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Canadian Astronomers Discover a Magnetar
trotski writes "The Globe and Mail is running an article about the discovery of a magnetar star by Canadian astronomers. The star, named SGR 1806-20, is located 40,000 light-years from earth. This neutron star is one of only four magnetars ever discovered. Magnetars are characterized by their huge magnetic fields, billions of times stronger than any magnets on Earth. Apparently, if this star was located as far away as the moon, it could demag floppy disks and suck change right out of your pocket."
Uhh- I don't believe that just because an item is non-ferrous, it is not susceptible to magnetic fields. I do believe that the more intense a magnetic field is, the more likely it is to affect a myriad of other 'non-ferrous' items.
The article doesn't explain how they go about detecting such a star
This one does. Sort of.
Try going near an MRI machine with change in your pocket. I made that mistake once, and it was tugging hard at the coins from across the room. >1 tesla magnetic fields need to be treated with respect - people can get seriously hurt if anything metallic gets brought into the room - they can get ripped out of your hand or pocket and will fly straight down the central bore where the patient is. I've heard stories of people being killed when someone walked into an MRI room with a pair of scissors in their pocket.
See my previous comment. A strong enough magnetic field really doesn't care what metal something is made of.
And that makes me the perfect candidate to post here. Seriously though, one would think that a neutron star's magnetic field would extend well past the distance from the moon to the Earth.
"Extending" and "being able to suck change out of pockets and slow down locomotives" are two very different things.
Dipole magnetic fields drop off with the cube of distance, so on the surface of the neutron star (about 80,000 times closer), it would be strong enough to produce very exotic effects.
They explain it was detected by observing the effects the stars magnetic field has on charged particles. With a magnetic field of 10^15 gauss (vs 1-5 for the sun and the 10 - 50 for the Earth), it was mentioned that it won't just suck change out of your pocket, but rearrange the molecules in your body. Sounds like fun, doesn't it.
It had been thought that SGRs are neutron stars with magnetic fields of ~1e14 Gauss (compared to the Crab's ~1e12 G or Earths ~1 G). This is a huge field that has enough energy (proportional to magnetic field squared) to power the huge blasts of radiation.
This new work by Samar Safi-Harb shows that the magnetic field is actually ~1e15 Gauss: 10x as strong and 100x the energy.
If there are any nearby planets with heavier elements and some range of chemistry, perhaps they could support life forms that derive their principal source of energy from such the magnetar's field.
This is an interesting thought. However, in this case, they (and the planet) would likely be boiled to vapour by the x- and gamma-ray bursts that let us know about the star's magnetic field in the first place.
Magnetic effects around gas giants, while far, far weaker, might still be strong enough to play a role in the evolution of any creatures on/in gas giant moons, though.
For a couple of interesting sci-fi books about life in and around neutron stars, check out "The Integral Trees"/"The Smoke Ring", by Larry Niven, and "Dragon's Egg", by Robert Forward.
It also depends on how big the magnet is. For instance, I work with an 8 Tesla magnet, but it is actually only a uniform field over a very small distance (probably less than 2mm), and the field falls off quickly. There is a magnet at the Ohio State University Medical School that is also 8 Tesla, but has a considerably larger bore (big enough to fit a human body). This magnet is considerably more dangerous. It is so much larger that everything you are thinking of scales, but at a much 'slower' rate. In other words, you have to get much farther away from the big magnet than you do from the little one to escape magnetic field strengths strong enough to erase credit cards, even though both magnets have the same magnetic field.