Thierry Legault Meets His Own Challenge: Image an ISS Transit of a Solar Prominence

When you’re Thierry Legault and you want to challenge yourself, the bar is set pretty high.

“This is a challenge I imagined some time ago,” Legault told Universe Today via email, “but I needed all the right conditions.”

The challenge? Capture a transit of the International Space Station of not just the Sun — which he’s done dozens of times — but in front of a solar prominence.

Legault said the transit of the prominence, which he captured on August 21, 2015, lasted 0.8 seconds. His camera was running at 40 frames per second, and he got about 32 shots in that time.

See a video of the transit in real time, and more, below:

We’ve described in our previous articles how Legault determines the exact location where he needs to be to capture the images he wants by considering the width of the visibility path, and trying to be as close to the center of the path as possible. But this challenge was a bit different.

“I took the last transit data from Calsky, the real position of the prominences, and made angles and distances calculations to place my telescope this time not on the central line of the transit but 1 mile north from it,” Legault said, “to have the ISS passing in front of the largest prominence.”

You can see some of Legault’s stunning and sometimes ground-breaking astrophotography here on Universe Today, such as images of the space shuttle or International Space Station crossing the Sun or Moon, or views of spy satellites in orbit.

If you want to try and master the art of astrophotography, you can learn from Legault by reading his book, “Astrophotography,” which is available on Amazon in a large format book or as a Kindle edition for those who might like to have a lit version while out in the field. It is also available at book retailers like Barnes and Noble and Shop Indie bookstores, or from the publisher, Rocky Nook, here.

For additional imagery and information, visit Legualt’s website.

How Bad Can Solar Storms Get?

Our Sun regularly pelts the Earth with all kinds of radiation and charged particles. Just how bad can these solar storms get?

In today’s episode, we’re going to remind you how looking outside of the snow globe can inspire your next existential crisis.

You guys remember the Sun right? Look how happy that little fella is. The Sun is our friend! Life started because of the Sun! Oooh, look, the Sun has a baby face! It’s a beautiful, ball of warmth and goodness, lighting up our skies and bringing happiness into our hearts.

It’s a round yellow circle in crayon. Very stable and firmly edged. Occasionally drawn with a orange lion’s mane for coronal effects. Nothing to be afraid, right?

Wake up sheeple. It’s time to pull back the curtain of the marketing world, big crayon fridge art and the children’s television conspiracy of our brightly glowing neighborhood monstrosity. That thing is more dangerous than you can ever imagine.

You know the Sun is a nuclear reaction right next door. Like it’s right there. RIGHT THERE! It’s a mass of incandescent gas, with a boiling bubbling surface of super-heated hydrogen. It’s filled with a deep yellow rage, expressed every few days by lashing out millions of kilometers into space with fiery death tendrils and blasts of super radiation.

The magnetic field lines on the Sun snap and reconnect, releasing a massive amount of radiation and creating solar flares. Solar plasma constrained in the magnetic loop is instantly released, smashed together and potentially generating x-ray radiation.

“Big deal. I get x-rayed all the time.” you might think. We the mighty humans have mastered the X-ray spectrum! Not so fast puny mortal. Just a single x-ray class flare can blast out more juice than 100 billion nuclear explosions.

 In this image, the Solar Dynamics Observatory (SDO) captured an X1.2 class solar flare, peaking on May 15, 2013. Credit: NASA/SDO
In this image, the Solar Dynamics Observatory (SDO) captured an X1.2 class solar flare, peaking on May 15, 2013. Credit: NASA/SDO

Then it’s just a quick 8 minute trip to your house, where the radiation hits us with no warning. Solar flares can lead to coronal mass ejections, and they can happen other times too, where huge bubbles of gas are ejected from the Sun and blasted into space. This cosmic goo can take a few hours to get to us, and are also excellent set-ups for nocturnal emission and dutch oven jokes.

Astronomers measure the impact of a solar storm on the Earth using a parameter called DST, or “disturbance storm time”. We measure the amount that the Earth’s protective magnetosphere flexes during a solar storm event. The bigger the negative number, the worse it is.

If we can see an aurora, a geomagnetic storms in the high altitudes, it measures about -50 nanoteslas. The worst storm in the modern era, the one that overloaded our power grid in 1989, measured about -600 nanoteslas.

The most potent solar storm we have on record was so powerful that people saw the Northern Lights as far south as Cuba. Telegraph lines sparked with electricity and telegraph towers caught on fire. This was in 1859 and was clearly named by Syfy’s steampunk division. This was known as the Carrington Event, and estimated in the -800 to -1750 nanotesla range.

Just in time for St. Patrick's Day - a
A spectacular green and red aurora photographed early this morning March 17, 2015, from Donnelly Creek, Alaska. Credit: Sebastian Saarloos

So, how powerful do these things need to be to cook out our meat parts? The good news is contrary to my earlier fear mongering, the most powerful flare our Sun can generate is harmless to life on Earth.

Don’t let your guard down, the Sun is still horribly dangerous. It’ll bake us alive faster than you can say “Hansel und Gretel”. Assuming you can drag that phrase out over a billion years. As far as flares go, and so long as we stay right here, we’ll be fine. We might even see a nice aurora in the sky.

For those of you who use technology on a regular basis, you might not be so lucky. Powerful solar storms can overload power grids and fry satellites. If the Carrington Event happened now, we’d have a lot of power go out, and a small orbital scrapyard of dead satellites.

Astronauts outside the Earth, perhaps bouncing around on the Moon, or traveling to Mars would be in a universe of trouble without a good method of shielding.

The solar flares that the Sun can produce is minuscule compared to other stars out there. In 2014, NASA’s Swift satellite witnessed a flare that generated more than 10,000 times more energy than the most powerful solar flare ever seen.

Solar flare on the surface of the Sun. Image credit: NASA
Solar flare on the surface of the Sun. Image credit: NASA

For a brief moment, the surface of the red dwarf star DG Canum Venaticorum lit up hotter than 200 million degrees Celsius. That’s 12 times hotter than the center of the Sun. A blast that powerful would have scoured all life from the face of the Earth. Except the future colony of tardigrade descendants. Remember, the water bears are always watching.

Young red dwarf stars are renowned for these powerful flares, and this is one of the reasons astronomers think they’re not great candidates for life. It would be hard to survive blast after blast of radiation from these unruly stars. Alternately, planets around these stars are could be living terrariums inspired by the Gamma World RPG.

Breathe easy and don’t worry. Perhaps the Sun is our friend, and it truly does have our best interests at heart.

It’s not a big fan of our technology, though, and it’s ready to battle alongside us when the robot revolution begins. Oh, also, wear sunscreen, as the Sun’s brand of love isn’t all that different from Doctor Manhattan.

Have you ever seen an aurora display? Tell us a cool story in the comments below.

Astrophotos: Crazy Solar Prominences

We’ve got three cool images of the hot Sun submitted by various astrophotographers! Raymond Gilchrist enhanced his image from June 23, 2012 of three solar prominences using Inspire Pro on his iPad. He used different colors to differentiate the the various “strands” of the prominences, which highlights the “texture” of these huge solar features. See more of Raymond’s great astrophotos at his Flickr page.

See more below:


Renown Australian amateur astronomy Month Leventhal captured this pyramid-shaped prominence on the NW limb of the Sun, which reaches an approximate height of 93,000km! Wow! Monty took this image early today (June 25, 2012) using a Canon 600D camera, H-alpha 6Å filter and a Meade S.C. 10 inch telescope.

This is an awesome look at the Sun on June 16th from Efrain Morales Rivera from the Jaicoa Observatory in Puerto Rico. Visible are a huge prominence, several active regions, (AR1504, 5, 7 & 8), and interesting filaments. At the time this image was taken, Efrain noted that AR1504 had developed a ‘beta-gamma-delta’ magnetic field that harbors energy for strong solar flares. See more at the Jaicoa Observatory website.

Lead image caption: Solar Prominences, imaged edited with Inspire Pro. Credit: Raymond Gilchrist.

Second image caption: Prominence on the NW limb reaching an approximate height of 93,000km. Credit: Monty Leventhal.

Third image caption: Several sunspots, prominences and filaments on the Sun on June 16th 13:27UT. Credit: Efrain Morales Rivera, Jaicoa Observatory

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Earth Vs. Stuff from the Sun

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The Sun is big. And comparatively, Earth is a tiny Lilliputian. We’ve all seen images comparing the size of Earth to the Sun, but here are two images from October 10, 2011 that really bring home the size-scale of features on the Sun when compared to the size of Earth. Amateur astronomer Ron Cottrell from Oro Valley, Arizona took these images of two different features on the the Sun yesterday, overlaying the size of the Earth for reference. Both are viewed in Hydrogen- Alpha light, and the first is a fiery-looking huge prominence from the northwest limb of the Sun. Yikes!

Below, see a comparison of Earth to a current sunspot:

The Earth compared to Sunspot 1312 on 10-10-11. Credit: Ron Cottrell.

This is sunspot 1312 which has a classic sunspot shape with a core a that’s larger than the Earth.

Ron used a 40mm Coronado telescope and a webcam to capture the images. He explains the colors of the Sun in Hydrogen-Alpha, and in particular why the prominence appears fiery red:

“The red color of the prominence is very close to the color collected in the image. The yellow disk is enhanced. I actually capture the disk image in black and white and add the color. I can choose any color. The final image is a composite of two separate images. Prominences are, in general, much fainter than the bright disk. Therefore, the prominence image is captured at a slower shutter speed, e.g. 1/25 sec, compared to the disk image captured at 1/100 sec. The two images are combined in PhotoShop.”

You can see more of Ron’s handiwork on his Flickr page.

And speaking of the Sun, activity on our closest star has been ramping up and last week a series of active regions were lined up one after the other across the upper half of the Sun. Interestingly, the Solar Dynamics Observatory was able to capture how these regions twisted and interacted with each other. The video shows activity from Sept. 28 – Oct. 2, 2011, as seen in extreme UV light. The magnetically intense active regions sported coils of arcing loops and numerous times these magnetic field lines above them can be seen connecting with the active region next door. Towards the end of the clip, a leading active region blasted out a coronal mass ejection, quickly succeeded by a blast from another active region. The disruption of the magnetic field from one likely triggered the second, a phenomenon that has been observed before by SDO.

Breaking News: Watch A Gigantic Looping Solar Prominence

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The Solar Dynamics Observatory never fails to deliver absolutely stunning images from the Sun: as of 18:49 UT today, the above picture is what the Sun looked like in the ultraviolet spectrum. The prominence that you are seeing looping off the Sun is estimated at over 700,000 km across, which is about the radius of the entire Sun. Amazing!

You can head over to the Solar Dynamics Observatory site to watch this gigantic loop of solar plasma develop in real time.

There’s nothing to worry about here on Earth, though – we are safe from such activity on the Sun, even if that prominence is big enough swallow up thousands of Earths. There is no coronal-mass ejection or flare to go along with this prominence, both phenomena on the Sun that can reach Earth and mess with satellites and our power grid.

As you can see (or rather, not see) in this visible light image below, the flare seems to only be visible in the ultraviolet. Other spectra of the Sun as imaged by the SDO are available here. Why is this? Phil Plait, the Bad Astronomer, explains it best:

“In visible light, the light from the extremely thin material in the prominence is totally overwhelmed by the intense emission from the Sun’s surface, and is invisible. It’s only when we filter out most of the Sun’s light (and let through light specifically given off by the plasma in the prominence) that we can see it at all,” he wrote.

The Sun in the visible light spectrum, as seen from SDO at 18:00 UT. The two visible sunspots seem to be unrelated to this large prominence. Image Credit: SDO

This video shows the buildup up this most recent spectacular solar show, as this portion of the Sun comes into view from a 48-hour period between December 4th and 6th:

[UPDATE]: Here is a video that shows the prominence eruption as it expanded:

Spaceweather.com also has some other fantastic images that are linked to on their front page. Prominences like this can come crashing down quickly when they become unstable, so head over to the SDO site to watch the action as it develops!

Source: The Bad Astronomer, SDO