Ghostly Ring Found Circling Dead Star

Roland Piquepaille writes "An international team of scientists has found a strange ring around a dead star by using images taken by NASA's Spitzer space telescope. This star, called SGR 1900+14, belongs to a class of objects known as magnetars. According to NASA, a magnetar is 'a highly magnetized neutron star and the remnant of a brilliant supernova explosion signaling the death throes of a massive star.' So far, about a dozen magnetars have been found. An amazing thing about these stellar objects is their magnetic field. One of the researchers said that 'magnetars possess magnetic fields a million billion times stronger than the magnetic field of the Earth.'

Comments

Pssst!

[Sta7ic]

"A million billion" is 10^6 * 10^9 = 10^15 ... we also call that "a quadrillion".

I'd be pretty excited about studying these things, were I a physical scientist. When you get some massively powerful EMF, electrons and protons must have very "interesting" behavior.

Re:Pssst!

[Tony Hoyle]

The standard for a billion has been 10^9 all over the world now for some years. The older value was abandoned in the UK in 1974.

Re:Pssst!

[fyoder]

Well, that depends... iirc, a billion in the UK is not the same thing as a billion here. A billion here is 10^9, whereas if memory serves me correctly a billion in the UK is a million million, or 10^12. Long and short scales

Had to look that up because it sounded nuts. However, looks like you're sort of right, other than for the fact that UK has abandoned the long scale in favour of the short. So a quadrillion there is now a thousand trillion as well, rather than a 'billiard'.

Re:Pssst!

[guruevi]

Well, we can withstand quite large magnetic fields. MRI scanners are up to 16T right now (experimental) and the side effects minimal. I work in a 3T environment, and the only thing that is a problem is metal in, on or around the body, they get ripped straight out into the bore as soon as you pass the .5 Gauss line. The other precaution is when body parts form loops (like crossed arms or legs or arms/hands holding other body parts) they could potentially cause electric shocks and minor burns. Minor tingling or heat sensations of the extremities is considered not harmful. I think however, in the range (really close since magnetic fields drop with distance) of these type of things you might be able to shock or burn somebody to dead since their body acts as a coil.

Re:Pssst!

[Lazarian]

I doubt any living thing could exist in magnetic fields that powerful. Wikipedia has some info...

The magnetic field of a magnetar would be lethal even at a distance of 1000 km, tearing tissues due to the diamagnetism of water.

Since magnetars rotate, I would guess that a person would probably be vaporized before being torn apart since you'd be travelling through magnetic flux fields. Such powerful fields have unusual effects on matter...

X-ray photons readily split in two or merge together. The vacuum itself is polarized, becoming strongly birefringent, like a calcite crystal. Atoms are deformed into long cylinders thinner than the quantum-relativistic wavelength of an electron.

In a field of about 105 teslas atomic orbitals deform into cigar shapes. At 1010 teslas, a hydrogen atom becomes a spindle 200 times narrower than its normal diameter.

I think the most powerful field ever generated in a lab was less than 200 tesla.

Re:Pssst!

[morethanapapercert]

I would have to venture a guess and say that there *must* be some upper limit on the number of Gauss a human body can be subjected to before physiological changes are noticed. Whatever that upper limit is though, it is far more powerful than anything you are likely to be exposed to on Earth. MRI machines expose you to fields of 5,000 to 30,000 Gauss. From Wikipedia and other sources I came up with the following values for common sources of magnetic flux energy: Earth's magnetic field .5 Gauss

small iron magnet 100 Gauss

small neodymium magnet 2,000 Gauss

big electromagnet 15,000 Gauss

Current FDA safety limit 80,000 Gauss (as of 2003)

World's most powerful MRI 94,000 Gauss (Uni of Illinois, makes the sodium ions flip instead of the water molecules. In testing, subjects noted odd sensations while being moved into the field, but once stationary the effects went away)

surface of a neutron star 10^12G (1,000,000,000,000 Gauss)

Re:Pssst!

[The_Wilschon]

they get ripped straight out into the bore as soon as you pass the .5 Gauss line. I think you must have meant .5 Tesla, as .5 Gauss is approximately the strength of the Earth's magnetic field.

Re:Pssst!

[reverseengineer]

The 16 Tesla field used to levitate that frog is towards the upper end of the field strength that can be safely tolerated for any duration by most organisms. A static magnetic field of 20T or more can interfere with enzymatic processes, and above 25T can interfere with nerve conduction. Pulsed magnetic fields can be considerably more dangerous at a given field strength, because they can induce eddy currents in the body which can cause cardiac arrhythmias, but you're still looking at around the 10T range unless your heart is particularly vulnerable.

In contrast, the 10^11T field of a magnetar would tear you to pieces even several thousand km away, and then tear those pieces into smaller, grotesquely elongated pieces, as the field strength is enough to distort the geometries of atomic orbitals. What would of course actually kill you on your way to a magnetar are the X-rays and gamma rays the thing throws out, and these forms of radiation should be considered among the effects of a cosmically strong magnetic field. However, assuming you could survive those, the magnetic field itself would still instantly kill you. A particular problem is that your body is made up of many different kinds of atoms and molecules, which will be affected by the intense field differently depending on whether they are ions, have a dipole moment, etc., so that you will in a literal sense be disintegrated.

Re:Pssst!

[ceoyoyo]

He meant the 5 Gauss line. It's not enough to rip things off you, but you can stick paper clips to the wall. Or erase all the credit cards in your pocket.

Re:Pssst!

[meringuoid]

Interesting that we can generate a field strong enough to noticeably deform atomic orbitals.

We can't. Copying and pasting from Wikipedia loses the superscript: that was 10^5 Tesla. Ten thousand Tesla. Way beyond our current capabilities :-)

Link with pic

[IronChef]

http://www.spitzer.caltech.edu/Media/releases/ssc2008-08/release.shtml

Re:Link with pic

[tulmad]

Uhh, the link the summary has a link to the pic as well It's right at the top of the article...

Re:not a ring

[Pollardito]

the ring is the empty looking space to the right of the star. the picture is kind of misleading because it seems like they're talking about a ring around that star, but the ring is instead circling an invisible object that's near it: "The magnetar itself is not visible in this image, as it has not been detected at infrared wavelengths (it has been seen in X-ray light)."