Happy Half-Birthday Solar Stormwatch….Part 2.
Solar Stormwatchers look for storms on short videos taken by the wide angled cameras on board the Stereo spacecraft. However, as well as solar storms the Heliospheric Imagers record anything else that wanders into view. Space is a busy place and the science team don’t know what’s common out there and what’s not or how the cameras are coping with their space environment. We are helping to provide the answers. These are just some of the weird and unexpected things we have found:
Most of the sungrazing comets we see in the STEREO images are likely to be from the Kreutz group whose orbits take them extremely close to the Sun at perihelion. They are named after Heinrich Kreutz, who first demonstrated that they were related and were in fact remnants of a larger comet that broke up centuries ago. The comets vary in size and some of the smaller ones, just a few meters across, don’t survive their trip around the Sun. All videos are dated which means we can go here to identify the comets we see.
We’ve also had some famous names turn up on camera. Click the images to see the videos.
This video has 10 comets!! Some are very hard to spot. Have a go! Clue – there are 6 in the Ahead camera and 4 in Behind.
If you gaze sunwards for long enough you will eventually see all the solar system planets as they orbit around the Sun. The Heliospheric Imagers have picked up several planets and brighter asteroids. Venus, Jupiter and Mercury, are bright and easy to spot. Mars and Saturn are a little trickier. They look a lot like stars but the way they move gives them away as all the planets appear to move relative to the starry background.
One planet is particularly easy to spot – Earth. Just after launch the Earth and Moon were up close in the Stereo cameras’ field of view. Because the cameras were designed to detect the tenuous and faint light scattered by the solar wind (100 million million times fainter than the Sun) the bright Earth-Moon system caused all sorts of odd reflections in the camera optics producing rings, flashes and all manner of fireworks. Click here and here to see what I mean.
|Earth and Moon
Thanks to fellow Mod Quialiss for producing the excellent guide to spotting planets including these labelled pictures.
As you might have guessed these are particles (interplanetary dust and bits of space junk) which strike the Stereo spacecraft. An unexpected discovery was the presence of much more dust out there than previously thought. When the data has been analysed the team will have a much better knowledge of the distribution of dust around the Sun. This is what a particle strike looks like:
40 minute exposures are required to image the faint solar storms so anything drifting through the camera’s field of view close to the spacecraft will appear as a bright streak.
Solar Stormwatch team member Chris Davis said:
“We think what we are seeing is sunlight scattered off bits of the spacecraft that are knocked off by dust impacts. They look so dramatic because of the sensitivity of the cameras and the proximity of the dust (like trying to take a photo when it’s snowing!)”
You might be forgiven for thinking that dust is just an inconvenience and can be ignored but space makes dust more of a problem as both the dust and the spacecraft are moving. The team have estimated that the impact of a dust particle on the spacecraft could be anything between 3 kilogrammes and 3 tonnes!
Photographing bright objects is always a problem. If you don’t get the exposure right the optics can’t cope and peculiar flares, reflections and ghosting result. As the Stereo’s Heliospheric Imagers are calibrated to take images of faint solar storms a planet or even a bright star plays mayhhem with the CCD and the results can be intriguing. Have a look at the collection of optical effects is on the forum.
And if star clusters and the Milky Way are your thing – we even have them in Solar Stormwatch.
||The Milky Way
What more could you possibly want from an on-line solar astronomy project?
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Next time: Part 3 – Art, chat and NASA inspired baking
Jules is a volunteer moderator for the Solar Stormwatch Forum.
Just 6 short months ago a new Zooniverse project was born. But this one was different. Not a galaxy or supernova in sight. Just one rather special star. Ours.
Solar Stormwatch was set up to track and monitor coronal mass ejections (CMEs) better known as solar storms. There’s a great deal we don’t know about solar storms. We know the Sun isn’t as quiet as it seems and that sometimes, huge solar explosions are hurled out across the solar system. As Chris Davis one of the Solar Stormwatch team says:
“Each one of these storms is a billion tons of material traveling at a million miles an hour, so they’re not inconsequential.”
One thing we do know is that they are spectacular to look at.
In fact they can be seriously spectacular.
There is a downside, however as with each solar storm comes a deadly blast of radiation so astronauts on the ISS need to know if a storm is on its way and which direction it’s heading so they can time their space walks carefully. Solar storms also have the potential to knock out communication satellites, damage power lines and disrupt mobile phone networks as well as produce spectacular auroral displays.
But no-one really knows what triggers them, why they happen or why they are different each time. To find the answers requires analysing thousands of solar storms. Acquiring data isn’t a problem. Since their launch in October 2006 the twin Stereo spacecraft have provided 25 terabytes of data – over 100,000 images. But that’s a lot of data for a small team in deepest darkest Oxfordshire to analyse. Ideally they needed a few thousand research assistants who were happy to offer their time freely and who wouldn’t drink all the team’s coffee and eat all their biscuits so the team turned to the crowdsourcing benefits of Citizen Science and on 22 February 2010 Solar Stormwatch went live.
So what have we found in the first 6 months? The Science Team at Rutherford Appleton are busy collating and analysing the results but in the meantime, while we eagerly wait for them, here’s a summary from a user’s perspective.
1. We have confirmed 229 storms from Solar Stormwatch Spot videos. This will help the team’s research into the speed, direction and frequency of solar storms. Each solar storm must be validated by several stormwatchers to count. The more people who mark a solar storm, the more likely it is that it really is a storm. To trigger further investigation the team need at least 20 people to spot the same solar storm.
2. We have also checked current (“live”) storm data. Around 25 solar storms have been found this way. To do this we use Stereo’s “beacon mode” data. This is a low quality version of the latest pictures transmitted every hour, so we can keep watch on events as they happen. The pictures are black and white, grainy and slightly mysterious but as near to real time as we can get and to see a storm appearing at the end of a video is always exciting. Then there is the wait for an hour or so for the next frame to be added, and then the next….
3. We have learned about circular storms – the “Perfect Storm.” Solar storms come in different shapes and sizes and exactly what kind of storms we see being hurled out from the Sun depends partly on their magnetic fields. The Sun behaves like a liquid which complicates things somewhat and the magnetic field lines that go through the “surface” twist and loop as the conductive fluid moves around. Without any further complications storms tend to end up in a helix shape and appear like a cylinder. If you look at a cylinder end on (the view we get from Stereo) you see a circle, a circular storm – a relatively simple uncomplicated storm. The “perfect” kind of storm to study.
Over 90,000 people have visited the site from 174 countries or principalities. The top 5 countries (ranked in order of highest number of visits) are:
- 1. UK (30%)
2. USA (25%)
3. Canada (5%)
4. Germany (3%)
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We have just been set a new stormwatching challenge and now we can trace and record individual storms in more detail and later in the year we will learn how to track storms. But Solar Stormwatch is so much more than just watching and measuring storms. In the last 6 months we have found all kinds of weird stuff – caused by camera flares, optical effects, spacecraft rolling manoeuvres and dust. In fact an early Solar Stormwatch discovery was that the Stereo spacecraft are encountering much more dust out there than expected and this has produced some interesting results. Stereo’s eyes have also spotted comets and planets including the Earth and Moon. And we have a real community with competitions, meet-ups, an art gallery and a virtual café with an endless supply of cake. But that’s enough for now. More about those next time.
Meanwhile – if you are reading this and haven’t considered Solar Stormwatch, why not try something a little different? You can do as much or as little as you want. You can choose the task you like best and stick to it or dabble in all of them while you learn about the effect of our nearest star on its neighbourhood. And if you need help just pop into the forum where you’ll get a warm welcome.
Next time: The Particles Strike Back….and other strange happenings.
Jules is a volunteer moderator for the Solar Stormwatch Forum.