The west limb of the Sun imaged by NuSTAR and SDO shows areas of high-energy x-rays above particularly active regions (NASA/JPL-Caltech/GSFC)
What if you had x-ray vision like Superman? Or if those funny-looking glasses they advertised in comic books in the 60s actually worked?* Then with those our Sun might look something like this, lighting up with brilliant flares of high-energy x-rays as seen by NASA’s super-sensitive NuSTAR Space Telescope (with a little help from SDO.)
The NuStar Space Telescope launched aboard a Orbital Sciences Pegasus rocket, on June 13, 2012. (Credit: NASA/Caltech-JPL)
Of course NASA’s orbiting NuSTAR x-ray telescope is not like a typical medical imaging system. Instead of looking for broken bones, NuSTAR (short for Nuclear Spectroscopic Telescope Array) is made to detect high-energy particles blasting across the Universe from exotic objects like supermassive black holes, pulsars, and supernovae.
But astronomers suggested turning NuSTAR’s gaze upon our own Sun to see what sorts of x-ray activity may be going on there.
“At first I thought the whole idea was crazy,” said Fiona Harrison, a Professor of Physics and Astronomy at Caltech and PI for the NuSTAR mission. “Why would we have the most sensitive high energy X-ray telescope ever built, designed to peer deep into the universe, look at something in our own back yard?”
As it turns out NuSTAR was able to reveal some very interesting features on the Sun, showing where the corona is being heated to very high temperatures. The image above shows NuSTAR’s first observations, overlaid onto data acquired by NASA’s Solar Dynamics Observatory.
NuSTAR data is shown in green and blue, revealing high-energy emission around – but not exactly aligned with – active regions on the Sun where solar plasma is being heated to more than 3 million degrees. The red represents ultraviolet light captured by SDO and shows material in the solar atmosphere at a slightly cooler 1 million degrees.
The NuSTAR data overlaid on the full disk SDO image, rotated so north on the Sun is up. (NASA/JPL-Caltech/GSFC)
Because the Sun isn’t terribly intense in high energy x-ray output it’s safe to observe it with NuSTAR — it’s not likely to burn out the telescope’s sensors. But what NuSTAR can detect may help astronomers determine the exact mechanisms behind the intense coronal heating that occurs in and above the Sun’s chromosphere. If so-called “nanoflares” — miniature and as-yet-invisible versions of solar flares — are responsible, for instance, NuSTAR might be able to catch them in action for the first time.
“NuSTAR will be exquisitely sensitive to the faintest X-ray activity happening in the solar atmosphere, and that includes possible nanoflares,” said David Smith, solar physicist and member of the NuSTAR team at the University of California, Santa Cruz.
In addition NuSTAR could potentially detect the presence of axions in the Sun’s core — hypothesized particles that may make up dark matter in the Universe.
NuSTAR may not be a “solar telescope” per se, but that won’t stop astronomers from using its unique abilities to learn more about the star we intimately share space with.
“NuSTAR will give us a unique look at the Sun, from the deepest to the highest parts of its atmosphere.”
– David Smith, solar physicist, University of California Santa Cruz
Artist's impression of the planets in our solar system, along with the Sun (at bottom). Credit: NASA
It’s is no secret that Earth is the only inhabited planet in our Solar System. All the planets besides Earth lack a breathable atmosphere for terrestrial beings, but also, many of them are too hot or too cold to sustain life. A “habitable zone” which exists within every system of planets orbiting a star. Those planets that are too close to their sun are molten and toxic, while those that are too far outside it are icy and frozen.
But at the same time, forces other than position relative to our Sun can affect surface temperatures. For example, some planets are tidally locked, which means that they have one of their sides constantly facing towards the Sun. Others are warmed by internal geological forces and achieve some warmth that does not depend on exposure to the Sun’s rays. So just how hot and cold are the worlds in our Solar System? What exactly are the surface temperatures on these rocky worlds and gas giants that make them inhospitable to life as we know it?
Mercury:
Of our eight planets, Mercury is closest to the Sun. As such, one would expect it to experience the hottest temperatures in our Solar System. However, since Mercury also has no atmosphere and it also spins very slowly compared to the other planets, the surface temperature varies quite widely.
What this means is that the side exposed to the Sun remains exposed for some time, allowing surface temperatures to reach up to a molten 465 °C. Meanwhile, on the dark side, temperatures can drop off to a frigid -184°C. Hence, Mercury varies between extreme heat and extreme cold and is not the hottest planet in our Solar System.
Venus is an incredibly hot and hostile world, due to a combination of its thick atmosphere and proximity to the Sun. Image Credit: NASA/JPL
Venus:
That honor goes to Venus, the second closest planet to the Sun which also has the highest average surface temperatures – reaching up to 460 °C on a regular basis. This is due in part to Venus’ proximity to the Sun, being just on the inner edge of the habitability zone, but also to Venus’ thick atmosphere, which is composed of heavy clouds of carbon dioxide and sulfur dioxide.
These gases create a strong greenhouse effect which traps a significant portion of the Sun’s heat in the atmosphere and turns the planet surface into a barren, molten landscape. The surface is also marked by extensive volcanoes and lava flows, and rained on by clouds of sulfuric acid. Not a hospitable place by any measure!
Earth:
Earth is the third planet from the Sun, and so far is the only planet that we know of that is capable of supporting life. The average surface temperature here is about 14 °C, but it varies due to a number of factors. For one, our world’s axis is tilted, which means that one hemisphere is slanted towards the Sun during certain times of the year while the other is slanted away.
This not only causes seasonal changes, but ensures that places located closer to the equator are hotter, while those located at the poles are colder. It’s little wonder then why the hottest temperature ever recorded on Earth was in the deserts of Iran (70.7 °C) while the lowest was recorded in Antarctica (-89.2 °C).
Mars’ thin atmosphere, visible on the horizon, is too weak to retain heat. Credit: NASA
Mars:
Mars’ average surface temperature is -55 °C, but the Red Planet also experiences some variability, with temperatures ranging as high as 20 °C at the equator during midday, to as low as -153 °C at the poles. On average though, it is much colder than Earth, being just on the outer edge of the habitable zone, and because of its thin atmosphere – which is not sufficient to retain heat.
In addition, its surface temperature can vary by as much as 20 °C due to Mars’ eccentric orbit around the Sun (meaning that it is closer to the Sun at certain points in its orbit than at others).
Jupiter:
Since Jupiter is a gas giant, it has no solid surface, so it has no surface temperature. But measurements taken from the top of Jupiter’s clouds indicate a temperature of approximately -145°C. Closer to the center, the planet’s temperature increases due to atmospheric pressure.
At the point where atmospheric pressure is ten times what it is on Earth, the temperature reaches 21°C, what we Earthlings consider a comfortable “room temperature”. At the core of the planet, the temperature is much higher, reaching as much as 35,700°C – hotter than even the surface of the Sun.
Saturn and its rings, as seen from above the planet by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute/Gordan Ugarkovic
Saturn:
Due to its distance from the Sun, Saturn is a rather cold gas giant planet, with an average temperature of -178 °Celsius. But because of Saturn’s tilt, the southern and northern hemispheres are heated differently, causing seasonal temperature variation.
And much like Jupiter, the temperature in the upper atmosphere of Saturn is cold, but increases closer to the center of the planet. At the core of the planet, temperatures are believed to reach as high as 11,700 °C.
Uranus:
Uranus is the coldest planet in our Solar System, with a lowest recorded temperature of -224°C. Despite its distance from the Sun, the largest contributing factor to its frigid nature has to do with its core.
Much like the other gas giants in our Solar System, the core of Uranus gives off far more heat than is absorbed from the Sun. However, with a core temperature of approximately 4,737 °C, Uranus’ interior gives of only one-fifth the heat that Jupiter’s does and less than half that of Saturn.
Neptune photographed by Voyager 2. Image credit: NASA/JPL
Neptune:
With temperatures dropping to -218°C in Neptune’s upper atmosphere, the planet is one of the coldest in our Solar System. And like all of the gas giants, Neptune has a much hotter core, which is around 7,000°C.
In short, the Solar System runs the gambit from extreme cold to extreme hot, with plenty of variance and only a few places that are temperate enough to sustain life. And of all of those, it is only planet Earth that seems to strike the careful balance required to sustain it perpetually.
We’ve talked about the biggest stars, but what about the smallest stars? What’s the smallest star you can see with your own eyes, and how small can they get?
Space and astronomy is always flaunting its size issues. Biggest star, hugest nebula, prettiest most talented massive galaxy, most infinite universe, and which comet came out on top in the bikini category. Blah blah blah.
In an effort to balance the scales a little we’re going look at the other end of the spectrum. Today we’re talking small stars. First, I’m going to get the Gary Coleman and Emmanuel Lewis joke out of the way, so we can start talking about adorable little teeny tiny fusion factories.
We get big stars when we’ve got many times the mass of the Sun’s worth of hydrogen in one spot. Unsurprisingly, to get smaller stars we’ll need less hydrogen, but there’s a line we can’t cross where there’s so little, that it won’t generate the temperature and pressure at its core to ignite solar fusion. Then it’s a blob, it’s a mess. It’s clean-up in aisle Andromeda. It’s who didn’t put the lid back on the jar marked H.
So how small can stars get? And what’s the smallest star we know about? In the traditional sense, a star is an object that has enough mass and pressure in its core that it can ignite fusion, crushing atoms of hydrogen into helium.
Fusion is exothermic, releasing energy. It’s this energy that counteracts the force of gravity pulling everything inward. That gives you the size of the star and keeps it from collapsing in on itself.
By some random coincidence and fluke of nature our Sun is exactly 1 solar mass. Actually, that’s not true at all, our shame is that we use our Sun as the measuring stick for other stars. This might be the root of this size business. We’re in an endless star measuring contest, with whose is the most massive and whose has the largest circumference?
So, as it turns out, you can still have fusion reactions within a star if you get all the way down to 7.5% of a solar mass. This is the version you know as a red dwarf. We haven’t had a chance to measure many red dwarf stars, but the nearest star, Proxima Centauri, has about 12.3% the mass of the Sun and measures only 200,000 kilometers across. In other words, the smallest possible red dwarf would only be about 50% larger than Jupiter.
There is an important distinction, this red dwarf star would have about EIGHTY times the mass of Jupiter. I know that sounds crazy, but when you pile on more hydrogen, it doesn’t make the star that much bigger. It only makes it denser as the gravity pulls the star together more and more.
At the time I’m recording this video, this is smallest known star at 9% the mass of the Sun, just a smidge over the smallest theoretical size.
X-Ray image of Proxima Centauri. Image credit: Chandra
Proxima Centauri is about 12% of a solar mass, and the closest star to Earth, after the Sun. But it’s much too dim to be seen without a telescope. In fact, no red dwarfs are visible with the unaided eye. The smallest star you can see is 61 Cygni, a binary pair with one star getting only 66% the size of the Sun. It’s only 11.4 light years away, and you can just barely see it in dark skies. After that it’s Spock’s home, Epsilon Eridani, with 74% the size of the Sun, then Alpha Centauri B with 87%, and then the Sun. So, here’s your new nerd party fact. The Sun is the 4th smallest star you can see with your own eyes. All the other stars you can see are much bigger than the Sun. They’re all gigantic terrifying monsters.
And in the end, our Sun is absolutely huge compared to the smallest stars out there. We here like to think of our Sun as perfectly adequate for our needs, it’s ours and all life on Earth is there because of it. It’s exactly the right size for us. So don’t you worry for one second about all those other big stars out there.
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Diagram of the Earths orbit around the Sun. Credit: NASA/H. Zell
Ever since the 16th century when Nicolaus Copernicus demonstrated that the Earth revolved around in the Sun, scientists have worked tirelessly to understand the relationship in mathematical terms. If this bright celestial body – upon which depends the seasons, the diurnal cycle, and all life on Earth – does not revolve around us, then what exactly is the nature of our orbit around it?
For several centuries, astronomers have applied the scientific method to answer this question, and have determined that the Earth’s orbit around the Sun has many fascinating characteristics. And what they have found has helped us to understanding why we measure time the way we do.
Orbital Characteristics:
First of all, the speed of the Earth’s orbit around the Sun is 108,000 km/h, which means that our planet travels 940 million km during a single orbit. The Earth completes one orbit every 365.242199 mean solar days, a fact which goes a long way towards explaining why need an extra calendar day every four years (aka. during a leap year).
The planet’s distance from the Sun varies as it orbits. In fact, the Earth is never the same distance from the Sun from day to day. When the Earth is closest to the Sun, it is said to be at perihelion. This occurs around January 3rd each year, when the Earth is at a distance of about 147,098,074 km.
The average distance of the Earth from the Sun is about 149.6 million km, which is also referred to as one astronomical unit (AU). When it is at its farthest distance from the Sun, Earth is said to be at aphelion – which happens around July 4th where the Earth reaches a distance of about 152,097,701 km.
And those of you in the northern hemisphere will notice that “warm” or “cold” weather does not coincide with how close the Earth is to the Sun. That is determined by axial tilt (see below).
Elliptical Orbit:
Next, there is the nature of the Earth’s orbit. Rather than being a perfect circle, the Earth moves around the Sun in an extended circular or oval pattern. This is what is known as an “elliptical” orbit. This orbital pattern was first described by Johannes Kepler, a German mathematician and astronomer, in his seminal work Astronomia nova (New Astronomy).
An illustration of Kepler’s three laws of motion, which show two planets that have elliptical orbits around the Sun. Credit: Wikipedia/Hankwang
After measuring the orbits of the Earth and Mars, he noticed that at times, the orbits of both planets appeared to be speeding up or slowing down. This coincided directly with the planets’ aphelion and perihelion, meaning that the planets’ distance from the Sun bore a direct relationship to the speed of their orbits. It also meant that both Earth and Mars did not orbit the Sun in perfectly circular patterns.
In describing the nature of elliptical orbits, scientists use a factor known as “eccentricity”, which is expressed in the form of a number between zero and one. If a planet’s eccentricity is close to zero, then the ellipse is nearly a circle. If it is close to one, the ellipse is long and slender.
Earth’s orbit has an eccentricity of less than 0.02, which means that it is very close to being circular. That is why the difference between the Earth’s distance from the Sun at perihelion and aphelion is very little – less than 5 million km.
Seasonal Change:
Third, there is the role Earth’s orbit plays in the seasons, which we referred to above. The four seasons are determined by the fact that the Earth is tilted 23.4° on its vertical axis, which is referred to as “axial tilt.” This quirk in our orbit determines the solstices – the point in the orbit of maximum axial tilt toward or away from the Sun – and the equinoxes, when the direction of the tilt and the direction to the Sun are perpendicular.
Over the course of a year the orientation of the axis remains fixed in space, producing changes in the distribution of solar radiation. Credit: NOAA/Thomas G. Andrews
In short, when the northern hemisphere is tilted away from the Sun, it experiences winter while the southern hemisphere experiences summer. Six months later, when the northern hemisphere is tilted towards the Sun, the seasonal order is reversed.
In the northern hemisphere, winter solstice occurs around December 21st, summer solstice is near June 21st, spring equinox is around March 20th and autumnal equinox is about September 23rd. The axial tilt in the southern hemisphere is exactly the opposite of the direction in the northern hemisphere. Thus the seasonal effects in the south are reversed.
While it is true that Earth does have a perihelion, or point at which it is closest to the sun, and an aphelion, its farthest point from the Sun, the difference between these distances is too minimal to have any significant impact on the Earth’s seasons and climate.
Lagrange Points:
Another interesting characteristic of the Earth’s orbit around the Sun has to do with Lagrange Points. These are the five positions in Earth’s orbital configuration around the Sun where where the combined gravitational pull of the Earth and the Sun provides precisely the centripetal force required to orbit with them.
The five Lagrange Points between the Earth are labelled (somewhat unimaginatively) L1 to L5. L1, L2, and L3 sit along a straight line that goes through the Earth and Sun. L1 sits between them, L3 is on the opposite side of the Sun from the Earth, and L2 is on the opposite side of the Earth from L1. These three Lagrange points are unstable, which means that a satellite placed at any one of them will move off course if disturbed in the slightest.
The L4 and L5 points lie at the tips of the two equilateral triangles where the Sun and Earth constitute the two lower points. These points liem along along Earth’s orbit, with L4 60° behind it and L5 60° ahead. These two Lagrange Points are stable, hence why they are popular destinations for satellites and space telescopes.
The study of Earth’s orbit around the Sun has taught scientists much about other planets as well. Knowing where a planet sits in relation to its parent star, its orbital period, its axial tilt, and a host of other factors are all central to determining whether or not life may exist on one, and whether or not human beings could one day live there.
It's not much, but it's the clearest view taken by NASA's Curiosity Rover of C/2013 A1 Siding Spring as it passed near Mars on October 19th. The comet is the fuzzy streak moving from right to left. Click for a full-sized view. Credit: NASA/JPL-Caltech/MSSS/TAMU
NASA’s Curiosity Rover spends most of its time staring at the ground, but like humans, it looks up once in a while too. As reported earlier, NASA ground controllers pointed the rover’s Mast Camera (mastcam) skyward to shoot a series of photos of Comet Siding Spring when it passed closest to the Red Planet on October 19th. Until recently, noise-speckled pictures available on the raw image site confounded interpretation. Was the comet there or wasn’t it? In these recently released versions, the fuzzy intruder is plain to see, tracking from right to left across the field of view.
Remember the monster sunspot group on bold display during last month’s partial solar eclipse? It was the largest group of the current solar cycle and largest recorded in 24 years. Here it is again (lower left) – returning for a second time – as seen by Curiosity on November 10th. Click for raw version. Credit: NASA/JPL-Caltech
Ten exposures of 25 seconds each were taken between 4:33 p.m. and 5:54 p.m. CDT on October 19th to create the animation. The few specks you see are electronic noise, but the sharp, bright streaks are stars that trailed during the time exposure. Curiosity’s Mastcam camera system has dual lenses – a 100mm f/10 lens with a 5.1° square field of view and a 34mm, f/8 lens with a 15° square field of view. NASA didn’t include the information about which camera was used to make the photos, but if I had to guess, the faster, wide-angle view would be my choice. Siding Spring was moving relatively quickly across the Martian sky at closest approach.
Sunspot region 2192 (lower left) has returned for an encore in this photo taken by NASA’s Solar Dynamics Observatory. The same group is visible in images taken 4 days earlier from Mars. Credit: NASA/SDO
Prowling through the Curiosity raw image files, I came across this photo of the Sun on November 10th. Three dark spots at the left are immediately obvious and a dead-ringer for Active Region 2192, now re-named 2209 as it rounds the Sun for Act II. You’ll recall this was the sunspot group that nearly stole the show during the October 23rd partial solar eclipse. From Mars’ perspective, which currently allows Curiosity to see further around the solar “backside”, AR 2209 showed up a few days before it was visible from Earth.
Because of Mars’ position relative to the Sun, Curiosity saw the return of sunspot group 2192 before it was visible from Earth. The Sun had to rotate about another 4 days to carry the group into Earth’s line of sight. Source: Solarsystemscope with additions by the author
Although it’s slimmed down in size, the region is still large enough to view with the naked eye through a safe solar filter. More importantly, it possesses a complex beta-gamma-delta magnetic field where magnetic north and south poles are in close proximity and ripe for reconnection and production of M-class and X-class flares. Already, the region’s crackled with three moderate M-class flares over the past two days. In no mood to take a back seat, AR 2209 continues to dominate solar activity even during round two.
Phobos is very small but orbits close enough for someone on the surface to see its shape with the naked eye, especially when it’s high in the sky and closest to the observer. Phobos is about 1/3 the size of our Moon. This photo was taken by Curiosity on October 20th and shows the moon’s largest crater, Stickney, at top. Credit: NASA/JPL-Caltech with toning by the author to bring out details
Mars possesses two small moons, Deimos and Phobos. Curiosity has photographed them both before including an occultation Deimos (9 miles/15 km) by the larger Phobos (13.5 miles/22 km). Phobos orbits closer to Mars than any other moon does to its primary in the Solar System, just 3,700 miles (6,000 km). As a result, it moves too fast for Mars’ rotation to overtake it the way Earth’s rotation overtakes the slower-moving Moon, causing it to set in the west overnight. Contrarian Phobos rises in the western sky and sets in the east just 4 hours 15 minutes later. When nearest the horizon and farthest from an observer, it’s apparent size is just 0.14º. At the zenith it grows to 0.20º of 1/3 the diameter of the Moon.
Phobos occults Deimos in real time photographed by the Curiosity Rover on August 1, 2013. Credit: NASA/JPL-Caltech
One longish observing session on the planet would cover a complete rise-set cycle during which Phobos would first appear as a crescent and finish up a full moon a few hours later. All this talk about Phobos is only meant to direct you to the picture above taken by Curiosity on October 20, 2014 when the moon was a thick crescent. As on Earth, where Earthshine fills out the remainder of the crescent Moon, so too does Mars-shine provide enough illumination to see the full outline of Phobos.
Four-wheel drive only! Curiosity took this photo showing a sea of dark dunes from the Pahrump Hills outcrop on November 13th. Credit: NASA/JPL-Caltech
Curiosity has also photographed Earth, sunsets and transits of Phobos across the Sun while rambling across the dusty red landscape since August 2012. Before we depart, it seems only fair to aim our gaze Mars-ward again to see what’s up. Or down. The rover’s been doing a geological “Walkabout” in the Pahrump Hills outcrop at the base of Mt. Sharp in Gale Crater since September. Earlier this fall it drilled and sampled rock there containing more hematite than at any of its previous stops. Hematite is an iron oxide that’s often associated with water.
The mission may spend weeks or months at the outcrop looking for and drilling new target rocks before moving further up the geological layer cake better known as Mt. Sharp.
On Sept. 18, 1977, Voyager 1 took three images of the Earth and Moon that were combined into this one image. The moon is artificially brightened to make it show up better. Credit: NASA
The Sun has so much more mass than the Earth. So, so, so much more mass. Almost everything in the Solar System is orbiting the Sun, and yet, the Moon refuses to leave our side. What gives?
The Sun contains 99.8% of the entire mass of the Solar System. It looks to us like everything seems to orbit the Sun, so why doesn’t the Sun capture the Moon from Earth like a schoolyard bully snatching the Earth’s lunch money. That would make sense right? It all fits in with our skewed view of social hierarchy based on an entities volume.
Good news! It’s already happened, In a way. The Sun has already captured the Moon. If you look at the orbit of the Moon, it orbits the Sun similar to the way Earth does. Normally the motion of the Moon around the Sun is drawn as a kind of Spirograph pattern, but its actual motion is basically the same orbit as Earth with a small wobble to it.
The Moon also orbits the Earth. You might think this is because the Earth is much closer to the Moon than the Sun. After all, the strength of gravity depends not only on the mass of an object, but also on its distance from you. But this isn’t the case. The Sun is about 400 times more distant from the Moon than the Earth, but the Sun is about 330,000 times more massive.
If you’re up for some napkin calculations, you little mathlete, by using Newton’s law of gravity, you find that even with its greater distance, the Sun pulls on the Moon about twice as hard as the Earth does.
So why can’t the Moon escape the Earth?
In order to escape the gravitational pull of a body, you need to be moving fast enough *relative to that body* to escape its pull. This is known as the escape velocity of the object.
It takes two to tango. The moon’s gravity raises a pair of watery bulges in the Earth’s oceans creating the tides, while Earth’s gravity stretches and compresses the moon to warm its interior. Illustration: Bob King
So, yes, the Sun is totally trying to rip the Moon away from the Earth, but the Earth is super clingy.
The speed of the Moon around the Earth is about 1 km/s. At the Moon’s distance from the Earth, the escape velocity is about 1.2 km/s. The Moon simply isn’t moving fast enough to escape the Earth.
Man, those numbers sure are close. I wonder if we could kickstart a rocket to stick on the side? So, even though the Moon can’t escape the Earth, it is gradually moving away. This is due to the tidal interactions between the Earth and Moon, which we talk about another video we’ll link at the end of this one.
So even though the Moon will never escape the Earth, it will continue to move away. So, what do you think? What kind of devious project should we start to get the Moon that little boost so it finally escapes the clingy Earth and all its clingy Klingon clingyness? Tell us in the comments below.
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The partial solar eclipse of October 23, 2014. Credit and copyright: Derek Mellott.
“The Sun looks like it has a bite taken out of it!” said one enthusiastic viewer of the partial solar eclipse on October 23. Although I only had my paper plate pinhole projector that I shared with a crowd of folks (you can see an image of it near the bottom of the images here), the funny-looking Sun projected onto the plate definitely looked like a cookie with bite out of it or a clipped fingernail. But thankfully, as the Moon moved in front of the Sun today, legions of astrophotographers were out to take fantastic images of the eclipse. And the gigantic sunspot named AR 2192 made a cameo appearance as well. Enjoy the gallery below!
Thanks to everyone who uploaded images to our Flickr page or shared their images on Twitter.
An artistic view of the Partial Solar Eclipse, October 23, 2014. Credit and copyright: A Nartist.The setting Sun, shadowed by the Moon and spotted with intense magnetic activity on October 23, 2014. Credit and copyright: Tavi Greiner.Solar eclipse over the Flatirons near Boulder, Colorado. A syzygy, with the Earth and Moon simultaneously transiting the Sun. Credit and copyright: Alex Parker.Partial Solar Eclipse of October 23, 2014, at 280mm. Credit and copyright: Forrest Tanaka.The sun sets while still in eclipse as seen from Duluth, Minn., Thursday evening October 23. Credit and copyright: Bob King.The solar eclipse on October 23, 2014, showing the Sun dotted by sunspots and airplane contrails. Credit and copyright: Greg Hogan.A cloudy closeup of the partial solar eclipse on October 23, 2014. Credit and copyright: JCC_Starguy on Flickr.The cusps of the Sun’s disk are just visible above the horizon as the solar eclipse of October 23, 2014, fades out over Iowa. Credit and copyright: Alan Boyle/NBC News.A partial solar eclipse is visable just before sunset Thursday, Oct. 23, 2014, in Arlington, VA. Photo Credit: (NASA/Bill Ingalls)The partial solar eclipse as viewed through a paper plate pinhole projector. Credit, copyright and pinhole: Nancy Atkinson.
Ron Cottrell captured the sunspot in all its swirly magnetic goodness in hydrogen-alpha light on October 19. To appreciate its size, he included the Earth (lower left) for reference. Credit: Ron Cottrell
That’s one big, black blemish on the Sun today! Rarely have we been witness to such an enormous sunspot. Lifting the #14 welder’s glass to my eyes this morning I about jumped back and bumped into the garage.
Properly shielded, it was very easy to see with the naked eye. Unlike some other naked eye sunspots, this one showed structure. The eastern end was darker, the western half grayer and more extended.
Watch the giant spot rotate into view and grow right before your eyes in this 72-hour time-lapse video taken by SOHO’s HMI imager Oct. 18-20, 2014
Through a small telescope, the mix of dark umbras scattered amid weirdly sculpted penumbral “islands” was incredible to see. Photographs like the one above are wonderful documents, but witnessing this beautiful complex magnetic mess with your own eyes is another experience altogether. Region 2192 continues to grow and size and complexity and is now the largest sunspot group of solar cycle 24which began in 2009 – more than five years ago!
Active region 2192 is now the largest sunspot group to appear in over five years. Compare to Jupiter and the Earth. Credit: SDO/HMI/Alex Young
Every sunspot marks a region on the Sun’s shiny outer skin called the photosphere where magnetic energy is concentrated. Strong magnetic fields within a sunspot group quell the turbulent churning of the photosphere, chilling the region by several thousand degrees. Sunspots appear dark against the Sun’s blazing disk because they’re cooler. Cooler meaning 8,000 F instead of 11,000 F, so yes, they’re still VERY hot.
Watch as Region 2192 crackles with energy and flares as seen in far ultraviolet light with NASA’s Solar Dynamics Observatory.
Energy stored in sunspots’ twisted magnetic fields can suddenly be released in violent, explosions called solar flares. Billions of tons of solar plasma – the sizzling mix of protons and electrons that composes the Sun – are heated to millions of degrees during the explosion and rapidly accelerated into space. Radiation from radio waves to X-rays and gamma rays fans out at the speed of light. Fortunately for us, our atmosphere and planetary magnetic field protect us from most of what flares can fling our way.
NASA’s Solar Dynamics Observatory took this photo of the Sun and Jupiter-sized sunspot region 2192 this morning Oct. 22 at 8:45 a.m. CDT. The view in a small telescope equipped with a safe solar filter is even better! Credit: NASA
But as the Sun rotates this monster into our line of sight, possibilities for Earth-directed flares and coronal mass ejections increase as do geomagnetic storms, the bringer of auroras. Already in the past 48 hours, the spot has dished out seven M-class flares and a powerful X-1 flare even before it has fully come into view. There’s more to come – Region 2192 harbors an unstable beta-gamma-delta magnetic field ripe for additional flaring including more of the X-classvariety.
The Sun on October 21 showing smaller sunspot regions along with our featured group. Credit: Sarah and Simon Fisher
There’s no doubt now that this behemoth will stick around to add a whole new dimension to tomorrow’s partial solar eclipse. I can’t wait to see the Moon’s black curve approach and at least partially occult the group from view. If you’re interested in getting some one-of-a-kind pictures of the scene, please see our own Dave Dickinson’s excellent guide on photographing the partial eclipse.
A sliver of a Moon rises in morning twilight today October 22 just a day away from its appointment with the Sun. Credit: Bob King
While we’re on the Moon, early morning risers had the pleasure of its company just one day before New Moon and solar eclipse. I was out watching the Orionid meteor shower. While not rich like the Perseids or Geminids I managed to catch a few including a few lucky shots with the camera.
An Orionid meteor slashes across the top of the frame directly above the constellation Orion early this morning October 22, 2014. Details: 24mm lens, f/2.8, 30-seconds at ISO 1600. Credit: Bob King
The shower has peaked but will still be active the remainder of the week if you’re inclined to take a look. And I can’t resist. How about one last sweet close-up photo of sunspot group 2192? I have a feeling you won’t mind.
Monster Sunspot AR12192 taken by Karzaman Ahmad on October 21, 2014, from Langkawi Nagtional Observatory, Malaysia. Credit: Karzaman Ahmad and shared at spaceweather.com. Click the image to see additional animations and photos on Alex Young’s site
It’s a-comin’: a “monster” sunspot is steadily rotating around the Sun’s southern hemisphere and will soon be in position to fire flares and CMEs in our direction — and this past weekend master solar photographer Alan Friedman captured it on camera!
The image above was taken in full-spectrum visible light on Sunday, Oct. 19 by Alan from his backyard in Buffalo, New York. Sunspots 2186 (at the top limb), 2187 (upper center), 2193 (the small middle cluster) and the enormous AR2192 are easily visible as dark blotches – “cooler” regions on the Sun’s surface where upwelling magnetic fields interrupt the convective processes that drive the Sun’s energy output.
This particular image was a single frame of video, unlike some of Alan’s other photographs. According to Alan the air turbulence was particularly bad that day, shooting between the clouds, so only this one frame was usable. Click the image for full-scale “wow” factor.
(And if you think AR2192 looks scary in that image, check it out in CaK bands here!)
Scale size of Earth compared to AR2192 on Oct. 20 (NASA/SDO/AIA. Diagram by J. Major.)
According to Spaceweather.com AR2192 has grown considerably over the past few days and has the potential to unleash M- and X-class flares in our direction now that it’s moving into Earth-facing position. It’s currently many times larger than Earth and will likely get even bigger… in fact, during this week’s partial solar eclipse AR2192 should be visible with the naked (but not unprotected!) eye for viewers across much of North America.
