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Monday, 6 April 2015

Mission into the inferno

Happy Easter everyone!

  Above: I have a stomach bug, and I look hanging so I'm not showing my face - but I'll show you how I track sunspots and solar facula* instead.
Mission into the inferno:

For most of our history mankind has been wondering what the big bright thing in the sky actually is.

No. No, it's not a big torch.Why would it be up there? It belongs in someones garage. I'm talking about the Sun you loonies.

Now we have telescopes, spaceships, and supercomputers, and we're finding out that the big bright Sun is a star, and it has all kinds of weird and wonderful features. In fact, the more we observe the Sun in detail the more of a complex and astounding place it becomes. For example: In 2013 the University of Central Lancashire launched a set of experimental optics into space on a sounding rocket about a year ago, to observe the UV Sun with five times the detail ever seen before. What they found (link here) was astounding:

"....small clumps of electrified gas (plasma) at a temperature of about one million degrees Celsius are seen racing along highways shaped by the Sun's magnetic field. These blobs travel at around 80 km per second (the equivalent of 235 times the speed of sound on Earth), fast enough to travel the distance from Glasgow to London in 7 seconds. The highways are 450 km across, roughly the length of Ireland from north to south.... ....Astronomers have long struggled to understand why, with a temperature of two million degrees, the corona is around 400 times hotter than the solar surface. Hi-C images reveal dynamic bright dots which switch on and off at high speed. These 'sparkles' typically last around 25 seconds, are about 680 km across (the size of the UK) and release at least one million million million million Joules of energy in each event or around 10,000 times the annual energy consumption of the population of the UK (based on information from the UK Department of Energy and Climate Change). The sparkles are thus a clear signal that enormous amounts of energy are being added into the corona and may then be released violently to heat the plasma"

Above: A video made from the images collected by the UClan mission. Courtesy of University of Central Lancashire.

Partly because of the complexities and mysteries of the Sun, and partly because most scientists and engineers view the story of Icarus as a challenge rather than a warning, a space mission is under development that will fly a robot space probe into the Sun's atmosphere. Launching in 2018, this will be extreme engineering at its most extreme: Over six years Solar Probe Plus will perform six slingshots of the planet Venus, to change its course and velocity. Then, as it falls past Mercury under the Sun's immense gravity, the probe will reach speeds of over 200 km per second.

Above: A CGI image of the completed probe, leaving Earth orbit. The solar panels are stowed away, behind the heat shield, and frankly the whole thing looks like it's flying backwards to me, but then it's not built for looks it's built to nosedive the Sun and get away with it. Image courtesy of NASA
The Sun will be a wall of light and heat, filling its sky, so the probes heatshield will be one of the most heatproof things ever built: A carbon-carbon carbon foam barrier 4 inches thick and weighing 1,350 lb. Sat in the shield's shadow, the probe will draw power from the torrent of light around it using solar panels - but normal panels would fry in the heat, so these will need to be cooled. But the heat isn't the only problem: High speed particles and dust, driven by the immense magnetic fields, will be just as much of a danger.

What mysteries would make it worth sending a multi-million dollar robot into such a furnace? Here are a few of them:

How does the solar wind begin?
The solar wind is a high speed stream of plasma sent out by the Sun. When it gets choppy we get solar storms, radiation spikes, aurora..... and damaged to satellites, and even to power grids here on Earth. But we understand very little about how the solar gets its speed and power.

Above: The tenous gas of the solar wind can wreak surprising havoc when it gets mad....

How complex is the structure of the magnetic field near the Sun's surface?
Everything about the Sun involves its immense magnetism in some way, and mapping the magnetic fields in detail will help us understand how our star works. Flares, prominences, storms, sunspots - they all grow out of the Sun's twisted and gnarled magnetic field.

Above: NASA gives a quick explanation of how the Sun is about to do something really strange...

What role does 'complex plasma' (ionised gas mixed with electrically charged dust) play in the mechanisms of the suns surface? 
Complex plasmas are known to behave in incredibly rich and complex ways - it can act like a crystal, a fluid, a vortex, or a flow. It can change the way magnetic and electric field propagate and have even been theorised to host patterns that are a deep space analogue to DNA.

For a bit more information - and by that I mean a lot more information - make a cup of tea or coffee and sit down to watch SETI's Stuart Bale give a talk on the mission:

Elsewhere in the Univerese:
For a long time people have wondered about colonising the Moon, but the harsh lunar surface - temperature swings of hundreds of degrees, micrometeorites, the full blast of solar storms, other kinds of radiation like cosmic rays - makes a tough challenge. To get around this it's been proposed that colonists might build their homes in the lava tubes - tunnels through the rock which lava flowed along in the ancient past:

Above: Lava breaking out of a lava tube and onto the surface. Courtesy of 
Now a theoretical study from Purdue University suggests that these tunnels might be  up to 5 kilometres across . Easily big enough to hold a city. The key to their immense size would be a combination of low low lunar gravity and the naturally strong arches lava tubes form.

Elsewhere on the internet:

Young star develops visibly over 18 years

White dwarf to blame for supernova

Black holes don't destroy information

Dark matter doesn't even 'see' itself.

* This is not a rude word, it's a brighter spot on the Sun. Shame on you...... and me, since I must've thought that too.

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