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Fraser
2006-Apr-07, 10:35 PM
SUMMARY: Think planets can only form around stars? Well, think again. NASA's Spitzer Space Telescope has uncovered evidence for a potential planet-forming disk around a pulsar. In a former life, the pulsar would have been a large star 10-20 times bigger than the Sun that eventually consumed its fuel and exploded as a supernova. The remaining debris has started to collect again, and could eventually turn into new planets. This helps explain how planets were discovered around another pulsar in 1992, including one that's Earth-sized.

View full article (http://www.universetoday.com/am/publish/pulsars_planets_too.html)
What do you think about this story? post your comments below.

Gerald Lukaniuk
2006-Apr-08, 04:23 PM
Is there any theoretical work on expelled matter actually finding its way back to a pulsar? It should at least be able to enter at the poles of its spinning and slow the dervish down. I don't want to go ATM unless its for money but "neutron cores" anyone?

Duane
2006-Apr-08, 04:25 PM
Hmmm, I can think of a certain ATM proponant or two who're probably having apoplexy over this announcement.

Gerald Lukaniuk
2006-Apr-08, 04:36 PM
Hmmm, I can think of a certain ATM proponant or two who're probably having apoplexy over this announcement.
Lets keep it our secret. Shall we?

antoniseb
2006-Apr-08, 06:58 PM
I saw this and it made me think of him and smile.

trinitree88
2006-Apr-08, 08:29 PM
Interesting. Of course there's nothing to prevent a pulsar from traveling relatively slowly through an extended debris field and gravitationally capturing enough material to accumulate a disk over time, or to even pick off a planet from a star system already formed, by traversing it perpendicular to the disk..(might even perturb and leave behind an outer planet orbiting at ~ 30 degrees to the disk as it does). If planets can capture moons, what's to stop a pulsar from doing the same?:think:
It would seem there is no guarantee that the observed pulsar in question has not experienced such a history. The idea that high transverse velocity pulsars not only exist but may interact in rare but violent ways is not mine...an article was written on the possibility of one colliding with the Earth, at ~ 1000 km/sec. The authors concluded it would pass through the entire body of the Earth, liquifying the crust,and boiling the oceans, returning it to a primal state, but that the Earth would survive as a planet eventually. I recall being quite surprised. Evidently the transfer of linear momentum, and kinetic energy in their model was insufficient to annihilate the Earth to vapor only. The diminutive size and extraordinary density played a big role. Kind of like shooting a jellyfish with a high powered rifle. Now, where was it? I recall a color artists' graphic showing the pulsar entering the atmosphere, pending impact...possibly Sky magazine??, Air & Space???...not Sci. Amer, nor I think Astronomy or Sky & Tel....circa 1995?...Pete.

Graham2001
2006-Apr-09, 01:41 AM
I don't see why this is news, we've known about planets orbiting pulsars since 1992! (http://www.astro.psu.edu/users/alex/pulsar_planets.htm).

Makes me feel old.

antoniseb
2006-Apr-09, 11:49 AM
I don't see why this is news, we've known about planets orbiting pulsars since 1992! (http://www.astro.psu.edu/users/alex/pulsar_planets.htm).

In 1992 we observed planets orbiting a pulsar. We didn't know how they got there. Since the pulsar was a millisecond pulsar, it seems reasonable that they got there as leftovers of the star that the pulsar ate to speed up. What is news here is that we saw planets forming around a pulsar from a disk.

Jerry
2006-Apr-10, 03:44 PM
Hmmm, I can think of a certain ATM proponant or two who're probably having apoplexy over this announcement.
Very thin logic - this boarders on wishful thinking. Is this a Planet forming disk, or accretion ring? Why aren't the rings of saturn lumping up into moons?

antoniseb
2006-Apr-10, 05:29 PM
Why aren't the rings of saturn lumping up into moons?

The rings of Saturn are inside the Roche limit. the planet forming disk is outside the Roche limit. It makes a big difference as far as collecting things is concerned.

quickjaguare
2006-Apr-10, 08:07 PM
Is there any theoretical work on expelled matter actually finding its way back to a pulsar? It should at least be able to enter at the poles of its spinning and slow the dervish down. I don't want to go ATM unless its for money but "neutron cores" anyone?


maybe but .... neutron cores?:eh:

quickjaguare
2006-Apr-10, 08:09 PM
Very thin logic - this boarders on wishful thinking. Is this a Planet forming disk, or accretion ring? Why aren't the rings of saturn lumping up into moons?


good point but if the rings are dust arent they eventually going to be moons?

antoniseb
2006-Apr-10, 10:53 PM
good point but if the rings are dust arent they eventually going to be moons?

No. If they are too close to Saturn, differential gravitation will prevent them from ever collecting into large units.

Gerald Lukaniuk
2006-Apr-12, 02:46 AM
maybe but .... neutron cores?:eh:
The only reason I do not go ATM with this is that I do not know if gravitation collapse exclude small neutron stars becoming one way trips for normal matter like black holes and that mixed charge plasmas could eventually surround one. Since they supposed result from inward pressure from an exploding star not strong enough to form a black hole like Superman squeezing a lump of coal we had better hope there is a minimum size to one lest we create one in a supercollider. It would be interesting if we ever see one cannibalizing a neighbor until it collapses into a black hole. The laws of physics might be different beyond the event horizon or over the rainbow but here Newton’s law of equal action reaction should send the critters after a big meal off to look for more..

Robert Fritzius
2006-Apr-12, 03:15 AM
Blew it on this post. See following entry.

Robert Fritzius
2006-Apr-12, 03:21 AM
Quoting from original article: "Pulsar planets would be bathed in intense radiation and would be quite different from those in our solar system. "These planets must be among the least hospitable places in the galaxy for the formation of life," said Dr. Charles Beichman, an astronomer at NASA's Jet Propulsion Laboratory and the California Institute of Technology, both in Pasadena, Calif."

Pulsars may turn out to be quite hospitable. A currently "unorthodox" version of relativity predicts that pulsars are not intrinsically bright in their immediate vicinities. See: A Ritzian Interpretation of Variable Stars

http://www.datasync.com/~rsf1/binaries.htm

zephyr46
2006-Apr-12, 04:33 AM
--------------------------------------------------------------------------------

Graham 2001

"I don't see why this is news, we've known about planets orbiting pulsars since 1992!.

Makes me feel old."

Mee too.

And I am only 32!

Weren't they large terrestrial planets?

Rocky and one of the first multiplanet systems?

Gerald Lukaniuk
2006-Apr-12, 06:33 PM
Interesting. Of course there's nothing to prevent a pulsar from traveling relatively slowly through an extended debris field and gravitationally capturing enough material to accumulate a disk over time, or to even pick off a planet from a star system already formed, by traversing it perpendicular to the disk..(might even perturb and leave behind an outer planet orbiting at ~ 30 degrees to the disk as it does). If planets can capture moons, what's to stop a pulsar from doing the same?:think:
It would seem there is no guarantee that the observed pulsar in question has not experienced such a history. The idea that high transverse velocity pulsars not only exist but may interact in rare but violent ways is not mine...an article was written on the possibility of one colliding with the Earth, at ~ 1000 km/sec. The authors concluded it would pass through the entire body of the Earth, liquifying the crust,and boiling the oceans, returning it to a primal state, but that the Earth would survive as a planet eventually. I recall being quite surprised. Evidently the transfer of linear momentum, and kinetic energy in their model was insufficient to annihilate the Earth to vapor only. The diminutive size and extraordinary density played a big role. Kind of like shooting a jellyfish with a high powered rifle. Now, where was it? I recall a color artists' graphic showing the pulsar entering the atmosphere, pending impact...possibly Sky magazine??, Air & Space???...not Sci. Amer, nor I think Astronomy or Sky & Tel....circa 1995?...Pete.
You are correct. Just like in the movies you see a big blast and some guy goes flying. Ofcourse what really went on is a big paper "firecracker" popping, possibly some flour.dust or propane anhd a guy bouncing off a spring board. If the same amount of gunpowder was in a pipe, he wouldn't need a springboard but the coroner would need tweezers. The planets could be there before but why they and the disk are equatorial could be new Physics.