineral mix, says Douglas Ming, a soil chemist at NASA's Johnson Space Center in Houston and the lead author of one of the six papers in Science.

Moreover, Cumberland's particular blend forms “in pretty benign conditions,” he says – fairly cold temperatures in waters that weren't too acidic or too basic.

Those are conditions “that are pretty unique, that microbes might have survived in,” he says.


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