Saturday, November 14, 2015

JUPITER PLANET HD WALLPAPER

JUPITER PLANET HD WALLPAPER

Jupiter Planet Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet with a mass one-thousandth that of the Sun, but two and a half times that of all the other planets in the Solar System combined. Wikipedia Radius: 69,911 km Mass: 1.898E27 kg (317.8 Earth mass) Distance from Sun: 778,500,000 km Gravity: 24.79 m/s² Surface area: 61,418,738,571 km² Moons: Europa, Io, Ganymede, Callisto, Amalthea, Carme, Pasiphae,
JUPITER PLANET WALLPAPER HD


    Jupiter
    Planet
    Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet with a mass one-thousandth that of the Sun, but two and a half times that of all the other planets in the Solar System combined. Wikipedia
    Radius69,911 km
    Mass1.898E27 kg (317.8 Earth mass)
    Distance from Sun778,500,000 km
    Gravity24.79 m/s²
    Surface area61,418,738,571 km²


Sunday, November 8, 2015

Bio-Mimicry and Space Exploration

Bio-Mimicry and Space Exploration:

A close-up of the spiral pattern in a sunflower. (Image Credit: Vishwas Krishna, unaltered, CC2.0)


Sunflowers doing what they do best: capturing sunlight. (Image Credit: OiMax, image unaltered, CC2.0)
“Those who are inspired by a model other than Nature, a mistress above all masters, are laboring in vain.

-Leonardo DaVinci

What DaVinci was talking about, though it wasn’t called it at the time, was biomimicry. Biomimicry is the practice of using designs from the natural world to solve technological and engineering problems. Were he alive today, there’s no doubt that Mr. DaVinci would be a big proponent of biomimicry.

Nature is more fascinating the deeper you look into it. When we look deeply into nature, we’re peering into a laboratory that is over 3 billion years old, where solutions to problems have been implemented, tested, and revised over the course of evolution. That’s why biomimicry is so elegant: on Earth, nature has had more than 3 billion years to solve problems, the same kinds of problems we need to solve to advance in space exploration.

The more powerful our technology gets, the deeper we can see into nature. As greater detail is revealed, more tantalizing solutions to engineering problems present themselves. Scientists who look to nature for solutions to engineering and design problems are reaping the rewards, and are making headway in several areas related to space exploration.

Flapping-Wing Micro Air Vehicles (MAVs)

MAVs are small, usually no bigger than 15 cm in length and 100 grams in weight. MAVs are not only small, they’re quiet. Fitted with chemical sniffers, cameras, or other equipment, they could be used to explore confined spaces too small for a human to access, or to stealthily explore areas of any size. Terrestrial uses could include hostage situations, assessing industrial accidents like Fukushima, or military uses. But it’s their potential use on other worlds yet to be explored that are the most fascinating.

MAVs have appeared in science fiction books and movies over the years. Think of the hunter-seekers in Dune, or the probes in Prometheus that were used to map the chamber ahead of the humans. Those designs are more advanced than anything currently being worked on, but flapping-wing MAVs are being researched and designed right now, and are the precursors to more advanced designs in the future.

High-speed cameras have spurred on the development of flapping-wing MAVs. The detailed images from high-speed cameras have allowed researchers to study bird and insect flight in great detail. And as it turns out, flapping-wing flight is much more complicated than initially thought. But it’s also much more versatile and resilient. That explains its persistence in nature, and its versatility in MAV design. Here’s some video from a high-speed camera capturing bees in flight.



The DelFly Explorer from the Delft University of Technology is one intriguing design of flapping-wing MAV. Its small and lightweight stereo vision system allows it to avoid obstacles and maintain its altitude on its own.



Flapping-wing MAVs don’t require a runway. They also have the advantage of being able to perch on small spaces to conserve energy. And they have the potential to be very quiet. This video shows a flapping-wing vehicle being developed by Airvironment.



Flapping-wing MAVs are highly manoeuvrable. Because they generate their lift from wing movement, rather than forward motion, they can travel very slowly, and even hover. They can even recover from collisions with obstacles in ways that fixed wing or rotary wing MAVs can’t. When a fixed wing vehicle collides with something, it loses its airspeed and its lift. When a rotary wing vehicle collides with something, it loses its rotor speed and its lift.

Because of their small size, flapping-wing MAVs are likely to be cheap to produce. They’ll never be able to carry the payload that a larger vehicle can, but they’ll have their role in exploration of other worlds.

Robotic probes have done all of the exploring for us on other worlds, at a much cheaper cost than sending people. While-flapping wing MAVs are presently being designed with terrestrial performance in mind, it’s an easy enough leap from that to designs for other worlds and other conditions. Imagine a small fleet of flapping-wing vehicles, designed for a thinner atmosphere and weaker gravity, released to map caves or other hard to reach areas, to locate water or minerals, or to map other features.

Ant Colonies and Collective Systems



Ant teamwork: a collective system in action. (Image Credit: Budzlife, image unaltered, CC2.0)


Ant teamwork: a collective system in action. (Image Credit: Budzlife, image unaltered, CC2.0)
Ants seem mindless when you look at them individually. But they do amazing things together. Not only do they build intricate and efficient colonies, they also use their bodies to build floating bridges, and bridges suspended in mid-air. This behaviour is called self-assembly.

Ant colonies and ant behaviour have a lot to teach us. There’s a whole field of research called Ant Colony Optimization that has implications for circuits and systems, communications, computational intelligence, control systems, and industrial electronics.

Here’s a video of Weaver ants building a bridge to span the gap between two suspended sticks. It takes them a while to get it. See if you can watch without cheering them on.



Ant colonies are one example of what are called collective systems. Other examples of collective systems in nature are bee and wasp hives, termite mounds, and even schools of fish. The robots in the next video have been designed to mimic natural collective systems. These robots can do very little alone, and are prone to error, but when they work together, they’re capable of self-assembling into complex shapes.



Self-assembling systems can be more adaptable to changing conditions. When it comes to exploring other worlds, robots that can self-assemble will be able to respond to unexpected changes in their surroundings and in environments of other worlds. It seems certain that self-assembly by collective systems will allow our future robotic explorers to traverse environments and survive situations that we can’t specifically design them for in advance. These robots will not only have artificial intelligence to think their way through problems, but will also be able to self-assemble themselves in different ways to overcome obstacles.

Robots Modelled on Animals

Exploring Mars with robotic rovers is an astonishing achievement. I had chills running down my spine when Curiosity landed on Mars. But our current rovers appear brittle and frail, and watching them move slowly and clumsily around the surface of Mars makes you wonder how much better they could be in the future. By using biomimicry to model robotic rovers on animals, we should be able to build much better rovers than we currently have.

Wheels are one of humanity’s earliest and greatest technologies. But do we even need wheels on Mars? Wheels get stuck, can’t traverse abrupt changes in height, and have other problems. There are no wheels in nature.

Snakes have their own unique solution to the problem of locomotion. Their ability to move over land, up and over obstacles, squeeze through tight places, and even swim, makes them very efficient predators. And I’ve never seen a snake with a broken let, or a busted axle. Could future rovers be modelled on terrestrial snakes?

This robot moves across the floor the same way snakes do.



Here’s another robot based on snakes, with the added capability of being at home in the water. This one looks like it’s enjoying itself.



This robot is not only based on snakes, but also inchworms and insects. It even has elements of self-assembly. Wheels would only hold it back.  Some segments could certainly hold sensors, and it could even retrieve samples for analysis. Watch as it reassembles itself to overcome obstacles.



It’s easy enough to think of multiple uses of snake bots. Imagine a larger platform, similar to the MSL Curiosity. Now imagine if its legs were actually several independent snake bots that could detach themselves, perform tasks like exploring difficult to access areas and retrieving sample, then returning to the larger platform. They would then deposit samples, download data, and re-attach themselves. Then the whole vehicle could move to a different location, with the snake bots carrying the platform.

If this sounds like science fiction, so what? We love science fiction.

Solar Power: Sunflowers in Space

The flow of energy from the sun is diluted to a trickle the further afield in the solar system we go. While we keep getting more and more efficient at collecting the sun’s energy, biomimicry offers the promise of a 20% reduction in solar panel space required, just by mimicking the sunflower.

Concentrated Solar Plants (CSPs) are made up of an array of mirrors, called heliostats, that track the sun as the Earth rotates. The heliostats are arranged in concentric circles, and they catch the sunlight and reflect it towards a central tower, where the heat is converted into electricity.

When researchers at MIT studied CSPs in more detail, they discovered that each of the heliostats spent part of the time shaded, making them less effective. As they worked with computer models to solve the problem, they noticed that possible solutions were similar to spiral patterns found in nature. From there, they looked at the sunflower for inspiration.



A close-up of the spiral pattern in a sunflower. (Image Credit: Vishwas Krishna, unaltered, CC2.0)


A close-up of the spiral pattern in a sunflower. (Image Credit: Vishwas Krishna, unaltered, CC2.0)
The sunflower isn’t a single flower. It’s a collection of small flowers called florets, much like the individual mirrors in a CSP. These florets are arranged in a spiral pattern with each floret oriented at 137 degrees to each other. This is called the ‘golden angle’, and when the florets are arranged like this, they form an array of interconnected spirals that conforms to the Fibonacci sequence. MIT researchers say that organizing individual mirrors the same way in a CSP will reduce the space needed by 20%.

Since we’re still putting everything we need for space exploration into space by blasting it out of Earth’s gravity well strapped to enormous, expensive rockets, a 20% reduction in space for the same amount of solar energy collected is a significant improvement.

Extremophiles and Biomimicry

Extremophiles are organisms adapted to thrive in extreme environmental conditions. As of 2013, there have been 865 extremophilic microorganisms identified. Their recognition has given new hope to finding life in extreme environments on other worlds. But more than that, mimicking extremophiles may help us explore these environments.



The tiny Tardigrade: Nature's toughest creature? (Image Credit: Katexic Publications, unaltered, CC2.0)


The tiny Tardigrade: Nature’s toughest creature? (Image Credit: Katexic Publications, unaltered, CC2.0)
Strictly speaking, Tardigrades are not exactly extremophiles, because though they can survive extremes, they are not adapted to thrive in them. However, their ability to withstand environmental extremes means they have a lot to teach us. There are about 1,150 species of Tardigrades, and they have the ability to survive in conditions that would kill human beings, and would quickly degrade the functioning of any robotic probes that we may send to extreme environments.

Tardigrades are actually tiny, aquatic, eight-legged micro-animals. They can withstand temperatures from just above absolute zero to well over the boiling point of water. They can survive pressures about six times greater than the pressure at the bottom of the deepest ocean trenches on Earth. Tardigrades can also go ten years without food or water, and can dry out to less than 3% water.



The Tardigrade: Earth's super-tiny superheroes. (Image Credit: ESA/Dr. Ralph O. Schill)


The Tardigrade: Earth’s super-tiny superheroes. (Image Credit: ESA/Dr. Ralph O. Schill)
They’re basically the super-tiny super heroes of the Earth.

But as far as space exploration goes, it’s their ability to withstand ionizing radiation thousands of times higher than humans can withstand, that interests us the most. Tardigrades are called nature’s toughest creatures, and it’s easy to see why.

It’s probably in the realm of science fiction to imagine a future where humans are genetically engineered with tardigrade genes to withstand radiation on other worlds. But if we survive long enough, there’s no doubt in my mind we will borrow genes from other terrestrial life to help us expand into other worlds. It’s only logical. But that’s a long way off, and tardigrade survival mechanisms may come into play much sooner.



Earth's protective cloak: the magnetosphere. (Image credit: NASA)


Earth’s protective cloak: the magnetosphere. (Image credit: NASA)
Worlds like Earth are lucky to be shrouded by a magnetosphere, which protects the biosphere from radiation. But many worlds, and all the moons of the other planets in our solar system—other than Ganymede—lack a magnetosphere. Mars itself is completely unprotected. The presence of radiation in space, and on worlds with no protective magnetosphere, not only kills living things, but can affect electronic devices by degrading their performance, shortening their lifespan, or causing complete failure.

Some of the instruments on the Juno probe, which is on its way to  Jupiter right now, are not expected to survive for the duration of the mission because of the extreme radiation around the giant gas planet. Solar panels themselves, which must be exposed to the sun in order to function, are particularly susceptible to ionizing radiation, which erodes their performance over time. Protecting electronics from ionizing radiation is an essential part of spacecraft and probe design.

Typically, the sensitive electronics in spacecraft and probes are shielded by aluminum, copper, or other materials. The Juno probe uses an innovative titanium vault to protect its most sensitive electronics. This adds bulk and weight to the probe, and still won’t provide complete protection. The Tardigrades have some other way of shielding themselves which is probably more elegant than this. It’s too soon to say exactly how tardigrades do it, but if pigmentation shielding has something to do with it, and we can figure it out, mimicking Tardigrades will change the way we design spacecraft and probes, and extend their lifespans in extreme radiation environments.

So how about it? Will our future exploration missions involve snake bots that can self-assemble into long chains to explore hard to reach areas? Will we unleash swarms of flapping-wing MAVs that work together to create detailed maps or surveys? Will our probes be able to explore extreme environments for much longer periods of time, thanks to Tardigrade-like protection from radiation? Will our first bases on the moon or other worlds be powered by sunflower-inspired Concentrated Solar Plants?

If Leonardo DaVinci was as smart as I think he was, then the answer to all those questions is yes.





About 

Evan Gough lives on the West Coast of Canada with his wife and daughter, where he plays in the mountains and works as a technical writer.

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Uranus’ “Frankenstein Moon” Miranda

Uranus’ “Frankenstein Moon” Miranda:

This color composite of the Uranian satellite Miranda was taken by Voyager 2 on Jan. 24, 1986, from a distance of 147,OOO kilometers (91,OOO miles). Credit: NASA/JPL


Color composite of the Uranian satellite Miranda, taken by Voyager 2 on Jan. 24, 1986, from a distance of 147,000 km (91,000 mi). Credit: NASA/JPL
Ever since the Voyager space probes ventured into the outer Solar System, scientists and astronomers have come to understand a great deal of this region of space. In addition to the four massive gas giants that call the outer Solar System home, a great deal has been learned about the many moons that circle them. And thanks to photographs and data obtained, human beings as a whole have come to understand just how strange and awe-inspiring our Solar System really is.

This is especially true of Miranda, the smallest and innermost of Uranus’ large moons – and some would say, the oddest-looking! Like the other major Uranian moons, its orbits close to its planet’s equator, is perpendicular to the Solar System’s ecliptic, and therefore has an extreme seasonal cycle. Combined with one of the most extreme and varied topographies in the Solar System, this makes Miranda an understandable source of interest!

Discovery and Naming:Miranda was discovered on February 16th, 1948, by Gerard Kuiper using the McDonald Observatory‘s Otto Struve Telescope at the University of Texas in Austin. Its motion around Uranus was confirmed on March 1st of the same year, making it the first satellite of Uranus to be discovered in almost a century (the previous ones being Ariel and Umbriel, which were both discovered in 1851 by William Lassell).



A montage of Uranus's moons. Image credit: NASA


A montage of Uranus’s moons. Image credit: NASA/JPL
Consistent with the names of the other moons, Kuiper decided to the name the object “Miranda” after the character in Shakespeare’s The Tempest. This continued the tradition set down by John Herschel, who suggested that all the large moons of Uranus – Ariel, Umbriel, Titania and Oberon – be named after characters from either The Tempest or Alexander Pope’s The Rape of the Lock.

Size, Mass and Orbit:With a mean radius of 235.8 ± 0.7 km and a mass of 6.59 ± 0.75 ×1019 kg, Miranda is 0.03697 Earths times the size of Earth and roughly 0.000011 as massive. Its modest size also makes it one of the smallest object in the Solar System to have achieved hydrostatic equilibrium, with only Saturn’s moon of Mimas being smaller.

Of Uranus’ five larger moons, Miranda is the closest, orbiting at an average distance (semi-major axis) of 129,390 km. It has a very minor eccentricity of 0.0013 and an inclination of 4.232° to Uranus’ equator. This is unusually high for a body so close to its parent planet – roughly ten times that of the other Uranian satellites.

Since there are no mean-motion resonances to explain this, it has been hypothesized that the moons occasionally pass through secondary resonances. At some point, this would have led Miranda into being locked in a temporary 3:1 resonance with Umbriel, and perhaps a 5:3 resonance with Ariel as well. This resonance would have altered the moon’s inclination, and also led to tidal heating in its interior (see below).



Size comparison of all the Solar Systems moons. Credit: The Planetary Society


Size comparison of all the Solar Systems moons. Credit: NASA/The Planetary Society
With an average orbital speed of 6.66 km/s, Miranda takes 1.4 days to complete a single orbit of Uranus. Its orbital period (also 34 hours) is synchronous with its rotational period, meaning that it is tidally-locked with Uranus and maintains one face towards it at all times. Given that it orbits around Uranus’ equator, which means its orbit is perpendicular to the Sun’s ecliptic, Uranus goes through an extreme seasonal cycle where the northern and southern hemispheres experience 42 years of lightness and darkness at a time.

Composition and Surface Structure:Miranda’s mean density (1.2 g/cm3) makes it the least dense of the Uranian moons. It also suggests that Miranda is largely composed of water ice (at least 60%), with the remainder likely consisting of silicate rock and organic compounds in the interior. The surface of Miranda is also the most diverse and extreme of all moons in the Solar System, with features that appear to be jumbled together in a haphazard fashion.

This consists of huge fault canyons as deep as 20 km (12 mi), terraced layers, and the juxtaposition of old and young surfaces seemingly at random. This patchwork of broken terrain indicates that intense geological activity took place in Miranda’s past, which is believed to have been driven by tidal heating during the time when it was in orbital resonance with Umbriel (and perhaps Ariel).

This resonance would have increased orbital eccentricity, and along with varying tidal forces from Uranus, would have caused warming in Miranda’s interior and led to resurfacing. In addition, the incomplete differentiation of the moon, whereby rock and ice were distributed more uniformly, could have led to an upwelling of lighter material in some areas, thus leading to young and older regions existing side by side.



Miranda


Uranus’ moon Miranda, imaged by the Voyager 2 space probe on January 24th, 1986. Credit: NASA/JPL-Caltech
Another theory is that Miranda was shattered by a massive impact, the fragments of which reassembled to produce a fractured core. In this scenario – which some scientists believe could have happened as many as five times – the denser fragments would have sunk deep into the interior, with water ice and volatiles setting on top of them and mirroring their fractured shape.

Overall, scientists recognize five types of geological features on Miranda, which includes craters, coronae (large grooved features), regiones (geological regions), rupes (scarps or canyons) and sulci (parallel grooves).

Miranda’s cratered regions are differentiated between younger, lightly-cratered regions and older, more-heavily cratered ones. The lightly cratered regions include ridges and valleys, which are separated from the more heavily-cratered areas by sharp boundaries of mismatched features. The largest known craters are about 30 km (20 mi) in diameter, with others lying in the range of 5 to 10 km (3 to 6 mi).

Miranda has the largest known cliff in the Solar System, which is known as Verona Rupes (named after the setting of Shakespeare’s Romeo and Juliet). This rupes has a drop-off of over 5 km (3.1 mi) – making it 12 times as deep as the Grand Canyon. Scientists suspect that Miranda’s ridges and canyons represent extensional tilt blocks – a tectonic event where tectonic plates stretch apart, forming patterns of jagged terrain with steep drops.



. Credit: NASA/JPL


Image taken by the Voyager 2 probe during its close approach on January 24th, 1986, with a resolution of about 700 m (2300 ft). Credit: NASA/JPL
The most well known coronae exist in the southern hemisphere, with three giant ‘racetrack’-like grooved structures that measure at least 200 km (120 mi) wide and up to 20 km (12 mi) deep. These features, named Arden, Elsinore and Inverness – all locations in Shakespeare’s plays – may have formed via extensional processes at the tops of diapirs (aka. upwellings of warm ice).

Other features may be due to cryovolcanic eruptions of icy magma, which would have been driven by tidal flexing and heating in the past. With an albedo of 0.32, Miranda’s surface is nearly as bright as that of Ariel, the brightest of the larger Uranian moons. It’s slightly darker appearance is likely due to the presence of carbonaceous material within its surface ice.

Exploration:Miranda’s apparent magnitude makes it invisible to many amateur telescopes. As a result, virtually all known information regarding its geology and geography was obtained during the only flyby of the Uranian system, which was made by Voyager 2 in 1986. During the flyby, Miranda’s southern hemisphere pointed towards the Sun (while the northern was shrouded in darkness), so only the southern hemisphere could be studied.

At this time, no future missions have been planned or are under consideration. But given Miranda’s “Frankenstein”-like appearance and the mysteries that still surround its history and geology, any future missions to study Uranus and its system of moons would be well-advised.



We have many interesting articles on Miranda and Uranus’ moons here at Universe Today. Here’s one about about why they call it the “Frankenstein Moon“, and one about Voyager 2‘s historic flyby. And here’s one that answers the question How Many Moons Does Uranus Have?

For more information, check out NASA’s Solar System Exploration page on Miranda.





About 

Matt Williams is the Curator of the Guide to Space for Universe Today, a a regular contributor to HeroX, a science fiction author, and a Taekwon-Do instructor. He lives with his family on Vancouver Island in beautiful BC.

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The Moon Greets the Planets in the November Dawn

The Moon Greets the Planets in the November Dawn:



A tri-planetary grouping from the morning of October 31st. Image credit and copyright: Joseph Brimacombe


A tri-planetary grouping from the morning of October 31st. Image credit and copyright: Joseph Brimacombe
So, did this past weekend’s shift back to Standard Time for most of North America throw you for a loop? Coming the day after Halloween, 2015 was the earliest we can now shift back off Daylight Saving Time. Sunday won’t fall on November 1st again until 2020. Expect evenings get darker sooner for northern hemisphere residents, while the planetary action remains in the dawn sky.

Though Mercury has exited the morning twilight stage, the planets Jupiter, Venus and Mars continue to put on a fine show, joined by the waning crescent Moon later this week. The action starts today on November 3rd, which finds +1.9 magnitude Mars passing just 0.68 degrees (40’, just over the apparent diameter of a Full Moon) from brilliant -3.9 magnitude Venus. Though the two nearest planets to the Earth appear to meet up in the dawn sky, Mars is actually 2.5 times more distant than Venus, which sits 74.4 million miles (124 million kilometres) from the Earth. Venus exhibits a 57% illuminated gibbous phase 21” across this week, versus Mars’ paltry 4.5” disc.



November 6th. Image credit: Starry Night Education Software


The lunar planetary lineup on the morning of November 6th… Image credit: Starry Night Education Software
Watch the scene shift, as the Moon joins the dance this weekend. The mornings of Friday, November 6th and Saturday, November 7th are key, as the Moon passes just two degrees from the Jupiter and Mars pair and just over one degree from Venus worldwide. Similar close pairings of the Moon and Venus adorn many national flags, possibly inspired by a close grouping of Venus and the Moon witnessed by skywatchers of yore.



November 7th


… and the view the next morning on November 7th. Image credit: Starry Night Education software
Saturday November 7th is also a fine time to try your hand at seeing Venus in the daytime, using the nearby crescent Moon as a guide. The Moon will be only four days from New, and the pair will be 46 degrees west of the Sun, an optimal situation as Venus just passed greatest western elongation 46.4 degrees west of the Sun on October 26th.



Nov 3


Mars meets Venus on November 3rd-4th… the center circle = 1 degree FoV. Image credit: Stellarium
Though Venus may seem like a difficult daytime object, it’s actually intrinsically brighter than the Moon per square arc second. Difficulty finding it stems from seeing it against a low contrast blue daytime sky, its small size, and lack of context and depth. The larger but dimmer Moon actually serves as a good anchor to complete this feat of visual athletics.



Venus from the morning of November 3rd. Image credit and copyright: Shahrin Ahmad


Venus from the morning of November 3rd. Image credit and copyright: Shahrin Ahmad
Looking for more? Comet C/2013 US10 Catalina will join the planetary lineup next lunation ‘round, hopefully shining at magnitude +5 as it glides past Venus and the Moon on December 7th. Karl Battams at the U.S. Naval Research Labs has confirmed that Comet US10 Catalina—which reaches perihelion this month on November 15th –should also briefly graze the field of view for SOHO’s LASCO C3 camera on November 7th.

There’s also a few notable lunar occultations this week. The Moon also occults the +5 magnitude star Chi Leonis for viewers around the Gulf of Mexico on November 4th, including a dramatic grazing event for Northern Florida. The Moon also occults the +3.5 magnitude star Omicron Leonis on Nov 4th for Alaska as well.



Image credit:


The occultation footprint for Chi Leonis. The solid lines indicate where the event will occur during darkness and twilight hours, while the dashed lines denote where the event transpires during the daytime. Image credit: Occult 4.2 software
See a bright star near the Venus this week? It’s none other than +3.6 magnitude Beta Virginis (Zavijava). The star passes 15’ from Venus on the morning of November 6th. Stick around ‘til 2069, and you can actually witness Venus occult Beta Virginis. Between Beta Virginis and Mars, Venus has the appearance this week of having the large pseudo-moon it never possessed. From Venus, our Moon would appear near magnitude +0.4 with a disk 6.4” this week, and range 12’ from the Earth.



Nov 7


The closeup view on the morning of November 7th along with a 5 degree Telrad FoV. image credit: Stellarium
Now for the wow factor. All of these disparate objects merely lie along our Earthbound line of sight this week. Traveling at the speed of light (186,282 miles or 299,792 kilometers a second), the Moon lies just over a second away. Venus, Mars and Jupiter are next, at 6, 18, and 49 light minutes out, respectively… and Beta Virginis? It lies 36 light years distant.

This pass of the Moon also sets us up for an occultation of Mars and a dramatic daytime occultation of Venus for North America during the next lunation…

More to come!

-Got pictures of the planetary grouping this week with the Moon? Be sure to send ’em in to Universe Today and our Flickr forum.





About 

David Dickinson is an Earth science teacher, freelance science writer, retired USAF veteran & backyard astronomer. He currently writes and ponders the universe from Tampa Bay, Florida.

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New Visualization Shows Incredible Variety of Extraterrestrial Worlds

New Visualization Shows Incredible Variety of Extraterrestrial Worlds:



This poster shows more than 500 exoplanets discovered before October 2015 arranged according to their temperature and density. Credit and copyright: Martin Vargic. Used by permission.


This poster shows more than 500 exoplanets discovered before October 2015 arranged according to their temperature and density. Credit and copyright: Martin Vargic. Used by permission.
Here’s a great new poster showing over 500 extrasolar planets (about one quarter of the total) that have been discovered since 1988. This visualization, created by graphic artist and writer Martin Vargic from Slovakia, is based on the estimated radius and temperature of the planets, however other factors, such as density, age or stellar metallicity were also taken into consideration. All the various known classes of exoplanets are shown on the graphic, such as super-Earths, hot Jupiters, hot Neptunes, water worlds, gas dwarfs or superdense diamond planets.

Click on the image for a larger version, or a gigantic version here.

I love seeing the variety in sizes, as well as the diversity of projected colors of all the alien worlds.


According to NASA’s Exoplanet Archive website, 1,903 extra solar have been discovered since 1988 as of October 22, 2015.

You may have already seen Vargic’s very cool Map of the Internet, and of special interest to UT readers a map of how the the constellations have changed over time and visualization of the Moon replaced with other bodies, as well as a wide variety of other maps and infographics. You can check out his work on his website, Halcyon Maps. He puts out new graphics each week.

There are lots of ways to plot exoplanets. On the Exoplanet Archive website, you can see plots for exoplanet mass vs. period, temperature, number of exoplanets discovered by year (2014 was a banner year), as well as how the planets were discovered (radial velocity, microlensing, timing variations and orbital brightness modulation).

Previously, we’ve featured other exoplanet visualizations, such as one of Kepler’s transiting exoplanets and exoplanet candidates, plus this cool video visualization of the planetary systems discovered by Kepler that have more than one transiting object, created by Daniel Fabrycky from the Kepler spacecraft science team:







About 

Nancy Atkinson is currently Universe Today's Contributing Editor. Previously she served as UT's Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is also a NASA/JPL Solar System Ambassador.

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Ion Propulsion: The Key to Deep Space Exploration

Ion Propulsion: The Key to Deep Space Exploration:

The comforting blue glow of an ion drive. Image Credit: NASA


The comforting blue glow of an ion drive. Image Credit: NASA
When we think of space travel, we tend to picture a massive rocket blasting off from Earth, with huge blast streams of fire and smoke coming out the bottom, as the enormous machine struggles to escape Earth’s gravity. Rockets are our only option for escaping Earth’s gravity well—for now. But once a spacecraft has broken its gravitational bond with Earth, we have other options for powering them. Ion propulsion, long dreamed of in science fiction, is now used to send probes and spacecraft on long journeys through space.

NASA first began researching ion propulsion in the 1950’s. In 1998, ion propulsion was successfully used as the main propulsion system on a spacecraft, powering the Deep Space 1 (DS1) on its mission to the asteroid 9969 Braille and Comet Borrelly. DS1 was designed not only to visit an asteroid and a comet, but to test twelve advanced, high-risk technologies, chief among them the ion propulsion system itself.

Ion propulsion systems generate a tiny amount of thrust. Hold nine quarters in your hand, feel Earth’s gravity pull on them, and you have an idea how little thrust they generate. They can’t be used for launching spacecraft from bodies with strong gravity. Their strength lies in continuing to generate thrust over time. This means that they can achieve very high top speeds. Ion thrusters can propel spacecraft to speeds over 320,000 kp/h (200,000 mph), but they must be in operation for a long time to achieve that speed.

An ion is an atom or a molecule that has either lost or gained an electron, and therefore has an electrical charge. So ionization is the process of giving a charge to an atom or a molecule, by adding or removing electrons. Once charged, an ion will want to move in relation to a magnetic field. That’s at the heart of ion drives. But certain atoms are better suited for this. NASA’s ion drives typically use xenon, an inert gas, because there’s no risk of explosion.



Detail of an ion drive. Image: NASA Glenn Research Center. Vectorization by Chabacano


Detail of an ion drive. Image: NASA Glenn Research Center. Vectorization by Chabacano
In an ion drive, the xenon isn’t a fuel. It isn’t combusted, and it has no inherent properties that make it useful as a fuel. The energy source for an ion drive has to come from somewhere else. This source can be electricity from solar cells, or electricity generated from decay heat from a nuclear material.

Ions are created by bombarding the xenon gas with high energy electrons. Once charged, these ions are drawn through a pair of electrostatic grids—called lenses—by their charges, and are expelled out of the chamber, producing thrust. This discharge is called the ion beam, and it is again injected with electrons, to neutralize its charge. Here’s a short video showing how ion drives work:



Unlike a traditional chemical rocket, where its thrust is limited by how much fuel it can carry and burn, the thrust generated by an ion drive is only limited by the strength of its electrical source. The amount of propellant a craft can carry, in this case xenon, is a secondary concern. NASA’s Dawn spacecraft used only 10 ounces of xenon propellant—that’s less than a soda can—for 27 hours of operation.



NASA Evolutionary Xenon Thruster. Image Credit: NASA


NASA Evolutionary Xenon Thruster. Image Credit: NASA
In theory, there is no limit to the strength of the electrical source powering the drive, and work is being done to develop even more powerful ion thrusters than we currently have. In 2012, NASA’s Evolutionary Xenon Thruster (NEXT) operated at 7000w for over 43,000 hours, in comparison to the ion drive on DS1 that used only 2100w. NEXT, and designs that will surpass it in the future, will allow spacecraft to go on extended missions to multiple asteroids, comets, the outer planets, and their moons.

Missions using ion propulsion include NASA’s Dawn mission, the Japanese Hayabusa mission to asteroid 25143 Itokawa, and the upcoming ESA missions Bepicolombo, which will head to Mercury in 2017, and LISA Pathfinder, which will study low frequency gravitational waves.

With the constant improvement in ion propulsion systems, this list will only grow.





About 

Evan Gough lives on the West Coast of Canada with his wife and daughter, where he plays in the mountains and works as a technical writer.

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NASA’s MAVEN Orbiter Discovers Solar Wind Stripped Away Mars Atmosphere Causing Radical Transformation

NASA’s MAVEN Orbiter Discovers Solar Wind Stripped Away Mars Atmosphere Causing Radical Transformation:

Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet's upper atmosphere. Credits: NASA/GSFC


Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet’s upper atmosphere. Credits: NASA/GSFC
NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) orbiter mission has determined that ancient Mars suffered drastic climate change and lost its thick atmosphere and surface bodies of potentially life giving liquid water because it lost tremendous quantities of gas to space via stripping by the solar wind, based on new findings that were announced today, Nov. 5, at a NASA media briefing and in a series of scientific publications.

The process of Mars dramatic transformation from a more Earth-like world to its barren state today started about 4.2 Billion years ago as the shielding effect of the global magnetic field was lost as the planets internal dynamo cooled, Bruce Jakosky, MAVEN principal investigator at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder, told Universe Today.

The radical transformation of ancient Mars from a warm world with significant bodies of standing water that could have supported life, to its current state as a cold, arid and desert-like world that’s rather inhospitable to life was caused by the loss of most the planet’s atmosphere as powerful streams of solar wind particles crashed into it and stripped it away due to the loss of the protective magnetic field as the planets core cooled.

“We think that the early magnetic field that Mars had would have protected the planet from direct impact by the solar wind and would have kept it from stripping gas off,” Jakosky told me.

“So it would have been the turn off of the magnetic field, that would have allowed the turn on of stripping of the atmosphere by the solar wind.”

“The evidence suggests that the magnetic field disappeared about 4.2 Billion years ago.”

The period of abundant surface water actively carving the Martian geology lasted until about 3.7 Billion years ago. The loss of the atmosphere by stripping of the solar wind took place from about 4.2 to 3.7 Billion years ago.



Billions of years ago, Mars was a very different world. Liquid water flowed in long rivers that emptied into lakes and shallow seas. A thick atmosphere blanketed the planet and kept it warm. Credit: NASA


Billions of years ago, Mars was a very different world. Liquid water flowed in long rivers that emptied into lakes and shallow seas. A thick atmosphere blanketed the planet and kept it warm. Credit: NASA
With the release of today’s results, the MAVEN science team has accomplished the primary goal of the mission, which was to determine how and why Mars lost its early, thick atmosphere and water over the past four billion years. The atmosphere is composed mostly of carbon dioxide.

Since water is a prerequisite for life as we know it, determining its fate and longevity on Mars is crucial for determining the habitability of the Red Planet and its potential for supporting martian microbes, past of present if they ever existed.

“The NASA Mars exploration program has been focused on finding water,” said Michael Meyer, lead scientist for the Mars Exploration Program at NASA Headquarters.

“Water is the prime ingredient needed for life. It is a major factor in the climate and for shaping geology. And it is a critical resource for future human exploration.”

NASA’s goal is to send humans on a ‘Journey to Mars’ during the 2030s.

This NASA video shows a visualization of the solar wind striking Mars:



Video caption: Created using data from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission, this visualization shows how the solar wind strips ions from the Mars’ upper atmosphere into space. Credits: NASA-GSFC/CU Boulder LASP/University of Iowa

MAVEN arrived in orbit at Mars just over one year ago on Sept. 21, 2014.

The $671 Million MAVEN spacecraft’s goal is to study Mars tenuous upper atmosphere in detail for the very first time by any spacecraft and to explore the mechanisms of how the planet lost its atmosphere and life giving water over billions of years as well as determine the rate of atmospheric loss.

The new MAVEN data have enabled researchers to measure the rate of Mars atmospheric loss of gas to space via the action of solar wind stripping as well as the erosional effect of solar storms.

Based on measurements from MAVEN’s suite of nine state-of-the-art scientific instruments, the solar wind is stripping away gas at a rate of about 100 grams (equivalent to roughly 1/4 pound) every second today, in the form of carbon dioxide and oxygen, said David Brain, MAVEN co-investigator at LASP.

“Most of the stripping [of the Martian atmosphere] by the solar wind at Mars was thought to have taken place very early in the history of the solar system when the sun was much more active and when the solar wind was more intense. So today the rate of loss at Mars is low,” Jakosky said at the briefing.

“Today’s Mars is a cold dry desert-like environment. The atmosphere is thin and it’s not capable of sustaining liquid water at the surface today, it would freeze or evaporate very quickly. However when we look at ancient Mars we see a different type of surface, one that had valleys that looked like they were carved by water and lakes that were standing for long periods of time. We see an environment that was much more able to support liquid water.”

The MAVEN results were published today in nearly four dozen scientific papers in the Nov. 5 issues of the journals Science and Geophysical Research Letters.

I asked Jakosky; How much gas would have been lost from ancient Mars and what is the rough estimate for the ancient rate of loss to arrive at Mars thin atmosphere today?

“For the amount of gas that we think you would have to have been removed – let me start with the current Mars atmosphere which has a thickness of 6 millibars, that’s just under 1% as thick as the Earth’s atmosphere,” Jakosky replied.

“So we think you would have to remove an amount of gas that is about equivalent to what’s in Earth’s atmosphere today.”

“So the rate would have to have been a factor of about 100 to 1000 times higher, than today’s loss of 100 grams per second in order to have removed the gas early in that time period, which is consistent with what the models have predicted that the loss rate would have been back then in early history.”



NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft celebrated one Earth year in orbit around Mars on Sept. 21, 2015. MAVEN was launched to Mars on Nov. 18, 2013 from Cape Canaveral Air Force Station in Florida and successfully entered Mars’ orbit on Sept. 21, 2014. Credit: NASA


NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft celebrated one Earth year in orbit around Mars on Sept. 21, 2015. MAVEN was launched to Mars on Nov. 18, 2013 from Cape Canaveral Air Force Station in Florida and successfully entered Mars’ orbit on Sept. 21, 2014. Credit: NASA
What is the solar wind and how does it strip away the atmosphere?

“The solar wind is a stream of particles, mainly protons and electrons, flowing from the sun’s atmosphere at a speed of about one million miles per hour. The magnetic field carried by the solar wind as it flows past Mars can generate an electric field, much as a turbine on Earth can be used to generate electricity. This electric field accelerates electrically charged gas atoms, called ions, in Mars’ upper atmosphere and shoots them into space,” according to a NASA description.



MAVEN is NASA’s next Mars orbiter and is due to blastoff on Nov. 18 from Cape Canaveral, Florida. It will study the evolution of the Red Planet’s atmosphere and climate. Universe Today visited MAVEN inside the clean room at the Kennedy Space Center. With solar panels unfurled, this is exactly how MAVEN looks when flying through space and circling Mars. Credit: Ken Kremer/kenkremer.com


MAVEN is NASA’s next Mars orbiter and is due to blastoff on Nov. 18 from Cape Canaveral, Florida. It will study the evolution of the Red Planet’s atmosphere and climate. Universe Today visited MAVEN inside the clean room at the Kennedy Space Center. With solar panels unfurled, this is exactly how MAVEN looks when flying through space and circling Mars. Credit: Ken Kremer/kenkremer.com
MAVEN is just now completing its primary mission and starts the extended mission phase on Nov. 16.

The 5,400 pound MAVEN probe carries nine sensors in three instrument suites to study why and exactly when did Mars undergo the radical climatic transformation.

MAVEN’s observations will be tied in with NASA’s ongoing Curiosity and Opportunity surface roving missions as well as MRO and Mars Odyssey to provide the most complete picture of the fourth rock from the sun that humanity has ever had.

MAVEN thundered to space on Nov. 18, 2013 following a flawless blastoff from Cape Canaveral Air Force Station’s Space Launch Complex 41 atop a powerful United Launch Alliance Atlas V rocket.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer



NASA’s MAVEN Mars orbiter, chief scientist Prof. Bruce Jakosky of CU-Boulder and Ken Kremer of Universe Today inside the clean room at the Kennedy Space Center on Sept. 27, 2013. MAVEN launched to Mars on Nov. 18, 2013 from Florida. Credit: Ken Kremer/kenkremer.com


NASA’s MAVEN Mars orbiter, chief scientist Prof. Bruce Jakosky of CU-Boulder and Ken Kremer of Universe Today inside the clean room at the Kennedy Space Center on Sept. 27, 2013. MAVEN launched to Mars on Nov. 18, 2013 from Florida. Credit: Ken Kremer/kenkremer.com




About 

Dr. Ken Kremer is a speaker, research scientist, freelance science journalist (Princeton, NJ) and photographer whose articles, space exploration images and Mars mosaics have appeared in magazines, books, websites and calendars including Astronomy Picture of the Day, NBC, BBC, SPACE.com, Spaceflight Now and the covers of Aviation Week & Space Technology, Spaceflight and the Explorers Club magazines. Ken has presented at numerous educational institutions, civic & religious organizations, museums and astronomy clubs. Ken has reported first hand from the Kennedy Space Center, Cape Canaveral, NASA Wallops, NASA Michoud/Stennis/Langley and on over 40 launches including 8 shuttle launches. He lectures on both Human and Robotic spaceflight - www.kenkremer.com. Follow Ken on Facebook and Twitter

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