The setting Sun as it passed over the church of a small village called Ås. You can clearly see two sunspots visible on the Sun (#2079 and #2077), both about the size of one Earth diameter. Credit and copyright: Göran Strand.
This is not your basic sunset timelapse! It combines a close-up view of the Sun with a solar telescope along with the landscape in the foreground. Astrophotographer Göran Strand from Sweden has been planning this photoshoot for a year, and it turned out spectacularly.
“Yesterday I went out to shoot a sunset I’ve planed since last summer,” Göran said via email. “This time of the year, the Sun passes right behind a big radar tower if you stand at the Swedish National Biathlon Arena in Östersund. The radar tower is located about 8 km away from the arena in a small village called Ås. I shoot the movie using my solar telescope to capture the structures on the Sun. The timing was perfect and the Sun looked really nice since it was full of sunspots and big filaments.”
Note the size of the Earth inserted for reference.
Below is a beautiful image taken a few days earlier by Göran of the setting Sun:
Here’s another marvel of technology: there are people on Earth who are formulating solar weather forecasts … for Venus. While that sounds counterintuitive — isn’t the sun far away from that planet? — it actually does have a big effect on the planet’s atmosphere. And with Venus Express taking the plunge into the planet’s atmosphere, it’s important to know how the sun is behaving to predict its effect.
As the spacecraft skims the top of the planet’s atmosphere, it’s possible that if an extreme weather event occurs, this could change the orbit from what would be predicted.
“The space weather reports will … allow us to better understand anomalous behaviour that we may subsequently observe on the spacecraft,” stated Adam Williams, Venus Express’ deputy spacecraft operations manager.
“And in extreme cases, we would be more ready to react to a serious situation. For example, if our startrackers were to be overloaded by radiation.”
We’re used to regular solar weather reports on Earth, but getting them ready for Venus — a first — is a bit more difficult. The European Space Agency is using observatories such as the Solar Dynamics Observatory, the Solar and Heliospheric Observatory and the Proba-2 spacecraft, just like it does for Earth forecasts.
On August 31, 2012 a long filament of solar material that had been hovering in the sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second.
Venus presents an extra challenge, however, because it’s 59 degrees ahead of Earth in its orbit (as things stand right now) and there are no spacecraft in between the Sun and Venus to see how conditions change as particles head toward the planet. The updates are being issued through ESA’s Space Weather Coordination Centre in Belgium.
By the way, we’re also lucky enough to get weather forecasts for another planet — Mars! Malin Space Science Systems provides weekly weather reports from the Red Planet through the Mars Color Imager (MARCI) on the Mars Reconnaissance Orbiter. Here’s part of its report from between May 26 and June 1. (Be sure to click through the link to watch a recent video of Mars rotating).
Dust storm frequency increased this week in the southern tropical latitudes west and north of Argyre with local storms of varying size and duration observed in Aonia, Solis, Syria, and Tharsis. Dust haze resulting from these storms was present in the western portions of Valles Marineris. Other storm activity occurred in Noachis, as well as in the northern hemisphere off the residual north polar cap. Diffuse water ice clouds were present over Utopia and equatorial latitudes. At southern mid-to-high latitudes, seasonal frost was present up to approximately 55 degrees south latitude. Other than occasional diffuse water ice clouds over Meridiani, skies were relatively storm free over the Opportunity rover site at Endeavor Crater and the Curiosity rover site at Gale Crater.
Artist's conception of the Titan Aerial Daughtercraft on Titan, a moon of Saturn. Credit: NASA
Sometimes a good idea takes some tinkering. You have a thought that it will work, but what it really requires is you take some money and time and test it out in a small form. This principle is sound if you’re trying to do home renovation (a paint splash on a wall can let you see if the color will work) and it is especially true if you’re planning a multi-million dollar mission to another planet.
This is the thought behind the NASA Innovative Advanced Concepts office, which announced a dozen far-flung drawing-board proposals that received $100,000 in Phase 1 funding for the next 9-12 months. There are vehicles to explore the soupy moon of Titan, a design to snag a tumbling asteroid, and other ideas to explore the solar system. (But be patient: These testbed ideas would take decades to come to fruition, if they are even accepted for further study and funding.) Check out a full list of the concepts below.
Titan Aerial Daughtercraft: A small rotorcraft that can touch down from a balloon or lander, with the idea being that it can jump between several spots to do close-up views. It would then bring its samples back to the “mothership” and possibly recharge there as well. “The autonomy needed for this concept is also applicable to exciting rotorcraft mission concepts for Mars and to in-situ exploration of Enceladus,” the description stated, referring to an icy moon of Saturn.
Titan Submarine: A small submarine would dive into Kraken Mare on Saturn’s moon, and there would be plenty to explore: 984 feet (300 meters) of depth, stretching across 621 miles (1,000 km). “Kraken Mare is comparable in size to the Great Lakes and represents an opportunity for an unprecedented planetary exploration mission,” the description stated. It would explore “chemical composition of the liquid, surface and subsurface currents, mixing and layering in the ‘water’ column, tides, wind and waves, bathymetry, and bottom features and composition.”
Comet Hitchhiker:This would be a “tethered” spacecraft that swings from comet to comet to explore icy bodies in the solar system. “First, the spacecraft harpoons a target as it makes a close flyby in order to attach a tether to the target. Then, as the target moves away, it reels out the tether while applying regenerative brake to give itself a moderate (<5g) acceleration as well as to harvest energy,” the description stated.
Artist’s conception of the Weightless Rendezvous And Net Grapple to Limit Excess Rotation (WRANGLER). Credit: NASA
Weightless Rendezvous And Net Grapple to Limit Excess Rotation (WRANGLER): This idea would capture space debris and small asteroids. It will use a small nanosatellite equipped with a “net capture device” and a winch. “The leverage offered by using a tether to extract angular momentum from a rotating space object enables a very small nanosatellite system to de-spin a very massive asteroid or large spacecraft,” the description stated.
The Aragoscope: A telescope that would look through an opaque disk at a distant object, which is different from the usual mirror arrangement.”Rather than block the view, the disk boosts the resolution of the system with no loss of collecting area,” the description states. This architecture … can be used to achieve the diffraction limit based on the size of the low cost disk, rather than the high cost telescope mirror.”
Mars Ecopoiesis Test Bed:A machine that would test how well bacteria from Earth could survive on Mars, which could be a precursor to “terraforming” the planet to make it more like our own. Researchers would select “pioneer organisms” and put them into a device that would embed itself into the Martian regolith (soil) in an area that would have liquid water. It would “completely seal itself to avoid planetary contamination, release carefully selected earth organisms (extremophiles like certain cyanobacteria), sense the presence or absence of a metabolic product (like O2), and report to a Mars-orbiting relay satellite,” the description states.
Artist’s conception of ChipSats. Credit: NASA
ChipSats: Instead of having an orbiter and a lander in separate missions, why not put them in one? While there have been combinations before (e.g. Cassini/Huygens), this is a bit different: This concept would have a set of tiny sensor chips (ChipSats) that deploy from a larger mothership to make a landing on a distant planet or moon.
Swarm Flyby Gravimetry: While whizzing by a comet or asteroid, a single spacecraft would release a swarm of tiny probes. “By tracking those probes, we can estimate the asteroid’s gravity field and infer its underlying composition and structure,” the description stated.
Probing icy worlds concept: How thick is the ice on Jupiter’s Europa or Ganymede, or Saturn’s Enceladus? Open question, and makes it hard to predict how tough of a drill one would need to probe the ice — or how well life could survive. This concept would send a probe to one of these locations and receive “a naturally occurring signal generated by interactions of deep penetrating cosmic ray neutrinos” to better get a sense of the depth. This could allow for maps of the ice.
The cracked ice surface of Europa. Credit: NASA/JPL
Heliopause Electrostatic Rapid Transit System (HERTS):This would be a mission that goes deep into the solar-system and out to the heliopause, the spot where the sun’s sphere of influence gives way to the interstellar medium. Using no propellant, the spacecraft would use solar wind protons to bring it out into the solar system. “The propulsion system consists of an array of electrically biased wires that extend outward 10 to 30 km [6.2 miles to 18.6 miles] from a rotating spacecraft,” the researchers stated.
3D Photocatalytic Air Processor:A new design to make it easier to generate oxygen on a spacecraft, using “abundant high-energy light in space,” the proposal states. ” The combination of novel photoelectrochemistry and 3-dimensional design allows tremendous mass saving, hardware complexity reduction, increases in deployment flexibility and removal efficiency.”
PERIapsis Subsurface Cave OPtical Explorer (PERISCOPE): A way to probe caves on the moon from orbit. Using a concept called “photon time-of-flight imaging”, the researchers say they would be able to bounce the signal off of the walls of the canyon to peer into the crevice and see what is there.
A sun pillar among the clouds at sunset create the look of second Sun on May 31, 2014. Credit: Dave Walker.
Sunset on Tatooine? Nah, just an unusual combination of a dazzling orange sunset, clouds and a sun pillar that creates an “echo” effect of the setting Sun. As seen by astrophotographer Dave Walker in the UK on May 31, 2014.
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An illustration of a Titanic lake by Ron Miller. All rights reserved. Used with permission.
Titan — that smoggy, orangy moon circling Saturn — is of great interest to exobiologists because its chemistry could be good for life. It has a thick atmosphere of nitrogen and methane and likely has lakes filled with liquid hydrocarbons, and scientists believe there is enough light filtering down into the atmosphere to drive chemical reactions.
It turns out the moon could also be a good analog to help us understand the atmospheres of exoplanets far beyond our solar system. From looking at sunsets on the moon, scientists led by NASA believe that a thick atmosphere could influence how we perceive a planet from afar.
First, a bit of information about how scientists learn about planet atmospheres in the first place. When a distant planet passes in front of its parent star, the light from the star passes through the atmosphere and gets distorted.
The spectra that telescopes pick up can then tell scientists information about what the atmosphere is made of, what temperature it is, and how it is structured. (This science, it should be noted, is in its very early stages and works best on very large exoplanets that are relatively close to Earth, since the planets are so small and far away.)
“Previously, it was unclear exactly how hazes were affecting observations of transiting exoplanets,” stated Tyler Robinson, a postdoctoral research fellow at NASA’s Ames Research Center who led the research. “So we turned to Titan, a hazy world in our own solar system that has been extensively studied by Cassini.”
Titan’s surface is almost completely hidden from view by its thick orange “smog” (NASA/JPL-Caltech/SSI. Composite by J. Major)
To do this, Robinson’s team used data from the Cassini spacecraft during four solar occultations, or times when Titan passed in front of our own sun from the perspective of the spacecraft. They found out that the moon’s hazy atmosphere makes it difficult to figure out what is in its spectra.
“The observations might be able to glean information only from a planet’s upper atmosphere,” NASA stated. “On Titan, that corresponds to about 90 to 190 miles (150 to 300 kilometers) above the moon’s surface, high above the bulk of its dense and complex atmosphere.”
The haze is even more powerful in the shorter (bluer) wavelengths of light, which contradicts previous studies assuming that all wavelengths of light would have the same distortions. Models of exoplanet atmospheres usually have simplified spectra because hazes are complex to model, requiring a lot of computer power.
Researchers hope to take these observations of Titan and then use them to better inform how exoplanet models are created.
The research was published May 26 in the Proceedings of the National Academy of Science.
Sun in H-alpha, prominences May 17, 2014. Credit and copyright: Mary Spicer.
It’s like a total solar eclipse — without the Moon! Using a special hydrogen-alpha filter that completely blocks the Sun’s photosphere (visible surface) these images show just the Sun’s corona and the dancing solar prominences. The filter blocks all light from the Sun except for the red light emitted by excited hydrogen atoms, which are responsible for the distinctive color of prominences and the chromosphere, the wispy, hot layer of gas that overlies the photosphere.
Of course, never look directly at the Sun with the naked eye or through a telescope without a special solar filter.
The image above by Mary Spicer was taken with a Coronado PST, 2 x Barlow plus Canon 1100D. ISO-3200 1/400 second exposure, processed in Lightroom and Focus Magic.
See more below:
Solar prominences on April 21, 2014. Credit and copyright: Roger Hutchinson.
These images by Roger Hutchinson were taken with a Lunt LS60 Ha, Skyris 618C, and 2.5x Powermate.
Solar prominences on May 18, 2014 in H-alpha. Credit and copyright: Roger Hutchinson.
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A circumscribed halo encloses the more common 22-degree halo around the sun Saturday morning (May 17. Credit: Bob King
Call it a porcine occultation. It took nearly a year but I finally got help from the ornamental pig in my wife’s flower garden. This weekend it became the preferred method for blocking the sun to better see and photograph a beautiful pair of solar halos. We often associate solar and lunar halos with winter because they require ice crystals for their formation, but they happen during all seasons.
Nature keeps it simple. Light refracting through or reflecting from six-sided plate and column (pencil-shaped) ice crystals in high clouds is responsible for almost all halos and their variations.
Lower clouds, like the puffy cumulus dotting the sky on a summer day, are composed of water droplets. A typical cumulus spans about a kilometer and contains 1.1 million pounds of water. Cirrostratus clouds are much higher (18,000 feet and up) and colder and formed instead of ice crystals. They’re often the first clouds to betray an incoming frontal system.
Cirrostratus are thin and fibrous and give the blue sky a milky look. Most halos and related phenomena originate in countless millions of hexagonal plate and pencil-shaped ice crystals wafting about like diamond dust in these often featureless clouds.
This is the top end of a hexagonal column-shaped ice crystal. Light refracting (bending) through the 60-degree angled faces of millions of these crystals is concentrated into a ring of light 22 degrees from the sun. As light leaves the crystal, the shorter blue and purple wavelengths are refracted slightly more than red, tinting the outer edge of the halo blue and inner edge red. Credit: Donalbein with additions by the author
In winter, the sun is generally low in the sky, making it hard to miss a halo. Come summer, when the sun is much higher up, halo spotters have to be more deliberate and make a point to look up more often. The 22-degree halo is the most common; it’s the inner of the two halos in the photo above. With a radius of 22 degrees, an outstretched hand at arm’s length will comfortably fit between sun and circle.
Light refracted or bent through millions of randomly oriented pencil-shaped crystals exits at angles from 22 degrees up to 50 degrees, however most of the light is concentrated around 22 degrees, resulting in the familiar 22-degree radius halo. No light gets bent and concentrated at angles fewer than 22 degrees, which is why the sky looks darker inside the halo than outside. Finally, a small fraction of the light exits the crystals between 22 and 50 degrees creating a soft outer edge to the circle as well as a large, more diffuse disk of light as far as 50 degrees from the sun.
The sun on Dec. 6, 2013 with a 22-degree halo and two luminous canine companions or sundogs. Similar halos and ‘moondogs’ can be seen around a bright moon. Credit: Bob King
Sundogs, also called mock suns or parhelia, are brilliant and often colorful patches of light that accompany the sun on either side of a halo. Not as frequent as halos, they’re still common enough to spot half a dozen times or more a year. Depending on how extensive the cloud cover is, you might see only one sundog instead of the more typical pair. Sundogs form when light refracts through hexagonal plate-shaped ice crystals with their flat sides parallel to the ground. They appear when the sun is near the horizon and on the same horizontal plane as the ice crystals. As in halos, red light is refracted less than blue, coloring the dog’s ‘head’ red and its hind quarters blue. Mock sun is an apt term as occasionally a sundog will shine with the intensity of a second sun. They’re responsible for some of the daytime ‘UFO’ sightings. Check this one one out on YouTube.
An especially colorful sundog with a ‘tail’. Red light is bent less than blue as it emerges from the ice crystal, tinting the sundog’s inner edge. Blue is bent more and colors the outer half. If you look closely, all colors of the rainbow are seen. Credit: Bob King
Wobbly crystals make for taller sundogs. Like real dogs, ice crystal sundogs can grow tails. These are part of the much larger parhelic circle, a rarely-seen narrow band of light encircling the entire sky at the sun’s altitude formed when millions of both plate and column crystals reflect light from their vertical faces. Short tails extend from each mock sun in the photo above.
About 2 hours after the flying pig image, the sun climbed beyond 50 degrees altitude. The circumscribed halo vanished! Credit: Bob King
There’s almost no end to atmospheric ice antics. Many are rare like the giant 46-degree halo or the 9 and 18-degree halos formed from pyramidal ice crystals. Oftentimes halos are accompanied by arcs or modified arcs as in the flying pig image. When the sun is low, you’ll occasionally see an arc shaped like a bird in flight tangent to the top of the halo and rarely, to its bottom. When the sun reaches an altitude of 29 degrees, these tangent arcs – both upper and lower – change shape and merge into a circumscribed halowrapped around and overlapping the top and bottom of the main halo. At 50 degrees altitude and beyond, the circumscribed halo disappears … for a time. If the clouds persist, you can watch it return when the sun dips below 29 degrees and the two arcs separate again.
Maybe you’re not a halo watcher, but anyone who keeps an eye on the weather and studies the daytime sky in preparation for a night of skywatching can enjoy these icy appetizers.
A mosaic of 46 images showing the transit of the ISS across the sun visible from southwest London on May 16, 2014 at 06:23 UT. Credit and copyright: Roger Hutchinson.
“I’ve been wanting to get one of these for ages!” said astrophotographer Roger Hutchinson from London, England. This awesome image of the International Space Station transiting across the Sun earlier today — which creates a “zipper”-like effect on the Sun’s surface – is a composite of 46 images, taken from Southwest SW London on May 16, 2014 at 06:23 UT. Roger used a Lunt LS60 Ha telescope and a Skyris 274C camera.
Amazing.
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Time-lapse photo of several lightning strikes at night. Credit: NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL)
As the northern hemisphere enters the hazy days of summer, thunderstorms will freckle many of our nights and days. What causes these sudden bursts of light that flash through the sky? Previous research showed that one cause is cosmic rays from space, generated by supernovas. But a new paper shows that something much closer and powerful is also responsible: solar wind from our own Sun.
First, a quick primer on what the solar wind is. It’s a continuous stream of particles from the Sun, and it tends to pick up when the Sun emits solar flares. These flares are more frequent when sunspots are in greater numbers on the star’s surface, which happens when the Sun’s magnetic activity increases. The Sun’s activity falls and rises on an 11-year cycle, and 2014 happens to be close to the peak of one of those cycles.
“Our main result,” said lead author Chris Scott (of the University of Reading) in a statement, “is that we have found evidence that high-speed solar wind streams can increase lightning rates. This may be an actual increase in lightning or an increase in the magnitude of lightning, lifting it above the detection threshold of measurement instruments.”
The researchers discovered “a substantial and significant increase in lightning rates” for up to 40 days after solar winds hit Earth’s atmosphere. The reasons behind this are still poorly understood, but the researchers say this could be because the air’s electrical charge changes as the particles (which are themselves electrically charged) hit the atmosphere.
If this is proven, this could give a new nuance to weather forecasters who could incorporate information about solar wind streams that are being watched by spacecraft. This stream of particles would change with the sun’s 27-day rotation, and researchers hope this could improve long-range forecasts.
The study is based on UK Met Office lightning strike data in the United Kingdom between 2000 and 2005, more specifically anything that happened within 500 kilometers (310 miles) of central England. They also used data from NASA’s Advanced Composition Explorer (ACE), a spacecraft that examines the solar wind.
After each event, the researchers uncovered an average of 422 lightning strikes in the United Kingdom in the next 40 days, compared to an average of 321 lightning strikes in between these events. (The peak was about 12 to 18 days after an event.)
Artist’s impression of the solar wind from the sun (left) interacting with Earth’s magnetosphere (right). Credit: NASA
The researchers pointed out that the magnetic field of Earth does deflect many of these particles, but in the cases observed the particles would have been energetic enough to move into “cloud-forming regions” of the Earth’s atmosphere.
“We propose that these particles, while not having sufficient energies to reach the ground and be detected there, nevertheless electrify the atmosphere as they collide with it, altering the electrical properties of the air and thus influencing the rate or intensity at which lightning occurs,” Scott stated.
Mercury starts its best period of visibility in the evening sky for skywatchers at mid-northern latitudes this weekend. This map shows the sky facing northwest about 40 minutes after sundown. Bright Jupiter also provides a convenient sightline for locating Mercury. Stellarium
Don’t let furtive Mercury slip through your fingers this spring. The next two and a half weeks will be the best time this year for observers north of the tropics to spot the sun-hugging planet. If you’ve never seen Mercury, you might be surprised how bright it can be. This is especially true early in its apparition when the planet looks like a miniature ‘full moon’.
Mercury, like Venus, displays phases as it revolves around the sun as seen from Earth’s perspective outside Mercury’s orbit. Both Mercury and Venus appear largest when nearly lined up between Earth and sun at inferior conjunction. Planets not to scale and phases shown are approximate. Credit: Bob King
Both Venus and Mercury pass through phases identical to those of the moon. When between us and the sun, Mercury’s a thin crescent, when off to one side, a ‘half-moon’ and when on the far side of the sun, a full moon. This apparition of the planet is excellent because Mercury’s path it steeply tilted to the horizon in mid-spring.
We start the weekend with Mercury nearly full and brighter than the star Arcturus. Twilight tempers its radiance, but :
* Find a location with a wide open view to the northwest as far down to the horizon as possible.
* Click HERE to get your sunset time and begin looking for the planet about 30-40 minutes after sunset in the direction of the sunset afterglow.
* Reach your arm out to the northwestern horizon and look a little more than one vertically-held fist (10-12 degrees) above it for a singular, star-like object. Found it? Congratulations – that’s Mercury!
* No luck? Start with binoculars instead and sweep the bright sunset glow until you find Mercury. Once you know exactly where to look, lower the binoculars from your eyes and you should see the planet without optical aid. And before I forget – be sure to focus the binoculars on a distant object like a cloud or the moon before beginning your sweeps. I guarantee you won’t find Mercury if it’s out of focus.
Through a telescope, Mercury looks like a gibbous moon right now but its phase will lessen as it moves farther to the ‘left’ or east of the sun. Greatest eastern elongation happens on May 24. On and around that date the planet will be farthest from the sun, standing 12-14 degrees high 40 minutes after sundown from most mid-northern locales.
Mercury is even better placed on May 19 but fades and begins to drop back down toward the horizon late in the month. Stellarium
The planet fades in late May and become difficult to see by early June. Inferior conjunction, when Mercury passes between the Earth and sun, occurs on June 19. Unlike Venus, which remains brilliant right up through its crescent phase, Mercury loses so much reflective surface area as a crescent that it fades to magnitude +3. Its greater distance from Earth, lack of reflective clouds and smaller size can’t compete with closer, brighter and bigger Venus.
When a planet crosses the disk of the sun it’s called a transit. Mercury’s path across the solar disk is seen from the Solar and Heliospheric Observatory (SOHO) on November 8, 2006. Credit: NASA.
Mercury’s 7-degree inclined orbit means it typically glides well above or below the sun’s disk at inferior conjunction. But anywhere from 3 up to 13 years in either November or May the planet passes directly between the Earth and sun at inferior conjunction and we witness a transit. This last happened for U.S. observers on Nov. 8, 2006; the next transit occurs exactly two years from today on May 9, 2016. That event will be widely visible across the Americas, Western Europe and Africa. After having so much fun watching the June 2012 transit of VenusI can’t wait.
