A concept for windsurfing on Venus from the NASA Innovative Advanced Concepts office. Credit: NASA
A windsailing rover could use the high speeds and hot temperatures of Venus to a robotic explorer’s advantage, according to an idea funded by NASA’s Innovative Advanced Concepts program.
The rover would not only be able to move around Venus, but would also have electronics inside able to withstand the temperatures of 450 degrees Celsius (840 degrees Fahrenheit).
The rover, which is nicknamed Zephyr, would spend most of its time on Venus doing analysis on the ground. Whenever the science team wants to move some distance, however, it would deploy a sail that could bring it across the surface. One vision sees it sailing for about 15 minutes a day for about a month.
Artist’s conception of the atmosphere of Venus. Credit: ESA
“A sail rover would be extraordinary for Venus. The sail has only two moving parts-just to set the sail and set the steering position-and that doesn’t require a lot of power. There’s no power required to actually drive,” stated Geoffrey Landis, who is with NASA’s Glenn Research Center.
“The fundamental elements of a rover for Venus are not beyond the bounds of physics,” Landis added. “We could survive the furnace of Venus if we can come up with an innovative concept for a rover that can move on extremely low power levels.”
Venus reflected in Boulder Lake north of Duluth, Minn. two nights ago. Credit: Bob King
Curious coincidences occur in the sky just as they do on Earth. Take tonight for instance. The moon is in gibbous phase or about 3/4 full – 78% to be exact – while Venus, which also undergoes phases identical to the moon, is likewise gibbous and 78% full.
That’s just cool. If you have telescope, focus on Venus low in the western sky just after sunset and see a perfect replica in miniature of tonight’s moon.
Look for Venus about a fist up in the west-southwest shortly after sunset. Stellarium
Be sure you’re out early as the planet is low to begin with and drops lower in the west with each passing minute. Provided the sky is haze-free, Venus isn’t difficult to spot even 5 minutes after sunset. Look about 10 degrees (one fist held at arm’s length) above the west-southwest horizon.
The moon and Venus are coincidentally in exactly the same phase tonight – 78% gibbous. Stellarium
The moon shows spectacular craters and mountains, but Venus hides its equally spectacular scenery of volcanic mountains, craters and cracked plains beneath a permanent cover of sulfur-dioxide-laced clouds. Clouds are excellent reflectors of sunlight. Not only is the planet brilliant because of them but looks as white as a shiny cue ball.
Venus’ changing position with relation to the Earth as it orbits around the sun causes it to exhibit phases like the moon. I’ve marked approximately where Venus is in mid-August. After gibbous, the planet will wane to half and then a crescent over the coming months as it catches up and passes the Earth. Illustration: Bob King
Tomorrow night the moon and Venus will go their own phase-y way, the moon fattening up toward full and Venus slowly slimming its waistline as it works its way toward the Earth. For now enjoy their temporary bond.
Over the past six years wind speeds in Venus' atmosphere have been steadily rising (ESA)
High-altitude winds on neighboring Venus have long been known to be quite speedy, whipping sulfuric-acid-laden clouds around the superheated planet at speeds well over 300 km/h (180 mph). And after over six years collecting data from orbit, ESA’s Venus Express has found that the winds there are steadily getting faster… and scientists really don’t know why.
Cloud structures in Venus’ atmosphere, seen by Venus Express’ Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) in 2007 (ESA)
By tracking the movements of distinct features in Venus’ cloud tops at an altitude of 70 km (43 miles) over a period of six years — which is 10 of Venus’ years — scientists have been able to monitor patterns in long-term global wind speeds.
What two separate studies have found is a rising trend in high-altitude wind speeds in a broad swath south of Venus’ equator, from around 300 km/h when Venus Express first entered orbit in 2006 to 400 km/h (250 mph) in 2012. That’s nearly double the wind speeds found in a category 4 hurricane here on Earth!
“This is an enormous increase in the already high wind speeds known in the atmosphere. Such a large variation has never before been observed on Venus, and we do not yet understand why this occurred,” said Igor Khatuntsev from the Space Research Institute in Moscow and lead author of a paper to be published in the journal Icarus.
Long-term studies based on tracking the motions of several hundred thousand cloud features, indicated here with arrows and ovals, reveal that the average wind speeds on Venus have increased from roughly 300 km/h to 400 km/h over the first six years of the mission. (Khatuntsev et al.)
A complementary Japanese-led study used a different tracking method to determine cloud motions, which arrived at similar results… as well as found other wind variations at lower altitudes in Venus’ southern hemisphere.
“Our analysis of cloud motions at low latitudes in the southern hemisphere showed that over the six years of study the velocity of the winds changed by up 70 km/h over a time scale of 255 Earth days – slightly longer than a year on Venus,” said Toru Kouyama from Japan’s Information Technology Research Institute. (Their results are to be published in the Journal of Geophysical Research.)
Both teams also identified daily wind speed variations on Venus, along with shifting wave patterns that suggest “upwelling motions in the morning at low latitudes and downwelling flow in the afternoon.” (via Cloud level winds from the Venus Express Monitoring Camera imaging, Khatuntsev et al.)
A day on Venus is longer than its year, as the planet takes 243 Earth days to complete a single rotation on its axis. Its atmosphere spins around it much more quickly than its surface rotates — a curious feature known as super-rotation.
“The atmospheric super-rotation of Venus is one of the great unexplained mysteries of the Solar System,” said ESA’s Venus Express Project Scientist Håkan Svedhem. “These results add more mystery to it, as Venus Express continues to surprise us with its ongoing observations of this dynamic, changing planet.”
Earth is the third planet from the Sun, and the climate here is just right for life. Here in our Solar System, there are planets both hotter and colder than Earth.
So… which one is the hottest?
You might think it’s Mercury, the planet closest to the Sun. Mercury orbits at a distance of only 58 million kilometers, travelling in a blast-furnace of scorching radiation. Its temperature can skyrocket to 700 Kelvin, or 426 degrees Celsius on the sunward side. In the shadows, temperatures plunge down to 80 Kelvin, which is -173 degrees Celsius
Mercury sure is hot, but Venus is hotter.
Venus imaged by Magellan Image Credit: NASA/JPLVenus is much further from the Sun, orbiting at a distance of more than 108 million kilometers. Average temperature there is a hellish 735 Kelvin, or 462 degrees Celsius – hot enough to melt lead.
Venus remains that same temperature no matter where you go on the planet. At the North Pole? 735 Kelvin. At night? 735 Kelvin. Daytime at the equator? You get the point.
So, why is Venus so much hotter than Mercury, even though it’s further away from the Sun? It’s all about the atmosphere.
Mercury is an airless world, not unlike the Moon. Venus, has a very thick atmosphere of CO2, which adds incredible pressure, and traps in the heat.
Atmosphere of Venus. Credit: ESAConsider our own planet. When you stand at sea level on Earth, you’re experiencing one atmosphere of pressure. But if you could stand on the surface of Venus – and trust me, you don’t want to – you’d experience ninety-two times as much atmospheric pressure. This is the same kind of pressure as being a kilometer underneath the surface of the ocean.
Venus also shows us what happens when carbon dioxide levels just keep on rising. Radiation from the Sun is absorbed by the planet, and the infrared heat emitted is trapped by the carbon dioxide, which creates a runaway greenhouse effect.
You might think a planet this hot with such extreme temperature and pressure, would be impossible to explore.
And if you did, you’d be wrong.
The Soviets sent a series of spacecraft called Venera, which parachuted down through the thick atmosphere and returned images from the surface of Venus. Although the first few missions were failures, this taught the Soviets just how hellish the Venusian environment really is. Surface of Venus by Venera.
Venera 13 made it down to the surface in nineteen-eighty-one and survived for one-hundred-and-twenty-seven minutes, sending back the first color pictures of Venus’ surface.
The hottest planet in our solar system is Venus,
When it comes to temperature, distance from the Sun matters, but it takes a backseat to wrapping a planet in a atmospheric blanket of carbon dioxide.
Looking west at sunset from latitude 30 degrees north. The ecliptic and Mercury's orbit along with a 10 degree field of view outlined for reference. All graphics created by the author using Starry Night).
If you’ve never seen Mercury, this week is a great time to try.
Over the past few weeks, observers worldwide have been following the outstanding tight triple conjunction of Mercury, Venus and Jupiter low to the west at dusk.
Jupiter has exited the evening sky, headed for conjunction with the Sun on June 19th. I caught what was probably our last glimpse of Jupiter for the season clinging to the murky horizon through binoculars just last week. If you’re “Jonesin’ for Jove,” you can follow its progress this week through superior conjunction as it transits the Solar Heliospheric Observatory’s LASCO C3 camera.
This leaves the two innermost worlds of our fair solar system visible low to the west at dusk. And tonight, they’re joined by a very slender waxing crescent Moon, just over two days after New phase.
The Moon, Venus and Mercury as seen from 30 degrees north tonight at 9PM EDT.
The evening of June 10th finds a 4% illuminated Moon passing just over 5 degrees (about 10 Full Moon diameters) south of Venus and Mercury. Venus will be the first to appear as the sky darkens, shining at magnitude -3.9 and Mercury will shine about 40 times fainter above it at magnitude +0.3.
Ashen light, also known as Earthshine will also be apparent on the darkened limb of the Moon. Another old-time term for this phenomenon is “the Old Moon in the New Moon’s Arms.” Ashen light is caused by sunlight being reflected off of the Earth and illuminating the nighttime Earthward facing portion of the Moon. Just how prominent this effect appears can vary depending on the total amount of cloud cover on the Earth’s Moonward facing side.
….and the orientation of the Moon, Mercury and Venus on the night of June 12th and ~9PM EDT.
This week sets the stage for the best dusk apparition of Mercury for northern hemisphere viewers in 2013. Orbiting the Sun every 88 Earth days, we see Mercury either favorably placed east of the Sun in the dusk sky or west of the Sun in the dawn sky roughly six times a year. Mercury’s orbit is markedly elliptical, and thus not all apparitions are created the same. An elongation near perihelion, when Mercury is 46 million kilometers from the Sun, can mean its only 17.9 degrees away from the Sun as viewed from the Earth. An elongation near aphelion, 69.8 million kilometers distant, has a maximum angular separation of 27.8 degrees.
This week’s greatest elongation of 24.3 degrees occurs on June 12th. It’s not the most extreme value for 2013, but does have another factor going for it; the angle of the ecliptic. As we approach the solstice of June 21st, the plane of the solar system as traced out by the orbit of the Earth is at a favorable angle relative to the horizon. Thus, an observer from 35 degrees north latitude sees Mercury 18.4 degrees above the horizon at sunset, while an observer at a similar latitude in the southern hemisphere only sees it slightly lower at 16.9 degrees.
Venus and the Moon make great guides to locate Mercury over the next few nights. It’s said that Copernicus himself never saw Mercury with his own eyes, though this oft repeated tale is probably apocryphal.
We also get a shot at a skewed “emoticon conjunction” tonight, not quite a “smiley face” (: as occurred between Jupiter, Venus and the Moon in 2008, but more of a “? :” Stick around until February 13th, 2056 and you’ll see a much tighter version of the same thing! A time exposure of a pass of the International Space Station placed near Mercury and Venus could result in a planetary “meh” conjunction akin to a “/:” Hey, just throwing that obscure challenge out there. Sure, there’s no scientific value to such alignments, except as testimony that the universe may just have a skewed sense of humor…
Through the telescope, Venus currently shows a 10” diameter gibbous phase, while Mercury is only slightly smaller at 8” and is just under half illuminated. No detail can be discerned on either world, as a backyard telescope will give you the same blank view of both worlds that vexed astronomers for centuries. These worlds had to await the dawn of the space age to give up their secrets. NASA’s MESSENGER spacecraft entered a permanent orbit around Mercury in 2011, and continues to return some outstanding science.
Both planets are catching up to us from the far side of their orbits. Mercury will pass within 2 degrees of Venus on June 20th, making for a fine wide field view in binoculars.
And now for the wow factor of what you’re seeing tonight. The Moon just passed apogee on June 9th and is currently about 416,500 kilometers or just over one light second distant. Mercury meanwhile, is 0.86 astronomical units (A.U.), or almost 133 million kilometers, or about 7 light minutes away. Finally, Venus is currently farther away from the Earth than the Sun at 1.59 A.U.s, or about 13.7 light minutes distant.
All this makes for a great show in the dusk skies this week. And yes, lunar apogee just after New sets us up for the closest Full Moon of 2013 (aka the internet sensation known as the “Super Moon”) on June 23rd. More to come on that soon!
Planets conjunction over Mont-Saint-Michel, Normandy, France on May 26. Credit: Thierry Legault -
www.astrophoto.fr
Triple planets (Venus/Jupiter/Mercury) conjunction over Mont-Saint-Michel, Normandy, France on May 26. Credit: Thierry Legault – www.astrophoto.fr Update: See expanded Conjunction astrophoto gallery below[/caption]
The rare astronomical coincidence of a spectacular triangular triple conjunction of 3 bright planets happening right now is certainly wowing the entire World of Earthlings! That is if our gallery of astrophotos assembled here is any indication.
Right at sunset, our Solar System’s two brightest planets – Venus and Jupiter – as well as the sun’s closest planet Mercury are very closely aligned for about a week in late May 2013 – starting several days ago and continuing throughout this week.
And, for an extra special bonus – did you know that a pair of spacecraft from Earth are orbiting two of those planets?
Have you seen it yet ?
Well you’re are in for a celestial treat. The conjunction is visible to the naked eye – look West to Northwest shortly after sunset. No telescopes or binoculars needed.
Triple conjunction shot on May 26 from a mile high in Payson,Az. 4 second exposure, ISO200, Canon 10D, 80mm f/5 lens. Credit: Chris Schur- http://www.schursastrophotography.com
Just check out our Universe Today collection of newly snapped astrophoto’s and videos sent to Nancy and Ken by stargazing enthusiasts from across the globe. See an earlier gallery – here.
Throughout May, the trio of wandering planets have been gradually gathering closer and closer.
On May 26 and 27, Venus, Jupiter and Mercury appear just 3 degrees apart as a spectacular triangularly shaped object in the sunset skies – which
adds a palatial pallet of splendid hues not possible at higher elevations.
And don’t dawdle if you want to see this celestial feast. The best times are 30 to 60 minutes after sunset – because thereafter they’ll disappear below the horizon.
The sky show will continue into late May as the planets alignment changes every day.
On May 28, Venus and Jupiter close in to within just 1 degree.
And on May 30 & 31, Venus, Jupiter and Mercury will form an imaginary line in the sky.
Triple planetary conjunctions are a rather rare occurrence. The last one took place in May 2011. And we won’t see another one until October 2015.
Indeed the wandering trio are also currently the three brightest planets visible. Venus is about magnitude minus 4, Jupiter is about minus 2.
While you’re enjoying the fantastic view, ponder this: The three planets are also joined by two orbiting spacecraft from humanity. NASA’s MESSENGER is orbiting Mercury. ESA’s Venus Express is orbiting Venus. And NASA’s Juno spacecraft is on a long looping trajectory to Jupiter.
Send Ken you conjunction photos to post here.
And don’t forget to “Send Your Name to Mars” aboard NASA’s MAVEN orbiter- details here. Deadline: July 1, 2013
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Learn more about Conjunctions, Mars, Curiosity, Opportunity, MAVEN, LADEE and NASA missions at Ken’s upcoming lecture presentations:
June 4: “Send your Name to Mars” and “CIBER Astro Sat, LADEE Lunar & Antares Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8:30 PM
June 11: “Send your Name to Mars” and “LADEE Lunar & Antares Rocket Launches from Virginia”; NJ State Museum Planetarium and Amateur Astronomers Association of Princeton (AAAP), Trenton, NJ, 730 PM.
May 25 conjunction over Malta. Canon 450D with a 55mm. lens and an exposure of 1/2 second at ISO 200 on a tripod. Credit: Leonard Ellul-MercerMay 26 triple conjunction from Warwick, NY snapped from Canon Rebel, 100mm – 300mm lens. Credit: Pietro CarboniTriple conjunction from Hondo, Texas taken with a Nikon D800 @ ISO 400 and a 2 second exposure with a Nikon 300mm Lens at F/4. Credit: Adrian New Sunset conjunction with fast moving clouds on May 26 through 10 x 50 binoculars from a seashore town -Marina di Pisa, Tuscany, Italy. Credit: Giuseppe Petricca
Caption: Taken on 2013-05-23 from Salem, Missouri. Canon T1i, Nikkor 105mm lens. 297 1/4s at 1s interval. Images assembled by QuickTime Pro. Credit: Joseph Shuster
May 26 sunset conjunction from Princeton, NJ. Credit: Ken Kremer -kenkremer.comTriple Planetary conjunction over Onset MA. Shot with a Nikon d7000 1/200 f 4 iso 100 at 110mm. Credit: Phillip DamianoPanoramic view over Almada City and Lisbon at the Nautical Twilight, with the Full moon rising above the Eastern horizon (right side of the image), while at the same time but in the opposite direction, the planets Venus, Mercury and Jupiter, are aligned in a triangle formation, setting in the Western horizon (left side of the image).In this panoramic picture is also visible the smooth light transition in the sky, with the end of Nautical Twilight and the beginning of Astronomical Twilight (almost night), at right. Facing to North, is visible the great lighted Monument Christ the King and at the left side of it, part of the 25 April Bridge that connects Almada to Lisbon. Canon 50D – ISO200; f/4; Exp. 1,6 Sec; 35mm. Panoramic of 10 images with about 200º, taken at 21h42 in 25/05/2013. Credit: Miguel Claro – www.miguelclaro.comThe triple conjunction of Venus, Mercury and Jupiter as seen over an Arizona desert landscape. Credit and copyright: Robert Sparks.Jupiter, Venus and Mercury triple conjunction seen here reflecting off Chatsworth Lake in Chatsworth, NJ. Jupiter (on the left) was 2.4° from Mercury (upper-right in the sky) and 2.0° from Venus (bottom right in the sky), while Venus and Mercury were 1.9° apart. Venus was at 2.6° altitude. Canon EOS 6D, 105 mm focal length, 1.3 seconds, f/6.3, ISO 800. Credit: Joe Stieber – sjastro.org/Triple conjunction on May 27 with WBZ radio towers south east of Boston. Hampton Hill, Hull, MA. Nikon D3x -iso200- 1.3 sec.at f2.8. Credit: Richard W. Green
Artist's conception of the solar system, often used in the Eyes on the Solar System 3D Simulator. Credit: NASA
Venus and Mars may be all right tonight, but there’s still a lot we don’t understand about these planets. Why does one, Venus, have such a thick atmosphere? Why is that of Mars so thin? And why is Earth’s atmosphere so different again from what we see on Venus and Mars?
A new JAXA (Japan Aerospace Exploration Agency) satellite aims to better understand what’s going on. It’s called SPRINT-A, for Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere.
JAXA has set an official launch date of Aug. 22 from the Uchinoura Space Center, although the window extends as far as Sept. 30. (Launches can be delayed due to weather and mechanical difficulties.) The satellite’s expected Earth orbit will range from 590 to 715 miles (950 to 1150 kilometers) above the planet.
“Venus and Earth may be called twin planets, and it recently becomes clear that three terrestrial planets in the solar system – including Mars – have very similar environments in the beginning era of the solar system,” JAXA stated in a press release.
Earth’s atmosphere was similar to that of Venus and Mars in the early solar system, but now it’s quite different, says JAXA. (Image: NASA/Suomi NPP)
The agency pointed out, however, that these three planets ended up with different fates. Venus has a runaway greenhouse effect on its planet, with surface temperatures reaching a scorching 752 degrees Fahrenheit (400 degrees Celsius). Mars, on the other hand, has a very thin atmosphere and more variable temperatures that can get a little chilly.
Understanding how atmospheres escape into outer space is the main goal of SPRINT-A. The sun, the scientists stated, had more intense activity in the past than what we see presently, which could have blown away the atmosphere on some terrestrial planets.
“The study on interaction of the strong solar wind on the atmosphere of the planet leads to acquiring knowledge of history in the early stage of the solar system,” JAXA stated.
Besides looking at the inner solar system, SPRINT-A will investigate a phenomenon related to a splotchy volcanic moon orbiting the planet Jupiter.
Io, a moon of Jupiter. The colors in this image have been enhanced to better show differences. Sulfur dioxide frost appears in white and grey, and other types of sulfur are in yellow and brown. Recent volcanic activity is marked by red and black blotches. Credit: NASA
SPRINT-A aims to better understand a ring of material surrounding Jupiter that came from Io.
Electrons and ions from the volcanic moon surround Jupiter and, as they collide, produce ultraviolet light in a process similar to what causes auroras in the upper atmosphere of Earth and other planets. How this happens is still being figured out, though.
It’s a pretty radiation-heavy environment in that region of the solar system. The spacecraft Galileo safely orbited the Jovian moons for years, but humans would have a little more trouble surviving the radiation without heavy shielding and careful precautions.
Starting Friday the moon will be your guide to Venus' return to the evening sky. This map shows the sky facing west-northwest about 30 minutes after sunset across the middle of the U.S., but it's useful from 30-50 degrees north. Venus will be 4 degrees high at the time. Friday's moon is very thin! Stellarium
Has Venus finally come out of hiding? For the past couple months it’s kept close to the sun, hidden in its glare, but come Friday, sky watchers in mid-northern latitudes may get their first shot at seeing the planet’s return to the evening sky.
It won’t be easy, but you’ll have help from the knife-edged crescent moon. Like a spring bloom raising its head from the dark earth, Venus will poke just 4 degrees above the western horizon a half hour after sunset. The moon will be about 2 degrees to the lower left of the planet. Seeing both requires a wide open view to the west and a clean, cloudless sky. It also helps to know when the sun sets for your location – easily found by clicking HERE.
Most any binoculars will prove useful for seeing Venus in twilight this week. One of my (inexpensive) favorites is a pair of Nikon Action 8x40s. Once you spot the planet in binoculars, try to see it with your naked eye. Credit: Bob King
Take along a pair of binoculars. They’ll help fish out both moon and planet in the bright twilight sky. It’s also advantageous to arrive at your viewing spot a little early. Enjoy the sunset, and then take a minute to make sure you’re binoculars are focused at infinity. If you don’t, Venus will be a blur and much harder to find. I usually focus mine on a cloud or the very farthest thing out along the horizon.
Once you’re all set, point your binoculars in the sunset direction and slowly sweep back and forth. Venus will be a short distance to the left or south of the brightest glow remaining along the horizon. Since most binoculars have a field of view of 4 or 5 degrees, when you place the horizon at the bottom of the view, the moon should appear in the middle of the field and Venus up near the top. Look higher and lower and farther left and right to be thorough. Once spotted in binoculars, take the visual challenge and see if you can find it without optical aid.
Venus punctuates a colorful sky low in the west at dusk in August 2008. Credit: Bob King
If you succeed, you’ll be rewarded with an elegant eyeful. Swamped in skylight, Venus will appear unusually meek but still possess its classic fiery brilliance. The newborn crescent will float just a degree and a half (three full moon diameters) away. From the U.S. east coast, the moon will be just 24 hours old; from the west coast 27 hours. Seeing such a young moon is a rarity in itself, but in the company of Venus that much finer.
Let’s say conditions aren’t ideal and you miss the pair on Friday. Well, try again on Saturday. The moon will be higher and much easier to see. Use it as a bow to shoot an imaginary arrow horizon-ward to Venus. And did I mention Jupiter? The planet that cheerily lit up our winter nights is now departing in the west. Watch for it to have a close encounter with Venus on the nights of May 27-28.
With its perpetual clouds, Venus would be a most distressing planet to any skywatcher unfortunate enough to live there. Yet it’s those same clouds that make it the most brilliant planet in the solar system seen from Earth. Clouds reflect sunlight splendidly. Combined with Venus’ proximity to Earth, it’s no wonder the planet earned the title of goddess of love and beauty.
As Venus and Earth revolve around the sun at different speeds, we see Venus from a constantly changing perspective. In May, the planet is slightly to the left or east of the sun and looks like a miniature full moon at dusk. Come Halloween it resembles a half-moon and a crescent at Christmas. Credit: Bob King
In the first 3 months of this year, Venus remained close to the sun in the morning sky and difficult to see. Then on March 28, it passed behind the sun on the opposite side of Earth’s orbit; astronomers call the lineup superior conjunction. Seen from Earth, Venus looked like a tiny full moon. We’re now about 6 weeks past conjunction and the planet has begun to peek out into the evening sky. At 98% illuminated, it still looks nearly full through a telescope, but that will change in the coming months as Venus approaches Earth in its speedier orbit. Watch for the goddess to grow larger in apparent size while at the same time slimming down her phase from full to half to crescent. Good luck getting re-acquainted this weekend!
Venus appears just off the edge of the dark disc of Saturn, in the upper part of the image, directly above the white streak of Saturn's G ring. Credit: NASA/JPL-Caltech/Space Science Institute
Two amazing images from the Cassini spacecraft today: We know how brightly Venus shines in our own night sky; now here’s visual proof it shines brightly even in the skies above Saturn. In one image it shines so brightly that it is even visible looking through Saturn’s rings! But in this absolutely stunning shot, above, Venus appears as a morning star, just off the edge of the planet. From Cassini, you’re looking directly above the edge of Saturn’s G ring to see the white dot, which is Venus. Lower down, Saturn’s E ring makes an appearance, looking blue thanks to the scattering properties of the dust that comprises the ring. (A bright spot near the E ring is a distant star, the Cassini CICLOPS team says.)
This beautiful image was taken on January 4, 2013.
On average, Venus and Saturn are about 1,321,200,000 km (820,955,619 mi or 8.83 astronomical units) apart, so that’s a nice, long distance shot! Venus is brighter in Saturn’s skies than Earth is, however, because Venus is covered in thick sulfuric acid clouds, making it very bright.
And here’s the other great shot, showing Saturn and its rings in true color:
NASA’s Cassini spacecraft spies the bright, cloudy terrestrial planet, Venus. Credit: NASA/JPL-Caltech/Space Science Institute
Venus is the white dot, just above and to the right of the image center. Again, its amazing that it shines through the rings.
This view looks toward the unilluminated side of the rings from about 17 degrees below the ring plane, and was taken in visible light (and it is a true-color image) with the Cassini spacecraft wide-angle camera on Nov. 10, 2012.
In an email about these images, Cassini imaging team lead Carolyn Porco said that even though Venus reaches nearly 900 degrees Fahrenheit (500 degrees Celsius) and has a surface pressure 100 times that of Earth’s, Venus is considered a twin of our planet because of their similar sizes, masses, rocky compositions and close orbits.
And so, she pointed out, “Think about Venus the next time you find yourself reveling in the thriving flora, balmy breezes, and temperate climate of a lovely day on Earth, and remember: you could be somewhere else!”
If you’ve ever wanted to see what it’s like to buzz Venus like only a spacecraft can, here’s your chance: this is a video animation of images taken by ESA’s Venus Express as it makes a pole-to-pole orbit of our neighboring world.
Captured in ultraviolet wavelengths, the images were acquired by the spacecraft’s Venus Monitoring Camera last January over a period of 18 hours. It’s truly a “day in the life” of Venus Express!
From ESA’s description of the video:
We join the spacecraft from a staggering 66,000 km above the south pole, staring down into the swirling south polar vortex. From this bird’s-eye view, half of the planet is in darkness, the ‘terminator’ marking the dividing line between the day and night sides of the planet.
Intricate features on smaller and smaller scales are revealed as Venus Express dives to just 250 km above the north pole and clouds flood the field of view, before regaining a global perspective as it climbs away from the north pole.
The observed pattern of bright and dark markings is caused by variations in an unknown absorbing chemical at the Venus cloud tops.
False-color image of cloud features on Venus. Captured by Venus Express from a distance of 30,000 km (18,640 miles) on December 8, 2011. (ESA/MPS/DLR/IDA)
