Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

Cosmic blast mystery solved in neutron star's intense death throes
The Register ^ | 5th July 2013 | By Rik Myslewski in San Francisco,

Posted on 07/08/2013 11:01:40 AM PDT by Ernest_at_the_Beach

'As if millions of voices suddenly cried out in terror and were suddenly silenced'

A pair of European astrophysicists believe they've solved the mystery of exceedingly bright, never-repeated flashes of radio waves that come to us from the distant past.

The source of those brief, intense flashes can be defined in two ways, depending upon whether you'd prefer to look at the event as a death or a birth.

"We suggest that a fast radio burst represents the final signal of a supramassive rotating neutron star that collapses to a black hole due to magnetic braking," write Heino Falcke of Radboud University in Nijmegen, the Netherlands, and Luciano Rezzolla of the Albert Einstein Institute in Potsdam, Germany in their paper (preprint, PDF) "Fast radio bursts: the last sign of supramassive neutron stars" published in this week's edition of Science.

Neutron stars are ludicrously dense objects. According to the press release outlining Falcke and Rezzolla's findings, "They are the size of a small city but have up to two times the mass of our Sun."

As you might assume, something that massive has an upper limit on its mass, otherwise it would collapse in upon itself and become a black hole – and you'd be right. There are, however, neutron stars that are larger than the critical mass of about two solar masses, but that manage to keep from falling in on themselves due to their high rotational velocity.

A supramassive neutron star on its way to becoming a 'blitzar'

Cleaning up the neighborhood in preparation from metamorphosis from neutron star to black hole

If an overweight neutron star is spinning fast enough, the centrifugal forces that are generated by that speedy rotation can counterbalance the forces of gravity, and keep the star from falling in on itself for millions of years – but not forever.

The reason for their inevitable doom is that neutron stars also have extremely powerful magnetic fields that radiate outward from them. "Over time," Falcke and Rezzolla write, "magnetic braking would clear out the immediate environment of the star and slow it down." And when it slows down sufficiently, the centrifugal forces diminish to an extent that gravity will achieve its inevitable victory.

Normally when a star collapses into a black hole, there is also a burst of optical and gamma-ray radiation. Not so in this scenario, seeing as that the rotating neutron star's magnetic field has already cleaned out the neighborhood, and that the event horizon of the black hole quickly engulfs the surface of the neutron star.

"All the neutron star has left is its magnetic field, but black holes cannot sustain magnetic fields, so the collapsing star has to get rid of them," explains Falcke. "When the black hole forms, the magnetic fields will be cut off from the star and snap like rubber bands," and that snap is what produces the immense, one-time radio flash that has been observed.

"All other signals you normally would expect – gamma rays, x-rays – simply disappear behind the event horizon of the black hole," says Flacke.

Falcke and Rezzolla have dubbed these objects blitzars – "blitz" being German for "flash" or "lightning". "A blitzar," Rezzola writes, "is at the same time the farewell signal of a dying neutron star and the first message from a newly born black hole."


TOPICS: Astronomy
KEYWORDS: blackhole; cosmos; neutronstar; star; stringtheory

1 posted on 07/08/2013 11:01:40 AM PDT by Ernest_at_the_Beach
[ Post Reply | Private Reply | View Replies]

To: SunkenCiv

fyi


2 posted on 07/08/2013 11:02:13 AM PDT by Ernest_at_the_Beach
[ Post Reply | Private Reply | To 1 | View Replies]

To: Ernest_at_the_Beach

Like an unshielded ignition coil crackles your radio.

I wonder what catalyst causes the field to collapse?


3 posted on 07/08/2013 12:16:29 PM PDT by PeaceBeWithYou (De Oppresso Liber! (50 million and counting in Afghanistan and Iraq))
[ Post Reply | Private Reply | To 1 | View Replies]

To: Ernest_at_the_Beach

For later


4 posted on 07/08/2013 12:23:36 PM PDT by muir_redwoods (Don't fire until you see the blue of their helmets)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Ernest_at_the_Beach; brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; ...

Thanks Ernest, extra to APoD members, and I plan to use this for the String Theory list as well. :’)


5 posted on 07/08/2013 5:09:56 PM PDT by SunkenCiv (McCain or Romney would have been worse, if you're a dumb ass.)
[ Post Reply | Private Reply | View Replies]

To: 6SJ7; AdmSmith; AFPhys; Arkinsaw; allmost; aristotleman; autumnraine; Beowulf; Bones75; BroJoeK; ...

Thanks Ernest.


· List topics · post a topic · subscribe · Google ·

6 posted on 07/08/2013 5:11:15 PM PDT by SunkenCiv (McCain or Romney would have been worse, if you're a dumb ass.)
[ Post Reply | Private Reply | View Replies]

To: Ernest_at_the_Beach

Seems to make sense, even to me.


7 posted on 07/08/2013 5:14:16 PM PDT by The Cajun (Sarah Palin, Mark Levin, Ted Cruz, Trey Gowdy......Nuff said.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Ernest_at_the_Beach

Always interesting. Thanks for posting.


8 posted on 07/09/2013 3:21:00 PM PDT by onedoug
[ Post Reply | Private Reply | To 1 | View Replies]

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson