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Monday, 1 June 2015

Lightsail-1 lives, new physics for solar sails, and bizarre patterns on the Moon

EDIT: Lightsail-1 (which I've said is effectively dead in space below) has contacted Earth this morning (1st of June). I bet the sighs of relief at the Planetary Society (who built the miniature spacecraft) were loud enough to shatter the windows. With the miniature solar sail's attitude controls still offline it isn't out of the woods yet, however the team may go ahead with the sail deployment as early as Tuesday.

No video message today I'm afraid, as I'm a bit under the weather. Trust me, that's all the detail you want.

Graphene could super charge solar sails

There's been a fair bit of news this year on efforts across the world to develop new space drives - the US airforce spacecraft X37-B is in orbit right now testing a new type of ion engine, and the experimental Lightsail-1 is in orbit testing it's experimental photon sail as we ... well it hopefully will be soon, having suffered the spaceship version of the bluescreen of death earlier this week.

Above: It looks like a wha-? Courtesy of USAF

The principle behind Lightsail-1is fairly simple: Photons (particles of light) carry a tiny bit of momentum, and when they reflect from a surface the transfer a tiny push to it. On Earth almost any other force out weighs this tiny push, but in space a huge, lightweight,  reflective sail can catch enough light to slowly increase its speed. The advantage is that, needing no fuel,  the sail can eventually accelerate up to immense speeds.

The downside is that word 'eventually': The thrust is less than the weight of a piece of tissue paper.

Above: The IKAROS, the first ever working solar sail spaceship. Courtesy of JAXA (which is why it say 'JAXA' in big letters in the corner)
But even as photon sails are getting popular something new is rearing its head: Yongsheng Chen of Nankai University in Tianjin, China, and his colleagues, may have discovered a game changer: When light is shone onto graphene sponge* the force created is many times bigger than it should be. In the test chamber the team were able to propel a piece of graphene 40 cm just by shining light on it! The effect seems to be down to the graphene expelling electrons back in the direction the light hitting it has come from. If the discovery holds up to scrutiny this makes graphene a light activated electron rocket -  an instant upgrade for the low thrust reflective sails being studied today. Their paper is here.

The Moon has mysteries on mysteries,  but one of the oddest has to be the strange patterns of light and dark swirls,  seemingly etched into its surface across hundreds of square kilometres.

Above: I'm talking about these things, just called 'swirls'. For a long time 'alien graffiti' was as likely explanation as any other for them. Courtesy of NASA.
It's been known for long time that the swirls occur in regions where magnetic fields breach the lunar crust and extend into space. But not all magnetic area have swirls, so exactly what the link is has stayed elusive. Now a multinational team of researchers have run comprehensive computer simulations on the effects of the magnetic fields on the solar wind near the Moon, and shown that certain field configurations can effectively divert the solar wind, weathering some areas of the moons surface dark, while leaving other parts preserved and bright for billions of years.

Wormholes are the ultimate space drive - an almost magical shortcut through a distorted volume of space time that can compress a journey of light years into seconds. If you're not sure what I mean: it's one of these 'bent sheet of rubber' shortcuts you've probably seen on sci-fi shows....
Above: A wormhole - if you can't travel the long way around space, tunnel through it instead. Courtesy of DavidDarling
But while building a wormhole is one thing, using it is another. Wormholes would need huge amounts of negative gravity material to hold them open, or they would slam shut on the user and pulverise them. The paper linked above suggests that, if our universe contains a warped extra dimension of a certain time then wormholes might be naturally stable, and not need this exotic matter.

Elsewhere on the internet:

*Science's latest wonder material. It's like the annoying mathlete/athlete/babe charmer you knew at school: Good at everything.

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