Friday, 19 July 2013

Forged in the heart of a dying star......


Thor. He's God of Thunder, Prince of Asgard, nice but a bit dim, and wields the mystical hammer Mjolnir.

In the 'Thor' movie we learn that Mjlnior was 'forged in the heart of a dying star'. The original Norse* myth tells that, using Mjolnir, Thor could:

"Strike as firmly as he wanted, whatever his aim, and the hammer would never fail, and if he threw it at something, it would never miss and never fly so far from his hand that it would not find its way back, and when he wanted, it would be so small that it could be carried inside his tunic."

He's just left it lying around. True, no-one else can move it as much as an inch, but what if your granny fell over it? You'd...you'd... you'd do absolutely nothing, wouldn't you?










Now astrophysics is oddly quiet on what the properties mallets, made in the heart of  dying stars by gods, would be. But it does tell us a few things about objects that are naturally forged in the heart's of dying stars:

White dwarfs:

Weighing as much as a star, but only as wide as a planet, a white dwarf is made of ultra dense degenerate matter. Its gravity is immense Near the surface of a white dwarf time would be measurably slowed down, and light rays would move in curves rather than straight lines....


The white dwarf Sirius B, almost invisible in the glare from the Sirius A star....

Pulsars:

Pulsars are formed by the deaths of larger stars: They are only tens of kilometres aros but weigh as much as a white dwarf, and most spin at incredible speeds. Space around these objects is wildly distorted: How much  an object weighs depends on which direction it moves in, time is hugely slowed, and the warping of light rays would allow a person on the surface to see over the horizon.

Actually, no: A person on the surface would be crushed by their own hair before they could think a single thought, but it's a nice theory.



Above: The Crab Nebular pulsar shown in X-ray's (blue) and visible light (mostly red). The pulsars gives out particle winds so strong that, here, you can see them forming shockwaves light years across...

What's more: they give out gales of high energy particles, and beams of radiation, which make them flash like lighthouses....

Magnetars:

Related to pulsars, these are the strongest magnets in the universe - the field could wipe every credit card on the Earth from halfway to the moon. From a thousand kilometres away it would distort the laws of chemistry enough to kill. Closer in it would distort atoms into long, ultra thin cylinders - under a magnetic field that intense your body would disintegrate in weird new forms of matter.....

An artists impression of a magnetar. Although if he painted it from real life I'll be worried.

Black holes:

Born from the deaths of the most massive stars, what introduction does it need? A black hole is gravity that has become so powerful it overrides all other forces of nature. Anything that goes in, never comes out - no special pleading, and no exceptions.......


Compared to all that, a size changing hammer doesn't sound so unlikely, does it?

*Yes, I know I'm mixing Norse Myth and a twenty-first century movie. But one, in a round-about way, inspired the other. And both the myth and the movie contribute to the popular ideas of what Mjolnir is. If you want to get technical: It's not clear from the myths that Mjolnir isn't actually an axe or club - and if I start down that route we'll be here all night....